1 files changed, 180 insertions, 87 deletions

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index ecb6513a6505..39f635812077 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -233,6 +233,7 @@
 /* Misc definitions */
 #define MAX310X_FIFO_SIZE		(128)
 #define MAX310x_REV_MASK		(0xf8)
+#define MAX310X_WRITE_BIT		0x80
 
 /* MAX3107 specific */
 #define MAX3107_REV_ID			(0xa0)
@@ -593,57 +594,118 @@ static int max310x_set_ref_clk(struct max310x_port *s, unsigned long freq,
 	return (int)bestfreq;
 }
 
-static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen)
+static void max310x_batch_write(struct uart_port *port, u8 *txbuf, unsigned int len)
 {
-	unsigned int sts, ch, flag;
+	u8 header[] = { (port->iobase + MAX310X_THR_REG) | MAX310X_WRITE_BIT };
+	struct spi_transfer xfer[] = {
+		{
+			.tx_buf = &header,
+			.len = sizeof(header),
+		}, {
+			.tx_buf = txbuf,
+			.len = len,
+		}
+	};
+	spi_sync_transfer(to_spi_device(port->dev), xfer, ARRAY_SIZE(xfer));
+}
 
-	if (unlikely(rxlen >= port->fifosize)) {
-		dev_warn_ratelimited(port->dev, "Possible RX FIFO overrun\n");
-		port->icount.buf_overrun++;
-		/* Ensure sanity of RX level */
-		rxlen = port->fifosize;
-	}
+static void max310x_batch_read(struct uart_port *port, u8 *rxbuf, unsigned int len)
+{
+	u8 header[] = { port->iobase + MAX310X_RHR_REG };
+	struct spi_transfer xfer[] = {
+		{
+			.tx_buf = &header,
+			.len = sizeof(header),
+		}, {
+			.rx_buf = rxbuf,
+			.len = len,
+		}
+	};
+	spi_sync_transfer(to_spi_device(port->dev), xfer, ARRAY_SIZE(xfer));
+}
 
-	while (rxlen--) {
-		ch = max310x_port_read(port, MAX310X_RHR_REG);
-		sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
+static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen)
+{
+	unsigned int sts, ch, flag, i;
+	u8 buf[MAX310X_FIFO_SIZE];
+
+	if (port->read_status_mask == MAX310X_LSR_RXOVR_BIT) {
+		/* We are just reading, happily ignoring any error conditions.
+		 * Break condition, parity checking, framing errors -- they
+		 * are all ignored. That means that we can do a batch-read.
+		 *
+		 * There is a small opportunity for race if the RX FIFO
+		 * overruns while we're reading the buffer; the datasheets says
+		 * that the LSR register applies to the "current" character.
+		 * That's also the reason why we cannot do batched reads when
+		 * asked to check the individual statuses.
+		 * */
 
-		sts &= MAX310X_LSR_RXPAR_BIT | MAX310X_LSR_FRERR_BIT |
-		       MAX310X_LSR_RXOVR_BIT | MAX310X_LSR_RXBRK_BIT;
+		sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
+		max310x_batch_read(port, buf, rxlen);
 
-		port->icount.rx++;
+		port->icount.rx += rxlen;
 		flag = TTY_NORMAL;
+		sts &= port->read_status_mask;
 
-		if (unlikely(sts)) {
-			if (sts & MAX310X_LSR_RXBRK_BIT) {
-				port->icount.brk++;
-				if (uart_handle_break(port))
-					continue;
-			} else if (sts & MAX310X_LSR_RXPAR_BIT)
-				port->icount.parity++;
-			else if (sts & MAX310X_LSR_FRERR_BIT)
-				port->icount.frame++;
-			else if (sts & MAX310X_LSR_RXOVR_BIT)
-				port->icount.overrun++;
-
-			sts &= port->read_status_mask;
-			if (sts & MAX310X_LSR_RXBRK_BIT)
-				flag = TTY_BREAK;
-			else if (sts & MAX310X_LSR_RXPAR_BIT)
-				flag = TTY_PARITY;
-			else if (sts & MAX310X_LSR_FRERR_BIT)
-				flag = TTY_FRAME;
-			else if (sts & MAX310X_LSR_RXOVR_BIT)
-				flag = TTY_OVERRUN;
+		if (sts & MAX310X_LSR_RXOVR_BIT) {
+			dev_warn_ratelimited(port->dev, "Hardware RX FIFO overrun\n");
+			port->icount.overrun++;
 		}
 
-		if (uart_handle_sysrq_char(port, ch))
-			continue;
+		for (i = 0; i < rxlen; ++i) {
+			uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, buf[i], flag);
+		}
+
+	} else {
+		if (unlikely(rxlen >= port->fifosize)) {
+			dev_warn_ratelimited(port->dev, "Possible RX FIFO overrun\n");
+			port->icount.buf_overrun++;
+			/* Ensure sanity of RX level */
+			rxlen = port->fifosize;
+		}
+
+		while (rxlen--) {
+			ch = max310x_port_read(port, MAX310X_RHR_REG);
+			sts = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
+
+			sts &= MAX310X_LSR_RXPAR_BIT | MAX310X_LSR_FRERR_BIT |
+			       MAX310X_LSR_RXOVR_BIT | MAX310X_LSR_RXBRK_BIT;
+
+			port->icount.rx++;
+			flag = TTY_NORMAL;
+
+			if (unlikely(sts)) {
+				if (sts & MAX310X_LSR_RXBRK_BIT) {
+					port->icount.brk++;
+					if (uart_handle_break(port))
+						continue;
+				} else if (sts & MAX310X_LSR_RXPAR_BIT)
+					port->icount.parity++;
+				else if (sts & MAX310X_LSR_FRERR_BIT)
+					port->icount.frame++;
+				else if (sts & MAX310X_LSR_RXOVR_BIT)
+					port->icount.overrun++;
+
+				sts &= port->read_status_mask;
+				if (sts & MAX310X_LSR_RXBRK_BIT)
+					flag = TTY_BREAK;
+				else if (sts & MAX310X_LSR_RXPAR_BIT)
+					flag = TTY_PARITY;
+				else if (sts & MAX310X_LSR_FRERR_BIT)
+					flag = TTY_FRAME;
+				else if (sts & MAX310X_LSR_RXOVR_BIT)
+					flag = TTY_OVERRUN;
+			}
 
-		if (sts & port->ignore_status_mask)
-			continue;
+			if (uart_handle_sysrq_char(port, ch))
+				continue;
 
-		uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, ch, flag);
+			if (sts & port->ignore_status_mask)
+				continue;
+
+			uart_insert_char(port, sts, MAX310X_LSR_RXOVR_BIT, ch, flag);
+		}
 	}
 
 	tty_flip_buffer_push(&port->state->port);
@@ -652,7 +714,7 @@ static void max310x_handle_rx(struct uart_port *port, unsigned int rxlen)
 static void max310x_handle_tx(struct uart_port *port)
 {
 	struct circ_buf *xmit = &port->state->xmit;
-	unsigned int txlen, to_send;
+	unsigned int txlen, to_send, until_end;
 
 	if (unlikely(port->x_char)) {
 		max310x_port_write(port, MAX310X_THR_REG, port->x_char);
@@ -666,28 +728,43 @@ static void max310x_handle_tx(struct uart_port *port)
 
 	/* Get length of data pending in circular buffer */
 	to_send = uart_circ_chars_pending(xmit);
+	until_end = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 	if (likely(to_send)) {
 		/* Limit to size of TX FIFO */
 		txlen = max310x_port_read(port, MAX310X_TXFIFOLVL_REG);
 		txlen = port->fifosize - txlen;
 		to_send = (to_send > txlen) ? txlen : to_send;
 
+		if (until_end < to_send) {
+			/* It's a circ buffer -- wrap around.
+			 * We could do that in one SPI transaction, but meh. */
+			max310x_batch_write(port, xmit->buf + xmit->tail, until_end);
+			max310x_batch_write(port, xmit->buf, to_send - until_end);
+		} else {
+			max310x_batch_write(port, xmit->buf + xmit->tail, to_send);
+		}
+
 		/* Add data to send */
 		port->icount.tx += to_send;
-		while (to_send--) {
-			max310x_port_write(port, MAX310X_THR_REG,
-					   xmit->buf[xmit->tail]);
-			xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
-		}
+		xmit->tail = (xmit->tail + to_send) & (UART_XMIT_SIZE - 1);
 	}
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 		uart_write_wakeup(port);
 }
 
-static void max310x_port_irq(struct max310x_port *s, int portno)
+static void max310x_start_tx(struct uart_port *port)
+{
+	struct max310x_one *one = container_of(port, struct max310x_one, port);
+
+	if (!work_pending(&one->tx_work))
+		schedule_work(&one->tx_work);
+}
+
+static irqreturn_t max310x_port_irq(struct max310x_port *s, int portno)
 {
 	struct uart_port *port = &s->p[portno].port;
+	irqreturn_t res = IRQ_NONE;
 
 	do {
 		unsigned int ists, lsr, rxlen;
@@ -698,6 +775,8 @@ static void max310x_port_irq(struct max310x_port *s, int portno)
 		if (!ists && !rxlen)
 			break;
 
+		res = IRQ_HANDLED;
+
 		if (ists & MAX310X_IRQ_CTS_BIT) {
 			lsr = max310x_port_read(port, MAX310X_LSR_IRQSTS_REG);
 			uart_handle_cts_change(port,
@@ -705,17 +784,16 @@ static void max310x_port_irq(struct max310x_port *s, int portno)
 		}
 		if (rxlen)
 			max310x_handle_rx(port, rxlen);
-		if (ists & MAX310X_IRQ_TXEMPTY_BIT) {
-			mutex_lock(&s->mutex);
-			max310x_handle_tx(port);
-			mutex_unlock(&s->mutex);
-		}
+		if (ists & MAX310X_IRQ_TXEMPTY_BIT)
+			max310x_start_tx(port);
 	} while (1);
+	return res;
 }
 
 static irqreturn_t max310x_ist(int irq, void *dev_id)
 {
 	struct max310x_port *s = (struct max310x_port *)dev_id;
+	bool handled = false;
 
 	if (s->devtype->nr > 1) {
 		do {
@@ -726,12 +804,15 @@ static irqreturn_t max310x_ist(int irq, void *dev_id)
 			val = ((1 << s->devtype->nr) - 1) & ~val;
 			if (!val)
 				break;
-			max310x_port_irq(s, fls(val) - 1);
+			if (max310x_port_irq(s, fls(val) - 1) == IRQ_HANDLED)
+				handled = true;
 		} while (1);
-	} else
-		max310x_port_irq(s, 0);
+	} else {
+		if (max310x_port_irq(s, 0) == IRQ_HANDLED)
+			handled = true;
+	}
 
-	return IRQ_HANDLED;
+	return IRQ_RETVAL(handled);
 }
 
 static void max310x_wq_proc(struct work_struct *ws)
@@ -744,14 +825,6 @@ static void max310x_wq_proc(struct work_struct *ws)
 	mutex_unlock(&s->mutex);
 }
 
-static void max310x_start_tx(struct uart_port *port)
-{
-	struct max310x_one *one = container_of(port, struct max310x_one, port);
-
-	if (!work_pending(&one->tx_work))
-		schedule_work(&one->tx_work);
-}
-
 static unsigned int max310x_tx_empty(struct uart_port *port)
 {
 	unsigned int lvl, sts;
@@ -1086,10 +1159,31 @@ static int max310x_gpio_direction_output(struct gpio_chip *chip,
 
 	return 0;
 }
+
+static int max310x_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
+				   unsigned long config)
+{
+	struct max310x_port *s = gpiochip_get_data(chip);
+	struct uart_port *port = &s->p[offset / 4].port;
+
+	switch (pinconf_to_config_param(config)) {
+	case PIN_CONFIG_DRIVE_OPEN_DRAIN:
+		max310x_port_update(port, MAX310X_GPIOCFG_REG,
+				1 << ((offset % 4) + 4),
+				1 << ((offset % 4) + 4));
+		return 0;
+	case PIN_CONFIG_DRIVE_PUSH_PULL:
+		max310x_port_update(port, MAX310X_GPIOCFG_REG,
+				1 << ((offset % 4) + 4), 0);
+		return 0;
+	default:
+		return -ENOTSUPP;
+	}
+}
 #endif
 
 static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
-			 struct regmap *regmap, int irq, unsigned long flags)
+			 struct regmap *regmap, int irq)
 {
 	int i, ret, fmin, fmax, freq, uartclk;
 	struct clk *clk_osc, *clk_xtal;
@@ -1169,23 +1263,6 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
 	uartclk = max310x_set_ref_clk(s, freq, xtal);
 	dev_dbg(dev, "Reference clock set to %i Hz\n", uartclk);
 
-#ifdef CONFIG_GPIOLIB
-	/* Setup GPIO cotroller */
-	s->gpio.owner		= THIS_MODULE;
-	s->gpio.parent		= dev;
-	s->gpio.label		= dev_name(dev);
-	s->gpio.direction_input	= max310x_gpio_direction_input;
-	s->gpio.get		= max310x_gpio_get;
-	s->gpio.direction_output= max310x_gpio_direction_output;
-	s->gpio.set		= max310x_gpio_set;
-	s->gpio.base		= -1;
-	s->gpio.ngpio		= devtype->nr * 4;
-	s->gpio.can_sleep	= 1;
-	ret = devm_gpiochip_add_data(dev, &s->gpio, s);
-	if (ret)
-		goto out_clk;
-#endif
-
 	mutex_init(&s->mutex);
 
 	for (i = 0; i < devtype->nr; i++) {
@@ -1237,9 +1314,27 @@ static int max310x_probe(struct device *dev, struct max310x_devtype *devtype,
 		devtype->power(&s->p[i].port, 0);
 	}
 
+#ifdef CONFIG_GPIOLIB
+	/* Setup GPIO cotroller */
+	s->gpio.owner		= THIS_MODULE;
+	s->gpio.parent		= dev;
+	s->gpio.label		= dev_name(dev);
+	s->gpio.direction_input	= max310x_gpio_direction_input;
+	s->gpio.get		= max310x_gpio_get;
+	s->gpio.direction_output= max310x_gpio_direction_output;
+	s->gpio.set		= max310x_gpio_set;
+	s->gpio.set_config	= max310x_gpio_set_config;
+	s->gpio.base		= -1;
+	s->gpio.ngpio		= devtype->nr * 4;
+	s->gpio.can_sleep	= 1;
+	ret = devm_gpiochip_add_data(dev, &s->gpio, s);
+	if (ret)
+		goto out_uart;
+#endif
+
 	/* Setup interrupt */
 	ret = devm_request_threaded_irq(dev, irq, NULL, max310x_ist,
-					IRQF_ONESHOT | flags, dev_name(dev), s);
+					IRQF_ONESHOT | IRQF_SHARED, dev_name(dev), s);
 	if (!ret)
 		return 0;
 
@@ -1293,7 +1388,7 @@ MODULE_DEVICE_TABLE(of, max310x_dt_ids);
 static struct regmap_config regcfg = {
 	.reg_bits = 8,
 	.val_bits = 8,
-	.write_flag_mask = 0x80,
+	.write_flag_mask = MAX310X_WRITE_BIT,
 	.cache_type = REGCACHE_RBTREE,
 	.writeable_reg = max310x_reg_writeable,
 	.volatile_reg = max310x_reg_volatile,
@@ -1304,7 +1399,6 @@ static struct regmap_config regcfg = {
 static int max310x_spi_probe(struct spi_device *spi)
 {
 	struct max310x_devtype *devtype;
-	unsigned long flags = 0;
 	struct regmap *regmap;
 	int ret;
 
@@ -1327,11 +1421,10 @@ static int max310x_spi_probe(struct spi_device *spi)
 		devtype = (struct max310x_devtype *)id_entry->driver_data;
 	}
 
-	flags = IRQF_TRIGGER_FALLING;
 	regcfg.max_register = devtype->nr * 0x20 - 1;
 	regmap = devm_regmap_init_spi(spi, &regcfg);
 
-	return max310x_probe(&spi->dev, devtype, regmap, spi->irq, flags);
+	return max310x_probe(&spi->dev, devtype, regmap, spi->irq);
 }
 
 static int max310x_spi_remove(struct spi_device *spi)