diff options
| author | Furquan Shaikh <furquan@google.com> | 2020-06-23 11:07:22 -0700 |
|---|---|---|
| committer | Furquan Shaikh <furquan@google.com> | 2020-07-01 17:54:34 +0000 |
| commit | 1247616304ebf9a8839a6808be2f12912b1d98f8 (patch) | |
| tree | 9870e15580b478b53c44d126f922b6cb2ff94ab8 /src/mainboard/google | |
| parent | 17c46042eb9350a1cdc0d6cb68bcfa1850abd0fd (diff) | |
mb/google/zork: Reconfigure PCIE_RST1_L as GPO driven low on sleep path
This change configures PCIE_RST1_L as GPO driven low on the sleep
path. This is required to keep PERST# asserted to devices until
coreboot deasserts it on S3 resume path. Without this change, on S3
resume, PCIE_RST1_L gets deasserted sooner than required resulting in
violation of PCIe reset timings.
With this change, the behavior of PCIE_RST1_L is as follows:
1. GPIO27 is configured as NF (PCIE_RST1_L) in coreboot
bootblock/romstage and driven high.
2. On S3 entry, GPIO27 is configured as GPO driven low.
* Boot out of G3: Timing should be met since GPIO_27 is pulled down by
default until coreboot configures it.
* S3 resume: Timing should be met since GPIO_27 is configured as GPO
low and it retains state across S3 entry/exit. So, should be low
until coreboot configures it.
* Warm reset: Timing should be met since it is configured as NF. So,
hardware guarantees the reset timing as seen in "warm reset.jpg" in
#46.
BUG=b:152582706
Signed-off-by: Furquan Shaikh <furquan@google.com>
Change-Id: Ia0ad1522edc438fd054d927ef4a2ab5c27329c00
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/coreboot/+/2261116
Reviewed-by: Aaron Durbin <adurbin@google.com>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42934
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Diffstat (limited to 'src/mainboard/google')
| -rw-r--r-- | src/mainboard/google/zork/variants/baseboard/gpio_baseboard_common.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/src/mainboard/google/zork/variants/baseboard/gpio_baseboard_common.c b/src/mainboard/google/zork/variants/baseboard/gpio_baseboard_common.c index e43b0b4cff..1dd2dd5b89 100644 --- a/src/mainboard/google/zork/variants/baseboard/gpio_baseboard_common.c +++ b/src/mainboard/google/zork/variants/baseboard/gpio_baseboard_common.c @@ -34,6 +34,8 @@ const __weak struct soc_amd_gpio *variant_early_gpio_table(size_t *size) static const struct soc_amd_gpio gpio_sleep_table[] = { /* PEN_POWER_EN */ PAD_GPO(GPIO_5, LOW), + /* PCIE_RST1_L */ + PAD_GPO(GPIO_27, LOW), /* EN_PWR_CAMERA */ PAD_GPO(GPIO_76, LOW), }; |