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PCI: iproc: Fix PCIe reset logic 

The current reset logic does not always properly reset the device.  For
example, in the case when the perst_b signal is already de-asserted in the
bootloader, the current reset logic fails to trigger a proper assert ->
de-assert reset sequence.

Fix the issue by always triggering the proper reset sequence.

Also explicitly select the desired reset source, i.e., perst_b, and reduce
the wait time after the device comes out of reset from 250 ms to 100 ms,
based on recommendation from the ASIC team.

Tested-by: Vladimir Dreizin <vdreizin@broadcom.com>
Tested-by: Darren Edamura <dedamura@broadcom.com>
Signed-off-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Vladimir Dreizin <vdreizin@broadcom.com>
Reviewed-by: Trac Hoang <trhoang@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
This commit is contained in:
Ray Jui 2015-09-15 17:39:18 -07:00 committed by Bjorn Helgaas
parent bdb8a1844f
commit 199ff14100
1 changed files with 10 additions and 5 deletions
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15
drivers/pci/host/pcie-iproc.c
View File

@ -31,6 +31,8 @@
#include "pcie-iproc.h"
#define CLK_CONTROL_OFFSET 0x000
#define EP_PERST_SOURCE_SELECT_SHIFT 2
#define EP_PERST_SOURCE_SELECT BIT(EP_PERST_SOURCE_SELECT_SHIFT)
#define EP_MODE_SURVIVE_PERST_SHIFT 1
#define EP_MODE_SURVIVE_PERST BIT(EP_MODE_SURVIVE_PERST_SHIFT)
#define RC_PCIE_RST_OUTPUT_SHIFT 0
@ -119,15 +121,18 @@ static void iproc_pcie_reset(struct iproc_pcie *pcie)
u32 val;
/*
* Configure the PCIe controller as root complex and send a downstream
* reset
* Select perst_b signal as reset source. Put the device into reset,
* and then bring it out of reset
*/
val = EP_MODE_SURVIVE_PERST | RC_PCIE_RST_OUTPUT;
val = readl(pcie->base + CLK_CONTROL_OFFSET);
val &= ~EP_PERST_SOURCE_SELECT & ~EP_MODE_SURVIVE_PERST &
~RC_PCIE_RST_OUTPUT;
writel(val, pcie->base + CLK_CONTROL_OFFSET);
udelay(250);
val &= ~EP_MODE_SURVIVE_PERST;
val |= RC_PCIE_RST_OUTPUT;
writel(val, pcie->base + CLK_CONTROL_OFFSET);
msleep(250);
msleep(100);
}
static int iproc_pcie_check_link(struct iproc_pcie *pcie, struct pci_bus *bus)