Skylake: Initialize GPIOs for UART2

FSP will initialize GPIOs during TempRamInit.
So configure LPSS UART2 GPIOs in native mode
after TempRamInit.

BRANCH=none
BUG=chrome-os-partner:41374
EST=Build and boot on RVP3. Check LPSS logs on UART2

Change-Id: I8016dd76a5bc06e90f9460273be7e83c5e8f8bb1
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: eb72e715ef3f566e900727ac8b9494bca1d5971c
Original-Change-Id: If1b1a1047ebd5e5f170d91972d11c51aa6fd84a9
Original-Signed-off-by: rsatapat <rishavnath.satapathy@intel.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/281604
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Commit-Queue: Wenkai Du <wenkai.du@intel.com>
Original-Tested-by: Wenkai Du <wenkai.du@intel.com>
Reviewed-on: http://review.coreboot.org/10995
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

2 files changed, 74 insertions, 2 deletions

diff --git a/src/soc/intel/skylake/include/soc/gpio.h b/src/soc/intel/skylake/include/soc/gpio.h
index efc666f4cd..03ed11988d 100644
--- a/src/soc/intel/skylake/include/soc/gpio.h
+++ b/src/soc/intel/skylake/include/soc/gpio.h
@@ -257,6 +257,18 @@ typedef struct {
 	  .owner = GPIO_OWNER_GPIO, \
 	  .conf1 = GPIO_SENSE_DISABLE }
 
+/* Number of pins used by SerialIo controllers */
+#define PCH_SERIAL_IO_PINS_PER_UART_CONTROLLER			4
+#define PCH_SERIAL_IO_PINS_PER_UART_CONTROLLER_NO_FLOW_CTRL	2
+
+/* Below defines are based on GPIO_CONFIG structure fields */
+#define GPIO_CONF_PAD_MODE_MASK		0xF
+#define GPIO_CONF_PAD_MODE_BIT_POS	0
+
+/* GPIO Pad Mode */
+#define B_PCH_GPIO_PAD_MODE	(0x1000 | 0x800 | 0x400)
+#define N_PCH_GPIO_PAD_MODE	10
+
 struct gpio_config {
 	u8 gpio;
 	u32 conf0;
diff --git a/src/soc/intel/skylake/romstage/uart.c b/src/soc/intel/skylake/romstage/uart.c
index 8aa1053150..c53643abc6 100644
--- a/src/soc/intel/skylake/romstage/uart.c
+++ b/src/soc/intel/skylake/romstage/uart.c
@@ -25,6 +25,9 @@
 #include <soc/pcr.h>
 #include <soc/romstage.h>
 #include <soc/serialio.h>
+#include <gpio.h>
+
+static void uartgpioinit(u8 hwflowcontrol);
 
 void pch_uart_init(void)
 {
@@ -32,7 +35,7 @@ void pch_uart_init(void)
 	u32 tmp;
 	u8 *base = (u8 *)CONFIG_TTYS0_BASE;
 
-	/* Set configured UART base address */
+	/* Set configured UART2 base address */
 	pci_write_config32(dev, PCI_BASE_ADDRESS_0, (u32)base);
 
 	/* Enable memory access and bus master */
@@ -40,7 +43,7 @@ void pch_uart_init(void)
 	tmp |= PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER;
 	pci_write_config32(dev, PCI_COMMAND, tmp);
 
-	/* Take UART out of reset */
+	/* Take UART2 out of reset */
 	tmp = read32(base + SIO_REG_PPR_RESETS);
 	tmp |= SIO_REG_PPR_RESETS_FUNC | SIO_REG_PPR_RESETS_APB |
 		SIO_REG_PPR_RESETS_IDMA;
@@ -56,4 +59,61 @@ void pch_uart_init(void)
 	/* Put UART2 in byte access mode for 16550 compatibility */
 	pcr_andthenor32(PID_SERIALIO, R_PCH_PCR_SERIAL_IO_GPPRVRW7, 0,
 		SIO_PCH_LEGACY_UART2);
+
+	/* Configure GPIO for UART2 in native mode*/
+	uartgpioinit(FALSE);
+}
+
+/*
+ * GPIO modes
+ */
+typedef struct {
+	GPIO_PAD	pad;
+	GPIO_PAD_MODE	mode;
+} GPIO_PAD_NATIVE_FUNCTION;
+
+/*
+ * GPP_C Community for UART2 GPIO
+ * pin order RXD/TXD/RTSB/CTSB
+ */
+static const GPIO_PAD_NATIVE_FUNCTION uartgpio[] = {
+	{GPIO_LP_GPP_C20, GpioPadModeNative1},
+	{GPIO_LP_GPP_C21, GpioPadModeNative1},
+	{GPIO_LP_GPP_C22, GpioPadModeNative1},
+	{GPIO_LP_GPP_C23, GpioPadModeNative1}
+};
+
+/*
+ * GPIO config registers
+ */
+static const GPIO_GROUP_INFO gpio_group_info = {
+	PID_GPIOCOM1,
+	R_PCH_PCR_GPIO_GPP_C_PADCFG_OFFSET,
+	V_PCH_GPIO_GPP_C_PAD_MAX,
+	R_PCH_PCR_GPIO_GPP_C_SMI_STS,
+	R_PCH_PCR_GPIO_GPP_C_SMI_EN
+};
+
+static void uartgpioinit(u8 hwflowcontrol)
+{
+	u32 index, pinsused, dw0reg, dw0regmask, padcfgreg, padnumber;
+
+	if (hwflowcontrol)
+		pinsused = PCH_SERIAL_IO_PINS_PER_UART_CONTROLLER;
+	else
+		pinsused = PCH_SERIAL_IO_PINS_PER_UART_CONTROLLER_NO_FLOW_CTRL;
+
+	for (index = 0; index < pinsused; index++) {
+		padnumber = GPIO_GET_PAD_NUMBER(uartgpio[index].pad);
+		padcfgreg = 0x8 * padnumber + gpio_group_info.padcfgoffset;
+		dw0regmask = (uartgpio[index].mode & GPIO_CONF_PAD_MODE_MASK)
+						>> GPIO_CONF_PAD_MODE_BIT_POS;
+		dw0regmask = (GpioHardwareDefault == dw0regmask) ?
+						0x0 : B_PCH_GPIO_PAD_MODE;
+		dw0reg = (((uartgpio[index].mode & GPIO_CONF_PAD_MODE_MASK) >>
+		(GPIO_CONF_PAD_MODE_BIT_POS + 1)) << N_PCH_GPIO_PAD_MODE);
+
+		pcr_andthenor32(gpio_group_info.community, padcfgreg,
+					~(u32)dw0regmask, (u32)dw0reg);
+	}
 }