4.20-stable review patch. If anyone has any objections, please let me know.
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From: Lukas Wunner lukas@wunner.de
commit dbc944115eed48af110646992893dc43321368d8 upstream.
If submission of a DMA TX transfer succeeds but submission of the corresponding RX transfer does not, the BCM2835 SPI driver terminates the TX transfer but neglects to reset the dma_pending flag to false.
Thus, if the next transfer uses interrupt mode (because it is shorter than BCM2835_SPI_DMA_MIN_LENGTH) and runs into a timeout, dmaengine_terminate_all() will be called both for TX (once more) and for RX (which was never started in the first place). Fix it.
Signed-off-by: Lukas Wunner lukas@wunner.de Fixes: 3ecd37edaa2a ("spi: bcm2835: enable dma modes for transfers meeting certain conditions") Cc: stable@vger.kernel.org # v4.2+ Cc: Mathias Duckeck m.duckeck@kunbus.de Cc: Frank Pavlic f.pavlic@kunbus.de Cc: Martin Sperl kernel@martin.sperl.org Cc: Noralf Trønnes noralf@tronnes.org Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/spi/spi-bcm2835.c | 1 + 1 file changed, 1 insertion(+)
--- a/drivers/spi/spi-bcm2835.c +++ b/drivers/spi/spi-bcm2835.c @@ -341,6 +341,7 @@ static int bcm2835_spi_transfer_one_dma( if (ret) { /* need to reset on errors */ dmaengine_terminate_all(master->dma_tx); + bs->dma_pending = false; bcm2835_spi_reset_hw(master); return ret; }