This is a note to let you know that I've just added the patch titled
spi: dw-mid: clear BUSY flag fist and test other one
to the 3.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
spi-dw-mid-clear-busy-flag-fist-and-test-other-one.patch
and it can be found in the queue-3.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 854d2f241d71f6ca08ccde30e6c7c2e403363e52 Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Date: Fri, 6 Mar 2015 14:42:01 +0200
Subject: spi: dw-mid: clear BUSY flag fist and test other one
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
commit 854d2f241d71f6ca08ccde30e6c7c2e403363e52 upstream.
The logic of DMA completion is broken now since test_and_clear_bit() never
returns the other bit is set. It means condition are always false and we have
spi_finalize_current_transfer() called per each DMA completion which is wrong.
The patch fixes logic by clearing BUSY bit first and then check for the other
one.
Fixes: 30c8eb52cc4a (spi: dw-mid: split rx and tx callbacks when DMA)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/spi/spi-dw-mid.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/spi/spi-dw-mid.c
+++ b/drivers/spi/spi-dw-mid.c
@@ -108,7 +108,8 @@ static void dw_spi_dma_tx_done(void *arg
{
struct dw_spi *dws = arg;
- if (test_and_clear_bit(TX_BUSY, &dws->dma_chan_busy) & BIT(RX_BUSY))
+ clear_bit(TX_BUSY, &dws->dma_chan_busy);
+ if (test_bit(RX_BUSY, &dws->dma_chan_busy))
return;
dw_spi_xfer_done(dws);
}
@@ -156,7 +157,8 @@ static void dw_spi_dma_rx_done(void *arg
{
struct dw_spi *dws = arg;
- if (test_and_clear_bit(RX_BUSY, &dws->dma_chan_busy) & BIT(TX_BUSY))
+ clear_bit(RX_BUSY, &dws->dma_chan_busy);
+ if (test_bit(TX_BUSY, &dws->dma_chan_busy))
return;
dw_spi_xfer_done(dws);
}
Patches currently in stable-queue which might be from andriy.shevchenko@xxxxxxxxxxxxxxx are
queue-3.19/spi-dw-mid-clear-busy-flag-fist-and-test-other-one.patch
queue-3.19/dmaengine-dw-append-module_alias-for-platform-driver.patch
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