[U-Boot] [PATCH] spi: Tegra2: Seaboard: fix UART corruption during SPI transactions
Tom Warren
twarren.nvidia at gmail.com
Wed May 9 19:34:16 CEST 2012
Simon Glass's proposal to fix this on Seaboard was NAK'd, so I
removed his NS16550 references and added a small delay before
SPI/UART muxing. Tested on my Seaboard with large SPI reads/writes
and saw no corruption (crc's matched) and no spurious comm chars.
Signed-off-by: Tom Warren <twarren at nvidia.com>
---
arch/arm/include/asm/arch-tegra2/uart-spi-switch.h | 4 +-
board/nvidia/common/uart-spi-switch.c | 27 +++++--------------
drivers/spi/tegra2_spi.c | 13 +++++++++-
include/configs/seaboard.h | 4 +++
4 files changed, 25 insertions(+), 23 deletions(-)
diff --git a/arch/arm/include/asm/arch-tegra2/uart-spi-switch.h b/arch/arm/include/asm/arch-tegra2/uart-spi-switch.h
index e4503b1..82ac180 100644
--- a/arch/arm/include/asm/arch-tegra2/uart-spi-switch.h
+++ b/arch/arm/include/asm/arch-tegra2/uart-spi-switch.h
@@ -29,7 +29,7 @@
* time! If the board file provides this, the board config will declare it.
* Let this be a lesson for others.
*/
-void pinmux_select_uart(NS16550_t regs);
+void pinmux_select_uart(void);
/*
* Signal that we are about the use the SPI bus.
@@ -38,7 +38,7 @@ void pinmux_select_spi(void);
#else /* not CONFIG_SPI_UART_SWITCH */
-static inline void pinmux_select_uart(NS16550_t regs) {}
+static inline void pinmux_select_uart(void) {}
static inline void pinmux_select_spi(void) {}
#endif
diff --git a/board/nvidia/common/uart-spi-switch.c b/board/nvidia/common/uart-spi-switch.c
index 23aa0b9..1ba1afd 100644
--- a/board/nvidia/common/uart-spi-switch.c
+++ b/board/nvidia/common/uart-spi-switch.c
@@ -21,7 +21,6 @@
*/
#include <common.h>
-#include <ns16550.h>
#include <asm/gpio.h>
#include <asm/arch/pinmux.h>
#include <asm/arch/uart-spi-switch.h>
@@ -40,7 +39,6 @@ enum spi_uart_switch {
/* Information about the spi/uart switch */
struct spi_uart {
int gpio; /* GPIO to control switch */
- NS16550_t regs; /* Address of UART affected */
u32 port; /* Port number of UART affected */
};
@@ -52,7 +50,6 @@ static void get_config(struct spi_uart *config)
{
#if defined CONFIG_SPI_CORRUPTS_UART
config->gpio = CONFIG_UART_DISABLE_GPIO;
- config->regs = (NS16550_t)CONFIG_SPI_CORRUPTS_UART;
config->port = CONFIG_SPI_CORRUPTS_UART_NR;
#else
config->gpio = -1;
@@ -101,34 +98,24 @@ static void spi_uart_switch(struct spi_uart *config,
if (switch_pos == SWITCH_BOTH || new_pos == switch_pos)
return;
- /* if the UART was selected, allow it to drain */
- if (switch_pos == SWITCH_UART)
- NS16550_drain(config->regs, config->port);
+ /* pre-delay, allow SPI/UART to settle, FIFO to empty, etc. */
+ udelay(CONFIG_SPI_CORRUPTS_UART_DLY);
/* We need to dynamically change the pinmux, shared w/UART RXD/CTS */
pinmux_set_func(PINGRP_GMC, new_pos == SWITCH_SPI ?
PMUX_FUNC_SFLASH : PMUX_FUNC_UARTD);
/*
- * On Seaboard, MOSI/MISO are shared w/UART.
- * Use GPIO I3 (UART_DISABLE) to tristate UART during SPI activity.
- * Enable UART later (cs_deactivate) so we can use it for U-Boot comms.
- */
+ * On Seaboard, MOSI/MISO are shared w/UART.
+ * Use GPIO I3 (UART_DISABLE) to tristate UART during SPI activity.
+ * Enable UART later (cs_deactivate) so we can use it for U-Boot comms.
+ */
gpio_direction_output(config->gpio, new_pos == SWITCH_SPI);
switch_pos = new_pos;
-
- /* if the SPI was selected, clear any junk bytes in the UART */
- if (switch_pos == SWITCH_UART) {
- /* TODO: What if it is part-way through clocking in junk? */
- udelay(100);
- NS16550_clear(config->regs, config->port);
- }
}
-void pinmux_select_uart(NS16550_t regs)
+void pinmux_select_uart(void)
{
- /* Also prevents calling spi_uart_switch() before relocation */
- if (regs == local.regs)
spi_uart_switch(&local, SWITCH_UART);
}
diff --git a/drivers/spi/tegra2_spi.c b/drivers/spi/tegra2_spi.c
index 56cb229..fe7b405 100644
--- a/drivers/spi/tegra2_spi.c
+++ b/drivers/spi/tegra2_spi.c
@@ -28,13 +28,18 @@
#include <spi.h>
#include <asm/io.h>
#include <asm/gpio.h>
-#include <ns16550.h>
#include <asm/arch/clk_rst.h>
#include <asm/arch/clock.h>
#include <asm/arch/pinmux.h>
#include <asm/arch/uart-spi-switch.h>
#include <asm/arch/tegra2_spi.h>
+#if defined(CONFIG_SPI_CORRUPTS_UART)
+ #define corrupt_delay() udelay(CONFIG_SPI_CORRUPTS_UART_DLY);
+#else
+ #define corrupt_delay()
+#endif
+
struct tegra_spi_slave {
struct spi_slave slave;
struct spi_tegra *regs;
@@ -161,14 +166,20 @@ void spi_cs_activate(struct spi_slave *slave)
/* CS is negated on Tegra, so drive a 1 to get a 0 */
setbits_le32(&spi->regs->command, SPI_CMD_CS_VAL);
+
+ corrupt_delay(); /* Let UART settle */
}
void spi_cs_deactivate(struct spi_slave *slave)
{
struct tegra_spi_slave *spi = to_tegra_spi(slave);
+ pinmux_select_uart();
+
/* CS is negated on Tegra, so drive a 0 to get a 1 */
clrbits_le32(&spi->regs->command, SPI_CMD_CS_VAL);
+
+ corrupt_delay(); /* Let SPI settle */
}
int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
diff --git a/include/configs/seaboard.h b/include/configs/seaboard.h
index 46d4228..a9fd15e 100644
--- a/include/configs/seaboard.h
+++ b/include/configs/seaboard.h
@@ -52,6 +52,10 @@
/* On Seaboard: GPIO_PI3 = Port I = 8, bit = 3 */
#define CONFIG_UART_DISABLE_GPIO GPIO_PI3
+#define CONFIG_SPI_UART_SWITCH
+#define CONFIG_SPI_CORRUPTS_UART NV_PA_APB_UARTD_BASE
+#define CONFIG_SPI_CORRUPTS_UART_NR 3
+#define CONFIG_SPI_CORRUPTS_UART_DLY 2500
#define CONFIG_MACH_TYPE MACH_TYPE_SEABOARD
#define CONFIG_SYS_BOARD_ODMDATA 0x300d8011 /* lp1, 1GB */
--
1.7.0.4
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