spi/fsl-espi: avoid infinite loops on fsl_espi_cpu_irq()

[cascardo/linux.git] / drivers / spi / spi-fsl-espi.c

diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
index 7cb0c19..8d85a3c 100644 (file)
--- a/drivers/spi/spi-fsl-espi.c
+++ b/drivers/spi/spi-fsl-espi.c
@@ -245,7 +245,12 @@ static int fsl_espi_bufs(struct spi_device *spi, struct spi_transfer *t)
        if (ret)
                return ret;
 
-       wait_for_completion(&mpc8xxx_spi->done);
+       /* Won't hang up forever, SPI bus sometimes got lost interrupts... */
+       ret = wait_for_completion_timeout(&mpc8xxx_spi->done, 2 * HZ);
+       if (ret == 0)
+               dev_err(mpc8xxx_spi->dev,
+                       "Transaction hanging up (left %d bytes)\n",
+                       mpc8xxx_spi->count);
 
        /* disable rx ints */
        mpc8xxx_spi_write_reg(&reg_base->mask, 0);
@@ -539,16 +544,31 @@ void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
        if (events & SPIE_NE) {
                u32 rx_data, tmp;
                u8 rx_data_8;
+               int rx_nr_bytes = 4;
+               int ret;
 
                /* Spin until RX is done */
-               while (SPIE_RXCNT(events) < min(4, mspi->len)) {
-                       cpu_relax();
-                       events = mpc8xxx_spi_read_reg(&reg_base->event);
+               if (SPIE_RXCNT(events) < min(4, mspi->len)) {
+                       ret = spin_event_timeout(
+                               !(SPIE_RXCNT(events =
+                               mpc8xxx_spi_read_reg(&reg_base->event)) <
+                                               min(4, mspi->len)),
+                                               10000, 0); /* 10 msec */
+                       if (!ret)
+                               dev_err(mspi->dev,
+                                        "tired waiting for SPIE_RXCNT\n");
                }
 
                if (mspi->len >= 4) {
                        rx_data = mpc8xxx_spi_read_reg(&reg_base->receive);
+               } else if (mspi->len <= 0) {
+                       dev_err(mspi->dev,
+                               "unexpected RX(SPIE_NE) interrupt occurred,\n"
+                               "(local rxlen %d bytes, reg rxlen %d bytes)\n",
+                               min(4, mspi->len), SPIE_RXCNT(events));
+                       rx_nr_bytes = 0;
                } else {
+                       rx_nr_bytes = mspi->len;
                        tmp = mspi->len;
                        rx_data = 0;
                        while (tmp--) {
@@ -559,7 +579,7 @@ void fsl_espi_cpu_irq(struct mpc8xxx_spi *mspi, u32 events)
                        rx_data <<= (4 - mspi->len) * 8;
                }
 
-               mspi->len -= 4;
+               mspi->len -= rx_nr_bytes;
 
                if (mspi->rx)
                        mspi->get_rx(rx_data, mspi);