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authorM'boumba Cedric Madianga <cedric.madianga@gmail.com>2016-12-13 16:40:48 +0300
committerVinod Koul <vinod.koul@intel.com>2017-01-03 06:53:17 +0300
commit2b12c5580e0a4c0ffd513d1522dd39b2464fb207 (patch)
tree8ab19ceb150fc730169f485c105591e11a3e31e6 /drivers/dma
parent8d1b76f031ce60c50d03674e6d1db0c5e5f55945 (diff)
downloadlinux-2b12c5580e0a4c0ffd513d1522dd39b2464fb207.tar.xz
dmaengine: stm32-dma: Fix residue computation issue in cyclic mode
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>
Diffstat (limited to 'drivers/dma')
-rw-r--r--drivers/dma/stm32-dma.c39
1 files changed, 26 insertions, 13 deletions
diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
index a8c2ad686173..8a29b028d39e 100644
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -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;
}