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>

src/mainboard/google/zork/romstage.c

@@ -20,8 +20,7 @@ void mainboard_romstage_entry_s3(int s3_resume)
 
 	gpios = variant_romstage_gpio_table(&num_gpios);
 	program_gpios(gpios, num_gpios);
-	gpios = variant_wifi_romstage_gpio_table(&num_gpios);
+	variant_pcie_power_reset_configure();
-	program_gpios(gpios, num_gpios);
 
 	mainboard_ec_init();
 

src/mainboard/google/zork/variants/baseboard/gpio_baseboard_dalboz.c

@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
 #include <baseboard/variants.h>
+#include <delay.h>
+#include <gpio.h>
 #include <soc/gpio.h>
 #include <soc/smi.h>
 #include <stdlib.h>
@@ -20,8 +22,6 @@ static const struct soc_amd_gpio gpio_set_stage_rom_pre_v3[] = {
 	PAD_NF(GPIO_27, PCIE_RST1_L, PULL_NONE),
 	/* NVME_AUX_RESET_L */
 	PAD_GPO(GPIO_40, HIGH),
-	/* WIFI_AUX_RESET_L */
-	PAD_GPO(GPIO_42, HIGH),
 	/* EN_PWR_TOUCHPAD_PS2 - reset */
 	PAD_GPO(GPIO_67, LOW),
 	/* EMMC_RESET - reset (default stuffing unused)*/
@@ -44,11 +44,6 @@ static const struct soc_amd_gpio gpio_set_stage_rom_pre_v3[] = {
 	PAD_GPO(GPIO_142, HIGH),
 };
 
-static const struct soc_amd_gpio gpio_set_wifi_pre_v3[] = {
-	/* EN_PWR_WIFI */
-	PAD_GPO(GPIO_29, HIGH),
-};
-
 static const struct soc_amd_gpio gpio_set_stage_rom_v3[] = {
 	/* PEN_POWER_EN - reset */
 	PAD_GPO(GPIO_5, LOW),
@@ -62,8 +57,6 @@ static const struct soc_amd_gpio gpio_set_stage_rom_v3[] = {
 	PAD_NF(GPIO_26, PCIE_RST_L, PULL_NONE),
 	/* PCIE_RST1_L - Variable timings (May remove) */
 	PAD_NF(GPIO_27, PCIE_RST1_L, PULL_NONE),
-	/* WIFI_AUX_RESET */
-	PAD_GPO(GPIO_29, LOW),
 	/* NVME_AUX_RESET_L */
 	PAD_GPO(GPIO_40, HIGH),
 	/* EMMC_RESET - reset (default stuffing unused)*/
@@ -86,11 +79,6 @@ static const struct soc_amd_gpio gpio_set_stage_rom_v3[] = {
 	PAD_GPO(GPIO_142, HIGH),
 };
 
-static const struct soc_amd_gpio gpio_set_wifi_v3[] = {
-	/* EN_PWR_WIFI */
-	PAD_GPO(GPIO_42, HIGH),
-};
-
 static const struct soc_amd_gpio gpio_set_stage_ram[] = {
 
 	/* PWR_BTN_L */
@@ -218,21 +206,6 @@ struct soc_amd_gpio *variant_romstage_gpio_table(size_t *size)
 	return gpio_set_stage_rom_pre_v3;
 }
 
-const __weak
-struct soc_amd_gpio *variant_wifi_romstage_gpio_table(size_t *size)
-{
-	uint32_t board_version;
-
-	if (!google_chromeec_cbi_get_board_version(&board_version) &&
-	    (board_version >= CONFIG_VARIANT_MIN_BOARD_ID_V3_SCHEMATICS)) {
-		*size = ARRAY_SIZE(gpio_set_wifi_v3);
-		return gpio_set_wifi_v3;
-	}
-
-	*size = ARRAY_SIZE(gpio_set_wifi_pre_v3);
-	return gpio_set_wifi_pre_v3;
-}
-
 const __weak
 struct soc_amd_gpio *variant_base_gpio_table(size_t *size)
 {
@@ -251,3 +224,61 @@ const __weak struct sci_source *get_gpe_table(size_t *num)
 {
 	return NULL;
 }
+
+static void wifi_power_reset_configure_v3(void)
+{
+	/*
+	 * Configure WiFi GPIOs such that:
+	 * - WIFI_AUX_RESET is configured first to assert PERST# to WiFi device.
+	 * - Enable power to WiFi using EN_PWR_WIFI.
+	 * - Wait for 50ms after power to WiFi is enabled.
+	 * - Deassert PERST# to WiFi device by driving WIFI_AUX_RESET low.
+	 */
+	static const struct soc_amd_gpio v3_wifi_table[] = {
+		/* WIFI_AUX_RESET */
+		PAD_GPO(GPIO_29, HIGH),
+		/* EN_PWR_WIFI */
+		PAD_GPO(GPIO_42, HIGH),
+	};
+	program_gpios(v3_wifi_table, ARRAY_SIZE(v3_wifi_table));
+
+	mdelay(50);
+	gpio_set(GPIO_29, 0);
+}
+
+static void wifi_power_reset_configure_pre_v3(void)
+{
+	/*
+	 * Configure WiFi GPIOs such that:
+	 * - WIFI_AUX_RESET_L is configured first to assert PERST# to WiFi device.
+	 * - Disable power to WiFi since GPIO_29 goes high on PWRGOOD but has a glitch on RESET#
+	 *   deassertion causing WiFi to enter a bad state.
+	 * - Wait 10ms for WiFi power to go low.
+	 * - Enable power to WiFi using EN_PWR_WIFI.
+	 * - Wait for 50ms after power to WiFi is enabled.
+	 * - Deassert WIFI_AUX_RESET_L.
+	 */
+	static const struct soc_amd_gpio pre_v3_wifi_table[] = {
+		/* WIFI_AUX_RESET_L */
+		PAD_GPO(GPIO_42, LOW),
+		/* EN_PWR_WIFI */
+		PAD_GPO(GPIO_29, LOW),
+	};
+	program_gpios(pre_v3_wifi_table, ARRAY_SIZE(pre_v3_wifi_table));
+
+	mdelay(10);
+	gpio_set(GPIO_29, 1);
+	mdelay(50);
+	gpio_set(GPIO_42, 1);
+}
+
+__weak void variant_pcie_power_reset_configure(void)
+{
+	uint32_t board_version;
+
+	if (!google_chromeec_cbi_get_board_version(&board_version) &&
+	    (board_version >= CONFIG_VARIANT_MIN_BOARD_ID_V3_SCHEMATICS))
+		wifi_power_reset_configure_v3();
+	else
+		wifi_power_reset_configure_pre_v3();
+}

src/mainboard/google/zork/variants/baseboard/gpio_baseboard_trembyle.c

@@ -1,6 +1,8 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
 #include <baseboard/variants.h>
+#include <delay.h>
+#include <gpio.h>
 #include <soc/gpio.h>
 #include <soc/smi.h>
 #include <stdlib.h>
@@ -20,8 +22,6 @@ static const struct soc_amd_gpio gpio_set_stage_rom_pre_v3[] = {
 	PAD_NF(GPIO_27, PCIE_RST1_L, PULL_NONE),
 	/* NVME_AUX_RESET_L */
 	PAD_GPO(GPIO_40, HIGH),
-	/* WIFI_AUX_RESET_L */
-	PAD_GPO(GPIO_42, HIGH),
 	/* EN_PWR_TOUCHPAD_PS2 - reset */
 	PAD_GPO(GPIO_67, LOW),
 	/* EMMC_RESET - reset (default stuffing unused)*/
@@ -42,11 +42,6 @@ static const struct soc_amd_gpio gpio_set_stage_rom_pre_v3[] = {
 	PAD_GPO(GPIO_142, HIGH),
 };
 
-static const struct soc_amd_gpio gpio_set_wifi_pre_v3[] = {
-	/* EN_PWR_WIFI */
-	PAD_GPO(GPIO_29, HIGH),
-};
-
 static const struct soc_amd_gpio gpio_set_stage_rom_v3[] = {
 	/* PEN_POWER_EN - reset */
 	PAD_GPO(GPIO_5, LOW),
@@ -66,8 +61,6 @@ static const struct soc_amd_gpio gpio_set_stage_rom_v3[] = {
 	PAD_GPO(GPIO_68, HIGH),
 	/* EN_PWR_CAMERA - reset */
 	PAD_GPO(GPIO_76, LOW),
-	/* WIFI_AUX_RESET_L */
-	PAD_GPO(GPIO_86, HIGH),
 	/* CLK_REQ0_L - WIFI */
 	PAD_NF(GPIO_92, CLK_REQ0_L, PULL_UP),
 	/* CLK_REQ1_L - SD Card */
@@ -82,11 +75,6 @@ static const struct soc_amd_gpio gpio_set_stage_rom_v3[] = {
 	PAD_GPO(GPIO_142, HIGH),
 };
 
-static const struct soc_amd_gpio gpio_set_wifi_v3[] = {
-	/* EN_PWR_WIFI */
-	PAD_GPO(GPIO_42, HIGH),
-};
-
 static const struct soc_amd_gpio gpio_set_stage_ram[] = {
 
 	/* PWR_BTN_L */
@@ -213,21 +201,6 @@ struct soc_amd_gpio *variant_romstage_gpio_table(size_t *size)
 	return gpio_set_stage_rom_pre_v3;
 }
 
-const __weak
-struct soc_amd_gpio *variant_wifi_romstage_gpio_table(size_t *size)
-{
-	uint32_t board_version;
-
-	if (!google_chromeec_cbi_get_board_version(&board_version) &&
-	    (board_version >= CONFIG_VARIANT_MIN_BOARD_ID_V3_SCHEMATICS)) {
-		*size = ARRAY_SIZE(gpio_set_wifi_v3);
-		return gpio_set_wifi_v3;
-	}
-
-	*size = ARRAY_SIZE(gpio_set_wifi_pre_v3);
-	return gpio_set_wifi_pre_v3;
-}
-
 const __weak
 struct soc_amd_gpio *variant_base_gpio_table(size_t *size)
 {
@@ -246,3 +219,61 @@ const __weak struct sci_source *get_gpe_table(size_t *num)
 {
 	return NULL;
 }
+
+static void wifi_power_reset_configure_v3(void)
+{
+	/*
+	 * Configure WiFi GPIOs such that:
+	 * - WIFI_AUX_RESET_L is configured first to assert PERST# to WiFi device.
+	 * - Enable power to WiFi using EN_PWR_WIFI.
+	 * - Wait for 50ms after power to WiFi is enabled.
+	 * - Deassert WIFI_AUX_RESET_L.
+	 */
+	static const struct soc_amd_gpio v3_wifi_table[] = {
+		/* WIFI_AUX_RESET_L */
+		PAD_GPO(GPIO_86, LOW),
+		/* EN_PWR_WIFI */
+		PAD_GPO(GPIO_42, HIGH),
+	};
+	program_gpios(v3_wifi_table, ARRAY_SIZE(v3_wifi_table));
+
+	mdelay(50);
+	gpio_set(GPIO_86, 1);
+}
+
+static void wifi_power_reset_configure_pre_v3(void)
+{
+	/*
+	 * Configure WiFi GPIOs such that:
+	 * - WIFI_AUX_RESET_L is configured first to assert PERST# to WiFi device.
+	 * - Disable power to WiFi since GPIO_29 goes high on PWRGOOD but has a glitch on RESET#
+	 *   deassertion causing WiFi to enter a bad state.
+	 * - Wait 10ms for WiFi power to go low.
+	 * - Enable power to WiFi using EN_PWR_WIFI.
+	 * - Wait for 50ms after power to WiFi is enabled.
+	 * - Deassert WIFI_AUX_RESET_L.
+	 */
+	static const struct soc_amd_gpio pre_v3_wifi_table[] = {
+		/* WIFI_AUX_RESET_L */
+		PAD_GPO(GPIO_42, LOW),
+		/* EN_PWR_WIFI */
+		PAD_GPO(GPIO_29, LOW),
+	};
+	program_gpios(pre_v3_wifi_table, ARRAY_SIZE(pre_v3_wifi_table));
+
+	mdelay(10);
+	gpio_set(GPIO_29, 1);
+	mdelay(50);
+	gpio_set(GPIO_42, 1);
+}
+
+__weak void variant_pcie_power_reset_configure(void)
+{
+	uint32_t board_version;
+
+	if (!google_chromeec_cbi_get_board_version(&board_version) &&
+	    (board_version >= CONFIG_VARIANT_MIN_BOARD_ID_V3_SCHEMATICS))
+		wifi_power_reset_configure_v3();
+	else
+		wifi_power_reset_configure_pre_v3();
+}

src/mainboard/google/zork/variants/baseboard/include/baseboard/variants.h

@@ -13,7 +13,6 @@
 const struct sci_source *get_gpe_table(size_t *num);
 const struct soc_amd_gpio *variant_early_gpio_table(size_t *size);
 const struct soc_amd_gpio *variant_romstage_gpio_table(size_t *size);
-const struct soc_amd_gpio *variant_wifi_romstage_gpio_table(size_t *size);
 /*
  * This function provides base GPIO configuration table. It is typically provided by
  * baseboard using a weak implementation. If GPIO configuration for a variant differs
@@ -29,6 +28,8 @@ const struct soc_amd_gpio *variant_override_gpio_table(size_t *size);
 void variant_romstage_entry(void);
 /* Modify devictree settings during ramstage. */
 void variant_devtree_update(void);
+/* Configure PCIe power and reset lines as per variant sequencing requirements. */
+void variant_pcie_power_reset_configure(void);
 
 /* Per variant FSP-S initialization, default implementation in baseboard and
  * overrideable by the variant. */

src/mainboard/google/zork/variants/berknip/Makefile.inc

@@ -2,6 +2,4 @@
 
 subdirs-y += ./spd
 
-romstage-y += ./romstage.c
-
 ramstage-y += gpio.c

src/mainboard/google/zork/variants/berknip/romstage.c

@@ -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;
-}

src/mainboard/google/zork/variants/morphius/Makefile.inc

@@ -2,6 +2,4 @@
 
 subdirs-y += ./spd
 
-romstage-y += ./romstage.c
-
 ramstage-y += gpio.c

src/mainboard/google/zork/variants/morphius/romstage.c

@@ -1,42 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#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>
-#include <delay.h>
-
-void variant_romstage_entry(void)
-{
-	//SET WIFI_PCIE_RESET_L HIGH
-	gpio_set(WIFI_PCIE_RESET_L, 1);
-
-	/* Power the wifi card */
-	/* wait 10ms to discharge EN_PWR_WIFI to 0V */
-	mdelay(10);
-	gpio_set(EN_PWR_WIFI, 1);
-
-	/* SET WIFI_PCIE_RESET_L LOW */
-	gpio_set(WIFI_PCIE_RESET_L, 0);
-
-	/* Qualcomm Atheros NFA344A needs at least 10ms delay */
-	mdelay(10);
-
-	/* SET WIFI_PCIE_RESET_L HIGH */
-	gpio_set(WIFI_PCIE_RESET_L, 1);
-}
-
-static const struct soc_amd_gpio morphius_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(morphius_gpio_set_wifi);
-	return morphius_gpio_set_wifi;
-}