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dmaengine: stm32-dma: Fix residue computation issue in cyclic mode

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This patch resolves the residue computation issue detected in cyclic mode.
Now, in cyclic mode, we increment next_sg variable as soon as a period is
transferred instead of after pushing a new sg request.
Then, we take into account that after transferring a complete buffer,
the next_sg variable is equal to 0.

Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Reviewed-by: Ludovic BARRE <ludovic.barre@st.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
M'boumba Cedric Madianga 2016-12-13 14:40:48 +01:00 committed by Vinod Koul
parent 8d1b76f031
commit 2b12c5580e
1 changed files with 26 additions and 13 deletions
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39
drivers/dma/stm32-dma.c
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@ -500,8 +500,6 @@ static void stm32_dma_configure_next_sg(struct stm32_dma_chan *chan)
dev_dbg(chan2dev(chan), "CT=0 <=> SM1AR: 0x%08x\n",
stm32_dma_read(dmadev, STM32_DMA_SM1AR(id)));
}
chan->next_sg++;
}
}
@ -510,6 +508,7 @@ static void stm32_dma_handle_chan_done(struct stm32_dma_chan *chan)
if (chan->desc) {
if (chan->desc->cyclic) {
vchan_cyclic_callback(&chan->desc->vdesc);
chan->next_sg++;
stm32_dma_configure_next_sg(chan);
} else {
chan->busy = false;
@ -846,26 +845,40 @@ static struct dma_async_tx_descriptor *stm32_dma_prep_dma_memcpy(
return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
}
static u32 stm32_dma_get_remaining_bytes(struct stm32_dma_chan *chan)
{
u32 dma_scr, width, ndtr;
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
width = STM32_DMA_SCR_PSIZE_GET(dma_scr);
ndtr = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
return ndtr << width;
}
static size_t stm32_dma_desc_residue(struct stm32_dma_chan *chan,
struct stm32_dma_desc *desc,
u32 next_sg)
{
struct stm32_dma_device *dmadev = stm32_dma_get_dev(chan);
u32 dma_scr, width, residue, count;
u32 residue = 0;
int i;
residue = 0;
/*
* In cyclic mode, for the last period, residue = remaining bytes from
* NDTR
*/
if (chan->desc->cyclic && next_sg == 0)
return stm32_dma_get_remaining_bytes(chan);
/*
* For all other periods in cyclic mode, and in sg mode,
* residue = remaining bytes from NDTR + remaining periods/sg to be
* transferred
*/
for (i = next_sg; i < desc->num_sgs; i++)
residue += desc->sg_req[i].len;
if (next_sg != 0) {
dma_scr = stm32_dma_read(dmadev, STM32_DMA_SCR(chan->id));
width = STM32_DMA_SCR_PSIZE_GET(dma_scr);
count = stm32_dma_read(dmadev, STM32_DMA_SNDTR(chan->id));
residue += count << width;
}
residue += stm32_dma_get_remaining_bytes(chan);
return residue;
}