IMX/SDMA : save the real count for one DMA transaction.
When we use the SDMA in the UART driver(such as imx6q), we will
meet one situation:
Assume we set 64 bytes for the RX DMA buffer.
The RX DMA buffer has received some data, but not full.
An Aging DMA request will be received by the SDMA controller if we enable the
IDDMAEN(UCR4[6]) in this case.
So the UART driver needs to know the count of the real received bytes,
and push them to upper layer.
Add two new fields to sdmac, and update the `residue` in sdma_tx_status().
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index d9e5933..f59fd8f 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -268,6 +268,8 @@
struct dma_async_tx_descriptor desc;
dma_cookie_t last_completed;
enum dma_status status;
+ unsigned int chn_count;
+ unsigned int chn_real_count;
};
#define IMX_DMA_SG_LOOP (1 << 0)
@@ -503,6 +505,7 @@
struct sdma_buffer_descriptor *bd;
int i, error = 0;
+ sdmac->chn_real_count = 0;
/*
* non loop mode. Iterate over all descriptors, collect
* errors and call callback function
@@ -512,6 +515,7 @@
if (bd->mode.status & (BD_DONE | BD_RROR))
error = -EIO;
+ sdmac->chn_real_count += bd->mode.count;
}
if (error)
@@ -519,9 +523,9 @@
else
sdmac->status = DMA_SUCCESS;
+ sdmac->last_completed = sdmac->desc.cookie;
if (sdmac->desc.callback)
sdmac->desc.callback(sdmac->desc.callback_param);
- sdmac->last_completed = sdmac->desc.cookie;
}
static void mxc_sdma_handle_channel(struct sdma_channel *sdmac)
@@ -941,6 +945,7 @@
goto err_out;
}
+ sdmac->chn_count = 0;
for_each_sg(sgl, sg, sg_len, i) {
struct sdma_buffer_descriptor *bd = &sdmac->bd[i];
int param;
@@ -957,6 +962,7 @@
}
bd->mode.count = count;
+ sdmac->chn_count += count;
if (sdmac->word_size > DMA_SLAVE_BUSWIDTH_4_BYTES) {
ret = -EINVAL;
@@ -1120,7 +1126,8 @@
last_used = chan->cookie;
- dma_set_tx_state(txstate, sdmac->last_completed, last_used, 0);
+ dma_set_tx_state(txstate, sdmac->last_completed, last_used,
+ sdmac->chn_count - sdmac->chn_real_count);
return sdmac->status;
}