spi: davinci: do not use DMA for vmalloc'ed buffers

Using vmalloc'ed buffers will fail since daVinci has
VIVT cache and only the kernel lowmem virtual address
is invalidated/flushed when performing DMA.
The virtual address returned from vmalloc() is not
invalidated/flushed and may contain stale data when
returning from spi_sync().
Fixes errors when running UBIFS over SPI NOR.
Revert this when all upper layer users of vmalloc'ed
buffers sent to SPI handles cache flushing/invalidating.

Signed-off-by: Frode Isaksen <fisaksen@baylibre.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/spi/spi-davinci.c b/drivers/spi/spi-davinci.c
index 75c658e4e487..f37bbdd18d61 100644
--- a/drivers/spi/spi-davinci.c
+++ b/drivers/spi/spi-davinci.c
@@ -482,7 +482,9 @@ static bool davinci_spi_can_dma(struct spi_master *master,
 
         if (spicfg)
                 can_dma = (spicfg->io_type == SPI_IO_TYPE_DMA) &&
-                        (xfer->len >= DMA_MIN_BYTES);
+                        (xfer->len >= DMA_MIN_BYTES) &&
+                        !is_vmalloc_addr(xfer->rx_buf) &&
+                        !is_vmalloc_addr(xfer->tx_buf);
 
         return can_dma;
 }