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From 6460bf849143979acff90f3664f78bf3907aad0f Mon Sep 17 00:00:00 2001
From: Martin Sperl <kernel@martin.sperl.org>
Date: Thu, 10 Sep 2015 09:32:14 +0000
Subject: [PATCH 182/203] backport: 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: <robert@axium.co.nz>
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
---
drivers/spi/spi-bcm2835.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -386,14 +386,14 @@ static bool bcm2835_spi_can_dma(struct s
/* 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;
}
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