atcspi200: Add timeout mechanism in spi_xfer()

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

diff --git a/drivers/spi/atcspi200_spi.c b/drivers/spi/atcspi200_spi.c
index 634cd565610c98c2ba0c202192c81d23e862fa22..775b9ffc25955b97a50688dea3c91fa0125940a6 100644 (file)
--- 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;