serial: at91: make usart and uart support dma transfer

index 3467462..6c71ccf 100644
@@ -140,11 +140,11 @@ struct atmel_uart_port {
 	u32			backup_imr;	/* IMR saved during suspend */
 	int			break_active;	/* break being received */
 
-	short			use_dma_rx;	/* enable PDC receiver */
+	short			use_pdc_rx;	/* enable PDC receiver */
 	short			pdc_rx_idx;	/* current PDC RX buffer */
 	struct atmel_dma_buffer	pdc_rx[2];	/* PDC receier */
 
-	short			use_dma_tx;	/* enable PDC transmitter */
+	short			use_pdc_tx;	/* enable PDC transmitter */
 	struct atmel_dma_buffer	pdc_tx;		/* PDC transmitter */
 
 	struct tasklet_struct	tasklet;

@@ -181,26 +181,26 @@ to_atmel_uart_port(struct uart_port *uart)
 }
 
 #ifdef CONFIG_SERIAL_ATMEL_PDC
-static bool atmel_use_dma_rx(struct uart_port *port)
+static bool atmel_use_pdc_rx(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-	return atmel_port->use_dma_rx;
+	return atmel_port->use_pdc_rx;
 }
 
-static bool atmel_use_dma_tx(struct uart_port *port)
+static bool atmel_use_pdc_tx(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-	return atmel_port->use_dma_tx;
+	return atmel_port->use_pdc_tx;
 }
 #else
-static bool atmel_use_dma_rx(struct uart_port *port)
+static bool atmel_use_pdc_rx(struct uart_port *port)
 {
 	return false;
 }
 
-static bool atmel_use_dma_tx(struct uart_port *port)
+static bool atmel_use_pdc_tx(struct uart_port *port)
 {
 	return false;
 }

@@ -233,7 +233,7 @@ void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 		mode |= ATMEL_US_USMODE_RS485;
 	} else {
 		dev_dbg(port->dev, "Setting UART to RS232\n");
-		if (atmel_use_dma_tx(port))
+		if (atmel_use_pdc_tx(port))
 			atmel_port->tx_done_mask = ATMEL_US_ENDTX |
 				ATMEL_US_TXBUFE;
 		else

@@ -345,7 +345,7 @@ static void atmel_stop_tx(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-	if (atmel_use_dma_tx(port)) {
+	if (atmel_use_pdc_tx(port)) {
 		/* disable PDC transmit */
 		UART_PUT_PTCR(port, ATMEL_PDC_TXTDIS);
 	}

@@ -364,7 +364,7 @@ static void atmel_start_tx(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-	if (atmel_use_dma_tx(port)) {
+	if (atmel_use_pdc_tx(port)) {
 		if (UART_GET_PTSR(port) & ATMEL_PDC_TXTEN)
 			/* The transmitter is already running.  Yes, we
 			   really need this.*/

@@ -390,7 +390,7 @@ static void atmel_start_rx(struct uart_port *port)
 
 	UART_PUT_CR(port, ATMEL_US_RXEN);
 
-	if (atmel_use_dma_rx(port)) {
+	if (atmel_use_pdc_rx(port)) {
 		/* enable PDC controller */
 		UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |
 			port->read_status_mask);

@@ -407,7 +407,7 @@ static void atmel_stop_rx(struct uart_port *port)
 {
 	UART_PUT_CR(port, ATMEL_US_RXDIS);
 
-	if (atmel_use_dma_rx(port)) {
+	if (atmel_use_pdc_rx(port)) {
 		/* disable PDC receive */
 		UART_PUT_PTCR(port, ATMEL_PDC_RXTDIS);
 		UART_PUT_IDR(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT |

@@ -572,7 +572,7 @@ atmel_handle_receive(struct uart_port *port, unsigned int pending)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-	if (atmel_use_dma_rx(port)) {
+	if (atmel_use_pdc_rx(port)) {
 		/*
 		 * PDC receive. Just schedule the tasklet and let it
 		 * figure out the details.

@@ -661,7 +661,7 @@ static irqreturn_t atmel_interrupt(int irq, void *dev_id)
 /*
  * Called from tasklet with ENDTX and TXBUFE interrupts disabled.
  */
-static void atmel_tx_dma(struct uart_port *port)
+static void atmel_tx_pdc(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	struct circ_buf *xmit = &port->state->xmit;

@@ -778,7 +778,7 @@ static void atmel_rx_from_ring(struct uart_port *port)
 	spin_lock(&port->lock);
 }
 
-static void atmel_rx_from_dma(struct uart_port *port)
+static void atmel_rx_from_pdc(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	struct tty_port *tport = &port->state->port;

@@ -868,8 +868,8 @@ static void atmel_tasklet_func(unsigned long data)
 	/* The interrupt handler does not take the lock */
 	spin_lock(&port->lock);
 
-	if (atmel_use_dma_tx(port))
-		atmel_tx_dma(port);
+	if (atmel_use_pdc_tx(port))
+		atmel_tx_pdc(port);
 	else
 		atmel_tx_chars(port);
 

@@ -893,8 +893,8 @@ static void atmel_tasklet_func(unsigned long data)
 		atmel_port->irq_status_prev = status;
 	}
 
-	if (atmel_use_dma_rx(port))
-		atmel_rx_from_dma(port);
+	if (atmel_use_pdc_rx(port))
+		atmel_rx_from_pdc(port);
 	else
 		atmel_rx_from_ring(port);
 

@@ -930,7 +930,7 @@ static int atmel_startup(struct uart_port *port)
 	/*
 	 * Initialize DMA (if necessary)
 	 */
-	if (atmel_use_dma_rx(port)) {
+	if (atmel_use_pdc_rx(port)) {
 		int i;
 
 		for (i = 0; i < 2; i++) {

@@ -964,7 +964,7 @@ static int atmel_startup(struct uart_port *port)
 		UART_PUT_RNPR(port, atmel_port->pdc_rx[1].dma_addr);
 		UART_PUT_RNCR(port, PDC_BUFFER_SIZE);
 	}
-	if (atmel_use_dma_tx(port)) {
+	if (atmel_use_pdc_tx(port)) {
 		struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
 		struct circ_buf *xmit = &port->state->xmit;
 

@@ -1000,7 +1000,7 @@ static int atmel_startup(struct uart_port *port)
 	/* enable xmit & rcvr */
 	UART_PUT_CR(port, ATMEL_US_TXEN | ATMEL_US_RXEN);
 
-	if (atmel_use_dma_rx(port)) {
+	if (atmel_use_pdc_rx(port)) {
 		/* set UART timeout */
 		UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
 		UART_PUT_CR(port, ATMEL_US_STTTO);

@@ -1031,7 +1031,7 @@ static void atmel_shutdown(struct uart_port *port)
 	/*
 	 * Shut-down the DMA.
 	 */
-	if (atmel_use_dma_rx(port)) {
+	if (atmel_use_pdc_rx(port)) {
 		int i;
 
 		for (i = 0; i < 2; i++) {

@@ -1044,7 +1044,7 @@ static void atmel_shutdown(struct uart_port *port)
 			kfree(pdc->buf);
 		}
 	}
-	if (atmel_use_dma_tx(port)) {
+	if (atmel_use_pdc_tx(port)) {
 		struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
 
 		dma_unmap_single(port->dev,

@@ -1080,7 +1080,7 @@ static void atmel_flush_buffer(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-	if (atmel_use_dma_tx(port)) {
+	if (atmel_use_pdc_tx(port)) {
 		UART_PUT_TCR(port, 0);
 		atmel_port->pdc_tx.ofs = 0;
 	}

@@ -1193,7 +1193,7 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
 	if (termios->c_iflag & (BRKINT | PARMRK))
 		port->read_status_mask |= ATMEL_US_RXBRK;
 
-	if (atmel_use_dma_rx(port))
+	if (atmel_use_pdc_rx(port))
 		/* need to enable error interrupts */
 		UART_PUT_IER(port, port->read_status_mask);
 

@@ -1430,13 +1430,14 @@ static void atmel_of_init_port(struct atmel_uart_port *atmel_port,
 
 	/* DMA/PDC usage specification */
 	if (of_get_property(np, "atmel,use-dma-rx", NULL))
-		atmel_port->use_dma_rx	= 1;
+		atmel_port->use_pdc_rx	= 1;
 	else
-		atmel_port->use_dma_rx	= 0;
+		atmel_port->use_pdc_rx	= 0;
+
 	if (of_get_property(np, "atmel,use-dma-tx", NULL))
-		atmel_port->use_dma_tx	= 1;
+		atmel_port->use_pdc_tx	= 1;
 	else
-		atmel_port->use_dma_tx	= 0;
+		atmel_port->use_pdc_tx	= 0;
 
 	/* rs485 properties */
 	if (of_property_read_u32_array(np, "rs485-rts-delay",

@@ -1467,8 +1468,8 @@ static void atmel_init_port(struct atmel_uart_port *atmel_port,
 	if (pdev->dev.of_node) {
 		atmel_of_init_port(atmel_port, pdev->dev.of_node);
 	} else {
-		atmel_port->use_dma_rx	= pdata->use_dma_rx;
-		atmel_port->use_dma_tx	= pdata->use_dma_tx;
+		atmel_port->use_pdc_rx	= pdata->use_dma_rx;
+		atmel_port->use_pdc_tx	= pdata->use_dma_tx;
 		atmel_port->rs485	= pdata->rs485;
 	}
 

@@ -1505,7 +1506,7 @@ static void atmel_init_port(struct atmel_uart_port *atmel_port,
 	/* Use TXEMPTY for interrupt when rs485 else TXRDY or ENDTX|TXBUFE */
 	if (atmel_port->rs485.flags & SER_RS485_ENABLED)
 		atmel_port->tx_done_mask = ATMEL_US_TXEMPTY;
-	else if (atmel_use_dma_tx(port)) {
+	else if (atmel_use_pdc_tx(port)) {
 		port->fifosize = PDC_BUFFER_SIZE;
 		atmel_port->tx_done_mask = ATMEL_US_ENDTX | ATMEL_US_TXBUFE;
 	} else {

@@ -1794,7 +1795,7 @@ static int atmel_serial_probe(struct platform_device *pdev)
 		goto err;
 	}
 
-	if (!atmel_use_dma_rx(&port->uart)) {
+	if (!atmel_use_pdc_rx(&port->uart)) {
 		ret = -ENOMEM;
 		data = kmalloc(sizeof(struct atmel_uart_char)
 				* ATMEL_SERIAL_RINGSIZE, GFP_KERNEL);

index 6c71ccf..2b0fe2e 100644
@@ -155,6 +155,12 @@ struct atmel_uart_port {
 
 	struct serial_rs485	rs485;		/* rs485 settings */
 	unsigned int		tx_done_mask;
+	int (*prepare_rx)(struct uart_port *port);
+	int (*prepare_tx)(struct uart_port *port);
+	void (*schedule_rx)(struct uart_port *port);
+	void (*schedule_tx)(struct uart_port *port);
+	void (*release_rx)(struct uart_port *port);
+	void (*release_tx)(struct uart_port *port);
 };
 
 static struct atmel_uart_port atmel_ports[ATMEL_MAX_UART];

@@ -658,6 +664,17 @@ static irqreturn_t atmel_interrupt(int irq, void *dev_id)
 	return pass_counter ? IRQ_HANDLED : IRQ_NONE;
 }
 
+static void atmel_release_tx_pdc(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
+
+	dma_unmap_single(port->dev,
+			 pdc->dma_addr,
+			 pdc->dma_size,
+			 DMA_TO_DEVICE);
+}
+
 /*
  * Called from tasklet with ENDTX and TXBUFE interrupts disabled.
  */

@@ -710,6 +727,23 @@ static void atmel_tx_pdc(struct uart_port *port)
 		uart_write_wakeup(port);
 }
 
+static int atmel_prepare_tx_pdc(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
+	struct circ_buf *xmit = &port->state->xmit;
+
+	pdc->buf = xmit->buf;
+	pdc->dma_addr = dma_map_single(port->dev,
+					pdc->buf,
+					UART_XMIT_SIZE,
+					DMA_TO_DEVICE);
+	pdc->dma_size = UART_XMIT_SIZE;
+	pdc->ofs = 0;
+
+	return 0;
+}
+
 static void atmel_rx_from_ring(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

@@ -778,6 +812,22 @@ static void atmel_rx_from_ring(struct uart_port *port)
 	spin_lock(&port->lock);
 }
 
+static void atmel_release_rx_pdc(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
+
+		dma_unmap_single(port->dev,
+				 pdc->dma_addr,
+				 pdc->dma_size,
+				 DMA_FROM_DEVICE);
+		kfree(pdc->buf);
+	}
+}
+
 static void atmel_rx_from_pdc(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

@@ -855,6 +905,45 @@ static void atmel_rx_from_pdc(struct uart_port *port)
 	UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
 }
 
+static int atmel_prepare_rx_pdc(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	int i;
+
+	for (i = 0; i < 2; i++) {
+		struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
+
+		pdc->buf = kmalloc(PDC_BUFFER_SIZE, GFP_KERNEL);
+		if (pdc->buf == NULL) {
+			if (i != 0) {
+				dma_unmap_single(port->dev,
+					atmel_port->pdc_rx[0].dma_addr,
+					PDC_BUFFER_SIZE,
+					DMA_FROM_DEVICE);
+				kfree(atmel_port->pdc_rx[0].buf);
+			}
+			atmel_port->use_pdc_rx = 0;
+			return -ENOMEM;
+		}
+		pdc->dma_addr = dma_map_single(port->dev,
+						pdc->buf,
+						PDC_BUFFER_SIZE,
+						DMA_FROM_DEVICE);
+		pdc->dma_size = PDC_BUFFER_SIZE;
+		pdc->ofs = 0;
+	}
+
+	atmel_port->pdc_rx_idx = 0;
+
+	UART_PUT_RPR(port, atmel_port->pdc_rx[0].dma_addr);
+	UART_PUT_RCR(port, PDC_BUFFER_SIZE);
+
+	UART_PUT_RNPR(port, atmel_port->pdc_rx[1].dma_addr);
+	UART_PUT_RNCR(port, PDC_BUFFER_SIZE);
+
+	return 0;
+}
+
 /*
  * tasklet handling tty stuff outside the interrupt handler.
  */

@@ -868,10 +957,7 @@ static void atmel_tasklet_func(unsigned long data)
 	/* The interrupt handler does not take the lock */
 	spin_lock(&port->lock);
 
-	if (atmel_use_pdc_tx(port))
-		atmel_tx_pdc(port);
-	else
-		atmel_tx_chars(port);
+	atmel_port->schedule_tx(port);
 
 	status = atmel_port->irq_status;
 	status_change = status ^ atmel_port->irq_status_prev;

@@ -893,14 +979,36 @@ static void atmel_tasklet_func(unsigned long data)
 		atmel_port->irq_status_prev = status;
 	}
 
-	if (atmel_use_pdc_rx(port))
-		atmel_rx_from_pdc(port);
-	else
-		atmel_rx_from_ring(port);
+	atmel_port->schedule_rx(port);
 
 	spin_unlock(&port->lock);
 }
 
+static void atmel_set_ops(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+	if (atmel_use_pdc_rx(port)) {
+		atmel_port->prepare_rx = &atmel_prepare_rx_pdc;
+		atmel_port->schedule_rx = &atmel_rx_from_pdc;
+		atmel_port->release_rx = &atmel_release_rx_pdc;
+	} else {
+		atmel_port->prepare_rx = NULL;
+		atmel_port->schedule_rx = &atmel_rx_from_ring;
+		atmel_port->release_rx = NULL;
+	}
+
+	if (atmel_use_pdc_tx(port)) {
+		atmel_port->prepare_tx = &atmel_prepare_tx_pdc;
+		atmel_port->schedule_tx = &atmel_tx_pdc;
+		atmel_port->release_tx = &atmel_release_tx_pdc;
+	} else {
+		atmel_port->prepare_tx = NULL;
+		atmel_port->schedule_tx = &atmel_tx_chars;
+		atmel_port->release_tx = NULL;
+	}
+}
+
 /*
  * Perform initialization and enable port for reception
  */

@@ -930,53 +1038,17 @@ static int atmel_startup(struct uart_port *port)
 	/*
 	 * Initialize DMA (if necessary)
 	 */
-	if (atmel_use_pdc_rx(port)) {
-		int i;
-
-		for (i = 0; i < 2; i++) {
-			struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
-
-			pdc->buf = kmalloc(PDC_BUFFER_SIZE, GFP_KERNEL);
-			if (pdc->buf == NULL) {
-				if (i != 0) {
-					dma_unmap_single(port->dev,
-						atmel_port->pdc_rx[0].dma_addr,
-						PDC_BUFFER_SIZE,
-						DMA_FROM_DEVICE);
-					kfree(atmel_port->pdc_rx[0].buf);
-				}
-				free_irq(port->irq, port);
-				return -ENOMEM;
-			}
-			pdc->dma_addr = dma_map_single(port->dev,
-						       pdc->buf,
-						       PDC_BUFFER_SIZE,
-						       DMA_FROM_DEVICE);
-			pdc->dma_size = PDC_BUFFER_SIZE;
-			pdc->ofs = 0;
-		}
-
-		atmel_port->pdc_rx_idx = 0;
-
-		UART_PUT_RPR(port, atmel_port->pdc_rx[0].dma_addr);
-		UART_PUT_RCR(port, PDC_BUFFER_SIZE);
-
-		UART_PUT_RNPR(port, atmel_port->pdc_rx[1].dma_addr);
-		UART_PUT_RNCR(port, PDC_BUFFER_SIZE);
+	if (atmel_port->prepare_rx) {
+		retval = atmel_port->prepare_rx(port);
+		if (retval < 0)
+			atmel_set_ops(port);
 	}
-	if (atmel_use_pdc_tx(port)) {
-		struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
-		struct circ_buf *xmit = &port->state->xmit;
 
-		pdc->buf = xmit->buf;
-		pdc->dma_addr = dma_map_single(port->dev,
-					       pdc->buf,
-					       UART_XMIT_SIZE,
-					       DMA_TO_DEVICE);
-		pdc->dma_size = UART_XMIT_SIZE;
-		pdc->ofs = 0;
+	if (atmel_port->prepare_tx) {
+		retval = atmel_port->prepare_tx(port);
+		if (retval < 0)
+			atmel_set_ops(port);
 	}
-
 	/*
 	 * If there is a specific "open" function (to register
 	 * control line interrupts)

@@ -1031,27 +1103,10 @@ static void atmel_shutdown(struct uart_port *port)
 	/*
 	 * Shut-down the DMA.
 	 */
-	if (atmel_use_pdc_rx(port)) {
-		int i;
-
-		for (i = 0; i < 2; i++) {
-			struct atmel_dma_buffer *pdc = &atmel_port->pdc_rx[i];
-
-			dma_unmap_single(port->dev,
-					 pdc->dma_addr,
-					 pdc->dma_size,
-					 DMA_FROM_DEVICE);
-			kfree(pdc->buf);
-		}
-	}
-	if (atmel_use_pdc_tx(port)) {
-		struct atmel_dma_buffer *pdc = &atmel_port->pdc_tx;
-
-		dma_unmap_single(port->dev,
-				 pdc->dma_addr,
-				 pdc->dma_size,
-				 DMA_TO_DEVICE);
-	}
+	if (atmel_port->release_rx)
+		atmel_port->release_rx(port);
+	if (atmel_port->release_tx)
+		atmel_port->release_tx(port);
 
 	/*
 	 * Disable all interrupts, port and break condition.

@@ -1473,6 +1528,8 @@ static void atmel_init_port(struct atmel_uart_port *atmel_port,
 		atmel_port->rs485	= pdata->rs485;
 	}
 
+	atmel_set_ops(port);
+
 	port->iotype		= UPIO_MEM;
 	port->flags		= UPF_BOOT_AUTOCONF;
 	port->ops		= &atmel_pops;

index 2b0fe2e..1176daa 100644
@@ -144,9 +144,15 @@ struct atmel_uart_port {
 	short			pdc_rx_idx;	/* current PDC RX buffer */
 	struct atmel_dma_buffer	pdc_rx[2];	/* PDC receier */
 
+	short                   use_dma_tx;     /* enable DMA transmitter */
 	short			use_pdc_tx;	/* enable PDC transmitter */
 	struct atmel_dma_buffer	pdc_tx;		/* PDC transmitter */
 
+	spinlock_t			lock_tx;	/* port lock */
+	struct dma_chan			*chan_tx;
+	struct dma_async_tx_descriptor	*desc_tx;
+	dma_cookie_t			cookie_tx;
+	struct scatterlist		sg_tx;
 	struct tasklet_struct	tasklet;
 	unsigned int		irq_status;
 	unsigned int		irq_status_prev;

@@ -212,6 +218,13 @@ static bool atmel_use_pdc_tx(struct uart_port *port)
 }
 #endif
 
+static bool atmel_use_dma_tx(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+	return atmel_port->use_dma_tx;
+}
+
 /* Enable or disable the rs485 support */
 void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 {

@@ -570,6 +583,182 @@ static void atmel_tx_chars(struct uart_port *port)
 		UART_PUT_IER(port, atmel_port->tx_done_mask);
 }
 
+static void atmel_complete_tx_dma(void *arg)
+{
+	struct atmel_uart_port *atmel_port = arg;
+	struct uart_port *port = &atmel_port->uart;
+	struct circ_buf *xmit = &port->state->xmit;
+	struct dma_chan *chan = atmel_port->chan_tx;
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	if (chan)
+		dmaengine_terminate_all(chan);
+	xmit->tail += sg_dma_len(&atmel_port->sg_tx);
+	xmit->tail &= UART_XMIT_SIZE - 1;
+
+	port->icount.tx += sg_dma_len(&atmel_port->sg_tx);
+
+	spin_lock_irq(&atmel_port->lock_tx);
+	async_tx_ack(atmel_port->desc_tx);
+	atmel_port->cookie_tx = -EINVAL;
+	atmel_port->desc_tx = NULL;
+	spin_unlock_irq(&atmel_port->lock_tx);
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	/* Do we really need this? */
+	if (!uart_circ_empty(xmit))
+		tasklet_schedule(&atmel_port->tasklet);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void atmel_release_tx_dma(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct dma_chan *chan = atmel_port->chan_tx;
+
+	if (chan) {
+		dmaengine_terminate_all(chan);
+		dma_release_channel(chan);
+		dma_unmap_sg(port->dev, &atmel_port->sg_tx, 1,
+				DMA_MEM_TO_DEV);
+	}
+
+	atmel_port->desc_tx = NULL;
+	atmel_port->chan_tx = NULL;
+	atmel_port->cookie_tx = -EINVAL;
+}
+
+/*
+ * Called from tasklet with TXRDY interrupt is disabled.
+ */
+static void atmel_tx_dma(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct circ_buf *xmit = &port->state->xmit;
+	struct dma_chan *chan = atmel_port->chan_tx;
+	struct dma_async_tx_descriptor *desc;
+	struct scatterlist *sg = &atmel_port->sg_tx;
+
+	/* Make sure we have an idle channel */
+	if (atmel_port->desc_tx != NULL)
+		return;
+
+	if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
+		/*
+		 * DMA is idle now.
+		 * Port xmit buffer is already mapped,
+		 * and it is one page... Just adjust
+		 * offsets and lengths. Since it is a circular buffer,
+		 * we have to transmit till the end, and then the rest.
+		 * Take the port lock to get a
+		 * consistent xmit buffer state.
+		 */
+		sg->offset = xmit->tail & (UART_XMIT_SIZE - 1);
+		sg_dma_address(sg) = (sg_dma_address(sg) &
+					~(UART_XMIT_SIZE - 1))
+					+ sg->offset;
+		sg_dma_len(sg) = CIRC_CNT_TO_END(xmit->head,
+						xmit->tail,
+						UART_XMIT_SIZE);
+		BUG_ON(!sg_dma_len(sg));
+
+		desc = dmaengine_prep_slave_sg(chan,
+						sg,
+						1,
+						DMA_MEM_TO_DEV,
+						DMA_PREP_INTERRUPT |
+						DMA_CTRL_ACK);
+		if (!desc) {
+			dev_err(port->dev, "Failed to send via dma!\n");
+			return;
+		}
+
+		dma_sync_sg_for_device(port->dev, sg, 1, DMA_MEM_TO_DEV);
+
+		atmel_port->desc_tx = desc;
+		desc->callback = atmel_complete_tx_dma;
+		desc->callback_param = atmel_port;
+		atmel_port->cookie_tx = dmaengine_submit(desc);
+
+	} else {
+		if (atmel_port->rs485.flags & SER_RS485_ENABLED) {
+			/* DMA done, stop TX, start RX for RS485 */
+			atmel_start_rx(port);
+		}
+	}
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+}
+
+static int atmel_prepare_tx_dma(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	dma_cap_mask_t		mask;
+	struct dma_slave_config config;
+	int ret, nent;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+
+	atmel_port->chan_tx = dma_request_slave_channel(port->dev, "tx");
+	if (atmel_port->chan_tx == NULL)
+		goto chan_err;
+	dev_info(port->dev, "using %s for tx DMA transfers\n",
+		dma_chan_name(atmel_port->chan_tx));
+
+	spin_lock_init(&atmel_port->lock_tx);
+	sg_init_table(&atmel_port->sg_tx, 1);
+	/* UART circular tx buffer is an aligned page. */
+	BUG_ON((int)port->state->xmit.buf & ~PAGE_MASK);
+	sg_set_page(&atmel_port->sg_tx,
+			virt_to_page(port->state->xmit.buf),
+			UART_XMIT_SIZE,
+			(int)port->state->xmit.buf & ~PAGE_MASK);
+	nent = dma_map_sg(port->dev,
+				&atmel_port->sg_tx,
+				1,
+				DMA_MEM_TO_DEV);
+
+	if (!nent) {
+		dev_dbg(port->dev, "need to release resource of dma\n");
+		goto chan_err;
+	} else {
+		dev_dbg(port->dev, "%s: mapped %d@%p to %x\n", __func__,
+			sg_dma_len(&atmel_port->sg_tx),
+			port->state->xmit.buf,
+			sg_dma_address(&atmel_port->sg_tx));
+	}
+
+	/* Configure the slave DMA */
+	memset(&config, 0, sizeof(config));
+	config.direction = DMA_MEM_TO_DEV;
+	config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+	config.dst_addr = port->mapbase + ATMEL_US_THR;
+
+	ret = dmaengine_device_control(atmel_port->chan_tx,
+					DMA_SLAVE_CONFIG,
+					(unsigned long)&config);
+	if (ret) {
+		dev_err(port->dev, "DMA tx slave configuration failed\n");
+		goto chan_err;
+	}
+
+	return 0;
+
+chan_err:
+	dev_err(port->dev, "TX channel not available, switch to pio\n");
+	atmel_port->use_dma_tx = 0;
+	if (atmel_port->chan_tx)
+		atmel_release_tx_dma(port);
+	return -EINVAL;
+}
+
 /*
  * receive interrupt handler.
  */

@@ -998,7 +1187,11 @@ static void atmel_set_ops(struct uart_port *port)
 		atmel_port->release_rx = NULL;
 	}
 
-	if (atmel_use_pdc_tx(port)) {
+	if (atmel_use_dma_tx(port)) {
+		atmel_port->prepare_tx = &atmel_prepare_tx_dma;
+		atmel_port->schedule_tx = &atmel_tx_dma;
+		atmel_port->release_tx = &atmel_release_tx_dma;
+	} else if (atmel_use_pdc_tx(port)) {
 		atmel_port->prepare_tx = &atmel_prepare_tx_pdc;
 		atmel_port->schedule_tx = &atmel_tx_pdc;
 		atmel_port->release_tx = &atmel_release_tx_pdc;

@@ -1489,10 +1682,18 @@ static void atmel_of_init_port(struct atmel_uart_port *atmel_port,
 	else
 		atmel_port->use_pdc_rx	= 0;
 
-	if (of_get_property(np, "atmel,use-dma-tx", NULL))
-		atmel_port->use_pdc_tx	= 1;
-	else
+	if (of_get_property(np, "atmel,use-dma-tx", NULL)) {
+		if (of_get_property(np, "dmas", NULL)) {
+			atmel_port->use_dma_tx	= 1;
+			atmel_port->use_pdc_tx	= 0;
+		} else {
+			atmel_port->use_dma_tx	= 0;
+			atmel_port->use_pdc_tx	= 1;
+		}
+	} else {
+		atmel_port->use_dma_tx	= 0;
 		atmel_port->use_pdc_tx	= 0;
+	}
 
 	/* rs485 properties */
 	if (of_property_read_u32_array(np, "rs485-rts-delay",

@@ -1525,6 +1726,7 @@ static void atmel_init_port(struct atmel_uart_port *atmel_port,
 	} else {
 		atmel_port->use_pdc_rx	= pdata->use_dma_rx;
 		atmel_port->use_pdc_tx	= pdata->use_dma_tx;
+		atmel_port->use_dma_tx	= 0;
 		atmel_port->rs485	= pdata->rs485;
 	}
 

index 1176daa..298b58c 100644
@@ -140,6 +140,7 @@ struct atmel_uart_port {
 	u32			backup_imr;	/* IMR saved during suspend */
 	int			break_active;	/* break being received */
 
+	short			use_dma_rx;	/* enable DMA receiver */
 	short			use_pdc_rx;	/* enable PDC receiver */
 	short			pdc_rx_idx;	/* current PDC RX buffer */
 	struct atmel_dma_buffer	pdc_rx[2];	/* PDC receier */

@@ -149,10 +150,15 @@ struct atmel_uart_port {
 	struct atmel_dma_buffer	pdc_tx;		/* PDC transmitter */
 
 	spinlock_t			lock_tx;	/* port lock */
+	spinlock_t			lock_rx;	/* port lock */
 	struct dma_chan			*chan_tx;
+	struct dma_chan			*chan_rx;
 	struct dma_async_tx_descriptor	*desc_tx;
+	struct dma_async_tx_descriptor	*desc_rx;
 	dma_cookie_t			cookie_tx;
+	dma_cookie_t			cookie_rx;
 	struct scatterlist		sg_tx;
+	struct scatterlist		sg_rx;
 	struct tasklet_struct	tasklet;
 	unsigned int		irq_status;
 	unsigned int		irq_status_prev;

@@ -225,6 +231,13 @@ static bool atmel_use_dma_tx(struct uart_port *port)
 	return atmel_port->use_dma_tx;
 }
 
+static bool atmel_use_dma_rx(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+	return atmel_port->use_dma_rx;
+}
+
 /* Enable or disable the rs485 support */
 void atmel_config_rs485(struct uart_port *port, struct serial_rs485 *rs485conf)
 {

@@ -759,6 +772,184 @@ chan_err:
 	return -EINVAL;
 }
 
+static void atmel_flip_buffer_rx_dma(struct uart_port *port,
+					char *buf, size_t count)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct tty_port *tport = &port->state->port;
+
+	dma_sync_sg_for_cpu(port->dev,
+				&atmel_port->sg_rx,
+				1,
+				DMA_DEV_TO_MEM);
+
+	tty_insert_flip_string(tport, buf, count);
+
+	dma_sync_sg_for_device(port->dev,
+				&atmel_port->sg_rx,
+				1,
+				DMA_DEV_TO_MEM);
+	/*
+	 * Drop the lock here since it might end up calling
+	 * uart_start(), which takes the lock.
+	 */
+	spin_unlock(&port->lock);
+	tty_flip_buffer_push(tport);
+	spin_lock(&port->lock);
+}
+
+static void atmel_complete_rx_dma(void *arg)
+{
+	struct uart_port *port = arg;
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+	tasklet_schedule(&atmel_port->tasklet);
+}
+
+static void atmel_release_rx_dma(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct dma_chan *chan = atmel_port->chan_rx;
+
+	if (chan) {
+		dmaengine_terminate_all(chan);
+		dma_release_channel(chan);
+		dma_unmap_sg(port->dev, &atmel_port->sg_rx, 1,
+				DMA_DEV_TO_MEM);
+	}
+
+	atmel_port->desc_rx = NULL;
+	atmel_port->chan_rx = NULL;
+	atmel_port->cookie_rx = -EINVAL;
+}
+
+static void atmel_rx_from_dma(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct circ_buf *ring = &atmel_port->rx_ring;
+	struct dma_chan *chan = atmel_port->chan_rx;
+	struct dma_tx_state state;
+	enum dma_status dmastat;
+	size_t pending, count;
+
+
+	/* Reset the UART timeout early so that we don't miss one */
+	UART_PUT_CR(port, ATMEL_US_STTTO);
+	dmastat = dmaengine_tx_status(chan,
+				atmel_port->cookie_rx,
+				&state);
+	/* Restart a new tasklet if DMA status is error */
+	if (dmastat == DMA_ERROR) {
+		dev_dbg(port->dev, "Get residue error, restart tasklet\n");
+		UART_PUT_IER(port, ATMEL_US_TIMEOUT);
+		tasklet_schedule(&atmel_port->tasklet);
+		return;
+	}
+	/* current transfer size should no larger than dma buffer */
+	pending = sg_dma_len(&atmel_port->sg_rx) - state.residue;
+	BUG_ON(pending > sg_dma_len(&atmel_port->sg_rx));
+
+	/*
+	 * This will take the chars we have so far,
+	 * ring->head will record the transfer size, only new bytes come
+	 * will insert into the framework.
+	 */
+	if (pending > ring->head) {
+		count = pending - ring->head;
+
+		atmel_flip_buffer_rx_dma(port, ring->buf + ring->head, count);
+
+		ring->head += count;
+		if (ring->head == sg_dma_len(&atmel_port->sg_rx))
+			ring->head = 0;
+
+		port->icount.rx += count;
+	}
+
+	UART_PUT_IER(port, ATMEL_US_TIMEOUT);
+}
+
+static int atmel_prepare_rx_dma(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	struct dma_async_tx_descriptor *desc;
+	dma_cap_mask_t		mask;
+	struct dma_slave_config config;
+	struct circ_buf		*ring;
+	int ret, nent;
+
+	ring = &atmel_port->rx_ring;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_CYCLIC, mask);
+
+	atmel_port->chan_rx = dma_request_slave_channel(port->dev, "rx");
+	if (atmel_port->chan_rx == NULL)
+		goto chan_err;
+	dev_info(port->dev, "using %s for rx DMA transfers\n",
+		dma_chan_name(atmel_port->chan_rx));
+
+	spin_lock_init(&atmel_port->lock_rx);
+	sg_init_table(&atmel_port->sg_rx, 1);
+	/* UART circular rx buffer is an aligned page. */
+	BUG_ON((int)port->state->xmit.buf & ~PAGE_MASK);
+	sg_set_page(&atmel_port->sg_rx,
+			virt_to_page(ring->buf),
+			ATMEL_SERIAL_RINGSIZE,
+			(int)ring->buf & ~PAGE_MASK);
+			nent = dma_map_sg(port->dev,
+					&atmel_port->sg_rx,
+					1,
+					DMA_DEV_TO_MEM);
+
+	if (!nent) {
+		dev_dbg(port->dev, "need to release resource of dma\n");
+		goto chan_err;
+	} else {
+		dev_dbg(port->dev, "%s: mapped %d@%p to %x\n", __func__,
+			sg_dma_len(&atmel_port->sg_rx),
+			ring->buf,
+			sg_dma_address(&atmel_port->sg_rx));
+	}
+
+	/* Configure the slave DMA */
+	memset(&config, 0, sizeof(config));
+	config.direction = DMA_DEV_TO_MEM;
+	config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
+	config.src_addr = port->mapbase + ATMEL_US_RHR;
+
+	ret = dmaengine_device_control(atmel_port->chan_rx,
+					DMA_SLAVE_CONFIG,
+					(unsigned long)&config);
+	if (ret) {
+		dev_err(port->dev, "DMA rx slave configuration failed\n");
+		goto chan_err;
+	}
+	/*
+	 * Prepare a cyclic dma transfer, assign 2 descriptors,
+	 * each one is half ring buffer size
+	 */
+	desc = dmaengine_prep_dma_cyclic(atmel_port->chan_rx,
+				sg_dma_address(&atmel_port->sg_rx),
+				sg_dma_len(&atmel_port->sg_rx),
+				sg_dma_len(&atmel_port->sg_rx)/2,
+				DMA_DEV_TO_MEM,
+				DMA_PREP_INTERRUPT);
+	desc->callback = atmel_complete_rx_dma;
+	desc->callback_param = port;
+	atmel_port->desc_rx = desc;
+	atmel_port->cookie_rx = dmaengine_submit(desc);
+
+	return 0;
+
+chan_err:
+	dev_err(port->dev, "RX channel not available, switch to pio\n");
+	atmel_port->use_dma_rx = 0;
+	if (atmel_port->chan_rx)
+		atmel_release_rx_dma(port);
+	return -EINVAL;
+}
+
 /*
  * receive interrupt handler.
  */

@@ -786,6 +977,13 @@ atmel_handle_receive(struct uart_port *port, unsigned int pending)
 			atmel_pdc_rxerr(port, pending);
 	}
 
+	if (atmel_use_dma_rx(port)) {
+		if (pending & ATMEL_US_TIMEOUT) {
+			UART_PUT_IDR(port, ATMEL_US_TIMEOUT);
+			tasklet_schedule(&atmel_port->tasklet);
+		}
+	}
+
 	/* Interrupt receive */
 	if (pending & ATMEL_US_RXRDY)
 		atmel_rx_chars(port);

@@ -1177,7 +1375,11 @@ static void atmel_set_ops(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-	if (atmel_use_pdc_rx(port)) {
+	if (atmel_use_dma_rx(port)) {
+		atmel_port->prepare_rx = &atmel_prepare_rx_dma;
+		atmel_port->schedule_rx = &atmel_rx_from_dma;
+		atmel_port->release_rx = &atmel_release_rx_dma;
+	} else if (atmel_use_pdc_rx(port)) {
 		atmel_port->prepare_rx = &atmel_prepare_rx_pdc;
 		atmel_port->schedule_rx = &atmel_rx_from_pdc;
 		atmel_port->release_rx = &atmel_release_rx_pdc;

@@ -1273,6 +1475,11 @@ static int atmel_startup(struct uart_port *port)
 		UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
 		/* enable PDC controller */
 		UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);
+	} else if (atmel_use_dma_rx(port)) {
+		UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
+		UART_PUT_CR(port, ATMEL_US_STTTO);
+
+		UART_PUT_IER(port, ATMEL_US_TIMEOUT);
 	} else {
 		/* enable receive only */
 		UART_PUT_IER(port, ATMEL_US_RXRDY);

@@ -1677,10 +1884,18 @@ static void atmel_of_init_port(struct atmel_uart_port *atmel_port,
 	u32 rs485_delay[2];
 
 	/* DMA/PDC usage specification */
-	if (of_get_property(np, "atmel,use-dma-rx", NULL))
-		atmel_port->use_pdc_rx	= 1;
-	else
+	if (of_get_property(np, "atmel,use-dma-rx", NULL)) {
+		if (of_get_property(np, "dmas", NULL)) {
+			atmel_port->use_dma_rx	= 1;
+			atmel_port->use_pdc_rx	= 0;
+		} else {
+			atmel_port->use_dma_rx	= 0;
+			atmel_port->use_pdc_rx	= 1;
+		}
+	} else {
+		atmel_port->use_dma_rx	= 0;
 		atmel_port->use_pdc_rx	= 0;
+	}
 
 	if (of_get_property(np, "atmel,use-dma-tx", NULL)) {
 		if (of_get_property(np, "dmas", NULL)) {

@@ -1726,6 +1941,7 @@ static void atmel_init_port(struct atmel_uart_port *atmel_port,
 	} else {
 		atmel_port->use_pdc_rx	= pdata->use_dma_rx;
 		atmel_port->use_pdc_tx	= pdata->use_dma_tx;
+		atmel_port->use_dma_rx	= 0;
 		atmel_port->use_dma_tx	= 0;
 		atmel_port->rs485	= pdata->rs485;
 	}

index 298b58c..ad787fd1 100644
@@ -1371,6 +1371,80 @@ static void atmel_tasklet_func(unsigned long data)
 	spin_unlock(&port->lock);
 }
 
+static int atmel_init_property(struct atmel_uart_port *atmel_port,
+				struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct atmel_uart_data *pdata = pdev->dev.platform_data;
+
+	if (np) {
+		/* DMA/PDC usage specification */
+		if (of_get_property(np, "atmel,use-dma-rx", NULL)) {
+			if (of_get_property(np, "dmas", NULL)) {
+				atmel_port->use_dma_rx  = 1;
+				atmel_port->use_pdc_rx  = 0;
+			} else {
+				atmel_port->use_dma_rx  = 0;
+				atmel_port->use_pdc_rx  = 1;
+			}
+		} else {
+			atmel_port->use_dma_rx  = 0;
+			atmel_port->use_pdc_rx  = 0;
+		}
+
+		if (of_get_property(np, "atmel,use-dma-tx", NULL)) {
+			if (of_get_property(np, "dmas", NULL)) {
+				atmel_port->use_dma_tx  = 1;
+				atmel_port->use_pdc_tx  = 0;
+			} else {
+				atmel_port->use_dma_tx  = 0;
+				atmel_port->use_pdc_tx  = 1;
+			}
+		} else {
+			atmel_port->use_dma_tx  = 0;
+			atmel_port->use_pdc_tx  = 0;
+		}
+
+	} else {
+		atmel_port->use_pdc_rx  = pdata->use_dma_rx;
+		atmel_port->use_pdc_tx  = pdata->use_dma_tx;
+		atmel_port->use_dma_rx  = 0;
+		atmel_port->use_dma_tx  = 0;
+	}
+
+	return 0;
+}
+
+static void atmel_init_rs485(struct atmel_uart_port *atmel_port,
+				struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct atmel_uart_data *pdata = pdev->dev.platform_data;
+
+	if (np) {
+		u32 rs485_delay[2];
+		/* rs485 properties */
+		if (of_property_read_u32_array(np, "rs485-rts-delay",
+					rs485_delay, 2) == 0) {
+			struct serial_rs485 *rs485conf = &atmel_port->rs485;
+
+			rs485conf->delay_rts_before_send = rs485_delay[0];
+			rs485conf->delay_rts_after_send = rs485_delay[1];
+			rs485conf->flags = 0;
+
+		if (of_get_property(np, "rs485-rx-during-tx", NULL))
+			rs485conf->flags |= SER_RS485_RX_DURING_TX;
+
+		if (of_get_property(np, "linux,rs485-enabled-at-boot-time",
+								NULL))
+			rs485conf->flags |= SER_RS485_ENABLED;
+		}
+	} else {
+		atmel_port->rs485       = pdata->rs485;
+	}
+
+}
+
 static void atmel_set_ops(struct uart_port *port)
 {
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);

@@ -1409,6 +1483,7 @@ static void atmel_set_ops(struct uart_port *port)
  */
 static int atmel_startup(struct uart_port *port)
 {
+	struct platform_device *pdev = to_platform_device(port->dev);
 	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 	struct tty_struct *tty = port->state->port.tty;
 	int retval;

@@ -1433,6 +1508,8 @@ static int atmel_startup(struct uart_port *port)
 	/*
 	 * Initialize DMA (if necessary)
 	 */
+	atmel_init_property(atmel_port, pdev);
+
 	if (atmel_port->prepare_rx) {
 		retval = atmel_port->prepare_rx(port);
 		if (retval < 0)

@@ -1878,55 +1955,6 @@ static struct uart_ops atmel_pops = {
 #endif
 };
 
-static void atmel_of_init_port(struct atmel_uart_port *atmel_port,
-					 struct device_node *np)
-{
-	u32 rs485_delay[2];
-
-	/* DMA/PDC usage specification */
-	if (of_get_property(np, "atmel,use-dma-rx", NULL)) {
-		if (of_get_property(np, "dmas", NULL)) {
-			atmel_port->use_dma_rx	= 1;
-			atmel_port->use_pdc_rx	= 0;
-		} else {
-			atmel_port->use_dma_rx	= 0;
-			atmel_port->use_pdc_rx	= 1;
-		}
-	} else {
-		atmel_port->use_dma_rx	= 0;
-		atmel_port->use_pdc_rx	= 0;
-	}
-
-	if (of_get_property(np, "atmel,use-dma-tx", NULL)) {
-		if (of_get_property(np, "dmas", NULL)) {
-			atmel_port->use_dma_tx	= 1;
-			atmel_port->use_pdc_tx	= 0;
-		} else {
-			atmel_port->use_dma_tx	= 0;
-			atmel_port->use_pdc_tx	= 1;
-		}
-	} else {
-		atmel_port->use_dma_tx	= 0;
-		atmel_port->use_pdc_tx	= 0;
-	}
-
-	/* rs485 properties */
-	if (of_property_read_u32_array(np, "rs485-rts-delay",
-					    rs485_delay, 2) == 0) {
-		struct serial_rs485 *rs485conf = &atmel_port->rs485;
-
-		rs485conf->delay_rts_before_send = rs485_delay[0];
-		rs485conf->delay_rts_after_send = rs485_delay[1];
-		rs485conf->flags = 0;
-
-		if (of_get_property(np, "rs485-rx-during-tx", NULL))
-			rs485conf->flags |= SER_RS485_RX_DURING_TX;
-
-		if (of_get_property(np, "linux,rs485-enabled-at-boot-time", NULL))
-			rs485conf->flags |= SER_RS485_ENABLED;
-	}
-}
-
 /*
  * Configure the port from the platform device resource info.
  */

@@ -1936,17 +1964,10 @@ static void atmel_init_port(struct atmel_uart_port *atmel_port,
 	struct uart_port *port = &atmel_port->uart;
 	struct atmel_uart_data *pdata = pdev->dev.platform_data;
 
-	if (pdev->dev.of_node) {
-		atmel_of_init_port(atmel_port, pdev->dev.of_node);
-	} else {
-		atmel_port->use_pdc_rx	= pdata->use_dma_rx;
-		atmel_port->use_pdc_tx	= pdata->use_dma_tx;
-		atmel_port->use_dma_rx	= 0;
-		atmel_port->use_dma_tx	= 0;
-		atmel_port->rs485	= pdata->rs485;
-	}
+	if (!atmel_init_property(atmel_port, pdev))
+		atmel_set_ops(port);
 
-	atmel_set_ops(port);
+	atmel_init_rs485(atmel_port, pdev);
 
 	port->iotype		= UPIO_MEM;
 	port->flags		= UPF_BOOT_AUTOCONF;

index ad787fd1..afecdfa 100644
@@ -41,6 +41,7 @@
 #include <linux/uaccess.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_data/atmel.h>
+#include <linux/timer.h>
 
 #include <asm/io.h>
 #include <asm/ioctls.h>

@@ -167,6 +168,7 @@ struct atmel_uart_port {
 
 	struct serial_rs485	rs485;		/* rs485 settings */
 	unsigned int		tx_done_mask;
+	struct timer_list       uart_timer;     /* dbgu timer */
 	int (*prepare_rx)(struct uart_port *port);
 	int (*prepare_tx)(struct uart_port *port);
 	void (*schedule_rx)(struct uart_port *port);

@@ -821,6 +823,9 @@ static void atmel_release_rx_dma(struct uart_port *port)
 	atmel_port->desc_rx = NULL;
 	atmel_port->chan_rx = NULL;
 	atmel_port->cookie_rx = -EINVAL;
+
+	if (port->line == 0)
+		del_timer_sync(&atmel_port->uart_timer);
 }
 
 static void atmel_rx_from_dma(struct uart_port *port)

@@ -950,6 +955,15 @@ chan_err:
 	return -EINVAL;
 }
 
+static void atmel_uart_timer_callback(unsigned long data)
+{
+	struct uart_port *port = (void *)data;
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+	tasklet_schedule(&atmel_port->tasklet);
+	mod_timer(&atmel_port->uart_timer, jiffies + uart_poll_timeout(port));
+}
+
 /*
  * receive interrupt handler.
  */

@@ -1213,6 +1227,9 @@ static void atmel_release_rx_pdc(struct uart_port *port)
 				 DMA_FROM_DEVICE);
 		kfree(pdc->buf);
 	}
+
+	if (port->line == 0)
+		del_timer_sync(&atmel_port->uart_timer);
 }
 
 static void atmel_rx_from_pdc(struct uart_port *port)

@@ -1546,17 +1563,36 @@ static int atmel_startup(struct uart_port *port)
 
 	if (atmel_use_pdc_rx(port)) {
 		/* set UART timeout */
-		UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
-		UART_PUT_CR(port, ATMEL_US_STTTO);
+		if (port->line == 0) {
+			setup_timer(&atmel_port->uart_timer,
+					atmel_uart_timer_callback,
+					(unsigned long)port);
+			mod_timer(&atmel_port->uart_timer,
+					jiffies + uart_poll_timeout(port));
+		/* set USART timeout */
+		} else {
+			UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
+			UART_PUT_CR(port, ATMEL_US_STTTO);
 
-		UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
+			UART_PUT_IER(port, ATMEL_US_ENDRX | ATMEL_US_TIMEOUT);
+		}
 		/* enable PDC controller */
 		UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);
 	} else if (atmel_use_dma_rx(port)) {
-		UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
-		UART_PUT_CR(port, ATMEL_US_STTTO);
+		/* set UART timeout */
+		if (port->line == 0) {
+			setup_timer(&atmel_port->uart_timer,
+					atmel_uart_timer_callback,
+					(unsigned long)port);
+			mod_timer(&atmel_port->uart_timer,
+					jiffies + uart_poll_timeout(port));
+		/* set USART timeout */
+		} else {
+			UART_PUT_RTOR(port, PDC_RX_TIMEOUT);
+			UART_PUT_CR(port, ATMEL_US_STTTO);
 
-		UART_PUT_IER(port, ATMEL_US_TIMEOUT);
+			UART_PUT_IER(port, ATMEL_US_TIMEOUT);
+		}
 	} else {
 		/* enable receive only */
 		UART_PUT_IER(port, ATMEL_US_RXRDY);

index afecdfa..769b90b 100644
@@ -99,6 +99,7 @@ static void atmel_stop_rx(struct uart_port *port);
 #define UART_PUT_BRGR(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_BRGR)
 #define UART_PUT_RTOR(port,v)	__raw_writel(v, (port)->membase + ATMEL_US_RTOR)
 #define UART_PUT_TTGR(port, v)	__raw_writel(v, (port)->membase + ATMEL_US_TTGR)
+#define UART_GET_IP_NAME(port)	__raw_readl((port)->membase + ATMEL_US_NAME)
 
  /* PDC registers */
 #define UART_PUT_PTCR(port,v)	__raw_writel(v, (port)->membase + ATMEL_PDC_PTCR)

@@ -169,6 +170,7 @@ struct atmel_uart_port {
 	struct serial_rs485	rs485;		/* rs485 settings */
 	unsigned int		tx_done_mask;
 	struct timer_list       uart_timer;     /* dbgu timer */
+	bool			is_usart;	/* usart or uart */
 	int (*prepare_rx)(struct uart_port *port);
 	int (*prepare_tx)(struct uart_port *port);
 	void (*schedule_rx)(struct uart_port *port);

@@ -1496,6 +1498,34 @@ static void atmel_set_ops(struct uart_port *port)
 }
 
 /*
+ * Get ip name usart or uart
+ */
+static int atmel_get_ip_name(struct uart_port *port)
+{
+	struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+	int name = UART_GET_IP_NAME(port);
+	int usart, uart;
+	/* usart and uart ascii */
+	usart = 0x55534152;
+	uart = 0x44424755;
+
+	atmel_port->is_usart = false;
+
+	if (name == usart) {
+		dev_dbg(port->dev, "This is usart\n");
+		atmel_port->is_usart = true;
+	} else if (name == uart) {
+		dev_dbg(port->dev, "This is uart\n");
+		atmel_port->is_usart = false;
+	} else {
+		dev_err(port->dev, "Not supported ip name, set to uart\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/*
  * Perform initialization and enable port for reception
  */
 static int atmel_startup(struct uart_port *port)

@@ -2359,6 +2389,13 @@ static int atmel_serial_probe(struct platform_device *pdev)
 		UART_PUT_CR(&port->uart, ATMEL_US_RTSEN);
 	}
 
+	/*
+	 * Get port name of usart or uart
+	 */
+	ret = atmel_get_ip_name(&port->uart);
+	if (ret < 0)
+		goto err_add_port;
+
 	return 0;
 
 err_add_port:

index fd68337..be201ca 100644
@@ -124,4 +124,6 @@
 #define ATMEL_US_NER		0x44			/* Number of Errors Register */
 #define ATMEL_US_IF		0x4c			/* IrDA Filter Register */
 
+#define ATMEL_US_NAME		0xf0			/* Ip Name */
+
 #endif

index 769b90b..67617a8 100644
@@ -826,7 +826,7 @@ static void atmel_release_rx_dma(struct uart_port *port)
 	atmel_port->chan_rx = NULL;
 	atmel_port->cookie_rx = -EINVAL;
 
-	if (port->line == 0)
+	if (!atmel_port->is_usart)
 		del_timer_sync(&atmel_port->uart_timer);
 }
 

@@ -1230,7 +1230,7 @@ static void atmel_release_rx_pdc(struct uart_port *port)
 		kfree(pdc->buf);
 	}
 
-	if (port->line == 0)
+	if (!atmel_port->is_usart)
 		del_timer_sync(&atmel_port->uart_timer);
 }
 

@@ -1593,7 +1593,7 @@ static int atmel_startup(struct uart_port *port)
 
 	if (atmel_use_pdc_rx(port)) {
 		/* set UART timeout */
-		if (port->line == 0) {
+		if (!atmel_port->is_usart) {
 			setup_timer(&atmel_port->uart_timer,
 					atmel_uart_timer_callback,
 					(unsigned long)port);

@@ -1610,7 +1610,7 @@ static int atmel_startup(struct uart_port *port)
 		UART_PUT_PTCR(port, ATMEL_PDC_RXTEN);
 	} else if (atmel_use_dma_rx(port)) {
 		/* set UART timeout */
-		if (port->line == 0) {
+		if (!atmel_port->is_usart) {
 			setup_timer(&atmel_port->uart_timer,
 					atmel_uart_timer_callback,
 					(unsigned long)port);