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spi: Tegra2: Seaboard: fix UART corruption during SPI transactions

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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@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Jimmy Zhang <jimmzhang@nvidia.com>
This commit is contained in:
Tom Warren 2012-05-15 14:32:40 -07:00 committed by Albert ARIBAUD
parent 558cd995d6
commit 078078cfa9
3 changed files with 21 additions and 23 deletions
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4
arch/arm/include/asm/arch-tegra2/uart-spi-switch.h
View File

@ -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

27
board/nvidia/common/uart-spi-switch.c
View File

@ -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);
}

13
drivers/spi/tegra2_spi.c
View File

@ -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,