[U-Boot] [PATCH 8/8] tegra2: Create SPI/UART switch code

[Simon Glass]

On Seaboard the UART and SPI interfere with each other. This causes the UART
to receive spurious zero bytes after SPI transactions and also means that
SPI can corrupt a few output characters when it starts up if they are still
in the UART buffer.

This updates the board to use the SPI/UART switch to avoid the problem.

For now this feature is turned off since it needs changes to the NS16550
UART to operate.

Signed-off-by: Simon Glass <sjg at chromium.org>
---
 board/nvidia/common/board.c      |    8 ++++++++
 board/nvidia/common/board.h      |    1 +
 board/nvidia/seaboard/seaboard.c |    3 +++
 3 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/board/nvidia/common/board.c b/board/nvidia/common/board.c
index 2591ebc..0403645 100644
--- a/board/nvidia/common/board.c
+++ b/board/nvidia/common/board.c
@@ -112,9 +112,13 @@ static void pin_mux_uart(int uart_ids)
  */
 int board_init(void)
 {
+	/* Do clocks and UART first so that printf() works */
 	clock_init();
 	clock_verify();
 
+#ifdef CONFIG_SPI_UART_SWITCH
+	gpio_config_uart();
+#endif
 #ifdef CONFIG_TEGRA2_SPI
 	spi_init();
 #endif
@@ -149,7 +153,11 @@ int board_early_init_f(void)
 	pin_mux_uart(uart_ids);
 
 	/* Initialize periph GPIOs */
+#ifdef CONFIG_SPI_UART_SWITCH
+	gpio_early_init_uart();
+#else
 	gpio_config_uart();
+#endif
 
 	/* Init UART, scratch regs, and start CPU */
 	tegra2_start();
diff --git a/board/nvidia/common/board.h b/board/nvidia/common/board.h
index 35acbca..2c89ff4 100644
--- a/board/nvidia/common/board.h
+++ b/board/nvidia/common/board.h
@@ -27,5 +27,6 @@
 void tegra2_start(void);
 void gpio_config_uart(void);
 int tegra2_mmc_init(int dev_index, int bus_width, int pwr_gpio, int cd_gpio);
+void gpio_early_init_uart(void);
 
 #endif	/* BOARD_H */
diff --git a/board/nvidia/seaboard/seaboard.c b/board/nvidia/seaboard/seaboard.c
index 2e8f4cc..2074e50 100644
--- a/board/nvidia/seaboard/seaboard.c
+++ b/board/nvidia/seaboard/seaboard.c
@@ -31,6 +31,8 @@
 #endif
 #include "../common/board.h"
 
+/* TODO: Remove this code when the SPI switch is working */
+#ifndef CONFIG_SPI_UART_SWITCH
 /*
  * Routine: gpio_config_uart_seaboard
  * Description: Force GPIO_PI3 low on Seaboard so UART4 works.
@@ -48,6 +50,7 @@ void gpio_config_uart(void)
 		return;
 	gpio_config_uart_seaboard();
 }
+#endif
 
 #ifdef CONFIG_TEGRA2_MMC
 /*
-- 
1.7.3.1