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authorLukas Wunner <lukas@wunner.de>2018-11-29 16:45:24 +0100
committerMark Brown <broonie@kernel.org>2018-12-04 17:51:55 +0100
commit2527704d8411e2b4241916e8b22505cb4519ce08 (patch)
tree8214b5bc0e342dc11a046b41a5f06e74d2416833 /drivers/spi
parentspi: bcm2835: Speed up FIFO access if fill level is known (diff)
downloadlinux-2527704d8411e2b4241916e8b22505cb4519ce08.tar.xz
linux-2527704d8411e2b4241916e8b22505cb4519ce08.zip
spi: bcm2835: Synchronize with callback on DMA termination
Commit b36f09c3c441 ("dmaengine: Add transfer termination synchronization support") deprecated dmaengine_terminate_all() in favor of dmaengine_terminate_sync() and dmaengine_terminate_async() to avoid freeing resources used by the DMA callback before its execution has concluded. Commit de92436ac40f ("dmaengine: bcm2835-dma: Use vchan_terminate_vdesc() instead of desc_free") amended the BCM2835 DMA driver with an implementation of ->device_synchronize(), which is a prerequisite for dmaengine_terminate_sync(). Thus, clients of the DMA driver (such as the BCM2835 SPI driver) may now be converted to the new API. It is generally desirable to use the _sync() variant except in atomic context. There is only a single occurrence where the BCM2835 SPI driver calls dmaengine_terminate_all() in atomic context and that is in bcm2835_spi_dma_done() (the RX DMA channel's callback) to terminate the TX DMA channel. The TX DMA channel doesn't have a callback (yet), hence it is safe to use the _async() variant there. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Frank Pavlic <f.pavlic@kunbus.de> Cc: Martin Sperl <kernel@martin.sperl.org> Cc: Noralf Trønnes <noralf@tronnes.org> Cc: Vinod Koul <vkoul@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi-bcm2835.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index 5af4cf74392c..35aebdfd3b4e 100644
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -514,7 +514,7 @@ static void bcm2835_spi_dma_done(void *data)
* situation otherwise...
*/
if (cmpxchg(&bs->dma_pending, true, false)) {
- dmaengine_terminate_all(master->dma_tx);
+ dmaengine_terminate_async(master->dma_tx);
bcm2835_spi_undo_prologue(bs);
}
@@ -605,7 +605,7 @@ static int bcm2835_spi_transfer_one_dma(struct spi_master *master,
ret = bcm2835_spi_prepare_sg(master, tfr, false);
if (ret) {
/* need to reset on errors */
- dmaengine_terminate_all(master->dma_tx);
+ dmaengine_terminate_sync(master->dma_tx);
bs->dma_pending = false;
goto err_reset_hw;
}
@@ -650,12 +650,12 @@ static bool bcm2835_spi_can_dma(struct spi_master *master,
static void bcm2835_dma_release(struct spi_master *master)
{
if (master->dma_tx) {
- dmaengine_terminate_all(master->dma_tx);
+ dmaengine_terminate_sync(master->dma_tx);
dma_release_channel(master->dma_tx);
master->dma_tx = NULL;
}
if (master->dma_rx) {
- dmaengine_terminate_all(master->dma_rx);
+ dmaengine_terminate_sync(master->dma_rx);
dma_release_channel(master->dma_rx);
master->dma_rx = NULL;
}
@@ -864,8 +864,8 @@ static void bcm2835_spi_handle_err(struct spi_master *master,
/* if an error occurred and we have an active dma, then terminate */
if (cmpxchg(&bs->dma_pending, true, false)) {
- dmaengine_terminate_all(master->dma_tx);
- dmaengine_terminate_all(master->dma_rx);
+ dmaengine_terminate_sync(master->dma_tx);
+ dmaengine_terminate_sync(master->dma_rx);
bcm2835_spi_undo_prologue(bs);
}
/* and reset */