@@ -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 +816,9 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac)
dmaengine_desc_get_callback_invoke(&desc->vd.tx, NULL);
spin_lock(&sdmac->vc.lock);
+ dma_wmb();
+ bd->mode.status |= BD_DONE;
+
if (error)
sdmac->status = old_status;
}
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 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. Fixes: 1ec1e82f2510 ("dmaengine: Add Freescale i.MX SDMA support") Signed-off-by: Philipp Puschmann <philipp.puschmann@emlix.com> --- Changelog v4: - fixed the fixes tag Changelog v3: - use correct dma_wmb() instead of dma_wb() - add fixes tag Changelog v2: - add dma_wb() drivers/dma/imx-sdma.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)