2 files changed, 135 insertions, 226 deletions

diff --git a/drivers/tty/serial/sirfsoc_uart.c b/drivers/tty/serial/sirfsoc_uart.c
index 6b1c92c1c27f..b6116413ca0d 100644
--- a/drivers/tty/serial/sirfsoc_uart.c
+++ b/drivers/tty/serial/sirfsoc_uart.c
@@ -36,8 +36,6 @@ sirfsoc_uart_pio_rx_chars(struct uart_port *port, unsigned int max_rx_count);
 static struct uart_driver sirfsoc_uart_drv;
 
 static void sirfsoc_uart_tx_dma_complete_callback(void *param);
-static void sirfsoc_uart_start_next_rx_dma(struct uart_port *port);
-static void sirfsoc_uart_rx_dma_complete_callback(void *param);
 static const struct sirfsoc_baudrate_to_regv baudrate_to_regv[] = {
 	{4000000, 2359296},
 	{3500000, 1310721},
@@ -465,144 +463,6 @@ static void sirfsoc_uart_tx_dma_complete_callback(void *param)
 	spin_unlock_irqrestore(&port->lock, flags);
 }
 
-static void sirfsoc_uart_insert_rx_buf_to_tty(
-		struct sirfsoc_uart_port *sirfport, int count)
-{
-	struct uart_port *port = &sirfport->port;
-	struct tty_port *tport = &port->state->port;
-	int inserted;
-
-	inserted = tty_insert_flip_string(tport,
-		sirfport->rx_dma_items[sirfport->rx_completed].xmit.buf, count);
-	port->icount.rx += inserted;
-}
-
-static void sirfsoc_rx_submit_one_dma_desc(struct uart_port *port, int index)
-{
-	struct sirfsoc_uart_port *sirfport = to_sirfport(port);
-
-	sirfport->rx_dma_items[index].xmit.tail =
-		sirfport->rx_dma_items[index].xmit.head = 0;
-	sirfport->rx_dma_items[index].desc =
-		dmaengine_prep_slave_single(sirfport->rx_dma_chan,
-		sirfport->rx_dma_items[index].dma_addr, SIRFSOC_RX_DMA_BUF_SIZE,
-		DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
-	if (IS_ERR_OR_NULL(sirfport->rx_dma_items[index].desc)) {
-		dev_err(port->dev, "DMA slave single fail\n");
-		return;
-	}
-	sirfport->rx_dma_items[index].desc->callback =
-		sirfsoc_uart_rx_dma_complete_callback;
-	sirfport->rx_dma_items[index].desc->callback_param = sirfport;
-	sirfport->rx_dma_items[index].cookie =
-		dmaengine_submit(sirfport->rx_dma_items[index].desc);
-	dma_async_issue_pending(sirfport->rx_dma_chan);
-}
-
-static void sirfsoc_rx_tmo_process_tl(unsigned long param)
-{
-	struct sirfsoc_uart_port *sirfport = (struct sirfsoc_uart_port *)param;
-	struct uart_port *port = &sirfport->port;
-	struct sirfsoc_register *ureg = &sirfport->uart_reg->uart_reg;
-	struct sirfsoc_int_en *uint_en = &sirfport->uart_reg->uart_int_en;
-	struct sirfsoc_int_status *uint_st = &sirfport->uart_reg->uart_int_st;
-	unsigned int count;
-	struct dma_tx_state tx_state;
-	unsigned long flags;
-	int i = 0;
-
-	spin_lock_irqsave(&port->lock, flags);
-	while (DMA_COMPLETE == dmaengine_tx_status(sirfport->rx_dma_chan,
-		sirfport->rx_dma_items[sirfport->rx_completed].cookie,
-		&tx_state)) {
-		sirfsoc_uart_insert_rx_buf_to_tty(sirfport,
-					SIRFSOC_RX_DMA_BUF_SIZE);
-		sirfport->rx_completed++;
-		sirfport->rx_completed %= SIRFSOC_RX_LOOP_BUF_CNT;
-		i++;
-		if (i > SIRFSOC_RX_LOOP_BUF_CNT)
-			break;
-	}
-	count = CIRC_CNT(sirfport->rx_dma_items[sirfport->rx_issued].xmit.head,
-		sirfport->rx_dma_items[sirfport->rx_issued].xmit.tail,
-		SIRFSOC_RX_DMA_BUF_SIZE);
-	if (count > 0)
-		sirfsoc_uart_insert_rx_buf_to_tty(sirfport, count);
-	wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl,
-			rd_regl(port, ureg->sirfsoc_rx_dma_io_ctrl) |
-			SIRFUART_IO_MODE);
-	sirfsoc_uart_pio_rx_chars(port, 4 - sirfport->rx_io_count);
-	if (sirfport->rx_io_count == 4) {
-		sirfport->rx_io_count = 0;
-		wr_regl(port, ureg->sirfsoc_int_st_reg,
-				uint_st->sirfsoc_rx_done);
-		if (!sirfport->is_atlas7)
-			wr_regl(port, ureg->sirfsoc_int_en_reg,
-				rd_regl(port, ureg->sirfsoc_int_en_reg) &
-				~(uint_en->sirfsoc_rx_done_en));
-		else
-			wr_regl(port, ureg->sirfsoc_int_en_clr_reg,
-					uint_en->sirfsoc_rx_done_en);
-		sirfsoc_uart_start_next_rx_dma(port);
-	} else {
-		wr_regl(port, ureg->sirfsoc_int_st_reg,
-				uint_st->sirfsoc_rx_done);
-		if (!sirfport->is_atlas7)
-			wr_regl(port, ureg->sirfsoc_int_en_reg,
-				rd_regl(port, ureg->sirfsoc_int_en_reg) |
-				(uint_en->sirfsoc_rx_done_en));
-		else
-			wr_regl(port, ureg->sirfsoc_int_en_reg,
-					uint_en->sirfsoc_rx_done_en);
-	}
-	spin_unlock_irqrestore(&port->lock, flags);
-	tty_flip_buffer_push(&port->state->port);
-}
-
-static void sirfsoc_uart_handle_rx_tmo(struct sirfsoc_uart_port *sirfport)
-{
-	struct uart_port *port = &sirfport->port;
-	struct sirfsoc_register *ureg = &sirfport->uart_reg->uart_reg;
-	struct sirfsoc_int_en *uint_en = &sirfport->uart_reg->uart_int_en;
-	struct dma_tx_state tx_state;
-	dmaengine_tx_status(sirfport->rx_dma_chan,
-		sirfport->rx_dma_items[sirfport->rx_issued].cookie, &tx_state);
-	dmaengine_terminate_all(sirfport->rx_dma_chan);
-	sirfport->rx_dma_items[sirfport->rx_issued].xmit.head =
-		SIRFSOC_RX_DMA_BUF_SIZE - tx_state.residue;
-	if (!sirfport->is_atlas7)
-		wr_regl(port, ureg->sirfsoc_int_en_reg,
-			rd_regl(port, ureg->sirfsoc_int_en_reg) &
-			~(uint_en->sirfsoc_rx_timeout_en));
-	else
-		wr_regl(port, ureg->sirfsoc_int_en_clr_reg,
-				uint_en->sirfsoc_rx_timeout_en);
-	tasklet_schedule(&sirfport->rx_tmo_process_tasklet);
-}
-
-static void sirfsoc_uart_handle_rx_done(struct sirfsoc_uart_port *sirfport)
-{
-	struct uart_port *port = &sirfport->port;
-	struct sirfsoc_register *ureg = &sirfport->uart_reg->uart_reg;
-	struct sirfsoc_int_en *uint_en = &sirfport->uart_reg->uart_int_en;
-	struct sirfsoc_int_status *uint_st = &sirfport->uart_reg->uart_int_st;
-
-	sirfsoc_uart_pio_rx_chars(port, 4 - sirfport->rx_io_count);
-	if (sirfport->rx_io_count == 4) {
-		sirfport->rx_io_count = 0;
-		if (!sirfport->is_atlas7)
-			wr_regl(port, ureg->sirfsoc_int_en_reg,
-				rd_regl(port, ureg->sirfsoc_int_en_reg) &
-				~(uint_en->sirfsoc_rx_done_en));
-		else
-			wr_regl(port, ureg->sirfsoc_int_en_clr_reg,
-					uint_en->sirfsoc_rx_done_en);
-		wr_regl(port, ureg->sirfsoc_int_st_reg,
-				uint_st->sirfsoc_rx_timeout);
-		sirfsoc_uart_start_next_rx_dma(port);
-	}
-}
-
 static irqreturn_t sirfsoc_uart_isr(int irq, void *dev_id)
 {
 	unsigned long intr_status;
@@ -659,12 +519,8 @@ recv_char:
 		uart_handle_cts_change(port, cts_status);
 		wake_up_interruptible(&state->port.delta_msr_wait);
 	}
-	if (sirfport->rx_dma_chan) {
-		if (intr_status & uint_st->sirfsoc_rx_timeout)
-			sirfsoc_uart_handle_rx_tmo(sirfport);
-		if (intr_status & uint_st->sirfsoc_rx_done)
-			sirfsoc_uart_handle_rx_done(sirfport);
-	} else if (intr_status & SIRFUART_RX_IO_INT_ST(uint_st)) {
+	if (!sirfport->rx_dma_chan &&
+		(intr_status & SIRFUART_RX_IO_INT_ST(uint_st))) {
 		/*
 		 * chip will trigger continuous RX_TIMEOUT interrupt
 		 * in RXFIFO empty and not trigger if RXFIFO recevice
@@ -734,47 +590,8 @@ recv_char:
 	return IRQ_HANDLED;
 }
 
-static void sirfsoc_uart_rx_dma_complete_tl(unsigned long param)
-{
-	struct sirfsoc_uart_port *sirfport = (struct sirfsoc_uart_port *)param;
-	struct uart_port *port = &sirfport->port;
-	struct sirfsoc_register *ureg = &sirfport->uart_reg->uart_reg;
-	struct sirfsoc_int_en *uint_en = &sirfport->uart_reg->uart_int_en;
-	struct dma_tx_state tx_state;
-	unsigned long flags;
-	int i = 0;
-
-	spin_lock_irqsave(&port->lock, flags);
-	while (DMA_COMPLETE == dmaengine_tx_status(sirfport->rx_dma_chan,
-		sirfport->rx_dma_items[sirfport->rx_completed].cookie,
-		&tx_state)) {
-		sirfsoc_uart_insert_rx_buf_to_tty(sirfport,
-					SIRFSOC_RX_DMA_BUF_SIZE);
-		if (rd_regl(port, ureg->sirfsoc_int_en_reg) &
-				uint_en->sirfsoc_rx_timeout_en)
-			sirfsoc_rx_submit_one_dma_desc(port,
-					sirfport->rx_completed++);
-		else
-			sirfport->rx_completed++;
-		sirfport->rx_completed %= SIRFSOC_RX_LOOP_BUF_CNT;
-		i++;
-		if (i > SIRFSOC_RX_LOOP_BUF_CNT)
-			break;
-	}
-	spin_unlock_irqrestore(&port->lock, flags);
-	tty_flip_buffer_push(&port->state->port);
-}
-
 static void sirfsoc_uart_rx_dma_complete_callback(void *param)
 {
-	struct sirfsoc_uart_port *sirfport = (struct sirfsoc_uart_port *)param;
-	unsigned long flags;
-
-	spin_lock_irqsave(&sirfport->port.lock, flags);
-	sirfport->rx_issued++;
-	sirfport->rx_issued %= SIRFSOC_RX_LOOP_BUF_CNT;
-	tasklet_schedule(&sirfport->rx_dma_complete_tasklet);
-	spin_unlock_irqrestore(&sirfport->port.lock, flags);
 }
 
 /* submit rx dma task into dmaengine */
@@ -783,14 +600,27 @@ static void sirfsoc_uart_start_next_rx_dma(struct uart_port *port)
 	struct sirfsoc_uart_port *sirfport = to_sirfport(port);
 	struct sirfsoc_register *ureg = &sirfport->uart_reg->uart_reg;
 	struct sirfsoc_int_en *uint_en = &sirfport->uart_reg->uart_int_en;
-	int i;
 	sirfport->rx_io_count = 0;
 	wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl,
 		rd_regl(port, ureg->sirfsoc_rx_dma_io_ctrl) &
 		~SIRFUART_IO_MODE);
-	for (i = 0; i < SIRFSOC_RX_LOOP_BUF_CNT; i++)
-		sirfsoc_rx_submit_one_dma_desc(port, i);
-	sirfport->rx_completed = sirfport->rx_issued = 0;
+	sirfport->rx_dma_items.xmit.tail =
+		sirfport->rx_dma_items.xmit.head = 0;
+	sirfport->rx_dma_items.desc =
+		dmaengine_prep_dma_cyclic(sirfport->rx_dma_chan,
+		sirfport->rx_dma_items.dma_addr, SIRFSOC_RX_DMA_BUF_SIZE,
+		SIRFSOC_RX_DMA_BUF_SIZE / 2,
+		DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT);
+	if (IS_ERR_OR_NULL(sirfport->rx_dma_items.desc)) {
+		dev_err(port->dev, "DMA slave single fail\n");
+		return;
+	}
+	sirfport->rx_dma_items.desc->callback =
+		sirfsoc_uart_rx_dma_complete_callback;
+	sirfport->rx_dma_items.desc->callback_param = sirfport;
+	sirfport->rx_dma_items.cookie =
+		dmaengine_submit(sirfport->rx_dma_items.desc);
+	dma_async_issue_pending(sirfport->rx_dma_chan);
 	if (!sirfport->is_atlas7)
 		wr_regl(port, ureg->sirfsoc_int_en_reg,
 				rd_regl(port, ureg->sirfsoc_int_en_reg) |
@@ -1059,6 +889,7 @@ static void sirfsoc_uart_set_termios(struct uart_port *port,
 		wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl, SIRFUART_DMA_MODE);
 	else
 		wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl, SIRFUART_IO_MODE);
+	sirfport->rx_period_time = 20000000;
 	/* Reset Rx/Tx FIFO Threshold level for proper baudrate */
 	if (set_baud < 1000000)
 		threshold_div = 1;
@@ -1110,6 +941,9 @@ static int sirfsoc_uart_startup(struct uart_port *port)
 	wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl,
 		rd_regl(port, ureg->sirfsoc_rx_dma_io_ctrl) |
 		SIRFUART_IO_MODE);
+	wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl,
+		rd_regl(port, ureg->sirfsoc_rx_dma_io_ctrl) &
+		~SIRFUART_RX_DMA_FLUSH);
 	wr_regl(port, ureg->sirfsoc_tx_dma_io_len, 0);
 	wr_regl(port, ureg->sirfsoc_rx_dma_io_len, 0);
 	wr_regl(port, ureg->sirfsoc_tx_rx_en, SIRFUART_RX_EN | SIRFUART_TX_EN);
@@ -1147,8 +981,16 @@ static int sirfsoc_uart_startup(struct uart_port *port)
 			goto init_rx_err;
 		}
 	}
-
 	enable_irq(port->irq);
+	if (sirfport->rx_dma_chan && !sirfport->is_hrt_enabled) {
+		sirfport->is_hrt_enabled = true;
+		sirfport->rx_period_time = 20000000;
+		sirfport->rx_dma_items.xmit.tail =
+			sirfport->rx_dma_items.xmit.head = 0;
+		hrtimer_start(&sirfport->hrt,
+			ns_to_ktime(sirfport->rx_period_time),
+			HRTIMER_MODE_REL);
+	}
 
 	return 0;
 init_rx_err:
@@ -1176,6 +1018,13 @@ static void sirfsoc_uart_shutdown(struct uart_port *port)
 	}
 	if (sirfport->tx_dma_chan)
 		sirfport->tx_dma_state = TX_DMA_IDLE;
+	if (sirfport->rx_dma_chan && sirfport->is_hrt_enabled) {
+		while ((rd_regl(port, ureg->sirfsoc_rx_fifo_status) &
+			SIRFUART_RX_FIFO_MASK) > 0)
+			;
+		sirfport->is_hrt_enabled = false;
+		hrtimer_cancel(&sirfport->hrt);
+	}
 }
 
 static const char *sirfsoc_uart_type(struct uart_port *port)
@@ -1310,6 +1159,70 @@ static struct uart_driver sirfsoc_uart_drv = {
 #endif
 };
 
+static enum hrtimer_restart
+	sirfsoc_uart_rx_dma_hrtimer_callback(struct hrtimer *hrt)
+{
+	struct sirfsoc_uart_port *sirfport;
+	struct uart_port *port;
+	int count, inserted;
+	struct dma_tx_state tx_state;
+	struct tty_struct *tty;
+	struct sirfsoc_register *ureg;
+	struct circ_buf *xmit;
+
+	sirfport = container_of(hrt, struct sirfsoc_uart_port, hrt);
+	port = &sirfport->port;
+	inserted = 0;
+	tty = port->state->port.tty;
+	ureg = &sirfport->uart_reg->uart_reg;
+	xmit = &sirfport->rx_dma_items.xmit;
+	dmaengine_tx_status(sirfport->rx_dma_chan,
+		sirfport->rx_dma_items.cookie, &tx_state);
+	xmit->head = SIRFSOC_RX_DMA_BUF_SIZE - tx_state.residue;
+	count = CIRC_CNT_TO_END(xmit->head, xmit->tail,
+			SIRFSOC_RX_DMA_BUF_SIZE);
+	while (count > 0) {
+		inserted = tty_insert_flip_string(tty->port,
+			(const unsigned char *)&xmit->buf[xmit->tail], count);
+		if (!inserted)
+			goto next_hrt;
+		port->icount.rx += inserted;
+		xmit->tail = (xmit->tail + inserted) &
+				(SIRFSOC_RX_DMA_BUF_SIZE - 1);
+		count = CIRC_CNT_TO_END(xmit->head, xmit->tail,
+				SIRFSOC_RX_DMA_BUF_SIZE);
+		tty_flip_buffer_push(tty->port);
+	}
+	/*
+	 * if RX DMA buffer data have all push into tty buffer, and there is
+	 * only little data(less than a dma transfer unit) left in rxfifo,
+	 * fetch it out in pio mode and switch back to dma immediately
+	 */
+	if (!inserted && !count &&
+		((rd_regl(port, ureg->sirfsoc_rx_fifo_status) &
+		SIRFUART_RX_FIFO_MASK) > 0)) {
+		/* switch to pio mode */
+		wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl,
+			rd_regl(port, ureg->sirfsoc_rx_dma_io_ctrl) |
+			SIRFUART_IO_MODE);
+		while ((rd_regl(port, ureg->sirfsoc_rx_fifo_status) &
+			SIRFUART_RX_FIFO_MASK) > 0) {
+			if (sirfsoc_uart_pio_rx_chars(port, 16) > 0)
+				tty_flip_buffer_push(tty->port);
+		}
+		wr_regl(port, ureg->sirfsoc_rx_fifo_op, SIRFUART_FIFO_RESET);
+		wr_regl(port, ureg->sirfsoc_rx_fifo_op, 0);
+		wr_regl(port, ureg->sirfsoc_rx_fifo_op, SIRFUART_FIFO_START);
+		/* switch back to dma mode */
+		wr_regl(port, ureg->sirfsoc_rx_dma_io_ctrl,
+			rd_regl(port, ureg->sirfsoc_rx_dma_io_ctrl) &
+			~SIRFUART_IO_MODE);
+	}
+next_hrt:
+	hrtimer_forward_now(hrt, ns_to_ktime(sirfport->rx_period_time));
+	return HRTIMER_RESTART;
+}
+
 static struct of_device_id sirfsoc_uart_ids[] = {
 	{ .compatible = "sirf,prima2-uart", .data = &sirfsoc_uart,},
 	{ .compatible = "sirf,atlas7-uart", .data = &sirfsoc_uart},
@@ -1325,7 +1238,6 @@ static int sirfsoc_uart_probe(struct platform_device *pdev)
 	struct uart_port *port;
 	struct resource *res;
 	int ret;
-	int i, j;
 	struct dma_slave_config slv_cfg = {
 		.src_maxburst = 2,
 	};
@@ -1413,12 +1325,9 @@ usp_no_flow_control:
 		ret = -EFAULT;
 		goto err;
 	}
-	tasklet_init(&sirfport->rx_dma_complete_tasklet,
-			sirfsoc_uart_rx_dma_complete_tl, (unsigned long)sirfport);
-	tasklet_init(&sirfport->rx_tmo_process_tasklet,
-			sirfsoc_rx_tmo_process_tl, (unsigned long)sirfport);
 	port->mapbase = res->start;
-	port->membase = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+	port->membase = devm_ioremap(&pdev->dev,
+			res->start, resource_size(res));
 	if (!port->membase) {
 		dev_err(&pdev->dev, "Cannot remap resource.\n");
 		ret = -ENOMEM;
@@ -1450,30 +1359,32 @@ usp_no_flow_control:
 	}
 
 	sirfport->rx_dma_chan = dma_request_slave_channel(port->dev, "rx");
-	for (i = 0; sirfport->rx_dma_chan && i < SIRFSOC_RX_LOOP_BUF_CNT; i++) {
-		sirfport->rx_dma_items[i].xmit.buf =
-			dma_alloc_coherent(port->dev, SIRFSOC_RX_DMA_BUF_SIZE,
-			&sirfport->rx_dma_items[i].dma_addr, GFP_KERNEL);
-		if (!sirfport->rx_dma_items[i].xmit.buf) {
-			dev_err(port->dev, "Uart alloc bufa failed\n");
-			ret = -ENOMEM;
-			goto alloc_coherent_err;
-		}
-		sirfport->rx_dma_items[i].xmit.head =
-			sirfport->rx_dma_items[i].xmit.tail = 0;
+	sirfport->rx_dma_items.xmit.buf =
+		dma_alloc_coherent(port->dev, SIRFSOC_RX_DMA_BUF_SIZE,
+		&sirfport->rx_dma_items.dma_addr, GFP_KERNEL);
+	if (!sirfport->rx_dma_items.xmit.buf) {
+		dev_err(port->dev, "Uart alloc bufa failed\n");
+		ret = -ENOMEM;
+		goto alloc_coherent_err;
 	}
+	sirfport->rx_dma_items.xmit.head =
+		sirfport->rx_dma_items.xmit.tail = 0;
 	if (sirfport->rx_dma_chan)
 		dmaengine_slave_config(sirfport->rx_dma_chan, &slv_cfg);
 	sirfport->tx_dma_chan = dma_request_slave_channel(port->dev, "tx");
 	if (sirfport->tx_dma_chan)
 		dmaengine_slave_config(sirfport->tx_dma_chan, &tx_slv_cfg);
+	if (sirfport->rx_dma_chan) {
+		hrtimer_init(&sirfport->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+		sirfport->hrt.function = sirfsoc_uart_rx_dma_hrtimer_callback;
+		sirfport->is_hrt_enabled = false;
+	}
 
 	return 0;
 alloc_coherent_err:
-	for (j = 0; j < i; j++)
-		dma_free_coherent(port->dev, SIRFSOC_RX_DMA_BUF_SIZE,
-				sirfport->rx_dma_items[j].xmit.buf,
-				sirfport->rx_dma_items[j].dma_addr);
+	dma_free_coherent(port->dev, SIRFSOC_RX_DMA_BUF_SIZE,
+			sirfport->rx_dma_items.xmit.buf,
+			sirfport->rx_dma_items.dma_addr);
 	dma_release_channel(sirfport->rx_dma_chan);
 err:
 	return ret;
@@ -1485,13 +1396,11 @@ static int sirfsoc_uart_remove(struct platform_device *pdev)
 	struct uart_port *port = &sirfport->port;
 	uart_remove_one_port(&sirfsoc_uart_drv, port);
 	if (sirfport->rx_dma_chan) {
-		int i;
 		dmaengine_terminate_all(sirfport->rx_dma_chan);
 		dma_release_channel(sirfport->rx_dma_chan);
-		for (i = 0; i < SIRFSOC_RX_LOOP_BUF_CNT; i++)
-			dma_free_coherent(port->dev, SIRFSOC_RX_DMA_BUF_SIZE,
-					sirfport->rx_dma_items[i].xmit.buf,
-					sirfport->rx_dma_items[i].dma_addr);
+		dma_free_coherent(port->dev, SIRFSOC_RX_DMA_BUF_SIZE,
+				sirfport->rx_dma_items.xmit.buf,
+				sirfport->rx_dma_items.dma_addr);
 	}
 	if (sirfport->tx_dma_chan) {
 		dmaengine_terminate_all(sirfport->tx_dma_chan);
diff --git a/drivers/tty/serial/sirfsoc_uart.h b/drivers/tty/serial/sirfsoc_uart.h
index 644f86529571..eb162b012eec 100644
--- a/drivers/tty/serial/sirfsoc_uart.h
+++ b/drivers/tty/serial/sirfsoc_uart.h
@@ -7,6 +7,7 @@
  */
 #include <linux/bitops.h>
 #include <linux/log2.h>
+#include <linux/hrtimer.h>
 struct sirfsoc_uart_param {
 	const char *uart_name;
 	const char *port_name;
@@ -293,6 +294,7 @@ struct sirfsoc_uart_register sirfsoc_uart = {
 
 #define SIRFUART_IO_MODE			BIT(0)
 #define SIRFUART_DMA_MODE			0x0
+#define SIRFUART_RX_DMA_FLUSH			0x4
 
 /* Baud Rate Calculation */
 #define SIRF_USP_MIN_SAMPLE_DIV			0x1
@@ -353,8 +355,7 @@ struct sirfsoc_uart_register sirfsoc_uart = {
 				 uint_st->sirfsoc_rx_timeout)
 #define SIRFUART_CTS_INT_ST(uint_st)	(uint_st->sirfsoc_cts)
 #define SIRFUART_RX_DMA_INT_EN(uint_en, uart_type)		\
-				(uint_en->sirfsoc_rx_timeout_en |\
-				 uint_en->sirfsoc_frm_err_en |\
+				(uint_en->sirfsoc_frm_err_en |\
 				 uint_en->sirfsoc_rx_oflow_en |\
 				 uint_en->sirfsoc_rxd_brk_en |\
 				((uart_type != SIRF_REAL_UART) ? \
@@ -369,7 +370,7 @@ struct sirfsoc_uart_register sirfsoc_uart = {
 #define SIRFSOC_PORT_TYPE			0xa5
 
 /* Uart Common Use Macro*/
-#define SIRFSOC_RX_DMA_BUF_SIZE	256
+#define SIRFSOC_RX_DMA_BUF_SIZE		(1024 * 32)
 #define BYTES_TO_ALIGN(dma_addr)	((unsigned long)(dma_addr) & 0x3)
 /* Uart Fifo Level Chk */
 #define SIRFUART_TX_FIFO_SC_OFFSET	0
@@ -385,8 +386,8 @@ struct sirfsoc_uart_register sirfsoc_uart = {
 #define SIRFUART_RX_FIFO_CHK_SC SIRFUART_TX_FIFO_CHK_SC
 #define	SIRFUART_RX_FIFO_CHK_LC SIRFUART_TX_FIFO_CHK_LC
 #define SIRFUART_RX_FIFO_CHK_HC SIRFUART_TX_FIFO_CHK_HC
+#define SIRFUART_RX_FIFO_MASK 0x7f
 /* Indicate how many buffers used */
-#define SIRFSOC_RX_LOOP_BUF_CNT		2
 
 /* For Fast Baud Rate Calculation */
 struct sirfsoc_baudrate_to_regv {
@@ -400,7 +401,7 @@ enum sirfsoc_tx_state {
 	TX_DMA_PAUSE,
 };
 
-struct sirfsoc_loop_buffer {
+struct sirfsoc_rx_buffer {
 	struct circ_buf			xmit;
 	dma_cookie_t			cookie;
 	struct dma_async_tx_descriptor	*desc;
@@ -420,17 +421,16 @@ struct sirfsoc_uart_port {
 	struct dma_chan			*tx_dma_chan;
 	dma_addr_t			tx_dma_addr;
 	struct dma_async_tx_descriptor	*tx_dma_desc;
-	struct tasklet_struct		rx_dma_complete_tasklet;
-	struct tasklet_struct		rx_tmo_process_tasklet;
 	unsigned int			rx_io_count;
 	unsigned long			transfer_size;
 	enum sirfsoc_tx_state		tx_dma_state;
 	unsigned int			cts_gpio;
 	unsigned int			rts_gpio;
 
-	struct sirfsoc_loop_buffer	rx_dma_items[SIRFSOC_RX_LOOP_BUF_CNT];
-	int				rx_completed;
-	int				rx_issued;
+	struct sirfsoc_rx_buffer	rx_dma_items;
+	struct hrtimer			hrt;
+	bool				is_hrt_enabled;
+	unsigned long			rx_period_time;
 };
 
 /* Register Access Control */