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| author | Amelie Delaunay <amelie.delaunay@foss.st.com> | 2023-10-04 18:35:29 +0200 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2023-10-09 11:10:30 +0530 |
| commit | a4b306eb83579c07b63dc65cd5bae53b7b4019d0 (patch) | |
| tree | 246e1aa0bea83c5564f2799dd5beacb93e32bfca | |
| parent | 81337b9a72dc58a5fa0ae8a042e8cb59f9bdec4a (diff) | |
| download | mailbox-a4b306eb83579c07b63dc65cd5bae53b7b4019d0.tar.gz | |
dmaengine: stm32-mdma: use Link Address Register to compute residue
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>
| -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 cc6f4b00091fec..da73e13b8c9def 100644 --- a/drivers/dma/stm32-mdma.c +++ b/drivers/dma/stm32-mdma.c @@ -777,8 +777,6 @@ 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; @@ -1324,12 +1322,21 @@ 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)); |