BD_DONE flag marks ownership of the buffer. When 1 SDMA owns the buffer, when 0 ARM owns it. When processing the buffers in sdma_update_channel_loop the ownership of the currently processed buffer was set to SDMA again before running the callback function of the the buffer and while the sdma script may be running in parallel. So there was the possibility to get the buffer overwritten by SDMA before it has been processed by kernel leading to kind of random errors in the upper layers, e.g. bluetooth. It may be further a good idea to make the status struct member volatile or access it using writel or similar to rule out that the compiler sets the BD_DONE flag before the callback routine has finished. Signed-off-by: Philipp Puschmann <philipp.puschmann@xxxxxxxxx> --- drivers/dma/imx-sdma.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c index a01f4b5d793c..1abb14ff394d 100644 --- a/drivers/dma/imx-sdma.c +++ b/drivers/dma/imx-sdma.c @@ -802,7 +802,6 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac) */ desc->chn_real_count = bd->mode.count; - bd->mode.status |= BD_DONE; bd->mode.count = desc->period_len; desc->buf_ptail = desc->buf_tail; desc->buf_tail = (desc->buf_tail + 1) % desc->num_bd; @@ -817,6 +816,8 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac) dmaengine_desc_get_callback_invoke(&desc->vd.tx, NULL); spin_lock(&sdmac->vc.lock); + bd->mode.status |= BD_DONE; + if (error) sdmac->status = old_status; } -- 2.23.0
