1 files changed, 113 insertions, 58 deletions

diff --git a/drivers/tty/serial/sccnxp.c b/drivers/tty/serial/sccnxp.c
index e869eab180be..08dbfb88d42c 100644
--- a/drivers/tty/serial/sccnxp.c
+++ b/drivers/tty/serial/sccnxp.c
@@ -24,8 +24,9 @@
 #include <linux/io.h>
 #include <linux/tty.h>
 #include <linux/tty_flip.h>
+#include <linux/spinlock.h>
 #include <linux/platform_device.h>
-#include <linux/platform_data/sccnxp.h>
+#include <linux/platform_data/serial-sccnxp.h>
 
 #define SCCNXP_NAME			"uart-sccnxp"
 #define SCCNXP_MAJOR			204
@@ -107,6 +108,7 @@ enum {
 struct sccnxp_port {
 	struct uart_driver	uart;
 	struct uart_port	port[SCCNXP_MAX_UARTS];
+	bool			opened[SCCNXP_MAX_UARTS];
 
 	const char		*name;
 	int			irq;
@@ -123,7 +125,10 @@ struct sccnxp_port {
 	struct console		console;
 #endif
 
-	struct mutex		sccnxp_mutex;
+	spinlock_t		lock;
+
+	bool			poll;
+	struct timer_list	timer;
 
 	struct sccnxp_pdata	pdata;
 };
@@ -175,14 +180,12 @@ static int sccnxp_update_best_err(int a, int b, int *besterr)
 	return 1;
 }
 
-struct baud_table {
+static const struct {
 	u8	csr;
 	u8	acr;
 	u8	mr0;
 	int	baud;
-};
-
-const struct baud_table baud_std[] = {
+} baud_std[] = {
 	{ 0,	ACR_BAUD0,	MR0_BAUD_NORMAL,	50, },
 	{ 0,	ACR_BAUD1,	MR0_BAUD_NORMAL,	75, },
 	{ 1,	ACR_BAUD0,	MR0_BAUD_NORMAL,	110, },
@@ -286,10 +289,6 @@ static void sccnxp_handle_rx(struct uart_port *port)
 {
 	u8 sr;
 	unsigned int ch, flag;
-	struct tty_struct *tty = tty_port_tty_get(&port->state->port);
-
-	if (!tty)
-		return;
 
 	for (;;) {
 		sr = sccnxp_port_read(port, SCCNXP_SR_REG);
@@ -305,14 +304,19 @@ static void sccnxp_handle_rx(struct uart_port *port)
 		if (unlikely(sr)) {
 			if (sr & SR_BRK) {
 				port->icount.brk++;
+				sccnxp_port_write(port, SCCNXP_CR_REG,
+						  CR_CMD_BREAK_RESET);
 				if (uart_handle_break(port))
 					continue;
 			} else if (sr & SR_PE)
 				port->icount.parity++;
 			else if (sr & SR_FE)
 				port->icount.frame++;
-			else if (sr & SR_OVR)
+			else if (sr & SR_OVR) {
 				port->icount.overrun++;
+				sccnxp_port_write(port, SCCNXP_CR_REG,
+						  CR_CMD_STATUS_RESET);
+			}
 
 			sr &= port->read_status_mask;
 			if (sr & SR_BRK)
@@ -334,9 +338,7 @@ static void sccnxp_handle_rx(struct uart_port *port)
 		uart_insert_char(port, sr, SR_OVR, ch, flag);
 	}
 
-	tty_flip_buffer_push(tty);
-
-	tty_kref_put(tty);
+	tty_flip_buffer_push(&port->state->port);
 }
 
 static void sccnxp_handle_tx(struct uart_port *port)
@@ -378,31 +380,48 @@ static void sccnxp_handle_tx(struct uart_port *port)
 		uart_write_wakeup(port);
 }
 
-static irqreturn_t sccnxp_ist(int irq, void *dev_id)
+static void sccnxp_handle_events(struct sccnxp_port *s)
 {
 	int i;
 	u8 isr;
-	struct sccnxp_port *s = (struct sccnxp_port *)dev_id;
-
-	mutex_lock(&s->sccnxp_mutex);
 
-	for (;;) {
+	do {
 		isr = sccnxp_read(&s->port[0], SCCNXP_ISR_REG);
 		isr &= s->imr;
 		if (!isr)
 			break;
 
-		dev_dbg(s->port[0].dev, "IRQ status: 0x%02x\n", isr);
-
 		for (i = 0; i < s->uart.nr; i++) {
-			if (isr & ISR_RXRDY(i))
+			if (s->opened[i] && (isr & ISR_RXRDY(i)))
 				sccnxp_handle_rx(&s->port[i]);
-			if (isr & ISR_TXRDY(i))
+			if (s->opened[i] && (isr & ISR_TXRDY(i)))
 				sccnxp_handle_tx(&s->port[i]);
 		}
-	}
+	} while (1);
+}
+
+static void sccnxp_timer(unsigned long data)
+{
+	struct sccnxp_port *s = (struct sccnxp_port *)data;
+	unsigned long flags;
 
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
+	sccnxp_handle_events(s);
+	spin_unlock_irqrestore(&s->lock, flags);
+
+	if (!timer_pending(&s->timer))
+		mod_timer(&s->timer, jiffies +
+			  usecs_to_jiffies(s->pdata.poll_time_us));
+}
+
+static irqreturn_t sccnxp_ist(int irq, void *dev_id)
+{
+	struct sccnxp_port *s = (struct sccnxp_port *)dev_id;
+	unsigned long flags;
+
+	spin_lock_irqsave(&s->lock, flags);
+	sccnxp_handle_events(s);
+	spin_unlock_irqrestore(&s->lock, flags);
 
 	return IRQ_HANDLED;
 }
@@ -410,8 +429,9 @@ static irqreturn_t sccnxp_ist(int irq, void *dev_id)
 static void sccnxp_start_tx(struct uart_port *port)
 {
 	struct sccnxp_port *s = dev_get_drvdata(port->dev);
+	unsigned long flags;
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
 
 	/* Set direction to output */
 	if (s->flags & SCCNXP_HAVE_IO)
@@ -419,7 +439,7 @@ static void sccnxp_start_tx(struct uart_port *port)
 
 	sccnxp_enable_irq(port, IMR_TXRDY);
 
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_unlock_irqrestore(&s->lock, flags);
 }
 
 static void sccnxp_stop_tx(struct uart_port *port)
@@ -430,20 +450,22 @@ static void sccnxp_stop_tx(struct uart_port *port)
 static void sccnxp_stop_rx(struct uart_port *port)
 {
 	struct sccnxp_port *s = dev_get_drvdata(port->dev);
+	unsigned long flags;
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
 	sccnxp_port_write(port, SCCNXP_CR_REG, CR_RX_DISABLE);
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_unlock_irqrestore(&s->lock, flags);
 }
 
 static unsigned int sccnxp_tx_empty(struct uart_port *port)
 {
 	u8 val;
+	unsigned long flags;
 	struct sccnxp_port *s = dev_get_drvdata(port->dev);
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
 	val = sccnxp_port_read(port, SCCNXP_SR_REG);
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_unlock_irqrestore(&s->lock, flags);
 
 	return (val & SR_TXEMT) ? TIOCSER_TEMT : 0;
 }
@@ -456,28 +478,30 @@ static void sccnxp_enable_ms(struct uart_port *port)
 static void sccnxp_set_mctrl(struct uart_port *port, unsigned int mctrl)
 {
 	struct sccnxp_port *s = dev_get_drvdata(port->dev);
+	unsigned long flags;
 
 	if (!(s->flags & SCCNXP_HAVE_IO))
 		return;
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
 
 	sccnxp_set_bit(port, DTR_OP, mctrl & TIOCM_DTR);
 	sccnxp_set_bit(port, RTS_OP, mctrl & TIOCM_RTS);
 
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_unlock_irqrestore(&s->lock, flags);
 }
 
 static unsigned int sccnxp_get_mctrl(struct uart_port *port)
 {
 	u8 bitmask, ipr;
+	unsigned long flags;
 	struct sccnxp_port *s = dev_get_drvdata(port->dev);
 	unsigned int mctrl = TIOCM_DSR | TIOCM_CTS | TIOCM_CAR;
 
 	if (!(s->flags & SCCNXP_HAVE_IO))
 		return mctrl;
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
 
 	ipr = ~sccnxp_read(port, SCCNXP_IPCR_REG);
 
@@ -506,7 +530,7 @@ static unsigned int sccnxp_get_mctrl(struct uart_port *port)
 		mctrl |= (ipr & bitmask) ? TIOCM_RNG : 0;
 	}
 
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_unlock_irqrestore(&s->lock, flags);
 
 	return mctrl;
 }
@@ -514,21 +538,23 @@ static unsigned int sccnxp_get_mctrl(struct uart_port *port)
 static void sccnxp_break_ctl(struct uart_port *port, int break_state)
 {
 	struct sccnxp_port *s = dev_get_drvdata(port->dev);
+	unsigned long flags;
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
 	sccnxp_port_write(port, SCCNXP_CR_REG, break_state ?
 			  CR_CMD_START_BREAK : CR_CMD_STOP_BREAK);
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_unlock_irqrestore(&s->lock, flags);
 }
 
 static void sccnxp_set_termios(struct uart_port *port,
 			       struct ktermios *termios, struct ktermios *old)
 {
 	struct sccnxp_port *s = dev_get_drvdata(port->dev);
+	unsigned long flags;
 	u8 mr1, mr2;
 	int baud;
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
 
 	/* Mask termios capabilities we don't support */
 	termios->c_cflag &= ~CMSPAR;
@@ -595,20 +621,22 @@ static void sccnxp_set_termios(struct uart_port *port,
 	/* Update timeout according to new baud rate */
 	uart_update_timeout(port, termios->c_cflag, baud);
 
+	/* Report actual baudrate back to core */
 	if (tty_termios_baud_rate(termios))
 		tty_termios_encode_baud_rate(termios, baud, baud);
 
 	/* Enable RX & TX */
 	sccnxp_port_write(port, SCCNXP_CR_REG, CR_RX_ENABLE | CR_TX_ENABLE);
 
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_unlock_irqrestore(&s->lock, flags);
 }
 
 static int sccnxp_startup(struct uart_port *port)
 {
 	struct sccnxp_port *s = dev_get_drvdata(port->dev);
+	unsigned long flags;
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
 
 	if (s->flags & SCCNXP_HAVE_IO) {
 		/* Outputs are controlled manually */
@@ -627,7 +655,9 @@ static int sccnxp_startup(struct uart_port *port)
 	/* Enable RX interrupt */
 	sccnxp_enable_irq(port, IMR_RXRDY);
 
-	mutex_unlock(&s->sccnxp_mutex);
+	s->opened[port->line] = 1;
+
+	spin_unlock_irqrestore(&s->lock, flags);
 
 	return 0;
 }
@@ -635,8 +665,11 @@ static int sccnxp_startup(struct uart_port *port)
 static void sccnxp_shutdown(struct uart_port *port)
 {
 	struct sccnxp_port *s = dev_get_drvdata(port->dev);
+	unsigned long flags;
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
+
+	s->opened[port->line] = 0;
 
 	/* Disable interrupts */
 	sccnxp_disable_irq(port, IMR_TXRDY | IMR_RXRDY);
@@ -648,7 +681,7 @@ static void sccnxp_shutdown(struct uart_port *port)
 	if (s->flags & SCCNXP_HAVE_IO)
 		sccnxp_set_bit(port, DIR_OP, 0);
 
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_unlock_irqrestore(&s->lock, flags);
 }
 
 static const char *sccnxp_type(struct uart_port *port)
@@ -722,10 +755,11 @@ static void sccnxp_console_write(struct console *co, const char *c, unsigned n)
 {
 	struct sccnxp_port *s = (struct sccnxp_port *)co->data;
 	struct uart_port *port = &s->port[co->index];
+	unsigned long flags;
 
-	mutex_lock(&s->sccnxp_mutex);
+	spin_lock_irqsave(&s->lock, flags);
 	uart_console_write(port, c, n, sccnxp_console_putchar);
-	mutex_unlock(&s->sccnxp_mutex);
+	spin_unlock_irqrestore(&s->lock, flags);
 }
 
 static int sccnxp_console_setup(struct console *co, char *options)
@@ -764,7 +798,7 @@ static int sccnxp_probe(struct platform_device *pdev)
 	}
 	platform_set_drvdata(pdev, s);
 
-	mutex_init(&s->sccnxp_mutex);
+	spin_lock_init(&s->lock);
 
 	/* Individual chip settings */
 	switch (chiptype) {
@@ -861,11 +895,19 @@ static int sccnxp_probe(struct platform_device *pdev)
 	} else
 		memcpy(&s->pdata, pdata, sizeof(struct sccnxp_pdata));
 
-	s->irq = platform_get_irq(pdev, 0);
-	if (s->irq <= 0) {
-		dev_err(&pdev->dev, "Missing irq resource data\n");
-		ret = -ENXIO;
-		goto err_out;
+	if (s->pdata.poll_time_us) {
+		dev_info(&pdev->dev, "Using poll mode, resolution %u usecs\n",
+			 s->pdata.poll_time_us);
+		s->poll = 1;
+	}
+
+	if (!s->poll) {
+		s->irq = platform_get_irq(pdev, 0);
+		if (s->irq < 0) {
+			dev_err(&pdev->dev, "Missing irq resource data\n");
+			ret = -ENXIO;
+			goto err_out;
+		}
 	}
 
 	/* Check input frequency */
@@ -929,13 +971,23 @@ static int sccnxp_probe(struct platform_device *pdev)
 	if (s->pdata.init)
 		s->pdata.init();
 
-	ret = devm_request_threaded_irq(&pdev->dev, s->irq, NULL, sccnxp_ist,
-					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
-					dev_name(&pdev->dev), s);
-	if (!ret)
+	if (!s->poll) {
+		ret = devm_request_threaded_irq(&pdev->dev, s->irq, NULL,
+						sccnxp_ist,
+						IRQF_TRIGGER_FALLING |
+						IRQF_ONESHOT,
+						dev_name(&pdev->dev), s);
+		if (!ret)
+			return 0;
+
+		dev_err(&pdev->dev, "Unable to reguest IRQ %i\n", s->irq);
+	} else {
+		init_timer(&s->timer);
+		setup_timer(&s->timer, sccnxp_timer, (unsigned long)s);
+		mod_timer(&s->timer, jiffies +
+			  usecs_to_jiffies(s->pdata.poll_time_us));
 		return 0;
-
-	dev_err(&pdev->dev, "Unable to reguest IRQ %i\n", s->irq);
+	}
 
 err_out:
 	platform_set_drvdata(pdev, NULL);
@@ -948,7 +1000,10 @@ static int sccnxp_remove(struct platform_device *pdev)
 	int i;
 	struct sccnxp_port *s = platform_get_drvdata(pdev);
 
-	devm_free_irq(&pdev->dev, s->irq, s);
+	if (!s->poll)
+		devm_free_irq(&pdev->dev, s->irq, s);
+	else
+		del_timer_sync(&s->timer);
 
 	for (i = 0; i < s->uart.nr; i++)
 		uart_remove_one_port(&s->uart, &s->port[i]);