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| author | Amelie Delaunay <amelie.delaunay@foss.st.com> | 2023-10-04 17:50:24 +0200 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2023-10-09 11:10:58 +0530 |
| commit | 67e13e89742c3b21ce177f612bf9ef32caae6047 (patch) | |
| tree | 9d3a74c0d3a5e418112d496afb293073352c6689 /drivers/dma | |
| parent | 2df467e908ce463cff1431ca1b00f650f7a514b4 (diff) | |
| download | lwn-67e13e89742c3b21ce177f612bf9ef32caae6047.tar.gz lwn-67e13e89742c3b21ce177f612bf9ef32caae6047.zip | |
dmaengine: stm32-dma: fix residue in case of MDMA chaining
In case of MDMA chaining, DMA is configured in Double-Buffer Mode (DBM)
with two periods, but if transfer has been prepared with _prep_slave_sg(),
the transfer is not marked cyclic (=!chan->desc->cyclic). However, as DBM
is activated for MDMA chaining, residue computation must take into account
cyclic constraints.
With only two periods in MDMA chaining, and no update due to Transfer
Complete interrupt masked, n_sg is always 0. If DMA current memory address
(depending on SxCR.CT and SxM0AR/SxM1AR) does not correspond, it means n_sg
should be increased.
Then, the residue of the current period is the one read from SxNDTR and
should not be overwritten with the full period length.
Fixes: 723795173ce1 ("dmaengine: stm32-dma: add support to trigger STM32 MDMA")
Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231004155024.2609531-2-amelie.delaunay@foss.st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/stm32-dma.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c index 7427acc82259..0b30151fb45c 100644 --- a/drivers/dma/stm32-dma.c +++ b/drivers/dma/stm32-dma.c @@ -1389,11 +1389,12 @@ static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan, residue = stm32_dma_get_remaining_bytes(chan); - if (chan->desc->cyclic && !stm32_dma_is_current_sg(chan)) { + if ((chan->desc->cyclic || chan->trig_mdma) && !stm32_dma_is_current_sg(chan)) { n_sg++; if (n_sg == chan->desc->num_sgs) n_sg = 0; - residue = sg_req->len; + if (!chan->trig_mdma) + residue = sg_req->len; } /* @@ -1403,7 +1404,7 @@ static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan, * residue = remaining bytes from NDTR + remaining * periods/sg to be transferred */ - if (!chan->desc->cyclic || n_sg != 0) + if ((!chan->desc->cyclic && !chan->trig_mdma) || n_sg != 0) for (i = n_sg; i < desc->num_sgs; i++) residue += desc->sg_req[i].len; |