[PATCH 3.19.y-ckt 048/130] spi: imx: Fix small DMA transfers

From: Kamal Mostafa
Date: Thu Aug 27 2015 - 18:40:59 EST

3.19.8-ckt6 -stable review patch. If anyone has any objections, please let me know.


From: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>

commit f6ee9b582d2db652497b73c1f117591dfb6d3a90 upstream.

DMA transfers must be greater than the watermark level size. spi_imx->rx_wml
and spi_imx->tx_wml contain the watermark level in 32bit words whereas struct
spi_transfer contains the transfer len in bytes. Fix the check if DMA is
possible for a transfer accordingly. This fixes transfers with sizes between
33 and 128 bytes for which previously was claimed that DMA is possible.

Fixes: f62caccd12c17e4 (spi: spi-imx: add DMA support)
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
drivers/spi/spi-imx.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 308c2d3..b9046f7 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -202,8 +202,9 @@ static bool spi_imx_can_dma(struct spi_master *master, struct spi_device *spi,
struct spi_imx_data *spi_imx = spi_master_get_devdata(master);

- if (spi_imx->dma_is_inited && (transfer->len > spi_imx->rx_wml)
- && (transfer->len > spi_imx->tx_wml))
+ if (spi_imx->dma_is_inited
+ && transfer->len > spi_imx->rx_wml * sizeof(u32)
+ && transfer->len > spi_imx->tx_wml * sizeof(u32))
return true;
return false;

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