diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.1/0176-spi-bcm2835-fix-overflow-in-calculation-of-transfer-.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.1/0176-spi-bcm2835-fix-overflow-in-calculation-of-transfer-.patch | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.1/0176-spi-bcm2835-fix-overflow-in-calculation-of-transfer-.patch b/target/linux/brcm2708/patches-4.1/0176-spi-bcm2835-fix-overflow-in-calculation-of-transfer-.patch new file mode 100644 index 0000000..4e55ba9 --- /dev/null +++ b/target/linux/brcm2708/patches-4.1/0176-spi-bcm2835-fix-overflow-in-calculation-of-transfer-.patch @@ -0,0 +1,53 @@ +From 6e1447aaad894f45595a45fc52ae5f7dbe072b2e Mon Sep 17 00:00:00 2001 +From: Martin Sperl <kernel@martin.sperl.org> +Date: Wed, 29 Jul 2015 07:34:10 +0000 +Subject: [PATCH 176/203] spi: bcm2835: fix overflow in calculation of transfer + time + +This resulted in the use of polling mode when other approaches +(dma or interrupts) would have been more appropriate. + +Happened for transfers longer than 477 bytes. + +Reported-by: Noralf Tronnes <noralf@tronnes.org> +Signed-off-by: Martin Sperl <kernel@martin.sperl.org> +Signed-off-by: Mark Brown <broonie@kernel.org> +(cherry picked from commit 0122a5183088e3117bb9c8fbe248914efb502f3f) +--- + drivers/spi/spi-bcm2835.c | 10 ++++++---- + 1 file changed, 6 insertions(+), 4 deletions(-) + +--- a/drivers/spi/spi-bcm2835.c ++++ b/drivers/spi/spi-bcm2835.c +@@ -480,7 +480,7 @@ static int bcm2835_spi_transfer_one_poll + struct spi_device *spi, + struct spi_transfer *tfr, + u32 cs, +- unsigned long xfer_time_us) ++ unsigned long long xfer_time_us) + { + struct bcm2835_spi *bs = spi_master_get_devdata(master); + unsigned long timeout; +@@ -531,7 +531,8 @@ static int bcm2835_spi_transfer_one(stru + { + struct bcm2835_spi *bs = spi_master_get_devdata(master); + unsigned long spi_hz, clk_hz, cdiv; +- unsigned long spi_used_hz, xfer_time_us; ++ unsigned long spi_used_hz; ++ unsigned long long xfer_time_us; + u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS); + + /* set clock */ +@@ -573,9 +574,10 @@ static int bcm2835_spi_transfer_one(stru + bs->rx_len = tfr->len; + + /* calculate the estimated time in us the transfer runs */ +- xfer_time_us = tfr->len ++ xfer_time_us = (unsigned long long)tfr->len + * 9 /* clocks/byte - SPI-HW waits 1 clock after each byte */ +- * 1000000 / spi_used_hz; ++ * 1000000; ++ do_div(xfer_time_us, spi_used_hz); + + /* for short requests run polling*/ + if (xfer_time_us <= BCM2835_SPI_POLLING_LIMIT_US) |