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pcie: add code to support PCIE clk power management

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Set PCIE "Enable Clock Power Management", if endp supports

BUG=chrome-os-partner:31424
BRANCH=none
TEST=build and boot on rambi, check Enable Clock Power Management
     in link control register is set properly

Change-Id: Ie54110d1ef42184cfcf47c9fe4d735960aebe47f
Signed-off-by: Kane Chen <kane.chen@intel.com>
Reviewed-on: https://chromium-review.googlesource.com/220742
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
This commit is contained in:
Kane Chen 2014-10-01 11:13:54 +08:00 • committed by chrome-internal-fetch
commit 13a423bc8b
3 changed files with 32 additions and 0 deletions
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8
src/device/Kconfig
View file

@ -254,6 +254,14 @@ config PCIEXP_ASPM
help
Detect and enable ASPM on PCIe links.
config PCIEXP_CLK_PM
prompt "Enable PCIe Clock Power Management"
bool
depends on PCIEXP_PLUGIN_SUPPORT
default n
help
Detect and enable Clock Power Management on PCIe.
config PCI_BUS_SEGN_BITS
int
default 0

22
src/device/pciexp_device.c
View file

@ -90,6 +90,23 @@ static void pciexp_enable_common_clock(device_t root, unsigned root_cap,
}
#endif /* CONFIG_PCIEXP_COMMON_CLOCK */
#if CONFIG_PCIEXP_CLK_PM
static void pciexp_enable_clock_power_pm(device_t endp, unsigned endp_cap)
{
/* check if per port clk req is supported in device */
u32 endp_ca;
u16 lnkctl;
endp_ca = pci_read_config32(endp, endp_cap + PCI_EXP_LNKCAP);
if ((endp_ca & PCI_EXP_CLK_PM) == 0) {
printk(BIOS_INFO, "PCIE CLK PM is not supported by endpoint");
return;
}
lnkctl = pci_read_config16(endp, endp_cap + PCI_EXP_LNKCTL);
lnkctl = lnkctl | PCI_EXP_EN_CLK_PM;
pci_write_config16(endp, endp_cap + PCI_EXP_LNKCTL, lnkctl);
}
#endif /* CONFIG_PCIEXP_CLK_PM */
#if CONFIG_PCIEXP_ASPM
/*
* Determine the ASPM L0s or L1 exit latency for a link
@ -200,6 +217,11 @@ static void pciexp_tune_dev(device_t dev)
pciexp_enable_common_clock(root, root_cap, dev, cap);
#endif
#if CONFIG_PCIEXP_CLK_PM
/* Check if per port CLK req is supported by endpoint*/
pciexp_enable_clock_power_pm(dev, cap);
#endif
#if CONFIG_PCIEXP_ASPM
/* Check for and enable ASPM */
enum aspm_type apmc = pciexp_enable_aspm(root, root_cap, dev, cap);

2
src/include/device/pci_def.h
View file

@ -374,9 +374,11 @@
#define PCI_EXP_LNKCAP_ASPMS 0xc00 /* ASPM Support */
#define PCI_EXP_LNKCAP_L0SEL 0x7000 /* L0s Exit Latency */
#define PCI_EXP_LNKCAP_L1EL 0x38000 /* L1 Exit Latency */
#define PCI_EXP_CLK_PM 0x40000 /* Clock Power Management */
#define PCI_EXP_LNKCTL 16 /* Link Control */
#define PCI_EXP_LNKCTL_RL 0x20 /* Retrain Link */
#define PCI_EXP_LNKCTL_CCC 0x40 /* Common Clock COnfiguration */
#define PCI_EXP_EN_CLK_PM 0x100 /* Enable Clock Power Management */
#define PCI_EXP_LNKSTA 18 /* Link Status */
#define PCI_EXP_LNKSTA_LT 0x800 /* Link Training */
#define PCI_EXP_LNKSTA_SLC 0x1000 /* Slot Clock Configuration */