diff mbox

spi: bcm2835: BUG: fix wrong use of PAGE_MASK

Message ID 1441877535-2218-1-git-send-email-kernel@martin.sperl.org (mailing list archive)
State Accepted
Commit 2a3fffd45822070309bcf0b1e1dae624d633824a
Headers show

Commit Message

Martin Sperl Sept. 10, 2015, 9:32 a.m. UTC 
From: Martin Sperl <kernel@martin.sperl.org>

There is a bug in the alignment checking of transfers,
that results in DMA not being used for un-aligned
transfers that do not cross page-boundries, which is valid.

This is due to a missconception of the meaning PAGE_MASK
when implementing that check originally - (PAGE_SIZE - 1) 
should have been used instead.

Also fixes a copy/paste error.

Reported-by: <robert@axium.co.nz>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
---
 drivers/spi/spi-bcm2835.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
diff mbox

Patch

diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index 59705ab..ed74786 100644
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -386,14 +386,14 @@  static bool bcm2835_spi_can_dma(struct spi_master *master,
 	/* otherwise we only allow transfers within the same page
 	 * to avoid wasting time on dma_mapping when it is not practical
 	 */
-	if (((size_t)tfr->tx_buf & PAGE_MASK) + tfr->len > PAGE_SIZE) {
+	if (((size_t)tfr->tx_buf & (PAGE_SIZE - 1)) + tfr->len > PAGE_SIZE) {
 		dev_warn_once(&spi->dev,
 			      "Unaligned spi tx-transfer bridging page\n");
 		return false;
 	}
-	if (((size_t)tfr->rx_buf & PAGE_MASK) + tfr->len > PAGE_SIZE) {
+	if (((size_t)tfr->rx_buf & (PAGE_SIZE - 1)) + tfr->len > PAGE_SIZE) {
 		dev_warn_once(&spi->dev,
-			      "Unaligned spi tx-transfer bridging page\n");
+			      "Unaligned spi rx-transfer bridging page\n");
 		return false;
 	}