dmaengine: imx-sdma - update the residue calculation for cyclic channels
The calculation of the DMA transaction residue supports only fixed
size data transfers. This implementation is not covering all
operations (e.g. data receiving) when we need to know the exact amount
of bytes transferred.
The loop channels handling was changed to clear the buffer
descriptor errors and use the bd->mode.count to calculate the
residue.
Tested-by: Peter Senna Tschudin <peter.senna@collabora.com>
Acked-by: Peter Senna Tschudin <peter.senna@collabora.com>
Reviewed-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Nandor Han <nandor.han@ge.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index aa35a77..3cb4738 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -651,6 +651,8 @@
static void sdma_update_channel_loop(struct sdma_channel *sdmac)
{
struct sdma_buffer_descriptor *bd;
+ int error = 0;
+ enum dma_status old_status = sdmac->status;
/*
* loop mode. Iterate over descriptors, re-setup them and
@@ -662,10 +664,20 @@
if (bd->mode.status & BD_DONE)
break;
- if (bd->mode.status & BD_RROR)
+ if (bd->mode.status & BD_RROR) {
+ bd->mode.status &= ~BD_RROR;
sdmac->status = DMA_ERROR;
+ error = -EIO;
+ }
+ /*
+ * We use bd->mode.count to calculate the residue, since contains
+ * the number of bytes present in the current buffer descriptor.
+ */
+
+ sdmac->chn_real_count = bd->mode.count;
bd->mode.status |= BD_DONE;
+ bd->mode.count = sdmac->period_len;
/*
* The callback is called from the interrupt context in order
@@ -679,6 +691,9 @@
sdmac->buf_tail++;
sdmac->buf_tail %= sdmac->num_bd;
+
+ if (error)
+ sdmac->status = old_status;
}
}
@@ -1349,7 +1364,8 @@
u32 residue;
if (sdmac->flags & IMX_DMA_SG_LOOP)
- residue = (sdmac->num_bd - sdmac->buf_tail) * sdmac->period_len;
+ residue = (sdmac->num_bd - sdmac->buf_tail) *
+ sdmac->period_len - sdmac->chn_real_count;
else
residue = sdmac->chn_count - sdmac->chn_real_count;