linux/drivers/pci/hotplug/pciehp_hpc.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* PCI Express PCI Hot Plug Driver
*
* Copyright (C) 1995,2001 Compaq Computer Corporation
* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
* Copyright (C) 2001 IBM Corp.
* Copyright (C) 2003-2004 Intel Corporation
*
* All rights reserved.
*
* Send feedback to <greg@kroah.com>,<kristen.c.accardi@intel.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/signal.h>
#include <linux/jiffies.h>
#include <linux/kthread.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/time.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 16:04:11 +08:00
#include <linux/slab.h>
#include "../pci.h"
#include "pciehp.h"
static inline struct pci_dev *ctrl_dev(struct controller *ctrl)
{
return ctrl->pcie->port;
}
PCI: pciehp: Convert to threaded IRQ pciehp's IRQ handler queues up a work item for each event signaled by the hardware. A more modern alternative is to let a long running kthread service the events. The IRQ handler's sole job is then to check whether the IRQ originated from the device in question, acknowledge its receipt to the hardware to quiesce the interrupt and wake up the kthread. One benefit is reduced latency to handle the IRQ, which is a necessity for realtime environments. Another benefit is that we can make pciehp simpler and more robust by handling events synchronously in process context, rather than asynchronously by queueing up work items. pciehp's usage of work items is a historic artifact, it predates the introduction of threaded IRQ handlers by two years. (The former was introduced in 2007 with commit 5d386e1ac402 ("pciehp: Event handling rework"), the latter in 2009 with commit 3aa551c9b4c4 ("genirq: add threaded interrupt handler support").) Convert pciehp to threaded IRQ handling by retrieving the pending events in pciehp_isr(), saving them for later consumption by the thread handler pciehp_ist() and clearing them in the Slot Status register. By clearing the Slot Status (and thereby acknowledging the events) in pciehp_isr(), we can avoid requesting the IRQ with IRQF_ONESHOT, which would have the unpleasant side effect of starving devices sharing the IRQ until pciehp_ist() has finished. pciehp_isr() does not count how many times each event occurred, but merely records the fact *that* an event occurred. If the same event occurs a second time before pciehp_ist() is woken, that second event will not be recorded separately, which is problematic according to commit fad214b0aa72 ("PCI: pciehp: Process all hotplug events before looking for new ones") because we may miss removal of a card in-between two back-to-back insertions. We're about to make pciehp_ist() resilient to missed events. The present commit regresses the driver's behavior temporarily in order to separate the changes into reviewable chunks. This doesn't affect regular slow-motion hotplug, only plug-unplug-plug operations that happen in a timespan shorter than wakeup of the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mayurkumar Patel <mayurkumar.patel@intel.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
2018-07-20 06:27:38 +08:00
static irqreturn_t pciehp_isr(int irq, void *dev_id);
static irqreturn_t pciehp_ist(int irq, void *dev_id);
static int pciehp_poll(void *data);
static inline int pciehp_request_irq(struct controller *ctrl)
{
int retval, irq = ctrl->pcie->irq;
if (pciehp_poll_mode) {
ctrl->poll_thread = kthread_run(&pciehp_poll, ctrl,
"pciehp_poll-%s",
slot_name(ctrl->slot));
return PTR_ERR_OR_ZERO(ctrl->poll_thread);
}
/* Installs the interrupt handler */
PCI: pciehp: Convert to threaded IRQ pciehp's IRQ handler queues up a work item for each event signaled by the hardware. A more modern alternative is to let a long running kthread service the events. The IRQ handler's sole job is then to check whether the IRQ originated from the device in question, acknowledge its receipt to the hardware to quiesce the interrupt and wake up the kthread. One benefit is reduced latency to handle the IRQ, which is a necessity for realtime environments. Another benefit is that we can make pciehp simpler and more robust by handling events synchronously in process context, rather than asynchronously by queueing up work items. pciehp's usage of work items is a historic artifact, it predates the introduction of threaded IRQ handlers by two years. (The former was introduced in 2007 with commit 5d386e1ac402 ("pciehp: Event handling rework"), the latter in 2009 with commit 3aa551c9b4c4 ("genirq: add threaded interrupt handler support").) Convert pciehp to threaded IRQ handling by retrieving the pending events in pciehp_isr(), saving them for later consumption by the thread handler pciehp_ist() and clearing them in the Slot Status register. By clearing the Slot Status (and thereby acknowledging the events) in pciehp_isr(), we can avoid requesting the IRQ with IRQF_ONESHOT, which would have the unpleasant side effect of starving devices sharing the IRQ until pciehp_ist() has finished. pciehp_isr() does not count how many times each event occurred, but merely records the fact *that* an event occurred. If the same event occurs a second time before pciehp_ist() is woken, that second event will not be recorded separately, which is problematic according to commit fad214b0aa72 ("PCI: pciehp: Process all hotplug events before looking for new ones") because we may miss removal of a card in-between two back-to-back insertions. We're about to make pciehp_ist() resilient to missed events. The present commit regresses the driver's behavior temporarily in order to separate the changes into reviewable chunks. This doesn't affect regular slow-motion hotplug, only plug-unplug-plug operations that happen in a timespan shorter than wakeup of the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mayurkumar Patel <mayurkumar.patel@intel.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
2018-07-20 06:27:38 +08:00
retval = request_threaded_irq(irq, pciehp_isr, pciehp_ist,
IRQF_SHARED, MY_NAME, ctrl);
if (retval)
ctrl_err(ctrl, "Cannot get irq %d for the hotplug controller\n",
irq);
return retval;
}
static inline void pciehp_free_irq(struct controller *ctrl)
{
if (pciehp_poll_mode)
kthread_stop(ctrl->poll_thread);
else
free_irq(ctrl->pcie->irq, ctrl);
}
static int pcie_poll_cmd(struct controller *ctrl, int timeout)
{
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 slot_status;
while (true) {
pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
PCI: pciehp: Handle invalid data when reading from non-existent devices It's platform-dependent, but an MMIO read to a non-existent PCI device generally returns data with all bits set. This happens when the host bridge or Root Complex times out waiting for a response from the device and fabricates return data to complete the CPU's read. One example, reported in the bugzilla below, involved this hierarchy: pci 0000:00:1c.0: PCI bridge to [bus 02-3a] Root Port pci 0000:02:00.0: PCI bridge to [bus 03-0a] Upstream Port pci 0000:03:03.0: PCI bridge to [bus 05-07] Downstream Port pci 0000:05:00.0: PCI bridge to [bus 06-07] Thunderbolt Upstream Port pci 0000:06:00.0: PCI bridge to [bus 07] Thunderbolt Downstream Port pci 0000:07:00.0: BCM57762 NIC Unplugging the Thunderbolt switch and the NIC below it resulted in this: pciehp 0000:03:03.0: Surprise Removal tg3 0000:07:00.0: tg3_abort_hw timed out, TX_MODE_ENABLE will not clear MAC_TX_MODE=ffffffff pciehp 0000:06:00.0: unloading service driver pciehp pciehp 0000:06:00.0: pcie_isr: intr_loc 11f pciehp 0000:06:00.0: Switch interrupt received pciehp 0000:06:00.0: Latch open on Slot pciehp 0000:06:00.0: Attention button interrupt received pciehp 0000:06:00.0: Button pressed on Slot pciehp 0000:06:00.0: Presence/Notify input change pciehp 0000:06:00.0: Card present on Slot pciehp 0000:06:00.0: Power fault interrupt received pciehp 0000:06:00.0: Data Link Layer State change pciehp 0000:06:00.0: Link Up event The pciehp driver correctly noticed that the Thunderbolt switch (05:00.0 and 06:00.0) and NIC (07:00.0) had been removed, and it called their driver remove methods. Since the NIC was already gone, tg3 received 0xffffffff when it tried to read from the device. The resulting timeout is a tg3 issue and not of interest here. Similarly, since the 06:00.0 Thunderbolt switch was already gone, pcie_isr() received 0xffff when it tried to read PCI_EXP_SLTSTA, and pciehp thought that was valid status showing that many events had happened: the latch had been opened, the attention button had been pressed, a card was now present, and the link was now up. These are all wrong, of course, but pciehp went on to try to power up and enumerate devices below the non-existent bridge: pciehp 0000:06:00.0: PCI slot - powering on due to button press pciehp 0000:06:00.0: Surprise Insertion pci 0000:07:00.0 id reading try 50 times with interval 20 ms to get ffffffff [bhelgaas: changelog, also check in pcie_poll_cmd() & pcie_do_write_cmd()] Link: https://bugzilla.kernel.org/show_bug.cgi?id=99841 Suggested-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Jarod Wilson <jarod@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2015-07-22 00:25:30 +08:00
if (slot_status == (u16) ~0) {
ctrl_info(ctrl, "%s: no response from device\n",
__func__);
return 0;
}
if (slot_status & PCI_EXP_SLTSTA_CC) {
pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
PCI_EXP_SLTSTA_CC);
return 1;
}
if (timeout < 0)
break;
msleep(10);
timeout -= 10;
}
return 0; /* timeout */
}
static void pcie_wait_cmd(struct controller *ctrl)
{
unsigned int msecs = pciehp_poll_mode ? 2500 : 1000;
unsigned long duration = msecs_to_jiffies(msecs);
unsigned long cmd_timeout = ctrl->cmd_started + duration;
unsigned long now, timeout;
int rc;
/*
* If the controller does not generate notifications for command
* completions, we never need to wait between writes.
*/
if (NO_CMD_CMPL(ctrl))
return;
if (!ctrl->cmd_busy)
return;
/*
* Even if the command has already timed out, we want to call
* pcie_poll_cmd() so it can clear PCI_EXP_SLTSTA_CC.
*/
now = jiffies;
if (time_before_eq(cmd_timeout, now))
timeout = 1;
else
timeout = cmd_timeout - now;
if (ctrl->slot_ctrl & PCI_EXP_SLTCTL_HPIE &&
ctrl->slot_ctrl & PCI_EXP_SLTCTL_CCIE)
rc = wait_event_timeout(ctrl->queue, !ctrl->cmd_busy, timeout);
else
rc = pcie_poll_cmd(ctrl, jiffies_to_msecs(timeout));
if (!rc)
ctrl_info(ctrl, "Timeout on hotplug command %#06x (issued %u msec ago)\n",
ctrl->slot_ctrl,
jiffies_to_msecs(jiffies - ctrl->cmd_started));
}
PCI: pciehp: Add quirk for Command Completed errata Several PCIe hotplug controllers have errata that mean they do not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Command Completed is never set for writes that only change software notification "Enable" bits. This results in timeouts like this: pciehp 0000:00:1c.0:pcie004: Timeout on hotplug command 0x1038 (issued 65284 msec ago) When this erratum is present, avoid these timeouts by marking commands "completed" immediately unless they change the "Control" bits. Here's the text of the Intel erratum CF118. We assume this applies to all Intel parts: CF118 PCIe Slot Status Register Command Completed bit not always updated on any configuration write to the Slot Control Register Problem: For PCIe root ports (devices 0 - 10) supporting hot-plug, the Slot Status Register (offset AAh) Command Completed (bit[4]) status is updated under the following condition: IOH will set Command Completed bit after delivering the new commands written in the Slot Controller register (offset A8h) to VPP. The IOH detects new commands written in Slot Control register by checking the change of value for Power Controller Control (bit[10]), Power Indicator Control (bits[9:8]), Attention Indicator Control (bits[7:6]), or Electromechanical Interlock Control (bit[11]) fields. Any other configuration writes to the Slot Control register without changing the values of these fields will not cause Command Completed bit to be set. The PCIe Base Specification Revision 2.0 or later describes the “Slot Control Register” in section 7.8.10, as follows (Reference section 7.8.10, Slot Control Register, Offset 18h). In hot-plug capable Downstream Ports, a write to the Slot Control register must cause a hot-plug command to be generated (see Section 6.7.3.2 for details on hot-plug commands). A write to the Slot Control register in a Downstream Port that is not hotplug capable must not cause a hot-plug command to be executed. The PCIe Spec intended that every write to the Slot Control Register is a command and expected a command complete status to abstract the VPP implementation specific nuances from the OS software. IOH PCIe Slot Control Register implementation is not fully conforming to the PCIe Specification in this respect. Implication: Software checking on the Command Completed status after writing to the Slot Control register may time out. Workaround: Software can read the Slot Control register and compare the existing and new values to determine if it should check the Command Completed status after writing to the Slot Control register. Per Sinan, the Qualcomm QDF2400 controller also does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html Link: https://lkml.kernel.org/r/8770820b-85a0-172b-7230-3a44524e6c9f@molgen.mpg.de Reported-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Tested-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Signed-off-by: Sinan Kaya <okaya@codeaurora.org> # Qcom quirk Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-05-04 07:39:38 +08:00
#define CC_ERRATUM_MASK (PCI_EXP_SLTCTL_PCC | \
PCI_EXP_SLTCTL_PIC | \
PCI_EXP_SLTCTL_AIC | \
PCI_EXP_SLTCTL_EIC)
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
static void pcie_do_write_cmd(struct controller *ctrl, u16 cmd,
u16 mask, bool wait)
{
struct pci_dev *pdev = ctrl_dev(ctrl);
PCI: pciehp: Add quirk for Command Completed errata Several PCIe hotplug controllers have errata that mean they do not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Command Completed is never set for writes that only change software notification "Enable" bits. This results in timeouts like this: pciehp 0000:00:1c.0:pcie004: Timeout on hotplug command 0x1038 (issued 65284 msec ago) When this erratum is present, avoid these timeouts by marking commands "completed" immediately unless they change the "Control" bits. Here's the text of the Intel erratum CF118. We assume this applies to all Intel parts: CF118 PCIe Slot Status Register Command Completed bit not always updated on any configuration write to the Slot Control Register Problem: For PCIe root ports (devices 0 - 10) supporting hot-plug, the Slot Status Register (offset AAh) Command Completed (bit[4]) status is updated under the following condition: IOH will set Command Completed bit after delivering the new commands written in the Slot Controller register (offset A8h) to VPP. The IOH detects new commands written in Slot Control register by checking the change of value for Power Controller Control (bit[10]), Power Indicator Control (bits[9:8]), Attention Indicator Control (bits[7:6]), or Electromechanical Interlock Control (bit[11]) fields. Any other configuration writes to the Slot Control register without changing the values of these fields will not cause Command Completed bit to be set. The PCIe Base Specification Revision 2.0 or later describes the “Slot Control Register” in section 7.8.10, as follows (Reference section 7.8.10, Slot Control Register, Offset 18h). In hot-plug capable Downstream Ports, a write to the Slot Control register must cause a hot-plug command to be generated (see Section 6.7.3.2 for details on hot-plug commands). A write to the Slot Control register in a Downstream Port that is not hotplug capable must not cause a hot-plug command to be executed. The PCIe Spec intended that every write to the Slot Control Register is a command and expected a command complete status to abstract the VPP implementation specific nuances from the OS software. IOH PCIe Slot Control Register implementation is not fully conforming to the PCIe Specification in this respect. Implication: Software checking on the Command Completed status after writing to the Slot Control register may time out. Workaround: Software can read the Slot Control register and compare the existing and new values to determine if it should check the Command Completed status after writing to the Slot Control register. Per Sinan, the Qualcomm QDF2400 controller also does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html Link: https://lkml.kernel.org/r/8770820b-85a0-172b-7230-3a44524e6c9f@molgen.mpg.de Reported-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Tested-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Signed-off-by: Sinan Kaya <okaya@codeaurora.org> # Qcom quirk Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-05-04 07:39:38 +08:00
u16 slot_ctrl_orig, slot_ctrl;
mutex_lock(&ctrl->ctrl_lock);
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
/*
* Always wait for any previous command that might still be in progress
*/
PCI: pciehp: Wait for hotplug command completion lazily Previously we issued a hotplug command and waited for it to complete. But there's no need to wait until we're ready to issue the *next* command. The next command will probably be much later, so the first one may have already completed and we may not have to actually wait at all. Because of hardware errata, some controllers generate command completion events for some commands but not others. In the case of Intel CF118 (see spec update reference), the controller indicates command completion only for Slot Control writes that change the value of the following bits: Power Controller Control Power Indicator Control Attention Indicator Control Electromechanical Interlock Control Changes to other bits, e.g., the interrupt enable bits, do not cause the Command Completed bit to be set. Controllers from AMD and Nvidia are reported to have similar errata. These errata cause timeouts when pcie_enable_notification() enables interrupts. Previously that timeout occurred at boot-time. With this change, the timeout occurs later, when we change the state of the slot power, indicators, or interlock. This speeds up boot but causes a timeout at the first hotplug event on the slot. Subsequent events don't timeout because only the first (boot-time) hotplug command updates Slot Control without touching the power/indicator/interlock controls. Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html Tested-by: Rajat Jain <rajatxjain@gmail.com> (IDT 807a controller) Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Yinghai Lu <yinghai@kernel.org>
2014-06-14 05:06:40 +08:00
pcie_wait_cmd(ctrl);
pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
PCI: pciehp: Handle invalid data when reading from non-existent devices It's platform-dependent, but an MMIO read to a non-existent PCI device generally returns data with all bits set. This happens when the host bridge or Root Complex times out waiting for a response from the device and fabricates return data to complete the CPU's read. One example, reported in the bugzilla below, involved this hierarchy: pci 0000:00:1c.0: PCI bridge to [bus 02-3a] Root Port pci 0000:02:00.0: PCI bridge to [bus 03-0a] Upstream Port pci 0000:03:03.0: PCI bridge to [bus 05-07] Downstream Port pci 0000:05:00.0: PCI bridge to [bus 06-07] Thunderbolt Upstream Port pci 0000:06:00.0: PCI bridge to [bus 07] Thunderbolt Downstream Port pci 0000:07:00.0: BCM57762 NIC Unplugging the Thunderbolt switch and the NIC below it resulted in this: pciehp 0000:03:03.0: Surprise Removal tg3 0000:07:00.0: tg3_abort_hw timed out, TX_MODE_ENABLE will not clear MAC_TX_MODE=ffffffff pciehp 0000:06:00.0: unloading service driver pciehp pciehp 0000:06:00.0: pcie_isr: intr_loc 11f pciehp 0000:06:00.0: Switch interrupt received pciehp 0000:06:00.0: Latch open on Slot pciehp 0000:06:00.0: Attention button interrupt received pciehp 0000:06:00.0: Button pressed on Slot pciehp 0000:06:00.0: Presence/Notify input change pciehp 0000:06:00.0: Card present on Slot pciehp 0000:06:00.0: Power fault interrupt received pciehp 0000:06:00.0: Data Link Layer State change pciehp 0000:06:00.0: Link Up event The pciehp driver correctly noticed that the Thunderbolt switch (05:00.0 and 06:00.0) and NIC (07:00.0) had been removed, and it called their driver remove methods. Since the NIC was already gone, tg3 received 0xffffffff when it tried to read from the device. The resulting timeout is a tg3 issue and not of interest here. Similarly, since the 06:00.0 Thunderbolt switch was already gone, pcie_isr() received 0xffff when it tried to read PCI_EXP_SLTSTA, and pciehp thought that was valid status showing that many events had happened: the latch had been opened, the attention button had been pressed, a card was now present, and the link was now up. These are all wrong, of course, but pciehp went on to try to power up and enumerate devices below the non-existent bridge: pciehp 0000:06:00.0: PCI slot - powering on due to button press pciehp 0000:06:00.0: Surprise Insertion pci 0000:07:00.0 id reading try 50 times with interval 20 ms to get ffffffff [bhelgaas: changelog, also check in pcie_poll_cmd() & pcie_do_write_cmd()] Link: https://bugzilla.kernel.org/show_bug.cgi?id=99841 Suggested-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Jarod Wilson <jarod@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2015-07-22 00:25:30 +08:00
if (slot_ctrl == (u16) ~0) {
ctrl_info(ctrl, "%s: no response from device\n", __func__);
goto out;
}
PCI: pciehp: Add quirk for Command Completed errata Several PCIe hotplug controllers have errata that mean they do not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Command Completed is never set for writes that only change software notification "Enable" bits. This results in timeouts like this: pciehp 0000:00:1c.0:pcie004: Timeout on hotplug command 0x1038 (issued 65284 msec ago) When this erratum is present, avoid these timeouts by marking commands "completed" immediately unless they change the "Control" bits. Here's the text of the Intel erratum CF118. We assume this applies to all Intel parts: CF118 PCIe Slot Status Register Command Completed bit not always updated on any configuration write to the Slot Control Register Problem: For PCIe root ports (devices 0 - 10) supporting hot-plug, the Slot Status Register (offset AAh) Command Completed (bit[4]) status is updated under the following condition: IOH will set Command Completed bit after delivering the new commands written in the Slot Controller register (offset A8h) to VPP. The IOH detects new commands written in Slot Control register by checking the change of value for Power Controller Control (bit[10]), Power Indicator Control (bits[9:8]), Attention Indicator Control (bits[7:6]), or Electromechanical Interlock Control (bit[11]) fields. Any other configuration writes to the Slot Control register without changing the values of these fields will not cause Command Completed bit to be set. The PCIe Base Specification Revision 2.0 or later describes the “Slot Control Register” in section 7.8.10, as follows (Reference section 7.8.10, Slot Control Register, Offset 18h). In hot-plug capable Downstream Ports, a write to the Slot Control register must cause a hot-plug command to be generated (see Section 6.7.3.2 for details on hot-plug commands). A write to the Slot Control register in a Downstream Port that is not hotplug capable must not cause a hot-plug command to be executed. The PCIe Spec intended that every write to the Slot Control Register is a command and expected a command complete status to abstract the VPP implementation specific nuances from the OS software. IOH PCIe Slot Control Register implementation is not fully conforming to the PCIe Specification in this respect. Implication: Software checking on the Command Completed status after writing to the Slot Control register may time out. Workaround: Software can read the Slot Control register and compare the existing and new values to determine if it should check the Command Completed status after writing to the Slot Control register. Per Sinan, the Qualcomm QDF2400 controller also does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html Link: https://lkml.kernel.org/r/8770820b-85a0-172b-7230-3a44524e6c9f@molgen.mpg.de Reported-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Tested-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Signed-off-by: Sinan Kaya <okaya@codeaurora.org> # Qcom quirk Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-05-04 07:39:38 +08:00
slot_ctrl_orig = slot_ctrl;
slot_ctrl &= ~mask;
slot_ctrl |= (cmd & mask);
ctrl->cmd_busy = 1;
smp_mb();
pcie_capability_write_word(pdev, PCI_EXP_SLTCTL, slot_ctrl);
ctrl->cmd_started = jiffies;
ctrl->slot_ctrl = slot_ctrl;
PCI: pciehp: Add quirk for Command Completed errata Several PCIe hotplug controllers have errata that mean they do not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Command Completed is never set for writes that only change software notification "Enable" bits. This results in timeouts like this: pciehp 0000:00:1c.0:pcie004: Timeout on hotplug command 0x1038 (issued 65284 msec ago) When this erratum is present, avoid these timeouts by marking commands "completed" immediately unless they change the "Control" bits. Here's the text of the Intel erratum CF118. We assume this applies to all Intel parts: CF118 PCIe Slot Status Register Command Completed bit not always updated on any configuration write to the Slot Control Register Problem: For PCIe root ports (devices 0 - 10) supporting hot-plug, the Slot Status Register (offset AAh) Command Completed (bit[4]) status is updated under the following condition: IOH will set Command Completed bit after delivering the new commands written in the Slot Controller register (offset A8h) to VPP. The IOH detects new commands written in Slot Control register by checking the change of value for Power Controller Control (bit[10]), Power Indicator Control (bits[9:8]), Attention Indicator Control (bits[7:6]), or Electromechanical Interlock Control (bit[11]) fields. Any other configuration writes to the Slot Control register without changing the values of these fields will not cause Command Completed bit to be set. The PCIe Base Specification Revision 2.0 or later describes the “Slot Control Register” in section 7.8.10, as follows (Reference section 7.8.10, Slot Control Register, Offset 18h). In hot-plug capable Downstream Ports, a write to the Slot Control register must cause a hot-plug command to be generated (see Section 6.7.3.2 for details on hot-plug commands). A write to the Slot Control register in a Downstream Port that is not hotplug capable must not cause a hot-plug command to be executed. The PCIe Spec intended that every write to the Slot Control Register is a command and expected a command complete status to abstract the VPP implementation specific nuances from the OS software. IOH PCIe Slot Control Register implementation is not fully conforming to the PCIe Specification in this respect. Implication: Software checking on the Command Completed status after writing to the Slot Control register may time out. Workaround: Software can read the Slot Control register and compare the existing and new values to determine if it should check the Command Completed status after writing to the Slot Control register. Per Sinan, the Qualcomm QDF2400 controller also does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html Link: https://lkml.kernel.org/r/8770820b-85a0-172b-7230-3a44524e6c9f@molgen.mpg.de Reported-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Tested-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Signed-off-by: Sinan Kaya <okaya@codeaurora.org> # Qcom quirk Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-05-04 07:39:38 +08:00
/*
* Controllers with the Intel CF118 and similar errata advertise
* Command Completed support, but they only set Command Completed
* if we change the "Control" bits for power, power indicator,
* attention indicator, or interlock. If we only change the
* "Enable" bits, they never set the Command Completed bit.
*/
if (pdev->broken_cmd_compl &&
(slot_ctrl_orig & CC_ERRATUM_MASK) == (slot_ctrl & CC_ERRATUM_MASK))
ctrl->cmd_busy = 0;
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
/*
* Optionally wait for the hardware to be ready for a new command,
* indicating completion of the above issued command.
*/
if (wait)
pcie_wait_cmd(ctrl);
PCI: pciehp: Handle invalid data when reading from non-existent devices It's platform-dependent, but an MMIO read to a non-existent PCI device generally returns data with all bits set. This happens when the host bridge or Root Complex times out waiting for a response from the device and fabricates return data to complete the CPU's read. One example, reported in the bugzilla below, involved this hierarchy: pci 0000:00:1c.0: PCI bridge to [bus 02-3a] Root Port pci 0000:02:00.0: PCI bridge to [bus 03-0a] Upstream Port pci 0000:03:03.0: PCI bridge to [bus 05-07] Downstream Port pci 0000:05:00.0: PCI bridge to [bus 06-07] Thunderbolt Upstream Port pci 0000:06:00.0: PCI bridge to [bus 07] Thunderbolt Downstream Port pci 0000:07:00.0: BCM57762 NIC Unplugging the Thunderbolt switch and the NIC below it resulted in this: pciehp 0000:03:03.0: Surprise Removal tg3 0000:07:00.0: tg3_abort_hw timed out, TX_MODE_ENABLE will not clear MAC_TX_MODE=ffffffff pciehp 0000:06:00.0: unloading service driver pciehp pciehp 0000:06:00.0: pcie_isr: intr_loc 11f pciehp 0000:06:00.0: Switch interrupt received pciehp 0000:06:00.0: Latch open on Slot pciehp 0000:06:00.0: Attention button interrupt received pciehp 0000:06:00.0: Button pressed on Slot pciehp 0000:06:00.0: Presence/Notify input change pciehp 0000:06:00.0: Card present on Slot pciehp 0000:06:00.0: Power fault interrupt received pciehp 0000:06:00.0: Data Link Layer State change pciehp 0000:06:00.0: Link Up event The pciehp driver correctly noticed that the Thunderbolt switch (05:00.0 and 06:00.0) and NIC (07:00.0) had been removed, and it called their driver remove methods. Since the NIC was already gone, tg3 received 0xffffffff when it tried to read from the device. The resulting timeout is a tg3 issue and not of interest here. Similarly, since the 06:00.0 Thunderbolt switch was already gone, pcie_isr() received 0xffff when it tried to read PCI_EXP_SLTSTA, and pciehp thought that was valid status showing that many events had happened: the latch had been opened, the attention button had been pressed, a card was now present, and the link was now up. These are all wrong, of course, but pciehp went on to try to power up and enumerate devices below the non-existent bridge: pciehp 0000:06:00.0: PCI slot - powering on due to button press pciehp 0000:06:00.0: Surprise Insertion pci 0000:07:00.0 id reading try 50 times with interval 20 ms to get ffffffff [bhelgaas: changelog, also check in pcie_poll_cmd() & pcie_do_write_cmd()] Link: https://bugzilla.kernel.org/show_bug.cgi?id=99841 Suggested-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Jarod Wilson <jarod@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2015-07-22 00:25:30 +08:00
out:
mutex_unlock(&ctrl->ctrl_lock);
}
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
/**
* pcie_write_cmd - Issue controller command
* @ctrl: controller to which the command is issued
* @cmd: command value written to slot control register
* @mask: bitmask of slot control register to be modified
*/
static void pcie_write_cmd(struct controller *ctrl, u16 cmd, u16 mask)
{
pcie_do_write_cmd(ctrl, cmd, mask, true);
}
/* Same as above without waiting for the hardware to latch */
static void pcie_write_cmd_nowait(struct controller *ctrl, u16 cmd, u16 mask)
{
pcie_do_write_cmd(ctrl, cmd, mask, false);
}
bool pciehp_check_link_active(struct controller *ctrl)
{
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 lnk_status;
bool ret;
pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
if (ret)
ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status);
return ret;
}
static void pcie_wait_link_active(struct controller *ctrl)
{
struct pci_dev *pdev = ctrl_dev(ctrl);
pcie_wait_for_link(pdev, true);
}
static bool pci_bus_check_dev(struct pci_bus *bus, int devfn)
{
u32 l;
int count = 0;
int delay = 1000, step = 20;
bool found = false;
do {
found = pci_bus_read_dev_vendor_id(bus, devfn, &l, 0);
count++;
if (found)
break;
msleep(step);
delay -= step;
} while (delay > 0);
if (count > 1 && pciehp_debug)
printk(KERN_DEBUG "pci %04x:%02x:%02x.%d id reading try %d times with interval %d ms to get %08x\n",
pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
PCI_FUNC(devfn), count, step, l);
return found;
}
int pciehp_check_link_status(struct controller *ctrl)
{
struct pci_dev *pdev = ctrl_dev(ctrl);
bool found;
u16 lnk_status;
/*
* Data Link Layer Link Active Reporting must be capable for
* hot-plug capable downstream port. But old controller might
* not implement it. In this case, we wait for 1000 ms.
*/
if (ctrl->link_active_reporting)
pcie_wait_link_active(ctrl);
else
msleep(1000);
/* wait 100ms before read pci conf, and try in 1s */
msleep(100);
found = pci_bus_check_dev(ctrl->pcie->port->subordinate,
PCI_DEVFN(0, 0));
PCI: pciehp: Tolerate initially unstable link When a device is hotplugged, Presence Detect and Link Up events often do not occur simultaneously, but with a lag of a few milliseconds. Only the first event received is relevant, the other one can be disregarded. Moreover, Stefan Roese reports that on certain platforms, Link State and Presence Detect may flap for up to 100 ms before stabilizing, suggesting that such events should be disregarded for at least this long: https://lkml.kernel.org/r/20180130084121.18653-1-sr@denx.de On slot enablement, pciehp_check_link_status() waits for 100 ms per PCIe r4.0, sec 6.7.3.3, then probes the hotplugged device's vendor register for up to 1 second. If this succeeds, the link is definitely up, so ignore any Presence Detect or Link State events that occurred up to this point. pciehp_check_link_status() then checks the Link Training bit in the Link Status register. This is the final opportunity to detect inaccessibility of the device and abort slot enablement. Any link or presence change that occurs afterwards will cause the slot to be disabled again immediately after attempting to enable it. The astute reviewer may appreciate that achieving this behavior would be more complicated had pciehp not just been converted to enable/disable the slot exclusively from the IRQ thread: When the slot is enabled via sysfs, each link or presence flap would otherwise cause the IRQ thread to run and it would have to sense that those events are belonging to a concurrent slot enablement operation and disregard them. It would be much more difficult than this mere 3 line change. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Stefan Roese <sr@denx.de>
2018-07-20 06:27:49 +08:00
/* ignore link or presence changes up to this point */
if (found)
atomic_and(~(PCI_EXP_SLTSTA_DLLSC | PCI_EXP_SLTSTA_PDC),
&ctrl->pending_events);
pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status);
if ((lnk_status & PCI_EXP_LNKSTA_LT) ||
!(lnk_status & PCI_EXP_LNKSTA_NLW)) {
ctrl_err(ctrl, "link training error: status %#06x\n",
lnk_status);
return -1;
}
pcie_update_link_speed(ctrl->pcie->port->subordinate, lnk_status);
if (!found)
return -1;
return 0;
}
static int __pciehp_link_set(struct controller *ctrl, bool enable)
{
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 lnk_ctrl;
pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &lnk_ctrl);
if (enable)
lnk_ctrl &= ~PCI_EXP_LNKCTL_LD;
else
lnk_ctrl |= PCI_EXP_LNKCTL_LD;
pcie_capability_write_word(pdev, PCI_EXP_LNKCTL, lnk_ctrl);
ctrl_dbg(ctrl, "%s: lnk_ctrl = %x\n", __func__, lnk_ctrl);
return 0;
}
static int pciehp_link_enable(struct controller *ctrl)
{
return __pciehp_link_set(ctrl, true);
}
int pciehp_get_raw_indicator_status(struct hotplug_slot *hotplug_slot,
u8 *status)
{
struct slot *slot = hotplug_slot->private;
struct pci_dev *pdev = ctrl_dev(slot->ctrl);
u16 slot_ctrl;
pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
*status = (slot_ctrl & (PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC)) >> 6;
return 0;
}
void pciehp_get_attention_status(struct slot *slot, u8 *status)
{
struct controller *ctrl = slot->ctrl;
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 slot_ctrl;
pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x, value read %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, slot_ctrl);
switch (slot_ctrl & PCI_EXP_SLTCTL_AIC) {
case PCI_EXP_SLTCTL_ATTN_IND_ON:
*status = 1; /* On */
break;
case PCI_EXP_SLTCTL_ATTN_IND_BLINK:
*status = 2; /* Blink */
break;
case PCI_EXP_SLTCTL_ATTN_IND_OFF:
*status = 0; /* Off */
break;
default:
*status = 0xFF;
break;
}
}
void pciehp_get_power_status(struct slot *slot, u8 *status)
{
struct controller *ctrl = slot->ctrl;
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 slot_ctrl;
pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &slot_ctrl);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x value read %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, slot_ctrl);
switch (slot_ctrl & PCI_EXP_SLTCTL_PCC) {
case PCI_EXP_SLTCTL_PWR_ON:
*status = 1; /* On */
break;
case PCI_EXP_SLTCTL_PWR_OFF:
*status = 0; /* Off */
break;
default:
*status = 0xFF;
break;
}
}
void pciehp_get_latch_status(struct slot *slot, u8 *status)
{
struct pci_dev *pdev = ctrl_dev(slot->ctrl);
u16 slot_status;
pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
*status = !!(slot_status & PCI_EXP_SLTSTA_MRLSS);
}
void pciehp_get_adapter_status(struct slot *slot, u8 *status)
{
struct pci_dev *pdev = ctrl_dev(slot->ctrl);
u16 slot_status;
pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
*status = !!(slot_status & PCI_EXP_SLTSTA_PDS);
}
int pciehp_query_power_fault(struct slot *slot)
{
struct pci_dev *pdev = ctrl_dev(slot->ctrl);
u16 slot_status;
pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
return !!(slot_status & PCI_EXP_SLTSTA_PFD);
}
int pciehp_set_raw_indicator_status(struct hotplug_slot *hotplug_slot,
u8 status)
{
struct slot *slot = hotplug_slot->private;
struct controller *ctrl = slot->ctrl;
pcie_write_cmd_nowait(ctrl, status << 6,
PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC);
return 0;
}
void pciehp_set_attention_status(struct slot *slot, u8 value)
{
struct controller *ctrl = slot->ctrl;
u16 slot_cmd;
if (!ATTN_LED(ctrl))
return;
switch (value) {
case 0: /* turn off */
slot_cmd = PCI_EXP_SLTCTL_ATTN_IND_OFF;
break;
case 1: /* turn on */
slot_cmd = PCI_EXP_SLTCTL_ATTN_IND_ON;
break;
case 2: /* turn blink */
slot_cmd = PCI_EXP_SLTCTL_ATTN_IND_BLINK;
break;
default:
return;
}
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
pcie_write_cmd_nowait(ctrl, slot_cmd, PCI_EXP_SLTCTL_AIC);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, slot_cmd);
}
void pciehp_green_led_on(struct slot *slot)
{
struct controller *ctrl = slot->ctrl;
if (!PWR_LED(ctrl))
return;
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
pcie_write_cmd_nowait(ctrl, PCI_EXP_SLTCTL_PWR_IND_ON,
PCI_EXP_SLTCTL_PIC);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL,
PCI_EXP_SLTCTL_PWR_IND_ON);
}
void pciehp_green_led_off(struct slot *slot)
{
struct controller *ctrl = slot->ctrl;
if (!PWR_LED(ctrl))
return;
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
pcie_write_cmd_nowait(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
PCI_EXP_SLTCTL_PIC);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL,
PCI_EXP_SLTCTL_PWR_IND_OFF);
}
void pciehp_green_led_blink(struct slot *slot)
{
struct controller *ctrl = slot->ctrl;
if (!PWR_LED(ctrl))
return;
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
pcie_write_cmd_nowait(ctrl, PCI_EXP_SLTCTL_PWR_IND_BLINK,
PCI_EXP_SLTCTL_PIC);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL,
PCI_EXP_SLTCTL_PWR_IND_BLINK);
}
int pciehp_power_on_slot(struct slot *slot)
{
struct controller *ctrl = slot->ctrl;
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 slot_status;
int retval;
/* Clear sticky power-fault bit from previous power failures */
pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
if (slot_status & PCI_EXP_SLTSTA_PFD)
pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
PCI_EXP_SLTSTA_PFD);
ctrl->power_fault_detected = 0;
pcie_write_cmd(ctrl, PCI_EXP_SLTCTL_PWR_ON, PCI_EXP_SLTCTL_PCC);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL,
PCI_EXP_SLTCTL_PWR_ON);
retval = pciehp_link_enable(ctrl);
if (retval)
ctrl_err(ctrl, "%s: Can not enable the link!\n", __func__);
return retval;
}
void pciehp_power_off_slot(struct slot *slot)
{
struct controller *ctrl = slot->ctrl;
pcie_write_cmd(ctrl, PCI_EXP_SLTCTL_PWR_OFF, PCI_EXP_SLTCTL_PCC);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL,
PCI_EXP_SLTCTL_PWR_OFF);
}
static irqreturn_t pciehp_isr(int irq, void *dev_id)
{
struct controller *ctrl = (struct controller *)dev_id;
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 status, events;
PCI: pciehp: Convert to threaded IRQ pciehp's IRQ handler queues up a work item for each event signaled by the hardware. A more modern alternative is to let a long running kthread service the events. The IRQ handler's sole job is then to check whether the IRQ originated from the device in question, acknowledge its receipt to the hardware to quiesce the interrupt and wake up the kthread. One benefit is reduced latency to handle the IRQ, which is a necessity for realtime environments. Another benefit is that we can make pciehp simpler and more robust by handling events synchronously in process context, rather than asynchronously by queueing up work items. pciehp's usage of work items is a historic artifact, it predates the introduction of threaded IRQ handlers by two years. (The former was introduced in 2007 with commit 5d386e1ac402 ("pciehp: Event handling rework"), the latter in 2009 with commit 3aa551c9b4c4 ("genirq: add threaded interrupt handler support").) Convert pciehp to threaded IRQ handling by retrieving the pending events in pciehp_isr(), saving them for later consumption by the thread handler pciehp_ist() and clearing them in the Slot Status register. By clearing the Slot Status (and thereby acknowledging the events) in pciehp_isr(), we can avoid requesting the IRQ with IRQF_ONESHOT, which would have the unpleasant side effect of starving devices sharing the IRQ until pciehp_ist() has finished. pciehp_isr() does not count how many times each event occurred, but merely records the fact *that* an event occurred. If the same event occurs a second time before pciehp_ist() is woken, that second event will not be recorded separately, which is problematic according to commit fad214b0aa72 ("PCI: pciehp: Process all hotplug events before looking for new ones") because we may miss removal of a card in-between two back-to-back insertions. We're about to make pciehp_ist() resilient to missed events. The present commit regresses the driver's behavior temporarily in order to separate the changes into reviewable chunks. This doesn't affect regular slow-motion hotplug, only plug-unplug-plug operations that happen in a timespan shorter than wakeup of the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mayurkumar Patel <mayurkumar.patel@intel.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
2018-07-20 06:27:38 +08:00
/*
* Interrupts only occur in D3hot or shallower (PCIe r4.0, sec 6.7.3.4).
*/
if (pdev->current_state == PCI_D3cold)
return IRQ_NONE;
pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &status);
if (status == (u16) ~0) {
ctrl_info(ctrl, "%s: no response from device\n", __func__);
return IRQ_NONE;
}
pciehp: Fix interrupt event handlig Current pciehp implementation disables and re-enables hotplug interrupts in its interrupt handler. This operation might be intend to guarantee that interrupts for the events newly occured during previous events are being handled will be successfully generated. But current implementaion has the following prolems. - Current interrupt service routin clears status changes without waiting command completion. Because of this, events might not be cleared properly. - Current interrupt service routine clears status changes caused by disabling or enabling hotplug interrupts itself. This will lose new events that occurs during previous interrupts are being handled. - Current implementation doesn't have any serialization mechanism between the code to wait for command completion and the interrupt handler that clears the command completion events caused by itself. There is clearly race conditions between them, and it may cause the problem that waiting for command completion doesn't work for example. To fix those problems, this patch stops disabling/re-enabling hotplug interrupts in interrupt service routine. Instead of this, this patch re-inspects Slot Status register after clearing what is presumed to be the last bending interrupt in order to guarantee that all interrupt events are serviced. Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-04-26 05:38:57 +08:00
/*
* Slot Status contains plain status bits as well as event
* notification bits; right now we only want the event bits.
pciehp: Fix interrupt event handlig Current pciehp implementation disables and re-enables hotplug interrupts in its interrupt handler. This operation might be intend to guarantee that interrupts for the events newly occured during previous events are being handled will be successfully generated. But current implementaion has the following prolems. - Current interrupt service routin clears status changes without waiting command completion. Because of this, events might not be cleared properly. - Current interrupt service routine clears status changes caused by disabling or enabling hotplug interrupts itself. This will lose new events that occurs during previous interrupts are being handled. - Current implementation doesn't have any serialization mechanism between the code to wait for command completion and the interrupt handler that clears the command completion events caused by itself. There is clearly race conditions between them, and it may cause the problem that waiting for command completion doesn't work for example. To fix those problems, this patch stops disabling/re-enabling hotplug interrupts in interrupt service routine. Instead of this, this patch re-inspects Slot Status register after clearing what is presumed to be the last bending interrupt in order to guarantee that all interrupt events are serviced. Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-04-26 05:38:57 +08:00
*/
events = status & (PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_CC |
PCI_EXP_SLTSTA_DLLSC);
/*
* If we've already reported a power fault, don't report it again
* until we've done something to handle it.
*/
if (ctrl->power_fault_detected)
events &= ~PCI_EXP_SLTSTA_PFD;
if (!events)
return IRQ_NONE;
pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, events);
ctrl_dbg(ctrl, "pending interrupts %#06x from Slot Status\n", events);
PCI: pciehp: Convert to threaded IRQ pciehp's IRQ handler queues up a work item for each event signaled by the hardware. A more modern alternative is to let a long running kthread service the events. The IRQ handler's sole job is then to check whether the IRQ originated from the device in question, acknowledge its receipt to the hardware to quiesce the interrupt and wake up the kthread. One benefit is reduced latency to handle the IRQ, which is a necessity for realtime environments. Another benefit is that we can make pciehp simpler and more robust by handling events synchronously in process context, rather than asynchronously by queueing up work items. pciehp's usage of work items is a historic artifact, it predates the introduction of threaded IRQ handlers by two years. (The former was introduced in 2007 with commit 5d386e1ac402 ("pciehp: Event handling rework"), the latter in 2009 with commit 3aa551c9b4c4 ("genirq: add threaded interrupt handler support").) Convert pciehp to threaded IRQ handling by retrieving the pending events in pciehp_isr(), saving them for later consumption by the thread handler pciehp_ist() and clearing them in the Slot Status register. By clearing the Slot Status (and thereby acknowledging the events) in pciehp_isr(), we can avoid requesting the IRQ with IRQF_ONESHOT, which would have the unpleasant side effect of starving devices sharing the IRQ until pciehp_ist() has finished. pciehp_isr() does not count how many times each event occurred, but merely records the fact *that* an event occurred. If the same event occurs a second time before pciehp_ist() is woken, that second event will not be recorded separately, which is problematic according to commit fad214b0aa72 ("PCI: pciehp: Process all hotplug events before looking for new ones") because we may miss removal of a card in-between two back-to-back insertions. We're about to make pciehp_ist() resilient to missed events. The present commit regresses the driver's behavior temporarily in order to separate the changes into reviewable chunks. This doesn't affect regular slow-motion hotplug, only plug-unplug-plug operations that happen in a timespan shorter than wakeup of the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mayurkumar Patel <mayurkumar.patel@intel.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
2018-07-20 06:27:38 +08:00
/*
* Command Completed notifications are not deferred to the
* IRQ thread because it may be waiting for their arrival.
*/
if (events & PCI_EXP_SLTSTA_CC) {
ctrl->cmd_busy = 0;
smp_mb();
wake_up(&ctrl->queue);
PCI: pciehp: Convert to threaded IRQ pciehp's IRQ handler queues up a work item for each event signaled by the hardware. A more modern alternative is to let a long running kthread service the events. The IRQ handler's sole job is then to check whether the IRQ originated from the device in question, acknowledge its receipt to the hardware to quiesce the interrupt and wake up the kthread. One benefit is reduced latency to handle the IRQ, which is a necessity for realtime environments. Another benefit is that we can make pciehp simpler and more robust by handling events synchronously in process context, rather than asynchronously by queueing up work items. pciehp's usage of work items is a historic artifact, it predates the introduction of threaded IRQ handlers by two years. (The former was introduced in 2007 with commit 5d386e1ac402 ("pciehp: Event handling rework"), the latter in 2009 with commit 3aa551c9b4c4 ("genirq: add threaded interrupt handler support").) Convert pciehp to threaded IRQ handling by retrieving the pending events in pciehp_isr(), saving them for later consumption by the thread handler pciehp_ist() and clearing them in the Slot Status register. By clearing the Slot Status (and thereby acknowledging the events) in pciehp_isr(), we can avoid requesting the IRQ with IRQF_ONESHOT, which would have the unpleasant side effect of starving devices sharing the IRQ until pciehp_ist() has finished. pciehp_isr() does not count how many times each event occurred, but merely records the fact *that* an event occurred. If the same event occurs a second time before pciehp_ist() is woken, that second event will not be recorded separately, which is problematic according to commit fad214b0aa72 ("PCI: pciehp: Process all hotplug events before looking for new ones") because we may miss removal of a card in-between two back-to-back insertions. We're about to make pciehp_ist() resilient to missed events. The present commit regresses the driver's behavior temporarily in order to separate the changes into reviewable chunks. This doesn't affect regular slow-motion hotplug, only plug-unplug-plug operations that happen in a timespan shorter than wakeup of the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mayurkumar Patel <mayurkumar.patel@intel.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
2018-07-20 06:27:38 +08:00
if (events == PCI_EXP_SLTSTA_CC)
return IRQ_HANDLED;
events &= ~PCI_EXP_SLTSTA_CC;
}
if (pdev->ignore_hotplug) {
ctrl_dbg(ctrl, "ignoring hotplug event %#06x\n", events);
return IRQ_HANDLED;
PCI: Add pci_ignore_hotplug() to ignore hotplug events for a device Powering off a hot-pluggable device, e.g., with pci_set_power_state(D3cold), normally generates a hot-remove event that unbinds the driver. Some drivers expect to remain bound to a device even while they power it off and back on again. This can be dangerous, because if the device is removed or replaced while it is powered off, the driver doesn't know that anything changed. But some drivers accept that risk. Add pci_ignore_hotplug() for use by drivers that know their device cannot be removed. Using pci_ignore_hotplug() tells the PCI core that hot-plug events for the device should be ignored. The radeon and nouveau drivers use this to switch between a low-power, integrated GPU and a higher-power, higher-performance discrete GPU. They power off the unused GPU, but they want to remain bound to it. This is a reimplementation of f244d8b623da ("ACPIPHP / radeon / nouveau: Fix VGA switcheroo problem related to hotplug") but extends it to work with both acpiphp and pciehp. This fixes a problem where systems with dual GPUs using the radeon drivers become unusable, freezing every few seconds (see bugzillas below). The resume of the radeon device may also fail, e.g., This fixes problems on dual GPU systems where the radeon driver becomes unusable because of problems while suspending the device, as in bug 79701: [drm] radeon: finishing device. radeon 0000:01:00.0: Userspace still has active objects ! radeon 0000:01:00.0: ffff8800cb4ec288 ffff8800cb4ec000 16384 4294967297 force free ... WARNING: CPU: 0 PID: 67 at /home/apw/COD/linux/drivers/gpu/drm/radeon/radeon_gart.c:234 radeon_gart_unbind+0xd2/0xe0 [radeon]() trying to unbind memory from uninitialized GART ! or while resuming it, as in bug 77261: radeon 0000:01:00.0: ring 0 stalled for more than 10158msec radeon 0000:01:00.0: GPU lockup ... radeon 0000:01:00.0: GPU pci config reset pciehp 0000:00:01.0:pcie04: Card not present on Slot(1-1) radeon 0000:01:00.0: GPU reset succeeded, trying to resume *ERROR* radeon: dpm resume failed radeon 0000:01:00.0: Wait for MC idle timedout ! Link: https://bugzilla.kernel.org/show_bug.cgi?id=77261 Link: https://bugzilla.kernel.org/show_bug.cgi?id=79701 Reported-by: Shawn Starr <shawn.starr@rogers.com> Reported-by: Jose P. <lbdkmjdf@sharklasers.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Alex Deucher <alexander.deucher@amd.com> Acked-by: Rajat Jain <rajatxjain@gmail.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Dave Airlie <airlied@redhat.com> CC: stable@vger.kernel.org # v3.15+
2014-09-11 03:45:01 +08:00
}
PCI: pciehp: Convert to threaded IRQ pciehp's IRQ handler queues up a work item for each event signaled by the hardware. A more modern alternative is to let a long running kthread service the events. The IRQ handler's sole job is then to check whether the IRQ originated from the device in question, acknowledge its receipt to the hardware to quiesce the interrupt and wake up the kthread. One benefit is reduced latency to handle the IRQ, which is a necessity for realtime environments. Another benefit is that we can make pciehp simpler and more robust by handling events synchronously in process context, rather than asynchronously by queueing up work items. pciehp's usage of work items is a historic artifact, it predates the introduction of threaded IRQ handlers by two years. (The former was introduced in 2007 with commit 5d386e1ac402 ("pciehp: Event handling rework"), the latter in 2009 with commit 3aa551c9b4c4 ("genirq: add threaded interrupt handler support").) Convert pciehp to threaded IRQ handling by retrieving the pending events in pciehp_isr(), saving them for later consumption by the thread handler pciehp_ist() and clearing them in the Slot Status register. By clearing the Slot Status (and thereby acknowledging the events) in pciehp_isr(), we can avoid requesting the IRQ with IRQF_ONESHOT, which would have the unpleasant side effect of starving devices sharing the IRQ until pciehp_ist() has finished. pciehp_isr() does not count how many times each event occurred, but merely records the fact *that* an event occurred. If the same event occurs a second time before pciehp_ist() is woken, that second event will not be recorded separately, which is problematic according to commit fad214b0aa72 ("PCI: pciehp: Process all hotplug events before looking for new ones") because we may miss removal of a card in-between two back-to-back insertions. We're about to make pciehp_ist() resilient to missed events. The present commit regresses the driver's behavior temporarily in order to separate the changes into reviewable chunks. This doesn't affect regular slow-motion hotplug, only plug-unplug-plug operations that happen in a timespan shorter than wakeup of the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mayurkumar Patel <mayurkumar.patel@intel.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
2018-07-20 06:27:38 +08:00
/* Save pending events for consumption by IRQ thread. */
atomic_or(events, &ctrl->pending_events);
return IRQ_WAKE_THREAD;
}
static irqreturn_t pciehp_ist(int irq, void *dev_id)
{
struct controller *ctrl = (struct controller *)dev_id;
struct slot *slot = ctrl->slot;
u32 events;
synchronize_hardirq(irq);
events = atomic_xchg(&ctrl->pending_events, 0);
if (!events)
return IRQ_NONE;
pciehp: Fix interrupt event handlig Current pciehp implementation disables and re-enables hotplug interrupts in its interrupt handler. This operation might be intend to guarantee that interrupts for the events newly occured during previous events are being handled will be successfully generated. But current implementaion has the following prolems. - Current interrupt service routin clears status changes without waiting command completion. Because of this, events might not be cleared properly. - Current interrupt service routine clears status changes caused by disabling or enabling hotplug interrupts itself. This will lose new events that occurs during previous interrupts are being handled. - Current implementation doesn't have any serialization mechanism between the code to wait for command completion and the interrupt handler that clears the command completion events caused by itself. There is clearly race conditions between them, and it may cause the problem that waiting for command completion doesn't work for example. To fix those problems, this patch stops disabling/re-enabling hotplug interrupts in interrupt service routine. Instead of this, this patch re-inspects Slot Status register after clearing what is presumed to be the last bending interrupt in order to guarantee that all interrupt events are serviced. Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-04-26 05:38:57 +08:00
/* Check Attention Button Pressed */
if (events & PCI_EXP_SLTSTA_ABP) {
ctrl_info(ctrl, "Slot(%s): Attention button pressed\n",
slot_name(slot));
pciehp_handle_button_press(slot);
}
/*
PCI: pciehp: Enable/disable exclusively from IRQ thread Besides the IRQ thread, there are several other places in the driver which enable or disable the slot: - pciehp_probe() enables the slot if it's occupied and the pciehp_force module parameter is used. - pciehp_resume() enables or disables the slot after system sleep. - pciehp_queue_pushbutton_work() enables or disables the slot after the 5 second delay following an Attention Button press. - pciehp_sysfs_enable_slot() and pciehp_sysfs_disable_slot() enable or disable the slot on sysfs write. This requires locking and complicates pciehp's state machine. A simplification can be achieved by enabling and disabling the slot exclusively from the IRQ thread. Amend the functions listed above to request slot enable/disablement from the IRQ thread by either synthesizing a Presence Detect Changed event or, in the case of a disable user request (via sysfs or an Attention Button press), submitting a newly introduced force disable request. The latter is needed because the slot shall be forced off despite being occupied. For this force disable request, avoid colliding with Slot Status register bits by using a bit number greater than 16. For synchronous execution of requests (on sysfs write), wait for the request to finish and retrieve the result. There can only ever be one sysfs write in flight due to the locking in kernfs_fop_write(), hence there is no risk of returning the result of a different sysfs request to user space. The POWERON_STATE and POWEROFF_STATE is now no longer entered by the above-listed functions, but solely by the IRQ thread when it begins a power transition. Afterwards, it moves to STATIC_STATE. The same applies to canceling the Attention Button work, it likewise becomes an IRQ thread only operation. An immediate consequence is that the POWERON_STATE and POWEROFF_STATE is never observed by the IRQ thread itself, only by functions called in a different context, such as pciehp_sysfs_enable_slot(). So remove handling of these states from pciehp_handle_button_press() and pciehp_handle_link_change() which are exclusively called from the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-20 06:27:46 +08:00
* Disable requests have higher priority than Presence Detect Changed
* or Data Link Layer State Changed events.
*/
PCI: pciehp: Enable/disable exclusively from IRQ thread Besides the IRQ thread, there are several other places in the driver which enable or disable the slot: - pciehp_probe() enables the slot if it's occupied and the pciehp_force module parameter is used. - pciehp_resume() enables or disables the slot after system sleep. - pciehp_queue_pushbutton_work() enables or disables the slot after the 5 second delay following an Attention Button press. - pciehp_sysfs_enable_slot() and pciehp_sysfs_disable_slot() enable or disable the slot on sysfs write. This requires locking and complicates pciehp's state machine. A simplification can be achieved by enabling and disabling the slot exclusively from the IRQ thread. Amend the functions listed above to request slot enable/disablement from the IRQ thread by either synthesizing a Presence Detect Changed event or, in the case of a disable user request (via sysfs or an Attention Button press), submitting a newly introduced force disable request. The latter is needed because the slot shall be forced off despite being occupied. For this force disable request, avoid colliding with Slot Status register bits by using a bit number greater than 16. For synchronous execution of requests (on sysfs write), wait for the request to finish and retrieve the result. There can only ever be one sysfs write in flight due to the locking in kernfs_fop_write(), hence there is no risk of returning the result of a different sysfs request to user space. The POWERON_STATE and POWEROFF_STATE is now no longer entered by the above-listed functions, but solely by the IRQ thread when it begins a power transition. Afterwards, it moves to STATIC_STATE. The same applies to canceling the Attention Button work, it likewise becomes an IRQ thread only operation. An immediate consequence is that the POWERON_STATE and POWEROFF_STATE is never observed by the IRQ thread itself, only by functions called in a different context, such as pciehp_sysfs_enable_slot(). So remove handling of these states from pciehp_handle_button_press() and pciehp_handle_link_change() which are exclusively called from the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-20 06:27:46 +08:00
if (events & DISABLE_SLOT)
pciehp_handle_disable_request(slot);
PCI: pciehp: Become resilient to missed events A hotplug port's Slot Status register does not count how often each type of event occurred, it only records the fact *that* an event has occurred. Previously pciehp queued a work item for each event. But if it missed an event, e.g. removal of a card in-between two back-to-back insertions, it queued up the wrong work item or no work item at all. Commit fad214b0aa72 ("PCI: pciehp: Process all hotplug events before looking for new ones") sought to improve the situation by shrinking the window during which events may be missed. But Stefan Roese reports unbalanced Card present and Link Up events, suggesting that we're still missing events if they occur very rapidly. Bjorn Helgaas responds that he considers pciehp's event handling "baroque" and calls for its simplification and rationalization: https://lkml.kernel.org/r/20180202192045.GA53759@bhelgaas-glaptop.roam.corp.google.com It gets worse once a hotplug port is runtime suspended: The port can signal an interrupt while it and its parents are in D3hot, i.e. while it is inaccessible. By the time we've runtime resumed all parents to D0 and read the port's Slot Status register, we may have missed an arbitrary number of events. Event handling therefore needs to be reworked to become resilient to missed events. Assume that a Presence Detect Changed event has occurred. Consider the following truth table: - Slot is in OFF_STATE and is currently empty. => Do nothing. (The event is trailing a Link Down or we've missed an insertion and subsequent removal.) - Slot is in OFF_STATE and is currently occupied. => Turn the slot on. - Slot is in ON_STATE and is currently empty. => Turn the slot off. - Slot is in ON_STATE and is currently occupied. => Turn the slot off, (Be cautious and assume the card in then back on. the slot isn't the same as before.) This leads to the following simple algorithm: 1 If the slot is in ON_STATE, turn it off unconditionally. 2 If the slot is currently occupied, turn it on. Because those actions are now carried out synchronously, rather than by scheduled work items, pciehp reacts to the *current* situation and missed events no longer matter. Data Link Layer State Changed events can be handled identically to Presence Detect Changed events. Note that in the above truth table, a Link Up trailing a Card present event didn't have to be accounted for: It is filtered out by pciehp_check_link_status(). As for Attention Button Pressed events, PCIe r4.0, sec 6.7.1.5 says: "Once the Power Indicator begins blinking, a 5-second abort interval exists during which a second depression of the Attention Button cancels the operation." In other words, the user can only expect the system to react to a button press after it starts blinking. Missed button presses that occur in-between are irrelevant. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Cc: Stefan Roese <sr@denx.de> Cc: Mayurkumar Patel <mayurkumar.patel@intel.com> Cc: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
2018-07-20 06:27:49 +08:00
else if (events & (PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC))
pciehp_handle_presence_or_link_change(slot, events);
pciehp: Fix interrupt event handlig Current pciehp implementation disables and re-enables hotplug interrupts in its interrupt handler. This operation might be intend to guarantee that interrupts for the events newly occured during previous events are being handled will be successfully generated. But current implementaion has the following prolems. - Current interrupt service routin clears status changes without waiting command completion. Because of this, events might not be cleared properly. - Current interrupt service routine clears status changes caused by disabling or enabling hotplug interrupts itself. This will lose new events that occurs during previous interrupts are being handled. - Current implementation doesn't have any serialization mechanism between the code to wait for command completion and the interrupt handler that clears the command completion events caused by itself. There is clearly race conditions between them, and it may cause the problem that waiting for command completion doesn't work for example. To fix those problems, this patch stops disabling/re-enabling hotplug interrupts in interrupt service routine. Instead of this, this patch re-inspects Slot Status register after clearing what is presumed to be the last bending interrupt in order to guarantee that all interrupt events are serviced. Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2008-04-26 05:38:57 +08:00
/* Check Power Fault Detected */
if ((events & PCI_EXP_SLTSTA_PFD) && !ctrl->power_fault_detected) {
ctrl->power_fault_detected = 1;
ctrl_err(ctrl, "Slot(%s): Power fault\n", slot_name(slot));
pciehp_set_attention_status(slot, 1);
pciehp_green_led_off(slot);
}
PCI: pciehp: Enable/disable exclusively from IRQ thread Besides the IRQ thread, there are several other places in the driver which enable or disable the slot: - pciehp_probe() enables the slot if it's occupied and the pciehp_force module parameter is used. - pciehp_resume() enables or disables the slot after system sleep. - pciehp_queue_pushbutton_work() enables or disables the slot after the 5 second delay following an Attention Button press. - pciehp_sysfs_enable_slot() and pciehp_sysfs_disable_slot() enable or disable the slot on sysfs write. This requires locking and complicates pciehp's state machine. A simplification can be achieved by enabling and disabling the slot exclusively from the IRQ thread. Amend the functions listed above to request slot enable/disablement from the IRQ thread by either synthesizing a Presence Detect Changed event or, in the case of a disable user request (via sysfs or an Attention Button press), submitting a newly introduced force disable request. The latter is needed because the slot shall be forced off despite being occupied. For this force disable request, avoid colliding with Slot Status register bits by using a bit number greater than 16. For synchronous execution of requests (on sysfs write), wait for the request to finish and retrieve the result. There can only ever be one sysfs write in flight due to the locking in kernfs_fop_write(), hence there is no risk of returning the result of a different sysfs request to user space. The POWERON_STATE and POWEROFF_STATE is now no longer entered by the above-listed functions, but solely by the IRQ thread when it begins a power transition. Afterwards, it moves to STATIC_STATE. The same applies to canceling the Attention Button work, it likewise becomes an IRQ thread only operation. An immediate consequence is that the POWERON_STATE and POWEROFF_STATE is never observed by the IRQ thread itself, only by functions called in a different context, such as pciehp_sysfs_enable_slot(). So remove handling of these states from pciehp_handle_button_press() and pciehp_handle_link_change() which are exclusively called from the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-20 06:27:46 +08:00
wake_up(&ctrl->requester);
return IRQ_HANDLED;
}
static int pciehp_poll(void *data)
{
struct controller *ctrl = data;
schedule_timeout_idle(10 * HZ); /* start with 10 sec delay */
while (!kthread_should_stop()) {
if (kthread_should_park())
kthread_parkme();
PCI: pciehp: Enable/disable exclusively from IRQ thread Besides the IRQ thread, there are several other places in the driver which enable or disable the slot: - pciehp_probe() enables the slot if it's occupied and the pciehp_force module parameter is used. - pciehp_resume() enables or disables the slot after system sleep. - pciehp_queue_pushbutton_work() enables or disables the slot after the 5 second delay following an Attention Button press. - pciehp_sysfs_enable_slot() and pciehp_sysfs_disable_slot() enable or disable the slot on sysfs write. This requires locking and complicates pciehp's state machine. A simplification can be achieved by enabling and disabling the slot exclusively from the IRQ thread. Amend the functions listed above to request slot enable/disablement from the IRQ thread by either synthesizing a Presence Detect Changed event or, in the case of a disable user request (via sysfs or an Attention Button press), submitting a newly introduced force disable request. The latter is needed because the slot shall be forced off despite being occupied. For this force disable request, avoid colliding with Slot Status register bits by using a bit number greater than 16. For synchronous execution of requests (on sysfs write), wait for the request to finish and retrieve the result. There can only ever be one sysfs write in flight due to the locking in kernfs_fop_write(), hence there is no risk of returning the result of a different sysfs request to user space. The POWERON_STATE and POWEROFF_STATE is now no longer entered by the above-listed functions, but solely by the IRQ thread when it begins a power transition. Afterwards, it moves to STATIC_STATE. The same applies to canceling the Attention Button work, it likewise becomes an IRQ thread only operation. An immediate consequence is that the POWERON_STATE and POWEROFF_STATE is never observed by the IRQ thread itself, only by functions called in a different context, such as pciehp_sysfs_enable_slot(). So remove handling of these states from pciehp_handle_button_press() and pciehp_handle_link_change() which are exclusively called from the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-20 06:27:46 +08:00
/* poll for interrupt events or user requests */
while (pciehp_isr(IRQ_NOTCONNECTED, ctrl) == IRQ_WAKE_THREAD ||
atomic_read(&ctrl->pending_events))
pciehp_ist(IRQ_NOTCONNECTED, ctrl);
if (pciehp_poll_time <= 0 || pciehp_poll_time > 60)
pciehp_poll_time = 2; /* clamp to sane value */
schedule_timeout_idle(pciehp_poll_time * HZ);
}
return 0;
}
static void pcie_enable_notification(struct controller *ctrl)
{
u16 cmd, mask;
/*
* TBD: Power fault detected software notification support.
*
* Power fault detected software notification is not enabled
* now, because it caused power fault detected interrupt storm
* on some machines. On those machines, power fault detected
* bit in the slot status register was set again immediately
* when it is cleared in the interrupt service routine, and
* next power fault detected interrupt was notified again.
*/
/*
* Always enable link events: thus link-up and link-down shall
* always be treated as hotplug and unplug respectively. Enable
* presence detect only if Attention Button is not present.
*/
cmd = PCI_EXP_SLTCTL_DLLSCE;
if (ATTN_BUTTN(ctrl))
cmd |= PCI_EXP_SLTCTL_ABPE;
else
cmd |= PCI_EXP_SLTCTL_PDCE;
if (!pciehp_poll_mode)
cmd |= PCI_EXP_SLTCTL_HPIE | PCI_EXP_SLTCTL_CCIE;
mask = (PCI_EXP_SLTCTL_PDCE | PCI_EXP_SLTCTL_ABPE |
PCI_EXP_SLTCTL_PFDE |
PCI_EXP_SLTCTL_HPIE | PCI_EXP_SLTCTL_CCIE |
PCI_EXP_SLTCTL_DLLSCE);
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
pcie_write_cmd_nowait(ctrl, cmd, mask);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, cmd);
}
void pcie_reenable_notification(struct controller *ctrl)
{
/*
* Clear both Presence and Data Link Layer Changed to make sure
* those events still fire after we have re-enabled them.
*/
pcie_capability_write_word(ctrl->pcie->port, PCI_EXP_SLTSTA,
PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC);
pcie_enable_notification(ctrl);
}
static void pcie_disable_notification(struct controller *ctrl)
{
u16 mask;
mask = (PCI_EXP_SLTCTL_PDCE | PCI_EXP_SLTCTL_ABPE |
PCI_EXP_SLTCTL_MRLSCE | PCI_EXP_SLTCTL_PFDE |
PCI_EXP_SLTCTL_HPIE | PCI_EXP_SLTCTL_CCIE |
PCI_EXP_SLTCTL_DLLSCE);
pcie_write_cmd(ctrl, 0, mask);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, 0);
}
/*
* pciehp has a 1:1 bus:slot relationship so we ultimately want a secondary
* bus reset of the bridge, but at the same time we want to ensure that it is
* not seen as a hot-unplug, followed by the hot-plug of the device. Thus,
* disable link state notification and presence detection change notification
* momentarily, if we see that they could interfere. Also, clear any spurious
* events after.
*/
int pciehp_reset_slot(struct slot *slot, int probe)
{
struct controller *ctrl = slot->ctrl;
struct pci_dev *pdev = ctrl_dev(ctrl);
u16 stat_mask = 0, ctrl_mask = 0;
if (probe)
return 0;
if (!ATTN_BUTTN(ctrl)) {
ctrl_mask |= PCI_EXP_SLTCTL_PDCE;
stat_mask |= PCI_EXP_SLTSTA_PDC;
}
ctrl_mask |= PCI_EXP_SLTCTL_DLLSCE;
stat_mask |= PCI_EXP_SLTSTA_DLLSC;
pcie_write_cmd(ctrl, 0, ctrl_mask);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, 0);
if (pciehp_poll_mode)
kthread_park(ctrl->poll_thread);
pci_reset_bridge_secondary_bus(ctrl->pcie->port);
pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, stat_mask);
PCI: pciehp: Wait for hotplug command completion where necessary The commit referenced below deferred waiting for command completion until the start of the next command, allowing hardware to do the latching asynchronously. Unfortunately, being ready to accept a new command is the only indication we have that the previous command is completed. In cases where we need that state change to be enabled, we must still wait for completion. For instance, pciehp_reset_slot() attempts to disable anything that might generate a surprise hotplug on slots that support presence detection. If we don't wait for those settings to latch before the secondary bus reset, we negate any value in attempting to prevent the spurious hotplug. Create a base function with optional wait and helper functions so that pcie_write_cmd() turns back into the "safe" interface which waits before and after issuing a command and add pcie_write_cmd_nowait(), which eliminates the trailing wait for asynchronous completion. The following functions are returned to their previous behavior: pciehp_power_on_slot pciehp_power_off_slot pcie_disable_notification pciehp_reset_slot The rationale is that pciehp_power_on_slot() enables the link and therefore relies on completion of power-on. pciehp_power_off_slot() and pcie_disable_notification() need a wait because data structures may be freed after these calls and continued signaling from the device would be unexpected. And, of course, pciehp_reset_slot() needs to wait for the scenario outlined above. Fixes: 3461a068661c ("PCI: pciehp: Wait for hotplug command completion lazily") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v3.17+
2015-06-09 07:10:50 +08:00
pcie_write_cmd_nowait(ctrl, ctrl_mask, ctrl_mask);
ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__,
pci_pcie_cap(ctrl->pcie->port) + PCI_EXP_SLTCTL, ctrl_mask);
if (pciehp_poll_mode)
kthread_unpark(ctrl->poll_thread);
return 0;
}
int pcie_init_notification(struct controller *ctrl)
{
if (pciehp_request_irq(ctrl))
return -1;
pcie_enable_notification(ctrl);
ctrl->notification_enabled = 1;
return 0;
}
void pcie_shutdown_notification(struct controller *ctrl)
{
if (ctrl->notification_enabled) {
pcie_disable_notification(ctrl);
pciehp_free_irq(ctrl);
ctrl->notification_enabled = 0;
}
}
static int pcie_init_slot(struct controller *ctrl)
{
struct pci_bus *subordinate = ctrl_dev(ctrl)->subordinate;
struct slot *slot;
slot = kzalloc(sizeof(*slot), GFP_KERNEL);
if (!slot)
return -ENOMEM;
down_read(&pci_bus_sem);
slot->state = list_empty(&subordinate->devices) ? OFF_STATE : ON_STATE;
up_read(&pci_bus_sem);
slot->ctrl = ctrl;
mutex_init(&slot->lock);
INIT_DELAYED_WORK(&slot->work, pciehp_queue_pushbutton_work);
ctrl->slot = slot;
return 0;
}
static void pcie_cleanup_slot(struct controller *ctrl)
{
struct slot *slot = ctrl->slot;
cancel_delayed_work_sync(&slot->work);
kfree(slot);
}
static inline void dbg_ctrl(struct controller *ctrl)
{
struct pci_dev *pdev = ctrl->pcie->port;
u16 reg16;
if (!pciehp_debug)
return;
ctrl_info(ctrl, "Slot Capabilities : 0x%08x\n", ctrl->slot_cap);
pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &reg16);
ctrl_info(ctrl, "Slot Status : 0x%04x\n", reg16);
pcie_capability_read_word(pdev, PCI_EXP_SLTCTL, &reg16);
ctrl_info(ctrl, "Slot Control : 0x%04x\n", reg16);
}
#define FLAG(x, y) (((x) & (y)) ? '+' : '-')
struct controller *pcie_init(struct pcie_device *dev)
{
struct controller *ctrl;
u32 slot_cap, link_cap;
struct pci_dev *pdev = dev->port;
ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL);
if (!ctrl)
goto abort;
ctrl->pcie = dev;
pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &slot_cap);
if (pdev->hotplug_user_indicators)
slot_cap &= ~(PCI_EXP_SLTCAP_AIP | PCI_EXP_SLTCAP_PIP);
PCI: pciehp: Assume NoCompl+ for Thunderbolt ports Certain Thunderbolt 1 controllers claim to support Command Completed events (value of 0b in the No Command Completed Support field of the Slot Capabilities register) but in reality they neither set the Command Completed bit in the Slot Status register nor signal a Command Completed interrupt: 8086:1513 CV82524 [Light Ridge 4C 2010] 8086:151a DSL2310 [Eagle Ridge 2C 2011] 8086:151b CVL2510 [Light Peak 2C 2010] 8086:1547 DSL3510 [Cactus Ridge 4C 2012] 8086:1548 DSL3310 [Cactus Ridge 2C 2012] 8086:1549 DSL2210 [Port Ridge 1C 2011] All known newer chips (Redwood Ridge and onwards) set No Command Completed Support, indicating that they do not support Command Completed events. The user-visible impact is that after unplugging such a device, 2 seconds elapse until pciehp is unbound. That's because on ->remove, pcie_write_cmd() is called via pcie_disable_notification() and every call to pcie_write_cmd() takes 2 seconds (1 second for each invocation of pcie_wait_cmd()): [ 337.942727] pciehp 0000:0a:00.0:pcie204: Timeout on hotplug command 0x1038 (issued 21176 msec ago) [ 340.014735] pciehp 0000:0a:00.0:pcie204: Timeout on hotplug command 0x0000 (issued 2072 msec ago) That by itself has always been unpleasant, but the situation has become worse with commit cc27b735ad3a ("PCI/portdrv: Turn off PCIe services during shutdown"): Now pciehp is unbound on ->shutdown. Because Thunderbolt controllers typically have 4 hotplug ports, every reboot and shutdown is now delayed by 8 seconds, plus another 2 seconds for every attached Thunderbolt 1 device. Thunderbolt hotplug slots are not physical slots that one inserts cards into, but rather logical hotplug slots implemented in silicon. Devices appear beyond those logical slots once a PCI tunnel is established on top of the Thunderbolt Converged I/O switch. One would expect commands written to the Slot Control register to be executed immediately by the silicon, so for simplicity we always assume NoCompl+ for Thunderbolt ports. Fixes: cc27b735ad3a ("PCI/portdrv: Turn off PCIe services during shutdown") Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com> Cc: stable@vger.kernel.org # v4.12+ Cc: Sinan Kaya <okaya@codeaurora.org> Cc: Yehezkel Bernat <yehezkel.bernat@intel.com> Cc: Michael Jamet <michael.jamet@intel.com> Cc: Andreas Noever <andreas.noever@gmail.com>
2018-01-17 23:48:39 +08:00
/*
* We assume no Thunderbolt controllers support Command Complete events,
* but some controllers falsely claim they do.
*/
if (pdev->is_thunderbolt)
slot_cap |= PCI_EXP_SLTCAP_NCCS;
ctrl->slot_cap = slot_cap;
mutex_init(&ctrl->ctrl_lock);
PCI: pciehp: Enable/disable exclusively from IRQ thread Besides the IRQ thread, there are several other places in the driver which enable or disable the slot: - pciehp_probe() enables the slot if it's occupied and the pciehp_force module parameter is used. - pciehp_resume() enables or disables the slot after system sleep. - pciehp_queue_pushbutton_work() enables or disables the slot after the 5 second delay following an Attention Button press. - pciehp_sysfs_enable_slot() and pciehp_sysfs_disable_slot() enable or disable the slot on sysfs write. This requires locking and complicates pciehp's state machine. A simplification can be achieved by enabling and disabling the slot exclusively from the IRQ thread. Amend the functions listed above to request slot enable/disablement from the IRQ thread by either synthesizing a Presence Detect Changed event or, in the case of a disable user request (via sysfs or an Attention Button press), submitting a newly introduced force disable request. The latter is needed because the slot shall be forced off despite being occupied. For this force disable request, avoid colliding with Slot Status register bits by using a bit number greater than 16. For synchronous execution of requests (on sysfs write), wait for the request to finish and retrieve the result. There can only ever be one sysfs write in flight due to the locking in kernfs_fop_write(), hence there is no risk of returning the result of a different sysfs request to user space. The POWERON_STATE and POWEROFF_STATE is now no longer entered by the above-listed functions, but solely by the IRQ thread when it begins a power transition. Afterwards, it moves to STATIC_STATE. The same applies to canceling the Attention Button work, it likewise becomes an IRQ thread only operation. An immediate consequence is that the POWERON_STATE and POWEROFF_STATE is never observed by the IRQ thread itself, only by functions called in a different context, such as pciehp_sysfs_enable_slot(). So remove handling of these states from pciehp_handle_button_press() and pciehp_handle_link_change() which are exclusively called from the IRQ thread. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2018-07-20 06:27:46 +08:00
init_waitqueue_head(&ctrl->requester);
init_waitqueue_head(&ctrl->queue);
dbg_ctrl(ctrl);
2014-06-15 00:56:31 +08:00
/* Check if Data Link Layer Link Active Reporting is implemented */
pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, &link_cap);
if (link_cap & PCI_EXP_LNKCAP_DLLLARC)
ctrl->link_active_reporting = 1;
/*
* Clear all remaining event bits in Slot Status register except
* Presence Detect Changed. We want to make sure possible
* hotplug event is triggered when the interrupt is unmasked so
* that we don't lose that event.
*/
pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_CC |
PCI_EXP_SLTSTA_DLLSC);
PCI: pciehp: Add quirk for Command Completed errata Several PCIe hotplug controllers have errata that mean they do not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Command Completed is never set for writes that only change software notification "Enable" bits. This results in timeouts like this: pciehp 0000:00:1c.0:pcie004: Timeout on hotplug command 0x1038 (issued 65284 msec ago) When this erratum is present, avoid these timeouts by marking commands "completed" immediately unless they change the "Control" bits. Here's the text of the Intel erratum CF118. We assume this applies to all Intel parts: CF118 PCIe Slot Status Register Command Completed bit not always updated on any configuration write to the Slot Control Register Problem: For PCIe root ports (devices 0 - 10) supporting hot-plug, the Slot Status Register (offset AAh) Command Completed (bit[4]) status is updated under the following condition: IOH will set Command Completed bit after delivering the new commands written in the Slot Controller register (offset A8h) to VPP. The IOH detects new commands written in Slot Control register by checking the change of value for Power Controller Control (bit[10]), Power Indicator Control (bits[9:8]), Attention Indicator Control (bits[7:6]), or Electromechanical Interlock Control (bit[11]) fields. Any other configuration writes to the Slot Control register without changing the values of these fields will not cause Command Completed bit to be set. The PCIe Base Specification Revision 2.0 or later describes the “Slot Control Register” in section 7.8.10, as follows (Reference section 7.8.10, Slot Control Register, Offset 18h). In hot-plug capable Downstream Ports, a write to the Slot Control register must cause a hot-plug command to be generated (see Section 6.7.3.2 for details on hot-plug commands). A write to the Slot Control register in a Downstream Port that is not hotplug capable must not cause a hot-plug command to be executed. The PCIe Spec intended that every write to the Slot Control Register is a command and expected a command complete status to abstract the VPP implementation specific nuances from the OS software. IOH PCIe Slot Control Register implementation is not fully conforming to the PCIe Specification in this respect. Implication: Software checking on the Command Completed status after writing to the Slot Control register may time out. Workaround: Software can read the Slot Control register and compare the existing and new values to determine if it should check the Command Completed status after writing to the Slot Control register. Per Sinan, the Qualcomm QDF2400 controller also does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html Link: https://lkml.kernel.org/r/8770820b-85a0-172b-7230-3a44524e6c9f@molgen.mpg.de Reported-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Tested-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Signed-off-by: Sinan Kaya <okaya@codeaurora.org> # Qcom quirk Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-05-04 07:39:38 +08:00
ctrl_info(ctrl, "Slot #%d AttnBtn%c PwrCtrl%c MRL%c AttnInd%c PwrInd%c HotPlug%c Surprise%c Interlock%c NoCompl%c LLActRep%c%s\n",
(slot_cap & PCI_EXP_SLTCAP_PSN) >> 19,
FLAG(slot_cap, PCI_EXP_SLTCAP_ABP),
FLAG(slot_cap, PCI_EXP_SLTCAP_PCP),
FLAG(slot_cap, PCI_EXP_SLTCAP_MRLSP),
FLAG(slot_cap, PCI_EXP_SLTCAP_AIP),
FLAG(slot_cap, PCI_EXP_SLTCAP_PIP),
FLAG(slot_cap, PCI_EXP_SLTCAP_HPC),
FLAG(slot_cap, PCI_EXP_SLTCAP_HPS),
FLAG(slot_cap, PCI_EXP_SLTCAP_EIP),
FLAG(slot_cap, PCI_EXP_SLTCAP_NCCS),
PCI: pciehp: Add quirk for Command Completed errata Several PCIe hotplug controllers have errata that mean they do not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Command Completed is never set for writes that only change software notification "Enable" bits. This results in timeouts like this: pciehp 0000:00:1c.0:pcie004: Timeout on hotplug command 0x1038 (issued 65284 msec ago) When this erratum is present, avoid these timeouts by marking commands "completed" immediately unless they change the "Control" bits. Here's the text of the Intel erratum CF118. We assume this applies to all Intel parts: CF118 PCIe Slot Status Register Command Completed bit not always updated on any configuration write to the Slot Control Register Problem: For PCIe root ports (devices 0 - 10) supporting hot-plug, the Slot Status Register (offset AAh) Command Completed (bit[4]) status is updated under the following condition: IOH will set Command Completed bit after delivering the new commands written in the Slot Controller register (offset A8h) to VPP. The IOH detects new commands written in Slot Control register by checking the change of value for Power Controller Control (bit[10]), Power Indicator Control (bits[9:8]), Attention Indicator Control (bits[7:6]), or Electromechanical Interlock Control (bit[11]) fields. Any other configuration writes to the Slot Control register without changing the values of these fields will not cause Command Completed bit to be set. The PCIe Base Specification Revision 2.0 or later describes the “Slot Control Register” in section 7.8.10, as follows (Reference section 7.8.10, Slot Control Register, Offset 18h). In hot-plug capable Downstream Ports, a write to the Slot Control register must cause a hot-plug command to be generated (see Section 6.7.3.2 for details on hot-plug commands). A write to the Slot Control register in a Downstream Port that is not hotplug capable must not cause a hot-plug command to be executed. The PCIe Spec intended that every write to the Slot Control Register is a command and expected a command complete status to abstract the VPP implementation specific nuances from the OS software. IOH PCIe Slot Control Register implementation is not fully conforming to the PCIe Specification in this respect. Implication: Software checking on the Command Completed status after writing to the Slot Control register may time out. Workaround: Software can read the Slot Control register and compare the existing and new values to determine if it should check the Command Completed status after writing to the Slot Control register. Per Sinan, the Qualcomm QDF2400 controller also does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html Link: https://lkml.kernel.org/r/8770820b-85a0-172b-7230-3a44524e6c9f@molgen.mpg.de Reported-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Tested-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Signed-off-by: Sinan Kaya <okaya@codeaurora.org> # Qcom quirk Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-05-04 07:39:38 +08:00
FLAG(link_cap, PCI_EXP_LNKCAP_DLLLARC),
pdev->broken_cmd_compl ? " (with Cmd Compl erratum)" : "");
if (pcie_init_slot(ctrl))
goto abort_ctrl;
return ctrl;
abort_ctrl:
kfree(ctrl);
abort:
return NULL;
}
void pciehp_release_ctrl(struct controller *ctrl)
{
pcie_cleanup_slot(ctrl);
kfree(ctrl);
}
PCI: pciehp: Add quirk for Command Completed errata Several PCIe hotplug controllers have errata that mean they do not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Command Completed is never set for writes that only change software notification "Enable" bits. This results in timeouts like this: pciehp 0000:00:1c.0:pcie004: Timeout on hotplug command 0x1038 (issued 65284 msec ago) When this erratum is present, avoid these timeouts by marking commands "completed" immediately unless they change the "Control" bits. Here's the text of the Intel erratum CF118. We assume this applies to all Intel parts: CF118 PCIe Slot Status Register Command Completed bit not always updated on any configuration write to the Slot Control Register Problem: For PCIe root ports (devices 0 - 10) supporting hot-plug, the Slot Status Register (offset AAh) Command Completed (bit[4]) status is updated under the following condition: IOH will set Command Completed bit after delivering the new commands written in the Slot Controller register (offset A8h) to VPP. The IOH detects new commands written in Slot Control register by checking the change of value for Power Controller Control (bit[10]), Power Indicator Control (bits[9:8]), Attention Indicator Control (bits[7:6]), or Electromechanical Interlock Control (bit[11]) fields. Any other configuration writes to the Slot Control register without changing the values of these fields will not cause Command Completed bit to be set. The PCIe Base Specification Revision 2.0 or later describes the “Slot Control Register” in section 7.8.10, as follows (Reference section 7.8.10, Slot Control Register, Offset 18h). In hot-plug capable Downstream Ports, a write to the Slot Control register must cause a hot-plug command to be generated (see Section 6.7.3.2 for details on hot-plug commands). A write to the Slot Control register in a Downstream Port that is not hotplug capable must not cause a hot-plug command to be executed. The PCIe Spec intended that every write to the Slot Control Register is a command and expected a command complete status to abstract the VPP implementation specific nuances from the OS software. IOH PCIe Slot Control Register implementation is not fully conforming to the PCIe Specification in this respect. Implication: Software checking on the Command Completed status after writing to the Slot Control register may time out. Workaround: Software can read the Slot Control register and compare the existing and new values to determine if it should check the Command Completed status after writing to the Slot Control register. Per Sinan, the Qualcomm QDF2400 controller also does not set the Command Completed bit unless writes to the Slot Command register change "Control" bits. Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html Link: https://lkml.kernel.org/r/8770820b-85a0-172b-7230-3a44524e6c9f@molgen.mpg.de Reported-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Tested-by: Paul Menzel <pmenzel+linux-pci@molgen.mpg.de> # Lenovo X60 Signed-off-by: Sinan Kaya <okaya@codeaurora.org> # Qcom quirk Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2018-05-04 07:39:38 +08:00
static void quirk_cmd_compl(struct pci_dev *pdev)
{
u32 slot_cap;
if (pci_is_pcie(pdev)) {
pcie_capability_read_dword(pdev, PCI_EXP_SLTCAP, &slot_cap);
if (slot_cap & PCI_EXP_SLTCAP_HPC &&
!(slot_cap & PCI_EXP_SLTCAP_NCCS))
pdev->broken_cmd_compl = 1;
}
}
DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_INTEL, PCI_ANY_ID,
PCI_CLASS_BRIDGE_PCI, 8, quirk_cmd_compl);
DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_QCOM, 0x0400,
PCI_CLASS_BRIDGE_PCI, 8, quirk_cmd_compl);
DECLARE_PCI_FIXUP_CLASS_EARLY(PCI_VENDOR_ID_QCOM, 0x0401,
PCI_CLASS_BRIDGE_PCI, 8, quirk_cmd_compl);