Hi Lucas,
Am 19.09.19 um 12:27 schrieb Lucas Stach: > Hi Philipp, > > On Do, 2019-09-19 at 12:23 +0200, Philipp Puschmann wrote: >> 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. >> >> Signed-off-by: Philipp Puschmann <philipp.puschm...@emlix.com> >> >> --- >> >> Changelog v2: >> - add dma_wb() >> >> drivers/dma/imx-sdma.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c >> index 9ba74ab7e912..e029a2443cfc 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 +816,9 @@ 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_wb(); > > Has this change been tested? The function you want here is called > dma_wmb(). embarrassingly you are right. c&p error and even have not tried to build it :/ V3 comes soon.. Regards, Philipp > > Regards, > Lucas > >> + bd->mode.status |= BD_DONE; >> + >> if (error) >> sdmac->status = old_status; >> } >
