Linux-libre 4.6.2-gnu

1 files changed, 341 insertions, 112 deletions

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index b1a6ba3c3..4743075ae 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -37,6 +37,7 @@
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/pm_runtime.h>
+#include <linux/timer.h>
 
 #include <asm/io.h>
 #include <asm/irq.h>
@@ -52,7 +53,7 @@
 #define DEBUG_AUTOCONF(fmt...)	do { } while (0)
 #endif
 
-#define BOTH_EMPTY 	(UART_LSR_TEMT | UART_LSR_THRE)
+#define BOTH_EMPTY	(UART_LSR_TEMT | UART_LSR_THRE)
 
 /*
  * Here we define the default xmit fifo size used for each type of UART.
@@ -250,9 +251,11 @@ static const struct serial8250_config uart_config[] = {
 		.fcr		= UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
 		.flags		= UART_CAP_FIFO | UART_CAP_AFE,
 	},
-/* tx_loadsz is set to 63-bytes instead of 64-bytes to implement
-workaround of errata A-008006 which states that tx_loadsz should  be
-configured less than Maximum supported fifo bytes */
+	/*
+	 * tx_loadsz is set to 63-bytes instead of 64-bytes to implement
+	 * workaround of errata A-008006 which states that tx_loadsz should
+	 * be configured less than Maximum supported fifo bytes.
+	 */
 	[PORT_16550A_FSL64] = {
 		.name		= "16550A_FSL64",
 		.fifo_size	= 64,
@@ -522,6 +525,20 @@ static void serial8250_clear_fifos(struct uart_8250_port *p)
 	}
 }
 
+static inline void serial8250_em485_rts_after_send(struct uart_8250_port *p)
+{
+	unsigned char mcr = serial_in(p, UART_MCR);
+
+	if (p->port.rs485.flags & SER_RS485_RTS_AFTER_SEND)
+		mcr |= UART_MCR_RTS;
+	else
+		mcr &= ~UART_MCR_RTS;
+	serial_out(p, UART_MCR, mcr);
+}
+
+static void serial8250_em485_handle_start_tx(unsigned long arg);
+static void serial8250_em485_handle_stop_tx(unsigned long arg);
+
 void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p)
 {
 	serial8250_clear_fifos(p);
@@ -546,6 +563,73 @@ void serial8250_rpm_put(struct uart_8250_port *p)
 }
 EXPORT_SYMBOL_GPL(serial8250_rpm_put);
 
+/**
+ *	serial8250_em485_init() - put uart_8250_port into rs485 emulating
+ *	@p:	uart_8250_port port instance
+ *
+ *	The function is used to start rs485 software emulating on the
+ *	&struct uart_8250_port* @p. Namely, RTS is switched before/after
+ *	transmission. The function is idempotent, so it is safe to call it
+ *	multiple times.
+ *
+ *	The caller MUST enable interrupt on empty shift register before
+ *	calling serial8250_em485_init(). This interrupt is not a part of
+ *	8250 standard, but implementation defined.
+ *
+ *	The function is supposed to be called from .rs485_config callback
+ *	or from any other callback protected with p->port.lock spinlock.
+ *
+ *	See also serial8250_em485_destroy()
+ *
+ *	Return 0 - success, -errno - otherwise
+ */
+int serial8250_em485_init(struct uart_8250_port *p)
+{
+	if (p->em485 != NULL)
+		return 0;
+
+	p->em485 = kmalloc(sizeof(struct uart_8250_em485), GFP_ATOMIC);
+	if (p->em485 == NULL)
+		return -ENOMEM;
+
+	setup_timer(&p->em485->stop_tx_timer,
+		serial8250_em485_handle_stop_tx, (unsigned long)p);
+	setup_timer(&p->em485->start_tx_timer,
+		serial8250_em485_handle_start_tx, (unsigned long)p);
+	p->em485->active_timer = NULL;
+
+	serial8250_em485_rts_after_send(p);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(serial8250_em485_init);
+
+/**
+ *	serial8250_em485_destroy() - put uart_8250_port into normal state
+ *	@p:	uart_8250_port port instance
+ *
+ *	The function is used to stop rs485 software emulating on the
+ *	&struct uart_8250_port* @p. The function is idempotent, so it is safe to
+ *	call it multiple times.
+ *
+ *	The function is supposed to be called from .rs485_config callback
+ *	or from any other callback protected with p->port.lock spinlock.
+ *
+ *	See also serial8250_em485_init()
+ */
+void serial8250_em485_destroy(struct uart_8250_port *p)
+{
+	if (p->em485 == NULL)
+		return;
+
+	del_timer(&p->em485->start_tx_timer);
+	del_timer(&p->em485->stop_tx_timer);
+
+	kfree(p->em485);
+	p->em485 = NULL;
+}
+EXPORT_SYMBOL_GPL(serial8250_em485_destroy);
+
 /*
  * These two wrappers ensure that enable_runtime_pm_tx() can be called more than
  * once and disable_runtime_pm_tx() will still disable RPM because the fifo is
@@ -1232,8 +1316,7 @@ static void autoconfig(struct uart_8250_port *up)
 out_lock:
 	spin_unlock_irqrestore(&port->lock, flags);
 	if (up->capabilities != old_capabilities) {
-		printk(KERN_WARNING
-		       "ttyS%d: detected caps %08x should be %08x\n",
+		pr_warn("ttyS%d: detected caps %08x should be %08x\n",
 		       serial_index(port), old_capabilities,
 		       up->capabilities);
 	}
@@ -1298,7 +1381,78 @@ static void autoconfig_irq(struct uart_8250_port *up)
 	port->irq = (irq > 0) ? irq : 0;
 }
 
-static inline void __stop_tx(struct uart_8250_port *p)
+static void serial8250_stop_rx(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	serial8250_rpm_get(up);
+
+	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
+	up->port.read_status_mask &= ~UART_LSR_DR;
+	serial_port_out(port, UART_IER, up->ier);
+
+	serial8250_rpm_put(up);
+}
+
+static void __do_stop_tx_rs485(struct uart_8250_port *p)
+{
+	if (!p->em485)
+		return;
+
+	serial8250_em485_rts_after_send(p);
+	/*
+	 * Empty the RX FIFO, we are not interested in anything
+	 * received during the half-duplex transmission.
+	 * Enable previously disabled RX interrupts.
+	 */
+	if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
+		serial8250_clear_fifos(p);
+
+		serial8250_rpm_get(p);
+
+		p->ier |= UART_IER_RLSI | UART_IER_RDI;
+		serial_port_out(&p->port, UART_IER, p->ier);
+
+		serial8250_rpm_put(p);
+	}
+}
+
+static void serial8250_em485_handle_stop_tx(unsigned long arg)
+{
+	struct uart_8250_port *p = (struct uart_8250_port *)arg;
+	struct uart_8250_em485 *em485 = p->em485;
+	unsigned long flags;
+
+	spin_lock_irqsave(&p->port.lock, flags);
+	if (em485 &&
+	    em485->active_timer == &em485->stop_tx_timer) {
+		__do_stop_tx_rs485(p);
+		em485->active_timer = NULL;
+	}
+	spin_unlock_irqrestore(&p->port.lock, flags);
+}
+
+static void __stop_tx_rs485(struct uart_8250_port *p)
+{
+	struct uart_8250_em485 *em485 = p->em485;
+
+	if (!em485)
+		return;
+
+	/*
+	 * __do_stop_tx_rs485 is going to set RTS according to config
+	 * AND flush RX FIFO if required.
+	 */
+	if (p->port.rs485.delay_rts_after_send > 0) {
+		em485->active_timer = &em485->stop_tx_timer;
+		mod_timer(&em485->stop_tx_timer, jiffies +
+			p->port.rs485.delay_rts_after_send * HZ / 1000);
+	} else {
+		__do_stop_tx_rs485(p);
+	}
+}
+
+static inline void __do_stop_tx(struct uart_8250_port *p)
 {
 	if (p->ier & UART_IER_THRI) {
 		p->ier &= ~UART_IER_THRI;
@@ -1307,6 +1461,28 @@ static inline void __stop_tx(struct uart_8250_port *p)
 	}
 }
 
+static inline void __stop_tx(struct uart_8250_port *p)
+{
+	struct uart_8250_em485 *em485 = p->em485;
+
+	if (em485) {
+		unsigned char lsr = serial_in(p, UART_LSR);
+		/*
+		 * To provide required timeing and allow FIFO transfer,
+		 * __stop_tx_rs485 must be called only when both FIFO and
+		 * shift register are empty. It is for device driver to enable
+		 * interrupt on TEMT.
+		 */
+		if ((lsr & BOTH_EMPTY) != BOTH_EMPTY)
+			return;
+
+		del_timer(&em485->start_tx_timer);
+		em485->active_timer = NULL;
+	}
+	__do_stop_tx(p);
+	__stop_tx_rs485(p);
+}
+
 static void serial8250_stop_tx(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
@@ -1324,12 +1500,10 @@ static void serial8250_stop_tx(struct uart_port *port)
 	serial8250_rpm_put(up);
 }
 
-static void serial8250_start_tx(struct uart_port *port)
+static inline void __start_tx(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 
-	serial8250_rpm_get_tx(up);
-
 	if (up->dma && !up->dma->tx_dma(up))
 		return;
 
@@ -1339,6 +1513,7 @@ static void serial8250_start_tx(struct uart_port *port)
 
 		if (up->bugs & UART_BUG_TXEN) {
 			unsigned char lsr;
+
 			lsr = serial_in(up, UART_LSR);
 			up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
 			if (lsr & UART_LSR_THRE)
@@ -1355,33 +1530,83 @@ static void serial8250_start_tx(struct uart_port *port)
 	}
 }
 
-static void serial8250_throttle(struct uart_port *port)
+static inline void start_tx_rs485(struct uart_port *port)
 {
-	port->throttle(port);
+	struct uart_8250_port *up = up_to_u8250p(port);
+	struct uart_8250_em485 *em485 = up->em485;
+	unsigned char mcr;
+
+	if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX))
+		serial8250_stop_rx(&up->port);
+
+	del_timer(&em485->stop_tx_timer);
+	em485->active_timer = NULL;
+
+	mcr = serial_in(up, UART_MCR);
+	if (!!(up->port.rs485.flags & SER_RS485_RTS_ON_SEND) !=
+	    !!(mcr & UART_MCR_RTS)) {
+		if (up->port.rs485.flags & SER_RS485_RTS_ON_SEND)
+			mcr |= UART_MCR_RTS;
+		else
+			mcr &= ~UART_MCR_RTS;
+		serial_out(up, UART_MCR, mcr);
+
+		if (up->port.rs485.delay_rts_before_send > 0) {
+			em485->active_timer = &em485->start_tx_timer;
+			mod_timer(&em485->start_tx_timer, jiffies +
+				up->port.rs485.delay_rts_before_send * HZ / 1000);
+			return;
+		}
+	}
+
+	__start_tx(port);
 }
 
-static void serial8250_unthrottle(struct uart_port *port)
+static void serial8250_em485_handle_start_tx(unsigned long arg)
 {
-	port->unthrottle(port);
+	struct uart_8250_port *p = (struct uart_8250_port *)arg;
+	struct uart_8250_em485 *em485 = p->em485;
+	unsigned long flags;
+
+	spin_lock_irqsave(&p->port.lock, flags);
+	if (em485 &&
+	    em485->active_timer == &em485->start_tx_timer) {
+		__start_tx(&p->port);
+		em485->active_timer = NULL;
+	}
+	spin_unlock_irqrestore(&p->port.lock, flags);
 }
 
-static void serial8250_stop_rx(struct uart_port *port)
+static void serial8250_start_tx(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
+	struct uart_8250_em485 *em485 = up->em485;
 
-	serial8250_rpm_get(up);
+	serial8250_rpm_get_tx(up);
 
-	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
-	up->port.read_status_mask &= ~UART_LSR_DR;
-	serial_port_out(port, UART_IER, up->ier);
+	if (em485 &&
+	    em485->active_timer == &em485->start_tx_timer)
+		return;
 
-	serial8250_rpm_put(up);
+	if (em485)
+		start_tx_rs485(port);
+	else
+		__start_tx(port);
+}
+
+static void serial8250_throttle(struct uart_port *port)
+{
+	port->throttle(port);
+}
+
+static void serial8250_unthrottle(struct uart_port *port)
+{
+	port->unthrottle(port);
 }
 
 static void serial8250_disable_ms(struct uart_port *port)
 {
-	struct uart_8250_port *up =
-		container_of(port, struct uart_8250_port, port);
+	struct uart_8250_port *up = up_to_u8250p(port);
 
 	/* no MSR capabilities */
 	if (up->bugs & UART_BUG_NOMSR)
@@ -1406,81 +1631,85 @@ static void serial8250_enable_ms(struct uart_port *port)
 	serial8250_rpm_put(up);
 }
 
+static void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
+{
+	struct uart_port *port = &up->port;
+	unsigned char ch;
+	char flag = TTY_NORMAL;
+
+	if (likely(lsr & UART_LSR_DR))
+		ch = serial_in(up, UART_RX);
+	else
+		/*
+		 * Intel 82571 has a Serial Over Lan device that will
+		 * set UART_LSR_BI without setting UART_LSR_DR when
+		 * it receives a break. To avoid reading from the
+		 * receive buffer without UART_LSR_DR bit set, we
+		 * just force the read character to be 0
+		 */
+		ch = 0;
+
+	port->icount.rx++;
+
+	lsr |= up->lsr_saved_flags;
+	up->lsr_saved_flags = 0;
+
+	if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
+		if (lsr & UART_LSR_BI) {
+			lsr &= ~(UART_LSR_FE | UART_LSR_PE);
+			port->icount.brk++;
+			/*
+			 * We do the SysRQ and SAK checking
+			 * here because otherwise the break
+			 * may get masked by ignore_status_mask
+			 * or read_status_mask.
+			 */
+			if (uart_handle_break(port))
+				return;
+		} else if (lsr & UART_LSR_PE)
+			port->icount.parity++;
+		else if (lsr & UART_LSR_FE)
+			port->icount.frame++;
+		if (lsr & UART_LSR_OE)
+			port->icount.overrun++;
+
+		/*
+		 * Mask off conditions which should be ignored.
+		 */
+		lsr &= port->read_status_mask;
+
+		if (lsr & UART_LSR_BI) {
+			DEBUG_INTR("handling break....");
+			flag = TTY_BREAK;
+		} else if (lsr & UART_LSR_PE)
+			flag = TTY_PARITY;
+		else if (lsr & UART_LSR_FE)
+			flag = TTY_FRAME;
+	}
+	if (uart_handle_sysrq_char(port, ch))
+		return;
+
+	uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
+}
+
 /*
  * serial8250_rx_chars: processes according to the passed in LSR
  * value, and returns the remaining LSR bits not handled
  * by this Rx routine.
  */
-unsigned char
-serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
+unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
 {
 	struct uart_port *port = &up->port;
-	unsigned char ch;
 	int max_count = 256;
-	char flag;
 
 	do {
-		if (likely(lsr & UART_LSR_DR))
-			ch = serial_in(up, UART_RX);
-		else
-			/*
-			 * Intel 82571 has a Serial Over Lan device that will
-			 * set UART_LSR_BI without setting UART_LSR_DR when
-			 * it receives a break. To avoid reading from the
-			 * receive buffer without UART_LSR_DR bit set, we
-			 * just force the read character to be 0
-			 */
-			ch = 0;
-
-		flag = TTY_NORMAL;
-		port->icount.rx++;
-
-		lsr |= up->lsr_saved_flags;
-		up->lsr_saved_flags = 0;
-
-		if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
-			if (lsr & UART_LSR_BI) {
-				lsr &= ~(UART_LSR_FE | UART_LSR_PE);
-				port->icount.brk++;
-				/*
-				 * We do the SysRQ and SAK checking
-				 * here because otherwise the break
-				 * may get masked by ignore_status_mask
-				 * or read_status_mask.
-				 */
-				if (uart_handle_break(port))
-					goto ignore_char;
-			} else if (lsr & UART_LSR_PE)
-				port->icount.parity++;
-			else if (lsr & UART_LSR_FE)
-				port->icount.frame++;
-			if (lsr & UART_LSR_OE)
-				port->icount.overrun++;
-
-			/*
-			 * Mask off conditions which should be ignored.
-			 */
-			lsr &= port->read_status_mask;
-
-			if (lsr & UART_LSR_BI) {
-				DEBUG_INTR("handling break....");
-				flag = TTY_BREAK;
-			} else if (lsr & UART_LSR_PE)
-				flag = TTY_PARITY;
-			else if (lsr & UART_LSR_FE)
-				flag = TTY_FRAME;
-		}
-		if (uart_handle_sysrq_char(port, ch))
-			goto ignore_char;
-
-		uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
-
-ignore_char:
+		serial8250_read_char(up, lsr);
+		if (--max_count == 0)
+			break;
 		lsr = serial_in(up, UART_LSR);
-	} while ((lsr & (UART_LSR_DR | UART_LSR_BI)) && (--max_count > 0));
-	spin_unlock(&port->lock);
+	} while (lsr & (UART_LSR_DR | UART_LSR_BI));
+
 	tty_flip_buffer_push(&port->state->port);
-	spin_lock(&port->lock);
 	return lsr;
 }
 EXPORT_SYMBOL_GPL(serial8250_rx_chars);
@@ -1513,11 +1742,9 @@ void serial8250_tx_chars(struct uart_8250_port *up)
 		port->icount.tx++;
 		if (uart_circ_empty(xmit))
 			break;
-		if (up->capabilities & UART_CAP_HFIFO) {
-			if ((serial_port_in(port, UART_LSR) & BOTH_EMPTY) !=
-			    BOTH_EMPTY)
-				break;
-		}
+		if ((up->capabilities & UART_CAP_HFIFO) &&
+		    (serial_in(up, UART_LSR) & BOTH_EMPTY) != BOTH_EMPTY)
+			break;
 	} while (--count > 0);
 
 	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
@@ -1746,6 +1973,7 @@ static void wait_for_xmitr(struct uart_8250_port *up, int bits)
 	/* Wait up to 1s for flow control if necessary */
 	if (up->port.flags & UPF_CONS_FLOW) {
 		unsigned int tmout;
+
 		for (tmout = 1000000; tmout; tmout--) {
 			unsigned int msr = serial_in(up, UART_MSR);
 			up->msr_saved_flags |= msr & MSR_SAVE_FLAGS;
@@ -1979,23 +2207,23 @@ int serial8250_do_startup(struct uart_port *port)
 
 	serial8250_set_mctrl(port, port->mctrl);
 
-	/* Serial over Lan (SoL) hack:
-	   Intel 8257x Gigabit ethernet chips have a
-	   16550 emulation, to be used for Serial Over Lan.
-	   Those chips take a longer time than a normal
-	   serial device to signalize that a transmission
-	   data was queued. Due to that, the above test generally
-	   fails. One solution would be to delay the reading of
-	   iir. However, this is not reliable, since the timeout
-	   is variable. So, let's just don't test if we receive
-	   TX irq. This way, we'll never enable UART_BUG_TXEN.
+	/*
+	 * Serial over Lan (SoL) hack:
+	 * Intel 8257x Gigabit ethernet chips have a 16550 emulation, to be
+	 * used for Serial Over Lan.  Those chips take a longer time than a
+	 * normal serial device to signalize that a transmission data was
+	 * queued. Due to that, the above test generally fails. One solution
+	 * would be to delay the reading of iir. However, this is not
+	 * reliable, since the timeout is variable. So, let's just don't
+	 * test if we receive TX irq.  This way, we'll never enable
+	 * UART_BUG_TXEN.
 	 */
 	if (up->port.flags & UPF_NO_TXEN_TEST)
 		goto dont_test_tx_en;
 
 	/*
-	 * Do a quick test to see if we receive an
-	 * interrupt when we enable the TX irq.
+	 * Do a quick test to see if we receive an interrupt when we enable
+	 * the TX irq.
 	 */
 	serial_port_out(port, UART_IER, UART_IER_THRI);
 	lsr = serial_port_in(port, UART_LSR);
@@ -2078,8 +2306,12 @@ void serial8250_do_shutdown(struct uart_port *port)
 	/*
 	 * Disable interrupts from this port
 	 */
+	spin_lock_irqsave(&port->lock, flags);
 	up->ier = 0;
 	serial_port_out(port, UART_IER, 0);
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	synchronize_irq(port->irq);
 
 	if (up->dma)
 		serial8250_release_dma(up);
@@ -2245,9 +2477,9 @@ static void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
 		serial_port_out(port, 0x2, quot_frac);
 }
 
-static unsigned int
-serial8250_get_baud_rate(struct uart_port *port, struct ktermios *termios,
-			 struct ktermios *old)
+static unsigned int serial8250_get_baud_rate(struct uart_port *port,
+					     struct ktermios *termios,
+					     struct ktermios *old)
 {
 	unsigned int tolerance = port->uartclk / 100;
 
@@ -2264,7 +2496,7 @@ serial8250_get_baud_rate(struct uart_port *port, struct ktermios *termios,
 
 void
 serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
-		          struct ktermios *old)
+			  struct ktermios *old)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 	unsigned char cval;
@@ -2577,8 +2809,7 @@ static int do_get_rxtrig(struct tty_port *port)
 {
 	struct uart_state *state = container_of(port, struct uart_state, port);
 	struct uart_port *uport = state->uart_port;
-	struct uart_8250_port *up =
-		container_of(uport, struct uart_8250_port, port);
+	struct uart_8250_port *up = up_to_u8250p(uport);
 
 	if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1)
 		return -EINVAL;
@@ -2614,8 +2845,7 @@ static int do_set_rxtrig(struct tty_port *port, unsigned char bytes)
 {
 	struct uart_state *state = container_of(port, struct uart_state, port);
 	struct uart_port *uport = state->uart_port;
-	struct uart_8250_port *up =
-		container_of(uport, struct uart_8250_port, port);
+	struct uart_8250_port *up = up_to_u8250p(uport);
 	int rxtrig;
 
 	if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1 ||
@@ -2739,8 +2969,7 @@ serial8250_verify_port(struct uart_port *port, struct serial_struct *ser)
 	return 0;
 }
 
-static const char *
-serial8250_type(struct uart_port *port)
+static const char *serial8250_type(struct uart_port *port)
 {
 	int type = port->type;