soc/intel/apollolake: provide function to set up uart pads and controller

Instead of pushing the same code into each mainboard for configuring the
the UART pads and initializing the host contoller provide a function
to perform all the actions on behalf of the mainboard. The set of pads
configured is dictated by the CONFIG_UART_FOR_CONSOLE Kconfig option.

Change-Id: I06c499c7ee056b970468e0386d4bb1bc26537247
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/13792
Tested-by: build bot (Jenkins)
Reviewed-by: Andrey Petrov <andrey.petrov@intel.com>

2 files changed, 34 insertions, 1 deletions

diff --git a/src/soc/intel/apollolake/include/soc/uart.h b/src/soc/intel/apollolake/include/soc/uart.h
index fd535fba23..16f09b14e0 100644
--- a/src/soc/intel/apollolake/include/soc/uart.h
+++ b/src/soc/intel/apollolake/include/soc/uart.h
@@ -25,4 +25,7 @@
 
 void lpss_console_uart_init(void);
 
+/* Initialize the console UART including the pads for the configured UART. */
+void soc_console_uart_init(void);
+
 #endif /* _SOC_APOLLOLAKE_UART_H_ */
diff --git a/src/soc/intel/apollolake/uart_early.c b/src/soc/intel/apollolake/uart_early.c
index d3b1d80fc3..4ee4a38607 100644
--- a/src/soc/intel/apollolake/uart_early.c
+++ b/src/soc/intel/apollolake/uart_early.c
@@ -22,12 +22,21 @@ static void lpss_uart_write(uint16_t reg, uint32_t val)
 	write32((void *)base, val);
 }
 
+static inline int invalid_uart_for_console(void)
+{
+	/* There are actually only 2 UARTS, and they are named UART1 and
+	 * UART2. They live at pci functions 1 and 2 respectively. */
+	if (CONFIG_UART_FOR_CONSOLE > 2 || CONFIG_UART_FOR_CONSOLE < 1)
+		return 1;
+	return 0;
+}
+
 void lpss_console_uart_init(void)
 {
 	uint32_t clk_sel;
 	device_t uart = _LPSS_PCI_DEV(UART, CONFIG_UART_FOR_CONSOLE & 3);
 
-	if (CONFIG_UART_FOR_CONSOLE > 2)
+	if (invalid_uart_for_console())
 		return;
 
 	/* Enable BAR0 for the UART -- this is where the 8250 registers hide */
@@ -59,3 +68,24 @@ unsigned int uart_platform_refclk(void)
 	/* That's within 0.5% of the actual value we've set earlier */
 	return 115200 * 16;
 }
+
+static const struct pad_config uart_gpios[] = {
+	PAD_CFG_NF(GPIO_42, NATIVE, DEEP, NF1),		/* UART1 RX */
+	PAD_CFG_NF(GPIO_43, NATIVE, DEEP, NF1),		/* UART1 TX */
+	PAD_CFG_NF(GPIO_46, NATIVE, DEEP, NF1),		/* UART2 RX */
+	PAD_CFG_NF(GPIO_47, NATIVE, DEEP, NF1),		/* UART2 TX */
+};
+
+void soc_console_uart_init(void)
+{
+	/* Get a 0-based pad index. See invalid_uart_for_console() above. */
+	const int pad_index = CONFIG_UART_FOR_CONSOLE - 1;
+
+	if (invalid_uart_for_console())
+		return;
+
+	/* Configure the 2 pads per UART. */
+	gpio_configure_pads(&uart_gpios[pad_index * 2], 2);
+
+	lpss_console_uart_init();
+}