1 files changed, 145 insertions, 68 deletions

diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c
index 339cef4c8256..81d5cb9b6569 100644
--- a/arch/mn10300/kernel/mn10300-serial.c
+++ b/arch/mn10300/kernel/mn10300-serial.c
@@ -408,6 +408,34 @@ static struct irq_chip mn10300_serial_pic = {
 	.irq_unmask	= mn10300_serial_nop,
 };
 
+static void mn10300_serial_low_mask(struct irq_data *d)
+{
+	unsigned long flags;
+	u16 tmp;
+
+	flags = arch_local_cli_save();
+	GxICR(d->irq) = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
+	tmp = GxICR(d->irq); /* flush write buffer */
+	arch_local_irq_restore(flags);
+}
+
+static void mn10300_serial_low_unmask(struct irq_data *d)
+{
+	unsigned long flags;
+	u16 tmp;
+
+	flags = arch_local_cli_save();
+	GxICR(d->irq) =
+		NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL) | GxICR_ENABLE;
+	tmp = GxICR(d->irq); /* flush write buffer */
+	arch_local_irq_restore(flags);
+}
+
+static struct irq_chip mn10300_serial_low_pic = {
+	.name		= "mnserial-low",
+	.irq_mask	= mn10300_serial_low_mask,
+	.irq_unmask	= mn10300_serial_low_unmask,
+};
 
 /*
  * serial virtual DMA interrupt jump table
@@ -416,25 +444,53 @@ struct mn10300_serial_int mn10300_serial_int_tbl[NR_IRQS];
 
 static void mn10300_serial_dis_tx_intr(struct mn10300_serial_port *port)
 {
-	unsigned long flags;
+	int retries = 100;
 	u16 x;
 
-	flags = arch_local_cli_save();
-	*port->tx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
-	x = *port->tx_icr;
-	arch_local_irq_restore(flags);
+	/* nothing to do if irq isn't set up */
+	if (!mn10300_serial_int_tbl[port->tx_irq].port)
+		return;
+
+	port->tx_flags |= MNSCx_TX_STOP;
+	mb();
+
+	/*
+	 * Here we wait for the irq to be disabled. Either it already is
+	 * disabled or we wait some number of retries for the VDMA handler
+	 * to disable it. The retries give the VDMA handler enough time to
+	 * run to completion if it was already in progress. If the VDMA IRQ
+	 * is enabled but the handler is not yet running when arrive here,
+	 * the STOP flag will prevent the handler from conflicting with the
+	 * driver code following this loop.
+	 */
+	while ((*port->tx_icr & GxICR_ENABLE) && retries-- > 0)
+		;
+	if (retries <= 0) {
+		*port->tx_icr =
+			NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
+		x = *port->tx_icr;
+	}
 }
 
 static void mn10300_serial_en_tx_intr(struct mn10300_serial_port *port)
 {
-	unsigned long flags;
 	u16 x;
 
-	flags = arch_local_cli_save();
+	/* nothing to do if irq isn't set up */
+	if (!mn10300_serial_int_tbl[port->tx_irq].port)
+		return;
+
+	/* stop vdma irq if not already stopped */
+	if (!(port->tx_flags & MNSCx_TX_STOP))
+		mn10300_serial_dis_tx_intr(port);
+
+	port->tx_flags &= ~MNSCx_TX_STOP;
+	mb();
+
 	*port->tx_icr =
-		NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL) | GxICR_ENABLE;
+		NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL) |
+		GxICR_ENABLE | GxICR_REQUEST | GxICR_DETECT;
 	x = *port->tx_icr;
-	arch_local_irq_restore(flags);
 }
 
 static void mn10300_serial_dis_rx_intr(struct mn10300_serial_port *port)
@@ -487,16 +543,17 @@ static void mn10300_serial_receive_interrupt(struct mn10300_serial_port *port)
 
 try_again:
 	/* pull chars out of the hat */
-	ix = port->rx_outp;
-	if (ix == port->rx_inp) {
+	ix = ACCESS_ONCE(port->rx_outp);
+	if (CIRC_CNT(port->rx_inp, ix, MNSC_BUFFER_SIZE) == 0) {
 		if (push && !tty->low_latency)
 			tty_flip_buffer_push(tty);
 		return;
 	}
 
+	smp_read_barrier_depends();
 	ch = port->rx_buffer[ix++];
 	st = port->rx_buffer[ix++];
-	smp_rmb();
+	smp_mb();
 	port->rx_outp = ix & (MNSC_BUFFER_SIZE - 1);
 	port->uart.icount.rx++;
 
@@ -778,8 +835,6 @@ static void mn10300_serial_start_tx(struct uart_port *_port)
 	struct mn10300_serial_port *port =
 		container_of(_port, struct mn10300_serial_port, uart);
 
-	u16 x;
-
 	_enter("%s{%lu}",
 	       port->name,
 	       CIRC_CNT(&port->uart.state->xmit.head,
@@ -787,14 +842,7 @@ static void mn10300_serial_start_tx(struct uart_port *_port)
 			UART_XMIT_SIZE));
 
 	/* kick the virtual DMA controller */
-	arch_local_cli();
-	x = *port->tx_icr;
-	x |= GxICR_ENABLE;
-
-	if (*port->_status & SC01STR_TBF)
-		x &= ~(GxICR_REQUEST | GxICR_DETECT);
-	else
-		x |= GxICR_REQUEST | GxICR_DETECT;
+	mn10300_serial_en_tx_intr(port);
 
 	_debug("CTR=%04hx ICR=%02hx STR=%04x TMD=%02hx TBR=%04hx ICR=%04hx",
 	       *port->_control, *port->_intr, *port->_status,
@@ -802,10 +850,6 @@ static void mn10300_serial_start_tx(struct uart_port *_port)
 	       (port->div_timer == MNSCx_DIV_TIMER_8BIT) ?
 	           *(volatile u8 *)port->_tmxbr : *port->_tmxbr,
 	       *port->tx_icr);
-
-	*port->tx_icr = x;
-	x = *port->tx_icr;
-	arch_local_sti();
 }
 
 /*
@@ -815,13 +859,17 @@ static void mn10300_serial_send_xchar(struct uart_port *_port, char ch)
 {
 	struct mn10300_serial_port *port =
 		container_of(_port, struct mn10300_serial_port, uart);
+	unsigned long flags;
 
 	_enter("%s,%02x", port->name, ch);
 
 	if (likely(port->gdbstub)) {
 		port->tx_xchar = ch;
-		if (ch)
+		if (ch) {
+			spin_lock_irqsave(&port->uart.lock, flags);
 			mn10300_serial_en_tx_intr(port);
+			spin_unlock_irqrestore(&port->uart.lock, flags);
+		}
 	}
 }
 
@@ -882,18 +930,21 @@ static void mn10300_serial_break_ctl(struct uart_port *_port, int ctl)
 {
 	struct mn10300_serial_port *port =
 		container_of(_port, struct mn10300_serial_port, uart);
+	unsigned long flags;
 
 	_enter("%s,%d", port->name, ctl);
 
+	spin_lock_irqsave(&port->uart.lock, flags);
 	if (ctl) {
 		/* tell the virtual DMA handler to assert BREAK */
-		port->tx_break = 1;
+		port->tx_flags |= MNSCx_TX_BREAK;
 		mn10300_serial_en_tx_intr(port);
 	} else {
-		port->tx_break = 0;
+		port->tx_flags &= ~MNSCx_TX_BREAK;
 		*port->_control &= ~SC01CTR_BKE;
 		mn10300_serial_en_tx_intr(port);
 	}
+	spin_unlock_irqrestore(&port->uart.lock, flags);
 }
 
 /*
@@ -916,6 +967,7 @@ static int mn10300_serial_startup(struct uart_port *_port)
 		return -ENOMEM;
 
 	port->rx_inp = port->rx_outp = 0;
+	port->tx_flags = 0;
 
 	/* finally, enable the device */
 	*port->_intr = SC01ICR_TI;
@@ -928,22 +980,23 @@ static int mn10300_serial_startup(struct uart_port *_port)
 	pint->port = port;
 	pint->vdma = mn10300_serial_vdma_tx_handler;
 
-	set_intr_level(port->rx_irq,
-		NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL));
-	set_intr_level(port->tx_irq,
-		NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL));
+	irq_set_chip(port->rx_irq, &mn10300_serial_low_pic);
+	irq_set_chip(port->tx_irq, &mn10300_serial_low_pic);
 	irq_set_chip(port->tm_irq, &mn10300_serial_pic);
 
 	if (request_irq(port->rx_irq, mn10300_serial_interrupt,
-			IRQF_DISABLED, port->rx_name, port) < 0)
+			IRQF_DISABLED | IRQF_NOBALANCING,
+			port->rx_name, port) < 0)
 		goto error;
 
 	if (request_irq(port->tx_irq, mn10300_serial_interrupt,
-			IRQF_DISABLED, port->tx_name, port) < 0)
+			IRQF_DISABLED | IRQF_NOBALANCING,
+			port->tx_name, port) < 0)
 		goto error2;
 
 	if (request_irq(port->tm_irq, mn10300_serial_interrupt,
-			IRQF_DISABLED, port->tm_name, port) < 0)
+			IRQF_DISABLED | IRQF_NOBALANCING,
+			port->tm_name, port) < 0)
 		goto error3;
 	mn10300_serial_mask_ack(port->tm_irq);
 
@@ -964,14 +1017,22 @@ error:
  */
 static void mn10300_serial_shutdown(struct uart_port *_port)
 {
+	unsigned long flags;
 	u16 x;
 	struct mn10300_serial_port *port =
 		container_of(_port, struct mn10300_serial_port, uart);
 
 	_enter("%s", port->name);
 
+	spin_lock_irqsave(&_port->lock, flags);
+	mn10300_serial_dis_tx_intr(port);
+
+	*port->rx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
+	x = *port->rx_icr;
+	port->tx_flags = 0;
+	spin_unlock_irqrestore(&_port->lock, flags);
+
 	/* disable the serial port and its baud rate timer */
-	port->tx_break = 0;
 	*port->_control &= ~(SC01CTR_TXE | SC01CTR_RXE | SC01CTR_BKE);
 	*port->_tmxmd = 0;
 
@@ -986,12 +1047,8 @@ static void mn10300_serial_shutdown(struct uart_port *_port)
 	free_irq(port->rx_irq, port);
 	free_irq(port->tx_irq, port);
 
-	arch_local_cli();
-	*port->rx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
-	x = *port->rx_icr;
-	*port->tx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
-	x = *port->tx_icr;
-	arch_local_sti();
+	mn10300_serial_int_tbl[port->tx_irq].port = NULL;
+	mn10300_serial_int_tbl[port->rx_irq].port = NULL;
 }
 
 /*
@@ -1317,7 +1374,8 @@ timer_okay:
 	if ((new->c_cflag & CREAD) == 0)
 		port->uart.ignore_status_mask |= (1 << TTY_NORMAL);
 
-	scxctr |= *port->_control & (SC01CTR_TXE | SC01CTR_RXE | SC01CTR_BKE);
+	scxctr |= SC01CTR_TXE | SC01CTR_RXE;
+	scxctr |= *port->_control & SC01CTR_BKE;
 	*port->_control = scxctr;
 
 	spin_unlock_irqrestore(&port->uart.lock, flags);
@@ -1519,17 +1577,24 @@ static void mn10300_serial_console_write(struct console *co,
 {
 	struct mn10300_serial_port *port;
 	unsigned i;
-	u16 scxctr, txicr, tmp;
+	u16 scxctr;
 	u8 tmxmd;
+	unsigned long flags;
+	int locked = 1;
 
 	port = mn10300_serial_ports[co->index];
 
+	local_irq_save(flags);
+	if (port->uart.sysrq) {
+		/* mn10300_serial_interrupt() already took the lock */
+		locked = 0;
+	} else if (oops_in_progress) {
+		locked = spin_trylock(&port->uart.lock);
+	} else
+		spin_lock(&port->uart.lock);
+
 	/* firstly hijack the serial port from the "virtual DMA" controller */
-	arch_local_cli();
-	txicr = *port->tx_icr;
-	*port->tx_icr = NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL);
-	tmp = *port->tx_icr;
-	arch_local_sti();
+	mn10300_serial_dis_tx_intr(port);
 
 	/* the transmitter may be disabled */
 	scxctr = *port->_control;
@@ -1565,12 +1630,12 @@ static void mn10300_serial_console_write(struct console *co,
 
 		while (*port->_status & SC01STR_TBF)
 			continue;
-		*(u8 *) port->_txb = ch;
+		*port->_txb = ch;
 
 		if (ch == 0x0a) {
 			while (*port->_status & SC01STR_TBF)
 				continue;
-			*(u8 *) port->_txb = 0xd;
+			*port->_txb = 0xd;
 		}
 	}
 
@@ -1583,10 +1648,11 @@ static void mn10300_serial_console_write(struct console *co,
 	if (!(scxctr & SC01CTR_TXE))
 		*port->_control = scxctr;
 
-	arch_local_cli();
-	*port->tx_icr = txicr;
-	tmp = *port->tx_icr;
-	arch_local_sti();
+	mn10300_serial_en_tx_intr(port);
+
+	if (locked)
+		spin_unlock(&port->uart.lock);
+	local_irq_restore(flags);
 }
 
 /*
@@ -1655,18 +1721,29 @@ static int mn10300_serial_poll_get_char(struct uart_port *_port)
 
 	_enter("%s", port->name);
 
-	do {
-		/* pull chars out of the hat */
-		ix = port->rx_outp;
-		if (ix == port->rx_inp)
-			return NO_POLL_CHAR;
+	if (mn10300_serial_int_tbl[port->rx_irq].port != NULL) {
+		do {
+			/* pull chars out of the hat */
+			ix = ACCESS_ONCE(port->rx_outp);
+			if (CIRC_CNT(port->rx_inp, ix, MNSC_BUFFER_SIZE) == 0)
+				return NO_POLL_CHAR;
 
-		ch = port->rx_buffer[ix++];
-		st = port->rx_buffer[ix++];
-		smp_rmb();
-		port->rx_outp = ix & (MNSC_BUFFER_SIZE - 1);
+			smp_read_barrier_depends();
+			ch = port->rx_buffer[ix++];
+			st = port->rx_buffer[ix++];
+			smp_mb();
+			port->rx_outp = ix & (MNSC_BUFFER_SIZE - 1);
 
-	} while (st & (SC01STR_FEF | SC01STR_PEF | SC01STR_OEF));
+		} while (st & (SC01STR_FEF | SC01STR_PEF | SC01STR_OEF));
+	} else {
+		do {
+			st = *port->_status;
+			if (st & (SC01STR_FEF | SC01STR_PEF | SC01STR_OEF))
+				continue;
+		} while (!(st & SC01STR_RBF));
+
+		ch = *port->_rxb;
+	}
 
 	return ch;
 }
@@ -1693,12 +1770,12 @@ static void mn10300_serial_poll_put_char(struct uart_port *_port,
 	tmp = *port->_intr;
 
 	if (ch == 0x0a) {
-		*(u8 *) port->_txb = 0x0d;
+		*port->_txb = 0x0d;
 		while (*port->_status & SC01STR_TBF)
 			continue;
 	}
 
-	*(u8 *) port->_txb = ch;
+	*port->_txb = ch;
 	while (*port->_status & SC01STR_TBF)
 		continue;