Re: [U-Boot] [PATCH v3] spi, spi_mxc: do not hang in spi_xchg_single

On Mon, Jul 14, 2014 at 1:52 PM, Heiko Schocher hs@denx.de wrote:

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 Cc: Jagannadha Sutradharudu Teki jagannadh.teki@gmail.com

---

• changes for v2:
  • use timer api to poll till TC bit is set as Jagan Teki suggested and make this timeout configurable through CONFIG_SYS_SPI_MXC_WAIT

-changes for v3:

• add comment from Jagan Teki: remove unneccessary udelay()

README | 4 ++++ drivers/spi/mxc_spi.c | 17 +++++++++++++++-- 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/README b/README index 4ac7399..0f24bd3 100644 --- a/README +++ b/README @@ -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.
  

diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c index f3f029d..2d5f385 100644 --- a/drivers/spi/mxc_spi.c +++ b/drivers/spi/mxc_spi.c @@ -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);
  

-- 1.8.3.1

Applied to u-boot-spi/master

thanks!