spi: imx: correct wml as the last sg length

Correct wml as the last rx sg length instead of the whole transfer
length. Otherwise, mtd_stresstest will be failed as below:

insmod mtd_stresstest.ko dev=0
=================================================
mtd_stresstest: MTD device: 0
mtd_stresstest: not NAND flash, assume page size is 512 bytes.
mtd_stresstest: MTD device size 4194304, eraseblock size 65536, page size 512, count of eraseblocks 64, pa0
mtd_stresstest: doing operations
mtd_stresstest: 0 operations done
mtd_test: mtd_read from 1ff532, size 880
mtd_test: mtd_read from 20c267, size 64998
spi_master spi0: I/O Error in DMA RX
m25p80 spi0.0: SPI transfer failed: -110
spi_master spi0: failed to transfer one message from queue
mtd_test: error: read failed at 0x20c267
mtd_stresstest: error -110 occurred
=================================================
insmod: ERROR: could not insert module mtd_stresstest.ko: Connection timed out

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index e861157e3459afa48dd725eaa59b87d25cf9b3ce..037abbb852a4defa87925bccbbec2c8126b15458 100644 (file)
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -217,7 +217,6 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
                         struct spi_transfer *transfer)
 {
        struct spi_imx_data *spi_imx = spi_master_get_devdata(master);
-       unsigned int bytes_per_word, i;
 
        if (!master->dma_rx)
                return false;
@@ -225,14 +224,6 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
        if (spi_imx->slave_mode)
                return false;
 
-       bytes_per_word = spi_imx_bytes_per_word(transfer->bits_per_word);
-
-       for (i = spi_imx->devtype_data->fifo_size / 2; i > 0; i--) {
-               if (!(transfer->len % (i * bytes_per_word)))
-                       break;
-       }
-
-       spi_imx->wml = i;
        spi_imx->dynamic_burst = 0;
 
        return true;
@@ -594,7 +585,7 @@ static void mx51_setup_wml(struct spi_imx_data *spi_imx)
         * and enable DMA request.
         */
 
-       writel(MX51_ECSPI_DMA_RX_WML(spi_imx->wml) |
+       writel(MX51_ECSPI_DMA_RX_WML(spi_imx->wml - 1) |
                MX51_ECSPI_DMA_TX_WML(spi_imx->wml) |
                MX51_ECSPI_DMA_RXT_WML(spi_imx->wml) |
                MX51_ECSPI_DMA_TEDEN | MX51_ECSPI_DMA_RXDEN |
@@ -1287,12 +1278,30 @@ static int spi_imx_dma_transfer(struct spi_imx_data *spi_imx,
        unsigned long timeout;
        struct spi_master *master = spi_imx->bitbang.master;
        struct sg_table *tx = &transfer->tx_sg, *rx = &transfer->rx_sg;
+       struct scatterlist *last_sg = sg_last(rx->sgl, rx->nents);
+       unsigned int bytes_per_word, i;
        int ret;
 
+       /* Get the right burst length from the last sg to ensure no tail data */
+       bytes_per_word = spi_imx_bytes_per_word(transfer->bits_per_word);
+       for (i = spi_imx->devtype_data->fifo_size / 2; i > 0; i--) {
+               if (!(sg_dma_len(last_sg) % (i * bytes_per_word)))
+                       break;
+       }
+       /* Use 1 as wml in case no available burst length got */
+       if (i == 0)
+               i = 1;
+
+       spi_imx->wml =  i;
+
        ret = spi_imx_dma_configure(master);
        if (ret)
                return ret;
 
+       if (!spi_imx->devtype_data->setup_wml) {
+               dev_err(spi_imx->dev, "No setup_wml()?\n");
+               return -EINVAL;
+       }
        spi_imx->devtype_data->setup_wml(spi_imx);
 
        /*