mb/google/brya: Fix brya0 WWAN poweron sequencing

The PCIe WWAN module used on brya0 requires control over 4 signals to
successfully power it on. It is desirable to do this before passing
control to the payload, because the modem requires a ~10 seconds
initialization phase before it can be used.

The corrected sequence looks like:
1) Drive device into full reset and enable power in bootblock
2) Deassert FCPO in romstage, after power rails stabilize
3) Deassert WLAN_RST#, then WLAN_PERST# in ramstage

BUG=b:187691798

Change-Id: I10f15a4dcfd86216c334fb24b4693ea250d35ee4
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57540
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com>

2 files changed, 25 insertions, 8 deletions

diff --git a/src/mainboard/google/brya/variants/baseboard/brya/gpio.c b/src/mainboard/google/brya/variants/baseboard/brya/gpio.c
index 4c756291d7..c11cf42254 100644
--- a/src/mainboard/google/brya/variants/baseboard/brya/gpio.c
+++ b/src/mainboard/google/brya/variants/baseboard/brya/gpio.c
@@ -158,8 +158,7 @@ static const struct pad_config gpio_table[] = {
 	/* D19 : I2S_MCLK1_OUT ==> I2S_MCLK_R */
 	PAD_CFG_NF(GPP_D19, NONE, DEEP, NF1),
 
-	/* E0  : SATAXPCIE0 ==> WWAN_PERST_L */
-	PAD_CFG_GPO(GPP_E0, 1, PLTRST),
+	/* E0  : see end of E group */
 	/* E1  : THC0_SPI1_IO2 ==> MEM_STRAP_2 */
 	PAD_CFG_GPI(GPP_E1, NONE, DEEP),
 	/* E2  : THC0_SPI1_IO3 ==> MEM_STRAP_1 */
@@ -206,6 +205,11 @@ static const struct pad_config gpio_table[] = {
 	PAD_CFG_NF(GPP_E22, NONE, DEEP, NF6),
 	/* E23 : DDPA_CTRLDATA ==> USB_C0_AUX_DC_N */
 	PAD_CFG_NF(GPP_E23, NONE, DEEP, NF6),
+	/* E0 : SATAXPCIE0 ==> WWAN_PERST_L
+	   NB. Driven high here so that it is sequenced after WWAN_RST_L; a
+	   PERST# signal would normally be reset by PLRST#, but here it will be
+	   explicitly programmed during a power-down sequence. */
+	PAD_CFG_GPO(GPP_E0, 1, DEEP),
 
 	/* F0  : CNV_BRI_DT ==> CNV_BRI_DT_STRAP */
 	PAD_CFG_NF(GPP_F0, NONE, DEEP, NF1),
diff --git a/src/mainboard/google/brya/variants/brya0/gpio.c b/src/mainboard/google/brya/variants/brya0/gpio.c
index cd3509526b..6ca5e98d53 100644
--- a/src/mainboard/google/brya/variants/brya0/gpio.c
+++ b/src/mainboard/google/brya/variants/brya0/gpio.c
@@ -50,11 +50,11 @@ static const struct pad_config early_gpio_table[] = {
 	PAD_CFG_GPO(GPP_D1, 0, DEEP),
 	/* D2  : ISH_GP2 ==> EN_FP_PWR */
 	PAD_CFG_GPO(GPP_D2, 1, DEEP),
-	/* E0  : SATAXPCIE0 ==> WWAN_PERST_L */
+	/* E0  : SATAXPCIE0 ==> WWAN_PERST_L (updated in ramstage) */
 	PAD_CFG_GPO(GPP_E0, 0, DEEP),
 	/* E13 : THC0_SPI1_IO2 ==> MEM_CH_SEL */
 	PAD_CFG_GPI(GPP_E13, NONE, DEEP),
-	/* E16 : RSVD_TP ==> WWAN_RST_L */
+	/* E16 : RSVD_TP ==> WWAN_RST_L (updated in ramstage) */
 	PAD_CFG_GPO(GPP_E16, 0, DEEP),
 	/* E15 : RSVD_TP ==> PCH_WP_OD */
 	PAD_CFG_GPI_GPIO_DRIVER(GPP_E15, NONE, DEEP),
@@ -70,6 +70,8 @@ static const struct pad_config early_gpio_table[] = {
 
 /* Early pad configuration in bootblock for board id 2 */
 static const struct pad_config early_gpio_table_id2[] = {
+	/* A12 : SATAXPCIE1 ==> EN_PP3300_WWAN */
+	PAD_CFG_GPO(GPP_A12, 1, DEEP),
 	/* A13 : PMC_I2C_SCL ==> GSC_PCH_INT_ODL */
 	PAD_CFG_GPI_APIC(GPP_A13, NONE, PLTRST, LEVEL, INVERT),
 	/* B7  : ISH_12C1_SDA ==> PCH_I2C_TPM_SDA */
@@ -87,16 +89,16 @@ static const struct pad_config early_gpio_table_id2[] = {
 	PAD_CFG_GPO(GPP_D1, 0, DEEP),
 	/* D2  : ISH_GP2 ==> EN_FP_PWR */
 	PAD_CFG_GPO(GPP_D2, 1, DEEP),
-	/* E0  : SATAXPCIE0 ==> WWAN_PERST_L */
+	/* E0  : SATAXPCIE0 ==> WWAN_PERST_L (updated in ramstage) */
 	PAD_CFG_GPO(GPP_E0, 0, DEEP),
 	/* E13 : THC0_SPI1_IO2 ==> MEM_CH_SEL */
 	PAD_CFG_GPI(GPP_E13, NONE, DEEP),
-	/* E16 : RSVD_TP ==> WWAN_RST_L */
+	/* E16 : RSVD_TP ==> WWAN_RST_L (updated in ramstage) */
 	PAD_CFG_GPO(GPP_E16, 0, DEEP),
 	/* E15 : RSVD_TP ==> PCH_WP_OD */
 	PAD_CFG_GPI_GPIO_DRIVER(GPP_E15, NONE, DEEP),
-	/* F21 : EXT_PWR_GATE2# ==> WWAN_FCPO_L (updated below) */
-	PAD_CFG_GPO(GPP_F21, 1, DEEP),
+	/* F21 : EXT_PWR_GATE2# ==> WWAN_FCPO_L (updated in romstage) */
+	PAD_CFG_GPO(GPP_F21, 0, DEEP),
 	/* H10 : UART0_RXD ==> UART_PCH_RX_DBG_TX */
 	PAD_CFG_NF(GPP_H10, NONE, DEEP, NF2),
 	/* H11 : UART0_TXD ==> UART_PCH_TX_DBG_RX */
@@ -105,6 +107,11 @@ static const struct pad_config early_gpio_table_id2[] = {
 	PAD_NC(GPP_H13, UP_20K),
 };
 
+static const struct pad_config romstage_gpio_table[] = {
+	/* F21 : EXT_PWR_GATE2# ==> WWAN_FCPO_L (set here for correct power sequencing) */
+	PAD_CFG_GPO(GPP_F21, 1, DEEP),
+};
+
 const struct pad_config *variant_gpio_override_table(size_t *num)
 {
 	const uint32_t id = board_id();
@@ -128,3 +135,9 @@ const struct pad_config *variant_early_gpio_table(size_t *num)
 	*num = ARRAY_SIZE(early_gpio_table_id2);
 	return early_gpio_table_id2;
 }
+
+const struct pad_config *variant_romstage_gpio_table(size_t *num)
+{
+	*num = ARRAY_SIZE(romstage_gpio_table);
+	return romstage_gpio_table;
+}