From: Lukas Wunner Date: Thu, 29 Nov 2018 15:45:24 +0000 (+0100) Subject: spi: bcm2835: Synchronize with callback on DMA termination X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=2527704d8411e2b4241916e8b22505cb4519ce08;p=openwrt%2Fstaging%2Fblogic.git 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 Cc: Frank Pavlic Cc: Martin Sperl Cc: Noralf Trønnes Cc: Vinod Koul Signed-off-by: Mark Brown --- 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 */