For uart rx dma data may not receive fully, so the number
of data read by sdma script once isn't always equal to period_len,
thus residue returned from sdma_tx_status() isn't valid for uart rx
dma. The old way to use chn_real_count to report residue should be
used for uart rx dma.
Signed-off-by: Jiada Wang <jiada_wang@xxxxxxxxxx>
---
drivers/dma/imx-sdma.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index 0f6fd42..1f1b64b 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -680,6 +680,11 @@ static void sdma_update_channel_loop(struct sdma_channel *sdmac)
bd->mode.status |= BD_DONE;
sdmac->buf_tail++;
sdmac->buf_tail %= sdmac->num_bd;
+ if (sdmac->peripheral_type == IMX_DMATYPE_UART) {
+ /* restore mode.count after counter readed */
+ sdmac->chn_real_count = bd->mode.count;
+ bd->mode.count = sdmac->chn_count;
+ }
}
}
@@ -1285,6 +1290,9 @@ static struct dma_async_tx_descriptor *sdma_prep_dma_cyclic(
goto err_out;
}
+ if (sdmac->peripheral_type == IMX_DMATYPE_UART)
+ sdmac->chn_count = period_len;
+
while (buf < buf_len) {
struct sdma_buffer_descriptor *bd = &sdmac->bd[i];
int param;
@@ -1361,7 +1369,8 @@ static enum dma_status sdma_tx_status(struct dma_chan *chan,
struct sdma_channel *sdmac = to_sdma_chan(chan);
u32 residue;
- if (sdmac->flags & IMX_DMA_SG_LOOP)
+ if ((sdmac->flags & IMX_DMA_SG_LOOP) &&
+ (sdmac->peripheral_type != IMX_DMATYPE_UART))
residue = (sdmac->num_bd - sdmac->buf_tail) * sdmac->period_len;
else
residue = sdmac->chn_count - sdmac->chn_real_count;
--
2.4.5
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