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Commit 2a3fffd4 authored by Martin Sperl's avatar Martin Sperl Committed by Mark Brown
Browse files

spi: bcm2835: BUG: fix wrong use of PAGE_MASK 



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: default avatar <robert@axium.co.nz>
Signed-off-by: default avatarMartin Sperl <kernel@martin.sperl.org>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
parent d770e558

drivers/spi/spi-bcm2835.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

	}