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spi, spi_mxc: do not hang in spi_xchg_single

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if status register do never set MXC_CSPICTRL_TC, spi_xchg_single
endless loops. Add a timeout here to prevent endless hang.

Signed-off-by: Heiko Schocher <hs@denx.de>
Cc: Dirk Behme <dirk.behme@gmail.com>
Reviewed-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
This commit is contained in:
Heiko Schocher 2014-07-14 10:22:11 +02:00 committed by Jagannadha Sutradharudu Teki
parent 22052c6236
commit f659b57361
2 changed files with 19 additions and 2 deletions
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4
README
View file

@ -2597,6 +2597,10 @@ CBFS (Coreboot Filesystem) support
Enables the driver for the SPI controllers on i.MX and MXC
SoCs. Currently i.MX31/35/51 are supported.
CONFIG_SYS_SPI_MXC_WAIT
Timeout for waiting until spi transfer completed.
default: (CONFIG_SYS_HZ/100) /* 10 ms */
- FPGA Support: CONFIG_FPGA
Enables FPGA subsystem.

17
drivers/spi/mxc_spi.c
View file

@ -30,6 +30,10 @@ static unsigned long spi_bases[] = {
#define reg_read readl
#define reg_write(a, v) writel(v, a)
#if !defined(CONFIG_SYS_SPI_MXC_WAIT)
#define CONFIG_SYS_SPI_MXC_WAIT (CONFIG_SYS_HZ/100) /* 10 ms */
#endif
struct mxc_spi_slave {
struct spi_slave slave;
unsigned long base;
@ -212,6 +216,8 @@ int spi_xchg_single(struct spi_slave *slave, unsigned int bitlen,
int nbytes = DIV_ROUND_UP(bitlen, 8);
u32 data, cnt, i;
struct cspi_regs *regs = (struct cspi_regs *)mxcs->base;
u32 ts;
int status;
debug("%s: bitlen %d dout 0x%x din 0x%x\n",
__func__, bitlen, (u32)dout, (u32)din);
@ -272,9 +278,16 @@ int spi_xchg_single(struct spi_slave *slave, unsigned int bitlen,
reg_write(&regs->ctrl, mxcs->ctrl_reg |
MXC_CSPICTRL_EN | MXC_CSPICTRL_XCH);
ts = get_timer(0);
status = reg_read(&regs->stat);
/* Wait until the TC (Transfer completed) bit is set */
while ((reg_read(&regs->stat) & MXC_CSPICTRL_TC) == 0)
;
while ((status & MXC_CSPICTRL_TC) == 0) {
if (get_timer(ts) > CONFIG_SYS_SPI_MXC_WAIT) {
printf("spi_xchg_single: Timeout!\n");
return -1;
}
status = reg_read(&regs->stat);
}
/* Transfer completed, clear any pending request */
reg_write(&regs->stat, MXC_CSPICTRL_TC | MXC_CSPICTRL_RXOVF);