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| author | Amelie Delaunay <amelie.delaunay@foss.st.com> | 2023-10-04 19:35:29 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-10-20 00:08:54 +0300 |
| commit | 721dbbabf14b507600e072afd17bc70f548f7021 (patch) | |
| tree | 607c7a8f98f3d35f7c75e4669aac8749c4b1e08e /drivers/dma | |
| parent | fe15819408bc10589a4dbfe092aef2f00bc0baff (diff) | |
| download | linux-721dbbabf14b507600e072afd17bc70f548f7021.tar.xz | |
dmaengine: stm32-mdma: use Link Address Register to compute residue
commit a4b306eb83579c07b63dc65cd5bae53b7b4019d0 upstream.
Current implementation relies on curr_hwdesc index. But to keep this index
up to date, Block Transfer interrupt (BTIE) has to be enabled.
If it is not, curr_hwdesc is not updated, and then residue is not reliable.
Rely on Link Address Register instead. And disable BTIE interrupt
in stm32_mdma_setup_xfer() because it is no more needed in case of
_prep_slave_sg() to maintain curr_hwdesc up to date.
It avoids extra interrupts and also ensures a reliable residue. These
improvements are required for STM32 DCMI camera capture use case, which
need STM32 DMA and MDMA chaining for good performance.
Fixes: 696874322771 ("dmaengine: stm32-mdma: add support to be triggered by STM32 DMA")
Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20231004163531.2864160-2-amelie.delaunay@foss.st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/stm32-mdma.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c index a815833a701e..de213b47e650 100644 --- a/drivers/dma/stm32-mdma.c +++ b/drivers/dma/stm32-mdma.c @@ -778,8 +778,6 @@ static int stm32_mdma_setup_xfer(struct stm32_mdma_chan *chan, /* Enable interrupts */ ccr &= ~STM32_MDMA_CCR_IRQ_MASK; ccr |= STM32_MDMA_CCR_TEIE | STM32_MDMA_CCR_CTCIE; - if (sg_len > 1) - ccr |= STM32_MDMA_CCR_BTIE; desc->ccr = ccr; return 0; @@ -1325,12 +1323,21 @@ static size_t stm32_mdma_desc_residue(struct stm32_mdma_chan *chan, { struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan); struct stm32_mdma_hwdesc *hwdesc; - u32 cbndtr, residue, modulo, burst_size; + u32 cisr, clar, cbndtr, residue, modulo, burst_size; int i; + cisr = stm32_mdma_read(dmadev, STM32_MDMA_CISR(chan->id)); + residue = 0; - for (i = curr_hwdesc + 1; i < desc->count; i++) { + /* Get the next hw descriptor to process from current transfer */ + clar = stm32_mdma_read(dmadev, STM32_MDMA_CLAR(chan->id)); + for (i = desc->count - 1; i >= 0; i--) { hwdesc = desc->node[i].hwdesc; + + if (hwdesc->clar == clar) + break;/* Current transfer found, stop cumulating */ + + /* Cumulate residue of unprocessed hw descriptors */ residue += STM32_MDMA_CBNDTR_BNDT(hwdesc->cbndtr); } cbndtr = stm32_mdma_read(dmadev, STM32_MDMA_CBNDTR(chan->id)); |