1 files changed, 222 insertions, 16 deletions

diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index 825c8192b944..c04618052e53 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -81,6 +81,8 @@ static void dbg(const char *fmt, ...)
 #define S3C24XX_SERIAL_MAJOR	204
 #define S3C24XX_SERIAL_MINOR	64
 
+#define S3C24XX_TX_PIO			1
+#define S3C24XX_TX_DMA			2
 /* macros to change one thing to another */
 
 #define tx_enabled(port) ((port)->unused[0])
@@ -157,33 +159,217 @@ static void s3c24xx_serial_rx_disable(struct uart_port *port)
 static void s3c24xx_serial_stop_tx(struct uart_port *port)
 {
 	struct s3c24xx_uart_port *ourport = to_ourport(port);
+	struct s3c24xx_uart_dma *dma = ourport->dma;
+	struct circ_buf *xmit = &port->state->xmit;
+	struct dma_tx_state state;
+	int count;
 
-	if (tx_enabled(port)) {
-		if (s3c24xx_serial_has_interrupt_mask(port))
-			__set_bit(S3C64XX_UINTM_TXD,
-				portaddrl(port, S3C64XX_UINTM));
-		else
-			disable_irq_nosync(ourport->tx_irq);
-		tx_enabled(port) = 0;
-		if (port->flags & UPF_CONS_FLOW)
-			s3c24xx_serial_rx_enable(port);
+	if (!tx_enabled(port))
+		return;
+
+	if (s3c24xx_serial_has_interrupt_mask(port))
+		__set_bit(S3C64XX_UINTM_TXD,
+			portaddrl(port, S3C64XX_UINTM));
+	else
+		disable_irq_nosync(ourport->tx_irq);
+
+	if (dma && dma->tx_chan && ourport->tx_in_progress == S3C24XX_TX_DMA) {
+		dmaengine_pause(dma->tx_chan);
+		dmaengine_tx_status(dma->tx_chan, dma->tx_cookie, &state);
+		dmaengine_terminate_all(dma->tx_chan);
+		dma_sync_single_for_cpu(ourport->port.dev,
+			dma->tx_transfer_addr, dma->tx_size, DMA_TO_DEVICE);
+		async_tx_ack(dma->tx_desc);
+		count = dma->tx_bytes_requested - state.residue;
+		xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
+		port->icount.tx += count;
 	}
+
+	tx_enabled(port) = 0;
+	ourport->tx_in_progress = 0;
+
+	if (port->flags & UPF_CONS_FLOW)
+		s3c24xx_serial_rx_enable(port);
+
+	ourport->tx_mode = 0;
+}
+
+static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport);
+
+static void s3c24xx_serial_tx_dma_complete(void *args)
+{
+	struct s3c24xx_uart_port *ourport = args;
+	struct uart_port *port = &ourport->port;
+	struct circ_buf *xmit = &port->state->xmit;
+	struct s3c24xx_uart_dma *dma = ourport->dma;
+	struct dma_tx_state state;
+	unsigned long flags;
+	int count;
+
+
+	dmaengine_tx_status(dma->tx_chan, dma->tx_cookie, &state);
+	count = dma->tx_bytes_requested - state.residue;
+	async_tx_ack(dma->tx_desc);
+
+	dma_sync_single_for_cpu(ourport->port.dev, dma->tx_transfer_addr,
+				dma->tx_size, DMA_TO_DEVICE);
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
+	port->icount.tx += count;
+	ourport->tx_in_progress = 0;
+
+	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+		uart_write_wakeup(port);
+
+	s3c24xx_serial_start_next_tx(ourport);
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void enable_tx_dma(struct s3c24xx_uart_port *ourport)
+{
+	struct uart_port *port = &ourport->port;
+	u32 ucon;
+
+	/* Mask Tx interrupt */
+	if (s3c24xx_serial_has_interrupt_mask(port))
+		__set_bit(S3C64XX_UINTM_TXD,
+			  portaddrl(port, S3C64XX_UINTM));
+	else
+		disable_irq_nosync(ourport->tx_irq);
+
+	/* Enable tx dma mode */
+	ucon = rd_regl(port, S3C2410_UCON);
+	ucon &= ~(S3C64XX_UCON_TXBURST_MASK | S3C64XX_UCON_TXMODE_MASK);
+	ucon |= (dma_get_cache_alignment() >= 16) ?
+		S3C64XX_UCON_TXBURST_16 : S3C64XX_UCON_TXBURST_1;
+	ucon |= S3C64XX_UCON_TXMODE_DMA;
+	wr_regl(port,  S3C2410_UCON, ucon);
+
+	ourport->tx_mode = S3C24XX_TX_DMA;
+}
+
+static void enable_tx_pio(struct s3c24xx_uart_port *ourport)
+{
+	struct uart_port *port = &ourport->port;
+	u32 ucon, ufcon;
+
+	/* Set ufcon txtrig */
+	ourport->tx_in_progress = S3C24XX_TX_PIO;
+	ufcon = rd_regl(port, S3C2410_UFCON);
+	wr_regl(port,  S3C2410_UFCON, ufcon);
+
+	/* Enable tx pio mode */
+	ucon = rd_regl(port, S3C2410_UCON);
+	ucon &= ~(S3C64XX_UCON_TXMODE_MASK);
+	ucon |= S3C64XX_UCON_TXMODE_CPU;
+	wr_regl(port,  S3C2410_UCON, ucon);
+
+	/* Unmask Tx interrupt */
+	if (s3c24xx_serial_has_interrupt_mask(port))
+		__clear_bit(S3C64XX_UINTM_TXD,
+			    portaddrl(port, S3C64XX_UINTM));
+	else
+		enable_irq(ourport->tx_irq);
+
+	ourport->tx_mode = S3C24XX_TX_PIO;
 }
 
-static void s3c24xx_serial_start_tx(struct uart_port *port)
+static void s3c24xx_serial_start_tx_pio(struct s3c24xx_uart_port *ourport)
+{
+	if (ourport->tx_mode != S3C24XX_TX_PIO)
+		enable_tx_pio(ourport);
+}
+
+static int s3c24xx_serial_start_tx_dma(struct s3c24xx_uart_port *ourport,
+				      unsigned int count)
+{
+	struct uart_port *port = &ourport->port;
+	struct circ_buf *xmit = &port->state->xmit;
+	struct s3c24xx_uart_dma *dma = ourport->dma;
+
+
+	if (ourport->tx_mode != S3C24XX_TX_DMA)
+		enable_tx_dma(ourport);
+
+	while (xmit->tail & (dma_get_cache_alignment() - 1)) {
+		if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)
+			return 0;
+		wr_regb(port, S3C2410_UTXH, xmit->buf[xmit->tail]);
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+		count--;
+	}
+
+	dma->tx_size = count & ~(dma_get_cache_alignment() - 1);
+	dma->tx_transfer_addr = dma->tx_addr + xmit->tail;
+
+	dma_sync_single_for_device(ourport->port.dev, dma->tx_transfer_addr,
+				dma->tx_size, DMA_TO_DEVICE);
+
+	dma->tx_desc = dmaengine_prep_slave_single(dma->tx_chan,
+				dma->tx_transfer_addr, dma->tx_size,
+				DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT);
+	if (!dma->tx_desc) {
+		dev_err(ourport->port.dev, "Unable to get desc for Tx\n");
+		return -EIO;
+	}
+
+	dma->tx_desc->callback = s3c24xx_serial_tx_dma_complete;
+	dma->tx_desc->callback_param = ourport;
+	dma->tx_bytes_requested = dma->tx_size;
+
+	ourport->tx_in_progress = S3C24XX_TX_DMA;
+	dma->tx_cookie = dmaengine_submit(dma->tx_desc);
+	dma_async_issue_pending(dma->tx_chan);
+	return 0;
+}
+
+static void s3c24xx_serial_start_next_tx(struct s3c24xx_uart_port *ourport)
+{
+	struct uart_port *port = &ourport->port;
+	struct circ_buf *xmit = &port->state->xmit;
+	unsigned long count;
+
+	/* Get data size up to the end of buffer */
+	count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+
+	if (!count) {
+		s3c24xx_serial_stop_tx(port);
+		return;
+	}
+
+	if (!ourport->dma || !ourport->dma->tx_chan || count < port->fifosize)
+		s3c24xx_serial_start_tx_pio(ourport);
+	else
+		s3c24xx_serial_start_tx_dma(ourport, count);
+}
+
+void s3c24xx_serial_start_tx(struct uart_port *port)
 {
 	struct s3c24xx_uart_port *ourport = to_ourport(port);
+	struct circ_buf *xmit = &port->state->xmit;
 
 	if (!tx_enabled(port)) {
 		if (port->flags & UPF_CONS_FLOW)
 			s3c24xx_serial_rx_disable(port);
 
-		if (s3c24xx_serial_has_interrupt_mask(port))
-			__clear_bit(S3C64XX_UINTM_TXD,
-				portaddrl(port, S3C64XX_UINTM));
-		else
-			enable_irq(ourport->tx_irq);
 		tx_enabled(port) = 1;
+		if (!ourport->dma || !ourport->dma->tx_chan) {
+			if (s3c24xx_serial_has_interrupt_mask(port))
+				__clear_bit(S3C64XX_UINTM_TXD,
+						portaddrl(port, S3C64XX_UINTM));
+			else
+				enable_irq(ourport->tx_irq);
+
+			s3c24xx_serial_start_tx_pio(ourport);
+		}
+	}
+
+	if (ourport->dma && ourport->dma->tx_chan) {
+		if (!uart_circ_empty(xmit) && !ourport->tx_in_progress)
+			s3c24xx_serial_start_next_tx(ourport);
 	}
 }
 
@@ -333,10 +519,17 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id)
 	struct uart_port *port = &ourport->port;
 	struct circ_buf *xmit = &port->state->xmit;
 	unsigned long flags;
-	int count = port->fifosize;
+	int count;
 
 	spin_lock_irqsave(&port->lock, flags);
 
+	count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
+
+	if (ourport->dma && ourport->dma->tx_chan && count >= port->fifosize) {
+		s3c24xx_serial_start_tx_dma(ourport, count);
+		goto out;
+	}
+
 	if (port->x_char) {
 		wr_regb(port, S3C2410_UTXH, port->x_char);
 		port->icount.tx++;
@@ -355,6 +548,7 @@ static irqreturn_t s3c24xx_serial_tx_chars(int irq, void *id)
 
 	/* try and drain the buffer... */
 
+	count = port->fifosize;
 	while (!uart_circ_empty(xmit) && count-- > 0) {
 		if (rd_regl(port, S3C2410_UFSTAT) & ourport->info->tx_fifofull)
 			break;
@@ -572,6 +766,7 @@ static void s3c24xx_serial_shutdown(struct uart_port *port)
 	if (ourport->dma)
 		s3c24xx_serial_release_dma(ourport);
 
+	ourport->tx_in_progress = 0;
 }
 
 static int s3c24xx_serial_startup(struct uart_port *port)
@@ -650,8 +845,19 @@ static int s3c64xx_serial_startup(struct uart_port *port)
 	tx_enabled(port) = 0;
 	ourport->tx_claimed = 1;
 
+	spin_lock_irqsave(&port->lock, flags);
+
+	ufcon = rd_regl(port, S3C2410_UFCON);
+	ufcon |= S3C2410_UFCON_RESETRX | S3C2410_UFCON_RESETTX;
+	wr_regl(port, S3C2410_UFCON, ufcon);
+
+	enable_rx_pio(ourport);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
 	/* Enable Rx Interrupt */
 	__clear_bit(S3C64XX_UINTM_RXD, portaddrl(port, S3C64XX_UINTM));
+
 	dbg("s3c64xx_serial_startup ok\n");
 	return ret;
 }