[PATCH] atcspi200: Add timeout mechanism in spi_xfer()

[Leo Liang <ycliang@andestech.com>]

On Thu, Apr 01, 2021 at 04:48:51PM +0800, Dylan Dai-Rong Jhong(??????) wrote:
> Adding timeout mechanism to avoid spi driver from stucking
> in the while loop in __atcspi200_spi_xfer().
> 
> Signed-off-by: Dylan Jhong <dylan@andestech.com>
> ---
>  drivers/spi/atcspi200_spi.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/spi/atcspi200_spi.c b/drivers/spi/atcspi200_spi.c
> index 634cd56561..775b9ffc25 100644
> --- a/drivers/spi/atcspi200_spi.c
> +++ b/drivers/spi/atcspi200_spi.c
> @@ -201,7 +201,7 @@ static int __atcspi200_spi_xfer(struct nds_spi_slave *ns,
>  		size_t cmd_len = ns->cmd_len;
>  		unsigned long data_len = bitlen / 8;
>  		int rf_cnt;
> -		int ret = 0;
> +		int ret = 0, timeout = 0;
>  
>  		max_tran_len = ns->max_transfer_length;
>  		switch (flags) {
> @@ -243,11 +243,12 @@ static int __atcspi200_spi_xfer(struct nds_spi_slave *ns,
>  			ns->tran_len = tran_len;
>  			num_blks = DIV_ROUND_UP(tran_len , CHUNK_SIZE);
>  			num_bytes = (tran_len) % CHUNK_SIZE;
> +			timeout = SPI_TIMEOUT;
>  			if(num_bytes == 0)
>  				num_bytes = CHUNK_SIZE;
>  			__atcspi200_spi_start(ns);
>  
> -			while (num_blks) {
> +			while (num_blks && (timeout--)) {
>  				event = in_le32(&ns->regs->status);
>  				if ((event & TXEPTY) && (data_out)) {
>  					__nspi_espi_tx(ns, dout);
> @@ -269,6 +270,11 @@ static int __atcspi200_spi_xfer(struct nds_spi_slave *ns,
>  						din = (unsigned char *)din + rx_bytes;
>  					}
>  				}
> +
> +				if (!timeout) {
> +					debug("spi_xfer: %s() timeout\n", __func__);
> +					break;
> +				}
>  			}
>  
>  			data_len -= tran_len;
> -- 
> 2.17.0
>

Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>