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Merge branch 'pci/aspm' into next 

* pci/aspm:
  PCI/ASPM: Add comment about L1 substate latency
  PCI/ASPM: Configure L1 substate settings
  PCI/ASPM: Calculate and save the L1.2 timing parameters
  PCI/ASPM: Read and set up L1 substate capabilities
  PCI/ASPM: Add support for L1 substates
  PCI/ASPM: Add L1 substate capability structure register definitions
This commit is contained in:
Bjorn Helgaas 2017-02-15 11:56:07 -06:00
parent ca0ef7fecc a142f4d3e5
commit 8f417ca9eb
3 changed files with 302 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/pci/pcie/Kconfig
View File

@ -71,6 +71,14 @@ config PCIEASPM_POWERSAVE
Enable PCI Express ASPM L0s and L1 where possible, even if the
BIOS did not.
config PCIEASPM_POWER_SUPERSAVE
bool "Power Supersave"
depends on PCIEASPM
help
Same as PCIEASPM_POWERSAVE, except it also enables L1 substates where
possible. This would result in higher power savings while staying in L1
where the components support it.
config PCIEASPM_PERFORMANCE
bool "Performance"
depends on PCIEASPM

291
drivers/pci/pcie/aspm.c
View File

@ -30,8 +30,29 @@
#define ASPM_STATE_L0S_UP (1) /* Upstream direction L0s state */
#define ASPM_STATE_L0S_DW (2) /* Downstream direction L0s state */
#define ASPM_STATE_L1 (4) /* L1 state */
#define ASPM_STATE_L1_1 (8) /* ASPM L1.1 state */
#define ASPM_STATE_L1_2 (0x10) /* ASPM L1.2 state */
#define ASPM_STATE_L1_1_PCIPM (0x20) /* PCI PM L1.1 state */
#define ASPM_STATE_L1_2_PCIPM (0x40) /* PCI PM L1.2 state */
#define ASPM_STATE_L1_SS_PCIPM (ASPM_STATE_L1_1_PCIPM | ASPM_STATE_L1_2_PCIPM)
#define ASPM_STATE_L1_2_MASK (ASPM_STATE_L1_2 | ASPM_STATE_L1_2_PCIPM)
#define ASPM_STATE_L1SS (ASPM_STATE_L1_1 | ASPM_STATE_L1_1_PCIPM |\
ASPM_STATE_L1_2_MASK)
#define ASPM_STATE_L0S (ASPM_STATE_L0S_UP | ASPM_STATE_L0S_DW)
#define ASPM_STATE_ALL (ASPM_STATE_L0S | ASPM_STATE_L1)
#define ASPM_STATE_ALL (ASPM_STATE_L0S | ASPM_STATE_L1 | \
ASPM_STATE_L1SS)
/*
* When L1 substates are enabled, the LTR L1.2 threshold is a timing parameter
* that decides whether L1.1 or L1.2 is entered (Refer PCIe spec for details).
* Not sure is there is a way to "calculate" this on the fly, but maybe we
* could turn it into a parameter in future. This value has been taken from
* the following files from Intel's coreboot (which is the only code I found
* to have used this):
* https://www.coreboot.org/pipermail/coreboot-gerrit/2015-March/021134.html
* https://review.coreboot.org/#/c/8832/
*/
#define LTR_L1_2_THRESHOLD_BITS ((1 << 21) | (1 << 23) | (1 << 30))
struct aspm_latency {
u32 l0s; /* L0s latency (nsec) */
@ -40,6 +61,7 @@ struct aspm_latency {
struct pcie_link_state {
struct pci_dev *pdev; /* Upstream component of the Link */
struct pci_dev *downstream; /* Downstream component, function 0 */
struct pcie_link_state *root; /* pointer to the root port link */
struct pcie_link_state *parent; /* pointer to the parent Link state */
struct list_head sibling; /* node in link_list */
@ -47,11 +69,11 @@ struct pcie_link_state {
struct list_head link; /* node in parent's children list */
/* ASPM state */
u32 aspm_support:3; /* Supported ASPM state */
u32 aspm_enabled:3; /* Enabled ASPM state */
u32 aspm_capable:3; /* Capable ASPM state with latency */
u32 aspm_default:3; /* Default ASPM state by BIOS */
u32 aspm_disable:3; /* Disabled ASPM state */
u32 aspm_support:7; /* Supported ASPM state */
u32 aspm_enabled:7; /* Enabled ASPM state */
u32 aspm_capable:7; /* Capable ASPM state with latency */
u32 aspm_default:7; /* Default ASPM state by BIOS */
u32 aspm_disable:7; /* Disabled ASPM state */
/* Clock PM state */
u32 clkpm_capable:1; /* Clock PM capable? */
@ -66,6 +88,14 @@ struct pcie_link_state {
* has one slot under it, so at most there are 8 functions.
*/
struct aspm_latency acceptable[8];
/* L1 PM Substate info */
struct {
u32 up_cap_ptr; /* L1SS cap ptr in upstream dev */
u32 dw_cap_ptr; /* L1SS cap ptr in downstream dev */
u32 ctl1; /* value to be programmed in ctl1 */
u32 ctl2; /* value to be programmed in ctl2 */
} l1ss;
};
static int aspm_disabled, aspm_force;
@ -76,11 +106,14 @@ static LIST_HEAD(link_list);
#define POLICY_DEFAULT 0 /* BIOS default setting */
#define POLICY_PERFORMANCE 1 /* high performance */
#define POLICY_POWERSAVE 2 /* high power saving */
#define POLICY_POWER_SUPERSAVE 3 /* possibly even more power saving */
#ifdef CONFIG_PCIEASPM_PERFORMANCE
static int aspm_policy = POLICY_PERFORMANCE;
#elif defined CONFIG_PCIEASPM_POWERSAVE
static int aspm_policy = POLICY_POWERSAVE;
#elif defined CONFIG_PCIEASPM_POWER_SUPERSAVE
static int aspm_policy = POLICY_POWER_SUPERSAVE;
#else
static int aspm_policy;
#endif
@ -88,7 +121,8 @@ static int aspm_policy;
static const char *policy_str[] = {
[POLICY_DEFAULT] = "default",
[POLICY_PERFORMANCE] = "performance",
[POLICY_POWERSAVE] = "powersave"
[POLICY_POWERSAVE] = "powersave",
[POLICY_POWER_SUPERSAVE] = "powersupersave"
};
#define LINK_RETRAIN_TIMEOUT HZ
@ -101,6 +135,9 @@ static int policy_to_aspm_state(struct pcie_link_state *link)
return 0;
case POLICY_POWERSAVE:
/* Enable ASPM L0s/L1 */
return (ASPM_STATE_L0S | ASPM_STATE_L1);
case POLICY_POWER_SUPERSAVE:
/* Enable Everything */
return ASPM_STATE_ALL;
case POLICY_DEFAULT:
return link->aspm_default;
@ -115,7 +152,8 @@ static int policy_to_clkpm_state(struct pcie_link_state *link)
/* Disable ASPM and Clock PM */
return 0;
case POLICY_POWERSAVE:
/* Disable Clock PM */
case POLICY_POWER_SUPERSAVE:
/* Enable Clock PM */
return 1;
case POLICY_DEFAULT:
return link->clkpm_default;
@ -278,11 +316,33 @@ static u32 calc_l1_acceptable(u32 encoding)
return (1000 << encoding);
}
/* Convert L1SS T_pwr encoding to usec */
static u32 calc_l1ss_pwron(struct pci_dev *pdev, u32 scale, u32 val)
{
switch (scale) {
case 0:
return val * 2;
case 1:
return val * 10;
case 2:
return val * 100;
}
dev_err(&pdev->dev, "%s: Invalid T_PwrOn scale: %u\n",
__func__, scale);
return 0;
}
struct aspm_register_info {
u32 support:2;
u32 enabled:2;
u32 latency_encoding_l0s;
u32 latency_encoding_l1;
/* L1 substates */
u32 l1ss_cap_ptr;
u32 l1ss_cap;
u32 l1ss_ctl1;
u32 l1ss_ctl2;
};
static void pcie_get_aspm_reg(struct pci_dev *pdev,
@ -297,6 +357,22 @@ static void pcie_get_aspm_reg(struct pci_dev *pdev,
info->latency_encoding_l1 = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &reg16);
info->enabled = reg16 & PCI_EXP_LNKCTL_ASPMC;
/* Read L1 PM substate capabilities */
info->l1ss_cap = info->l1ss_ctl1 = info->l1ss_ctl2 = 0;
info->l1ss_cap_ptr = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_L1SS);
if (!info->l1ss_cap_ptr)
return;
pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CAP,
&info->l1ss_cap);
if (!(info->l1ss_cap & PCI_L1SS_CAP_L1_PM_SS)) {
info->l1ss_cap = 0;
return;
}
pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CTL1,
&info->l1ss_ctl1);
pci_read_config_dword(pdev, info->l1ss_cap_ptr + PCI_L1SS_CTL2,
&info->l1ss_ctl2);
}
static void pcie_aspm_check_latency(struct pci_dev *endpoint)
@ -327,6 +403,14 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint)
* Check L1 latency.
* Every switch on the path to root complex need 1
* more microsecond for L1. Spec doesn't mention L0s.
*
* The exit latencies for L1 substates are not advertised
* by a device. Since the spec also doesn't mention a way
* to determine max latencies introduced by enabling L1
* substates on the components, it is not clear how to do
* a L1 substate exit latency check. We assume that the
* L1 exit latencies advertised by a device include L1
* substate latencies (and hence do not do any check).
*/
latency = max_t(u32, link->latency_up.l1, link->latency_dw.l1);
if ((link->aspm_capable & ASPM_STATE_L1) &&
@ -338,6 +422,60 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint)
}
}
/*
* The L1 PM substate capability is only implemented in function 0 in a
* multi function device.
*/
static struct pci_dev *pci_function_0(struct pci_bus *linkbus)
{
struct pci_dev *child;
list_for_each_entry(child, &linkbus->devices, bus_list)
if (PCI_FUNC(child->devfn) == 0)
return child;
return NULL;
}
/* Calculate L1.2 PM substate timing parameters */
static void aspm_calc_l1ss_info(struct pcie_link_state *link,
struct aspm_register_info *upreg,
struct aspm_register_info *dwreg)
{
u32 val1, val2, scale1, scale2;
link->l1ss.up_cap_ptr = upreg->l1ss_cap_ptr;
link->l1ss.dw_cap_ptr = dwreg->l1ss_cap_ptr;
link->l1ss.ctl1 = link->l1ss.ctl2 = 0;
if (!(link->aspm_support & ASPM_STATE_L1_2_MASK))
return;
/* Choose the greater of the two T_cmn_mode_rstr_time */
val1 = (upreg->l1ss_cap >> 8) & 0xFF;
val2 = (upreg->l1ss_cap >> 8) & 0xFF;
if (val1 > val2)
link->l1ss.ctl1 |= val1 << 8;
else
link->l1ss.ctl1 |= val2 << 8;
/*
* We currently use LTR L1.2 threshold to be fixed constant picked from
* Intel's coreboot.
*/
link->l1ss.ctl1 |= LTR_L1_2_THRESHOLD_BITS;
/* Choose the greater of the two T_pwr_on */
val1 = (upreg->l1ss_cap >> 19) & 0x1F;
scale1 = (upreg->l1ss_cap >> 16) & 0x03;
val2 = (dwreg->l1ss_cap >> 19) & 0x1F;
scale2 = (dwreg->l1ss_cap >> 16) & 0x03;
if (calc_l1ss_pwron(link->pdev, scale1, val1) >
calc_l1ss_pwron(link->downstream, scale2, val2))
link->l1ss.ctl2 |= scale1 | (val1 << 3);
else
link->l1ss.ctl2 |= scale2 | (val2 << 3);
}
static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
{
struct pci_dev *child, *parent = link->pdev;
@ -353,8 +491,9 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
/* Get upstream/downstream components' register state */
pcie_get_aspm_reg(parent, &upreg);
child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
child = pci_function_0(linkbus);
pcie_get_aspm_reg(child, &dwreg);
link->downstream = child;
/*
* If ASPM not supported, don't mess with the clocks and link,
@ -397,6 +536,28 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1);
link->latency_dw.l1 = calc_l1_latency(dwreg.latency_encoding_l1);
/* Setup L1 substate */
if (upreg.l1ss_cap & dwreg.l1ss_cap & PCI_L1SS_CAP_ASPM_L1_1)
link->aspm_support |= ASPM_STATE_L1_1;
if (upreg.l1ss_cap & dwreg.l1ss_cap & PCI_L1SS_CAP_ASPM_L1_2)
link->aspm_support |= ASPM_STATE_L1_2;
if (upreg.l1ss_cap & dwreg.l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_1)
link->aspm_support |= ASPM_STATE_L1_1_PCIPM;
if (upreg.l1ss_cap & dwreg.l1ss_cap & PCI_L1SS_CAP_PCIPM_L1_2)
link->aspm_support |= ASPM_STATE_L1_2_PCIPM;
if (upreg.l1ss_ctl1 & dwreg.l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_1)
link->aspm_enabled |= ASPM_STATE_L1_1;
if (upreg.l1ss_ctl1 & dwreg.l1ss_ctl1 & PCI_L1SS_CTL1_ASPM_L1_2)
link->aspm_enabled |= ASPM_STATE_L1_2;
if (upreg.l1ss_ctl1 & dwreg.l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_1)
link->aspm_enabled |= ASPM_STATE_L1_1_PCIPM;
if (upreg.l1ss_ctl1 & dwreg.l1ss_ctl1 & PCI_L1SS_CTL1_PCIPM_L1_2)
link->aspm_enabled |= ASPM_STATE_L1_2_PCIPM;
if (link->aspm_support & ASPM_STATE_L1SS)
aspm_calc_l1ss_info(link, &upreg, &dwreg);
/* Save default state */
link->aspm_default = link->aspm_enabled;
@ -435,6 +596,92 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
}
}
static void pci_clear_and_set_dword(struct pci_dev *pdev, int pos,
u32 clear, u32 set)
{
u32 val;
pci_read_config_dword(pdev, pos, &val);
val &= ~clear;
val |= set;
pci_write_config_dword(pdev, pos, val);
}
/* Configure the ASPM L1 substates */
static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state)
{
u32 val, enable_req;
struct pci_dev *child = link->downstream, *parent = link->pdev;
u32 up_cap_ptr = link->l1ss.up_cap_ptr;
u32 dw_cap_ptr = link->l1ss.dw_cap_ptr;
enable_req = (link->aspm_enabled ^ state) & state;
/*
* Here are the rules specified in the PCIe spec for enabling L1SS:
* - When enabling L1.x, enable bit at parent first, then at child
* - When disabling L1.x, disable bit at child first, then at parent
* - When enabling ASPM L1.x, need to disable L1
* (at child followed by parent).
* - The ASPM/PCIPM L1.2 must be disabled while programming timing
* parameters
*
* To keep it simple, disable all L1SS bits first, and later enable
* what is needed.
*/
/* Disable all L1 substates */
pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
PCI_L1SS_CTL1_L1SS_MASK, 0);
pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
PCI_L1SS_CTL1_L1SS_MASK, 0);
/*
* If needed, disable L1, and it gets enabled later
* in pcie_config_aspm_link().
*/
if (enable_req & (ASPM_STATE_L1_1 | ASPM_STATE_L1_2)) {
pcie_capability_clear_and_set_word(child, PCI_EXP_LNKCTL,
PCI_EXP_LNKCTL_ASPM_L1, 0);
pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
PCI_EXP_LNKCTL_ASPM_L1, 0);
}
if (enable_req & ASPM_STATE_L1_2_MASK) {
/* Program T_pwr_on in both ports */
pci_write_config_dword(parent, up_cap_ptr + PCI_L1SS_CTL2,
link->l1ss.ctl2);
pci_write_config_dword(child, dw_cap_ptr + PCI_L1SS_CTL2,
link->l1ss.ctl2);
/* Program T_cmn_mode in parent */
pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
0xFF00, link->l1ss.ctl1);
/* Program LTR L1.2 threshold in both ports */
pci_clear_and_set_dword(parent, dw_cap_ptr + PCI_L1SS_CTL1,
0xE3FF0000, link->l1ss.ctl1);
pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
0xE3FF0000, link->l1ss.ctl1);
}
val = 0;
if (state & ASPM_STATE_L1_1)
val |= PCI_L1SS_CTL1_ASPM_L1_1;
if (state & ASPM_STATE_L1_2)
val |= PCI_L1SS_CTL1_ASPM_L1_2;
if (state & ASPM_STATE_L1_1_PCIPM)
val |= PCI_L1SS_CTL1_PCIPM_L1_1;
if (state & ASPM_STATE_L1_2_PCIPM)
val |= PCI_L1SS_CTL1_PCIPM_L1_2;
/* Enable what we need to enable */
pci_clear_and_set_dword(parent, up_cap_ptr + PCI_L1SS_CTL1,
PCI_L1SS_CAP_L1_PM_SS, val);
pci_clear_and_set_dword(child, dw_cap_ptr + PCI_L1SS_CTL1,
PCI_L1SS_CAP_L1_PM_SS, val);
}
static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
{
pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
@ -444,11 +691,23 @@ static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
{
u32 upstream = 0, dwstream = 0;
struct pci_dev *child, *parent = link->pdev;
struct pci_dev *child = link->downstream, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
/* Nothing to do if the link is already in the requested state */
/* Enable only the states that were not explicitly disabled */
state &= (link->aspm_capable & ~link->aspm_disable);
/* Can't enable any substates if L1 is not enabled */
if (!(state & ASPM_STATE_L1))
state &= ~ASPM_STATE_L1SS;
/* Spec says both ports must be in D0 before enabling PCI PM substates*/
if (parent->current_state != PCI_D0 || child->current_state != PCI_D0) {
state &= ~ASPM_STATE_L1_SS_PCIPM;
state |= (link->aspm_enabled & ASPM_STATE_L1_SS_PCIPM);
}
/* Nothing to do if the link is already in the requested state */
if (link->aspm_enabled == state)
return;
/* Convert ASPM state to upstream/downstream ASPM register state */
@ -460,6 +719,10 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
upstream |= PCI_EXP_LNKCTL_ASPM_L1;
dwstream |= PCI_EXP_LNKCTL_ASPM_L1;
}
if (link->aspm_capable & ASPM_STATE_L1SS)
pcie_config_aspm_l1ss(link, state);
/*
* Spec 2.0 suggests all functions should be configured the
* same setting for ASPM. Enabling ASPM L1 should be done in
@ -612,7 +875,8 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
* the BIOS's expectation, we'll do so once pci_enable_device() is
* called.
*/
if (aspm_policy != POLICY_POWERSAVE) {
if (aspm_policy != POLICY_POWERSAVE &&
aspm_policy != POLICY_POWER_SUPERSAVE) {
pcie_config_aspm_path(link);
pcie_set_clkpm(link, policy_to_clkpm_state(link));
}
@ -712,7 +976,8 @@ void pcie_aspm_powersave_config_link(struct pci_dev *pdev)
if (aspm_disabled || !link)
return;
if (aspm_policy != POLICY_POWERSAVE)
if (aspm_policy != POLICY_POWERSAVE &&
aspm_policy != POLICY_POWER_SUPERSAVE)
return;
down_read(&pci_bus_sem);

16
include/uapi/linux/pci_regs.h
View File

@ -682,6 +682,7 @@
#define PCI_EXT_CAP_ID_PMUX 0x1A /* Protocol Multiplexing */
#define PCI_EXT_CAP_ID_PASID 0x1B /* Process Address Space ID */
#define PCI_EXT_CAP_ID_DPC 0x1D /* Downstream Port Containment */
#define PCI_EXT_CAP_ID_L1SS 0x1E /* L1 PM Substates */
#define PCI_EXT_CAP_ID_PTM 0x1F /* Precision Time Measurement */
#define PCI_EXT_CAP_ID_MAX PCI_EXT_CAP_ID_PTM
@ -985,4 +986,19 @@
#define PCI_PTM_CTRL_ENABLE 0x00000001 /* PTM enable */
#define PCI_PTM_CTRL_ROOT 0x00000002 /* Root select */
/* L1 PM Substates */
#define PCI_L1SS_CAP 4 /* capability register */
#define PCI_L1SS_CAP_PCIPM_L1_2 1 /* PCI PM L1.2 Support */
#define PCI_L1SS_CAP_PCIPM_L1_1 2 /* PCI PM L1.1 Support */
#define PCI_L1SS_CAP_ASPM_L1_2 4 /* ASPM L1.2 Support */
#define PCI_L1SS_CAP_ASPM_L1_1 8 /* ASPM L1.1 Support */
#define PCI_L1SS_CAP_L1_PM_SS 16 /* L1 PM Substates Support */
#define PCI_L1SS_CTL1 8 /* Control Register 1 */
#define PCI_L1SS_CTL1_PCIPM_L1_2 1 /* PCI PM L1.2 Enable */
#define PCI_L1SS_CTL1_PCIPM_L1_1 2 /* PCI PM L1.1 Support */
#define PCI_L1SS_CTL1_ASPM_L1_2 4 /* ASPM L1.2 Support */
#define PCI_L1SS_CTL1_ASPM_L1_1 8 /* ASPM L1.1 Support */
#define PCI_L1SS_CTL1_L1SS_MASK 0x0000000F
#define PCI_L1SS_CTL2 0xC /* Control Register 2 */
#endif /* LINUX_PCI_REGS_H */