diff options
author | Furquan Shaikh <furquan@google.com> | 2020-06-22 10:45:12 -0700 |
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committer | Furquan Shaikh <furquan@google.com> | 2020-06-25 08:08:37 +0000 |
commit | 8302585c152926c086107cdf11f48040d0d873d5 (patch) | |
tree | 8d1d1aaa91797d16e5e6e47e7831558d0a52b5b6 /src/mainboard/google/zork/variants/berknip/romstage.c | |
parent | 462f3ed111e049cc95e2ee2ce4f4e88a415cc912 (diff) |
mb/google/zork: Add support for WiFi power sequencing
This change replaces variant_wifi_romstage_gpio_table() with
variant_pcie_power_reset_configure() to handle the reset and power
sequencing for WiFi devices pre- and post- v3 version of schematics.
These are the requirements that need to be satisfied:
1. As per PCI Express M.2 Specification Revision 3.0,
Version 1.2, Section 3.1.4 "Power-up Timing", PERST# should stay
disabled until `TPVPGL` time duration after device power has
stabilized. Value of TPVPGL is implementation specific.
2. For Intel WiFi chip, it is known to get into a bad state if the
above requirement is violated and hence requires a power cycle.
3. On pre-v3 schematics:
- For both dalboz and trembyle references, GPIO42 drives
WIFI_AUX_RESET_L which is pulled up to PP3300_WIFI.
- For both dalboz and trembyle references, PP3300_WIFI is controlled
using GPIO29. This pad gets pulled high by default on PWRGOOD
because of internal pull-up. But, at RESET# it is known to have a
glitch. When GPIO29 gets pulled high, it causes WIFI_AUX_RESET_L to
be pulled high as well. This violates the PCIe power sequencing
requirements. Hence, for pre-v3 schematics on both dalboz and
trembyle, following sequence needs to be followed:
a. Assert WIFI_AUX_RESET_L.
b. Disable power to WiFi.
c. Wait 10ms to allow WiFi power to go low.
d. Enable power to WiFi.
e. Wait 50ms as per PCIe specification.
f. Deassert WIFI_AUX_RESET_L.
4. On v3 schematics:
- For trembyle: WIFI_AUX_RESET_L is driven by GPIO86 which has an
internal PU as well as an external PU to PP3300_WIFI.
- For dalboz: WIFI_AUX_RESET is driven by GPIO29. This is active
high and has an internal PU. It also has an external 1K PD to
overcome internal PU.
- For both dalboz and trembyle references, PP3300_WIFI is
controlled by GPIO42 which has an internal PU and external
PD. Trembyle schematics have a comment saying strong PD of 2.2K but
the stuffed resistor is a weak one (499K). ON dalboz, it uses a
weak PD (which doesn't look correct and instead should be a strong
PD just like trembyle). Having a strong PD ensures that the WiFi
power is kept disabled when coming out of G3 until coreboot
configures GPIO42 as high.
- Thus, for v3 schematics, following sequence needs to be followed:
a. Assert WIFI_AUX_RESET{_L} signal.
b. Enable power to WiFi.
c. Wait 50ms as per PCIe specification.
d. Deassert WIFI_AUX_RESET{_L} signal.
BUG=b:157686402, b:158257076
TEST=Verified that QCA and AX200 cards both continue working. Tested
QCA on Dalboz and Trembyle. Tested AX200 on morphius.
Signed-off-by: Furquan Shaikh <furquan@google.com>
Change-Id: I532131ee911d5efb5130d8710f3e01578f6c9627
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42738
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'src/mainboard/google/zork/variants/berknip/romstage.c')
-rw-r--r-- | src/mainboard/google/zork/variants/berknip/romstage.c | 27 |
1 files changed, 0 insertions, 27 deletions
diff --git a/src/mainboard/google/zork/variants/berknip/romstage.c b/src/mainboard/google/zork/variants/berknip/romstage.c deleted file mode 100644 index 67ad31c6d8..0000000000 --- a/src/mainboard/google/zork/variants/berknip/romstage.c +++ /dev/null @@ -1,27 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ - -#include <stddef.h> -#include <soc/romstage.h> -#include <baseboard/variants.h> -#include <ec/google/chromeec/ec.h> - -#include <gpio.h> -#include <soc/gpio.h> -#include <variant/gpio.h> - -void variant_romstage_entry(void) -{ - /* Power the wifi card */ - gpio_set(EN_PWR_WIFI, 1); -} - -static const struct soc_amd_gpio berknip_gpio_set_wifi[] = { - /* EN_PWR_WIFI - Power off. Pull high in romstage.c */ - PAD_GPO(GPIO_29, LOW), -}; - -const struct soc_amd_gpio *variant_wifi_romstage_gpio_table(size_t *size) -{ - *size = ARRAY_SIZE(berknip_gpio_set_wifi); - return berknip_gpio_set_wifi; -} |