[PATCH 2/2] serial: 8250-mtk: modify uart DMA rx

[Long Cheng]

Modify uart rx and complete for DMA

Signed-off-by: Long Cheng <long.cheng@xxxxxxxxxxxx>
---
 drivers/tty/serial/8250/8250_mtk.c |   49 +++++++++++++++---------------------
 1 file changed, 20 insertions(+), 29 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 417c7c8..f470ded 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -47,7 +47,6 @@
 #define MTK_UART_DMA_EN_RX	0x5
 
 #define MTK_UART_ESCAPE_CHAR	0x77	/* Escape char added under sw fc */
-#define MTK_UART_TX_SIZE	UART_XMIT_SIZE
 #define MTK_UART_RX_SIZE	0x8000
 #define MTK_UART_TX_TRIGGER	1
 #define MTK_UART_RX_TRIGGER	MTK_UART_RX_SIZE
@@ -89,28 +88,30 @@ static void mtk8250_dma_rx_complete(void *param)
 	struct mtk8250_data *data = up->port.private_data;
 	struct tty_port *tty_port = &up->port.state->port;
 	struct dma_tx_state state;
+	int copied, total, cnt;
 	unsigned char *ptr;
-	int copied;
 
-	dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr,
-				dma->rx_size, DMA_FROM_DEVICE);
+	if (data->rx_status == DMA_RX_SHUTDOWN)
+		return;
 
 	dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
+	total = dma->rx_size - state.residue;
+	cnt = total;
 
-	if (data->rx_status == DMA_RX_SHUTDOWN)
-		return;
+	if ((data->rx_pos + cnt) > dma->rx_size)
+		cnt = dma->rx_size - data->rx_pos;
 
-	if ((data->rx_pos + state.residue) <= dma->rx_size) {
-		ptr = (unsigned char *)(data->rx_pos + dma->rx_buf);
-		copied = tty_insert_flip_string(tty_port, ptr, state.residue);
-	} else {
-		ptr = (unsigned char *)(data->rx_pos + dma->rx_buf);
-		copied = tty_insert_flip_string(tty_port, ptr,
-						dma->rx_size - data->rx_pos);
+	ptr = (unsigned char *)(data->rx_pos + dma->rx_buf);
+	copied = tty_insert_flip_string(tty_port, ptr, cnt);
+	data->rx_pos += cnt;
+
+	if (total > cnt) {
 		ptr = (unsigned char *)(dma->rx_buf);
-		copied += tty_insert_flip_string(tty_port, ptr,
-				data->rx_pos + state.residue - dma->rx_size);
+		cnt = total - cnt;
+		copied += tty_insert_flip_string(tty_port, ptr, cnt);
+		data->rx_pos = cnt;
 	}
+
 	up->port.icount.rx += copied;
 
 	tty_flip_buffer_push(tty_port);
@@ -121,9 +122,7 @@ static void mtk8250_dma_rx_complete(void *param)
 static void mtk8250_rx_dma(struct uart_8250_port *up)
 {
 	struct uart_8250_dma *dma = up->dma;
-	struct mtk8250_data *data = up->port.private_data;
 	struct dma_async_tx_descriptor	*desc;
-	struct dma_tx_state	 state;
 
 	desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
 					   dma->rx_size, DMA_DEV_TO_MEM,
@@ -138,12 +137,6 @@ static void mtk8250_rx_dma(struct uart_8250_port *up)
 
 	dma->rx_cookie = dmaengine_submit(desc);
 
-	dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
-	data->rx_pos = state.residue;
-
-	dma_sync_single_for_device(dma->rxchan->device->dev, dma->rx_addr,
-				   dma->rx_size, DMA_FROM_DEVICE);
-
 	dma_async_issue_pending(dma->rxchan);
 }
 
@@ -156,13 +149,11 @@ static void mtk8250_dma_enable(struct uart_8250_port *up)
 	if (data->rx_status != DMA_RX_START)
 		return;
 
-	dma->rxconf.direction		= DMA_DEV_TO_MEM;
-	dma->rxconf.src_addr_width	= dma->rx_size / 1024;
-	dma->rxconf.src_addr		= dma->rx_addr;
+	dma->rxconf.src_port_window_size	= dma->rx_size;
+	dma->rxconf.src_addr				= dma->rx_addr;
 
-	dma->txconf.direction		= DMA_MEM_TO_DEV;
-	dma->txconf.dst_addr_width	= MTK_UART_TX_SIZE / 1024;
-	dma->txconf.dst_addr		= dma->tx_addr;
+	dma->txconf.dst_port_window_size	= UART_XMIT_SIZE;
+	dma->txconf.dst_addr				= dma->tx_addr;
 
 	serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR |
 		UART_FCR_CLEAR_XMIT);
-- 
1.7.9.5