From c98c406eb2c518c7c5bc922fafa1f9fdcb7b76f4 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 12 Dec 2012 15:36:37 +0000
Subject: [PATCH 01/11] MN10300: ttySM: Use memory barriers correctly in
 circular buffer logic

Use memory barriers correctly in the circular buffer logic used in the driver,
as documented in Documentation/circular-buffers.txt.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
---
 arch/mn10300/kernel/mn10300-serial.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c
index 339cef4c825..131b81f9d6c 100644
--- a/arch/mn10300/kernel/mn10300-serial.c
+++ b/arch/mn10300/kernel/mn10300-serial.c
@@ -487,16 +487,17 @@ 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++;
 
@@ -1657,13 +1658,14 @@ static int mn10300_serial_poll_get_char(struct uart_port *_port)
 
 	do {
 		/* 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)
 			return NO_POLL_CHAR;
 
+		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);
 
 	} while (st & (SC01STR_FEF | SC01STR_PEF | SC01STR_OEF));

From 7d361cb754720d69695a3efc973e9a1a51e46b21 Mon Sep 17 00:00:00 2001
From: Mark Salter <msalter@redhat.com>
Date: Wed, 12 Dec 2012 15:36:37 +0000
Subject: [PATCH 02/11] MN10300: cleanup IRQ affinity setting

The irq_set_affinity handler for the mn10300 cpu pic had some hard-coded IRQs
which were not to be migrated from one cpu to another. This patch cleans those
up by using a combination of IRQF_NOBALANCING and specialized irq chips with
no irq_set_affinity handler. This maintains the previous behavior by using
generic IRQ interfaces rather than hard coding IRQ numbers in the default
irq_set_affinity handler.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/kernel/irq.c            | 50 ++--------------------------
 arch/mn10300/kernel/mn10300-serial.c |  9 +++--
 arch/mn10300/kernel/smp.c            | 10 +++++-
 3 files changed, 17 insertions(+), 52 deletions(-)

diff --git a/arch/mn10300/kernel/irq.c b/arch/mn10300/kernel/irq.c
index 35932a8de8b..6ab3b73efcf 100644
--- a/arch/mn10300/kernel/irq.c
+++ b/arch/mn10300/kernel/irq.c
@@ -142,57 +142,11 @@ mn10300_cpupic_setaffinity(struct irq_data *d, const struct cpumask *mask,
 			   bool force)
 {
 	unsigned long flags;
-	int err;
 
 	flags = arch_local_cli_save();
-
-	/* check irq no */
-	switch (d->irq) {
-	case TMJCIRQ:
-	case RESCHEDULE_IPI:
-	case CALL_FUNC_SINGLE_IPI:
-	case LOCAL_TIMER_IPI:
-	case FLUSH_CACHE_IPI:
-	case CALL_FUNCTION_NMI_IPI:
-	case DEBUGGER_NMI_IPI:
-#ifdef CONFIG_MN10300_TTYSM0
-	case SC0RXIRQ:
-	case SC0TXIRQ:
-#ifdef CONFIG_MN10300_TTYSM0_TIMER8
-	case TM8IRQ:
-#elif CONFIG_MN10300_TTYSM0_TIMER2
-	case TM2IRQ:
-#endif /* CONFIG_MN10300_TTYSM0_TIMER8 */
-#endif /* CONFIG_MN10300_TTYSM0 */
-
-#ifdef CONFIG_MN10300_TTYSM1
-	case SC1RXIRQ:
-	case SC1TXIRQ:
-#ifdef CONFIG_MN10300_TTYSM1_TIMER12
-	case TM12IRQ:
-#elif defined(CONFIG_MN10300_TTYSM1_TIMER9)
-	case TM9IRQ:
-#elif defined(CONFIG_MN10300_TTYSM1_TIMER3)
-	case TM3IRQ:
-#endif /* CONFIG_MN10300_TTYSM1_TIMER12 */
-#endif /* CONFIG_MN10300_TTYSM1 */
-
-#ifdef CONFIG_MN10300_TTYSM2
-	case SC2RXIRQ:
-	case SC2TXIRQ:
-	case TM10IRQ:
-#endif /* CONFIG_MN10300_TTYSM2 */
-		err = -1;
-		break;
-
-	default:
-		set_bit(d->irq, irq_affinity_request);
-		err = 0;
-		break;
-	}
-
+	set_bit(d->irq, irq_affinity_request);
 	arch_local_irq_restore(flags);
-	return err;
+	return 0;
 }
 #endif /* CONFIG_SMP */
 
diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c
index 131b81f9d6c..4968cfe66c0 100644
--- a/arch/mn10300/kernel/mn10300-serial.c
+++ b/arch/mn10300/kernel/mn10300-serial.c
@@ -936,15 +936,18 @@ static int mn10300_serial_startup(struct uart_port *_port)
 	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);
 
diff --git a/arch/mn10300/kernel/smp.c b/arch/mn10300/kernel/smp.c
index e62c223e4c4..95983cd21e7 100644
--- a/arch/mn10300/kernel/smp.c
+++ b/arch/mn10300/kernel/smp.c
@@ -130,10 +130,12 @@ static irqreturn_t smp_call_function_interrupt(int irq, void *dev_id);
 
 static struct irqaction reschedule_ipi = {
 	.handler	= smp_reschedule_interrupt,
+	.flags		= IRQF_NOBALANCING,
 	.name		= "smp reschedule IPI"
 };
 static struct irqaction call_function_ipi = {
 	.handler	= smp_call_function_interrupt,
+	.flags		= IRQF_NOBALANCING,
 	.name		= "smp call function IPI"
 };
 
@@ -141,7 +143,7 @@ static struct irqaction call_function_ipi = {
 static irqreturn_t smp_ipi_timer_interrupt(int irq, void *dev_id);
 static struct irqaction local_timer_ipi = {
 	.handler	= smp_ipi_timer_interrupt,
-	.flags		= IRQF_DISABLED,
+	.flags		= IRQF_DISABLED | IRQF_NOBALANCING,
 	.name		= "smp local timer IPI"
 };
 #endif
@@ -180,6 +182,7 @@ static void init_ipi(void)
 
 #ifdef CONFIG_MN10300_CACHE_ENABLED
 	/* set up the cache flush IPI */
+	irq_set_chip(FLUSH_CACHE_IPI, &mn10300_ipi_type);
 	flags = arch_local_cli_save();
 	__set_intr_stub(NUM2EXCEP_IRQ_LEVEL(FLUSH_CACHE_GxICR_LV),
 			mn10300_low_ipi_handler);
@@ -189,6 +192,7 @@ static void init_ipi(void)
 #endif
 
 	/* set up the NMI call function IPI */
+	irq_set_chip(CALL_FUNCTION_NMI_IPI, &mn10300_ipi_type);
 	flags = arch_local_cli_save();
 	GxICR(CALL_FUNCTION_NMI_IPI) = GxICR_NMI | GxICR_ENABLE | GxICR_DETECT;
 	tmp16 = GxICR(CALL_FUNCTION_NMI_IPI);
@@ -199,6 +203,10 @@ static void init_ipi(void)
 	__set_intr_stub(NUM2EXCEP_IRQ_LEVEL(SMP_BOOT_GxICR_LV),
 			mn10300_low_ipi_handler);
 	arch_local_irq_restore(flags);
+
+#ifdef CONFIG_KERNEL_DEBUGGER
+	irq_set_chip(DEBUGGER_NMI_IPI, &mn10300_ipi_type);
+#endif
 }
 
 /**

From 8d160027ff234bddea627ba54c2b85efa1884867 Mon Sep 17 00:00:00 2001
From: Mark Salter <msalter@redhat.com>
Date: Wed, 12 Dec 2012 15:36:38 +0000
Subject: [PATCH 03/11] MN10300: fix serial port vdma irq setup for SMP

The builtin SoC serial ports have no FIFOs and use a virtual DMA mechanism
based on high priority IRQs to avoid overruns. These high priority interrupts
are pinned to cpu#0 on SMP systems. This patch fixes a problem with SMP where
the set_intr_level() interface is used to set the priority for these IRQs. The
set_intr_level() function sets priority on the local cpu but on SMP systems,
this code may be run on some other cpu than the one handling the interrupts.
Instead of setting interrupt level explicitly, this patch uses a special
irq_chip for these interrupts so that the mask/unmask methods can set the
interrupt level implicitly.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/kernel/mn10300-serial.c | 34 ++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c
index 4968cfe66c0..cac0f0da920 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
@@ -929,10 +957,8 @@ 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,

From 8f0bcbcab016324c2a3ba4cc715e8e523c29a578 Mon Sep 17 00:00:00 2001
From: Mark Salter <msalter@redhat.com>
Date: Wed, 12 Dec 2012 15:36:38 +0000
Subject: [PATCH 04/11] MN10300: fix SMP synchronization between txdma and
 serial driver

The SoC serial port driver uses a high priority interrupt to handle tx of
characters in the tx ring buffer. The driver needs to disable/enable this IRQ
from outside of irq context. The original code to do this is not foolproof on
SMP machines because the IRQ running on one core could still access the serial
port for a short time after the driver running on another core disables the
interrupt. This patch adds a flag to tell the IRQ handler that the driver
wants to disable the interrupt. After seeing the flag, the IRQ handler will
immediately disable the interrupt and exit. After setting the flag, the driver
will wait for interrupt to be disabled by the IRQ handler.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/kernel/asm-offsets.c        |   2 +-
 arch/mn10300/kernel/mn10300-serial-low.S |   9 +-
 arch/mn10300/kernel/mn10300-serial.c     | 121 +++++++++++++++--------
 arch/mn10300/kernel/mn10300-serial.h     |   6 +-
 4 files changed, 90 insertions(+), 48 deletions(-)

diff --git a/arch/mn10300/kernel/asm-offsets.c b/arch/mn10300/kernel/asm-offsets.c
index 96f24fab7de..47b3bb0c04f 100644
--- a/arch/mn10300/kernel/asm-offsets.c
+++ b/arch/mn10300/kernel/asm-offsets.c
@@ -96,7 +96,7 @@ void foo(void)
 	OFFSET(__rx_outp,		mn10300_serial_port, rx_outp);
 	OFFSET(__uart_state,		mn10300_serial_port, uart.state);
 	OFFSET(__tx_xchar,		mn10300_serial_port, tx_xchar);
-	OFFSET(__tx_break,		mn10300_serial_port, tx_break);
+	OFFSET(__tx_flags,		mn10300_serial_port, tx_flags);
 	OFFSET(__intr_flags,		mn10300_serial_port, intr_flags);
 	OFFSET(__rx_icr,		mn10300_serial_port, rx_icr);
 	OFFSET(__tx_icr,		mn10300_serial_port, tx_icr);
diff --git a/arch/mn10300/kernel/mn10300-serial-low.S b/arch/mn10300/kernel/mn10300-serial-low.S
index dfc1b6f2fa9..b95e76caf4f 100644
--- a/arch/mn10300/kernel/mn10300-serial-low.S
+++ b/arch/mn10300/kernel/mn10300-serial-low.S
@@ -118,8 +118,8 @@ ENTRY(mn10300_serial_vdma_tx_handler)
 	movbu	d2,(e3)			# ACK the interrupt
 	movhu	(e3),d2			# flush
 
-	btst	0x01,(__tx_break,a3)	# handle transmit break request
-	bne	mnsc_vdma_tx_break
+	btst	0xFF,(__tx_flags,a3)	# handle transmit flags
+	bne	mnsc_vdma_tx_flags
 
 	movbu	(SCxSTR,e2),d2		# don't try and transmit a char if the
 					# buffer is not empty
@@ -171,10 +171,13 @@ mnsc_vdma_tx_empty:
 	bset	MNSCx_TX_EMPTY,(__intr_flags,a3)
 	bra	mnsc_vdma_tx_done
 
-mnsc_vdma_tx_break:
+mnsc_vdma_tx_flags:
+	btst	MNSCx_TX_STOP,(__tx_flags,a3)
+	bne	mnsc_vdma_tx_stop
 	movhu	(SCxCTR,e2),d2		# turn on break mode
 	or	SC01CTR_BKE,d2
 	movhu	d2,(SCxCTR,e2)
+mnsc_vdma_tx_stop:
 	mov	+(NUM2GxICR_LEVEL(CONFIG_MN10300_SERIAL_IRQ_LEVEL)|GxICR_DETECT),d2
 	movhu	d2,(e3)			# disable transmit interrupts on this
 					# channel
diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c
index cac0f0da920..587545cb7e4 100644
--- a/arch/mn10300/kernel/mn10300-serial.c
+++ b/arch/mn10300/kernel/mn10300-serial.c
@@ -444,25 +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)
@@ -807,8 +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,
@@ -816,14 +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,
@@ -831,10 +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();
 }
 
 /*
@@ -844,13 +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);
+		}
 	}
 }
 
@@ -911,18 +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);
 }
 
 /*
@@ -945,6 +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;
@@ -994,14 +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;
 
@@ -1016,12 +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;
 }
 
 /*
@@ -1549,17 +1576,24 @@ 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;
@@ -1613,10 +1647,11 @@ 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);
 }
 
 /*
diff --git a/arch/mn10300/kernel/mn10300-serial.h b/arch/mn10300/kernel/mn10300-serial.h
index 6796499bf78..0004e61619a 100644
--- a/arch/mn10300/kernel/mn10300-serial.h
+++ b/arch/mn10300/kernel/mn10300-serial.h
@@ -29,6 +29,10 @@
 #define MNSCx_TX_SPACE		0x04
 #define MNSCx_TX_EMPTY		0x08
 
+/* tx_flags bits */
+#define MNSCx_TX_BREAK		0x01
+#define MNSCx_TX_STOP		0x02
+
 #ifndef __ASSEMBLY__
 
 struct mn10300_serial_port {
@@ -36,7 +40,7 @@ struct mn10300_serial_port {
 	unsigned		rx_inp;		/* pointer to rx input offset */
 	unsigned		rx_outp;	/* pointer to rx output offset */
 	u8			tx_xchar;	/* high-priority XON/XOFF buffer */
-	u8			tx_break;	/* transmit break request */
+	u8			tx_flags;	/* transmit break/stop request */
 	u8			intr_flags;	/* interrupt flags */
 	volatile u16		*rx_icr;	/* Rx interrupt control register */
 	volatile u16		*tx_icr;	/* Tx interrupt control register */

From 97a70b14395be0ca61b9fa56f8ff5f6313c26423 Mon Sep 17 00:00:00 2001
From: Mark Salter <msalter@redhat.com>
Date: Wed, 12 Dec 2012 15:36:38 +0000
Subject: [PATCH 05/11] MN10300: ttySM: clean up unnecessary casting

The ttySM uart data register pointers are declared as void* pointers. Change
them to u8* pointers so we don't need to use casts in the code.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/kernel/mn10300-serial.c | 8 ++++----
 arch/mn10300/kernel/mn10300-serial.h | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c
index 587545cb7e4..b7b5a4c270f 100644
--- a/arch/mn10300/kernel/mn10300-serial.c
+++ b/arch/mn10300/kernel/mn10300-serial.c
@@ -1629,12 +1629,12 @@ 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;
 		}
 	}
 
@@ -1759,12 +1759,12 @@ 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;
 
diff --git a/arch/mn10300/kernel/mn10300-serial.h b/arch/mn10300/kernel/mn10300-serial.h
index 0004e61619a..01791c68ea1 100644
--- a/arch/mn10300/kernel/mn10300-serial.h
+++ b/arch/mn10300/kernel/mn10300-serial.h
@@ -58,8 +58,8 @@ struct mn10300_serial_port {
 	volatile u16		*_control;	/* control register pointer */
 	volatile u8		*_status;	/* status register pointer */
 	volatile u8		*_intr;		/* interrupt register pointer */
-	volatile void		*_rxb;		/* receive buffer register pointer */
-	volatile void		*_txb;		/* transmit buffer register pointer */
+	volatile u8		*_rxb;		/* receive buffer register pointer */
+	volatile u8		*_txb;		/* transmit buffer register pointer */
 	volatile u16		*_tmicr;	/* timer interrupt control register */
 	volatile u8		*_tmxmd;	/* baud rate timer mode register */
 	volatile u16		*_tmxbr;	/* baud rate timer base register */

From 0369c360e5825e34ff58c140aa7fbb9855ad1e4a Mon Sep 17 00:00:00 2001
From: Mark Salter <msalter@redhat.com>
Date: Wed, 12 Dec 2012 15:36:39 +0000
Subject: [PATCH 06/11] MN10300: fix debug polling in ttySM driver

The debug polling interface for the SoC serial ports did not work in the case
where the serial ports were not also used as a console. In that case, the
uart driver startup function will not be called so tx and rx would not be
enabled in the hardware control register. Also, vdma interrupts would not be
enabled which the poll_get_char function relied on. This patch makes sure that
the rx and tx enables are set as a consequence of the uart set_termios call
which is the only initialization done for the debug polling interface. Also,
the poll_get_char now handles the case where vdma interrupts are not enabled.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/kernel/mn10300-serial.c | 35 ++++++++++++++++++----------
 1 file changed, 23 insertions(+), 12 deletions(-)

diff --git a/arch/mn10300/kernel/mn10300-serial.c b/arch/mn10300/kernel/mn10300-serial.c
index b7b5a4c270f..81d5cb9b656 100644
--- a/arch/mn10300/kernel/mn10300-serial.c
+++ b/arch/mn10300/kernel/mn10300-serial.c
@@ -1374,7 +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);
@@ -1720,19 +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 = ACCESS_ONCE(port->rx_outp);
-		if (CIRC_CNT(port->rx_inp, ix, MNSC_BUFFER_SIZE) == 0)
-			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;
 
-		smp_read_barrier_depends();
-		ch = port->rx_buffer[ix++];
-		st = port->rx_buffer[ix++];
-		smp_mb();
-		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;
 }

From 83c2dc15ce824450e7044b9f90cd529c25747ae0 Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 12 Dec 2012 15:36:39 +0000
Subject: [PATCH 07/11] MN10300: Handle cacheable PCI regions in pci_iomap()

Handle cacheable PCI regions in pci_iomap().  If IORESOURCE_CACHEABLE is set
then we AND away the 0x20000000 "flag".

Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/include/asm/io.h         |  2 +-
 arch/mn10300/unit-asb2305/pci-iomap.c | 35 +++++++++++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 arch/mn10300/unit-asb2305/pci-iomap.c

diff --git a/arch/mn10300/include/asm/io.h b/arch/mn10300/include/asm/io.h
index 139df8c53de..70f1c06e29d 100644
--- a/arch/mn10300/include/asm/io.h
+++ b/arch/mn10300/include/asm/io.h
@@ -258,7 +258,7 @@ static inline void __iomem *__ioremap(unsigned long offset, unsigned long size,
 
 static inline void __iomem *ioremap(unsigned long offset, unsigned long size)
 {
-	return (void __iomem *) offset;
+	return (void __iomem *)(offset & ~0x20000000);
 }
 
 /*
diff --git a/arch/mn10300/unit-asb2305/pci-iomap.c b/arch/mn10300/unit-asb2305/pci-iomap.c
new file mode 100644
index 00000000000..bd65dae17f3
--- /dev/null
+++ b/arch/mn10300/unit-asb2305/pci-iomap.c
@@ -0,0 +1,35 @@
+/* ASB2305 PCI I/O mapping handler
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#include <linux/pci.h>
+#include <linux/module.h>
+
+/*
+ * Create a virtual mapping cookie for a PCI BAR (memory or IO)
+ */
+void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
+{
+	resource_size_t start = pci_resource_start(dev, bar);
+	resource_size_t len = pci_resource_len(dev, bar);
+	unsigned long flags = pci_resource_flags(dev, bar);
+
+	if (!len || !start)
+		return NULL;
+
+	if ((flags & IORESOURCE_IO) || (flags & IORESOURCE_MEM)) {
+		if (flags & IORESOURCE_CACHEABLE && !(flags & IORESOURCE_IO))
+			return ioremap(start, len);
+		else
+			return ioremap_nocache(start, len);
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL(pci_iomap);

From 3d7b6a674e266999a90ff1e21c6c839e30200c51 Mon Sep 17 00:00:00 2001
From: Kautuk Consul <consul.kautuk@gmail.com>
Date: Wed, 12 Dec 2012 15:36:39 +0000
Subject: [PATCH 08/11] mn10300/mm/fault.c: Port OOM changes to do_page_fault

Commit d065bd810b6deb67d4897a14bfe21f8eb526ba99
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e0525d393d48a7d59f870b3bc061a30ccdb
(x86,mm: make pagefault killable)

The above commits introduced changes into the x86 pagefault handler
for making the page fault handler retryable as well as killable.

These changes reduce the mmap_sem hold time, which is crucial
during OOM killer invocation.

Port these changes to mn10300.

Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/mm/fault.c | 33 +++++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/arch/mn10300/mm/fault.c b/arch/mn10300/mm/fault.c
index 90f346f7392..d48a84fd7fa 100644
--- a/arch/mn10300/mm/fault.c
+++ b/arch/mn10300/mm/fault.c
@@ -123,7 +123,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
 	struct mm_struct *mm;
 	unsigned long page;
 	siginfo_t info;
-	int write, fault;
+	int fault;
+	unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
 
 #ifdef CONFIG_GDBSTUB
 	/* handle GDB stub causing a fault */
@@ -170,6 +171,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
 	if (in_atomic() || !mm)
 		goto no_context;
 
+retry:
 	down_read(&mm->mmap_sem);
 
 	vma = find_vma(mm, address);
@@ -220,7 +222,6 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long fault_code,
  */
 good_area:
 	info.si_code = SEGV_ACCERR;
-	write = 0;
 	switch (fault_code & (MMUFCR_xFC_PGINVAL|MMUFCR_xFC_TYPE)) {
 	default:	/* 3: write, present */
 	case MMUFCR_xFC_TYPE_WRITE:
@@ -232,7 +233,7 @@ good_area:
 	case MMUFCR_xFC_PGINVAL | MMUFCR_xFC_TYPE_WRITE:
 		if (!(vma->vm_flags & VM_WRITE))
 			goto bad_area;
-		write++;
+		flags |= FAULT_FLAG_WRITE;
 		break;
 
 		/* read from protected page */
@@ -251,7 +252,11 @@ good_area:
 	 * make sure we exit gracefully rather than endlessly redo
 	 * the fault.
 	 */
-	fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
+	fault = handle_mm_fault(mm, vma, address, flags);
+
+	if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+		return;
+
 	if (unlikely(fault & VM_FAULT_ERROR)) {
 		if (fault & VM_FAULT_OOM)
 			goto out_of_memory;
@@ -259,10 +264,22 @@ good_area:
 			goto do_sigbus;
 		BUG();
 	}
-	if (fault & VM_FAULT_MAJOR)
-		current->maj_flt++;
-	else
-		current->min_flt++;
+	if (flags & FAULT_FLAG_ALLOW_RETRY) {
+		if (fault & VM_FAULT_MAJOR)
+			current->maj_flt++;
+		else
+			current->min_flt++;
+		if (fault & VM_FAULT_RETRY) {
+			flags &= ~FAULT_FLAG_ALLOW_RETRY;
+
+			 /* No need to up_read(&mm->mmap_sem) as we would
+			 * have already released it in __lock_page_or_retry
+			 * in mm/filemap.c.
+			 */
+
+			goto retry;
+		}
+	}
 
 	up_read(&mm->mmap_sem);
 	return;

From 00a2f9151838abf0e84ed05ac1282bf57ac4d01c Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 12 Dec 2012 15:36:40 +0000
Subject: [PATCH 09/11] MN10300: ASB2305 PCI code needs linux/irq.h

ASB2305 PCI code needs to #include linux/irq.h for XIRQ1 so that it can set
the CPU interrupt priority level on the PCI interrupt.

Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/unit-asb2305/pci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/mn10300/unit-asb2305/pci.c b/arch/mn10300/unit-asb2305/pci.c
index 6dce9fc2cf3..a3239b0f965 100644
--- a/arch/mn10300/unit-asb2305/pci.c
+++ b/arch/mn10300/unit-asb2305/pci.c
@@ -17,6 +17,7 @@
 #include <linux/init.h>
 #include <linux/ioport.h>
 #include <linux/delay.h>
+#include <linux/irq.h>
 #include <asm/io.h>
 #include "pci-asb2305.h"
 

From 0c6e686ce4f7a346f8e6f39202025ddce525ac8a Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 12 Dec 2012 15:36:40 +0000
Subject: [PATCH 10/11] MN10300: Get rid of unused variable from ASB2305 PCI
 code

Get rid of an unused variable in pcibios_fixup_device_resources() which leads
to the following warning:

arch/mn10300/unit-asb2305/pci.c: In function 'pcibios_fixup_device_resources':
arch/mn10300/unit-asb2305/pci.c:324:24: warning: unused variable 'region' [-Wunused-variable]

Whilst we're at it, merge the two integer variable declarations into one line.

Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/unit-asb2305/pci.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/mn10300/unit-asb2305/pci.c b/arch/mn10300/unit-asb2305/pci.c
index a3239b0f965..e2059486d3f 100644
--- a/arch/mn10300/unit-asb2305/pci.c
+++ b/arch/mn10300/unit-asb2305/pci.c
@@ -304,9 +304,7 @@ static int __devinit is_valid_resource(struct pci_dev *dev, int idx)
 
 static void __devinit pcibios_fixup_device_resources(struct pci_dev *dev)
 {
-	struct pci_bus_region region;
-	int i;
-	int limit;
+	int limit, i;
 
 	if (dev->bus->number != 0)
 		return;

From 76583cffb77533fe564aaf21d184b89a5f419ffe Mon Sep 17 00:00:00 2001
From: David Howells <dhowells@redhat.com>
Date: Wed, 12 Dec 2012 15:36:40 +0000
Subject: [PATCH 11/11] MN10300: Use asm-generic/pci_iomap.h

The declarations from MN10300's pci_iomap() was removed by commit
34f1bdee1910f7efe3c32e1a891dba4fd21cb3b6 but asm-generic/pci_iomap.h wasn't
then #included from asm/io.h.

Signed-off-by: David Howells <dhowells@redhat.com>
---
 arch/mn10300/include/asm/io.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/mn10300/include/asm/io.h b/arch/mn10300/include/asm/io.h
index 70f1c06e29d..e6ed0d897cc 100644
--- a/arch/mn10300/include/asm/io.h
+++ b/arch/mn10300/include/asm/io.h
@@ -14,6 +14,7 @@
 #include <asm/page.h> /* I/O is all done through memory accesses */
 #include <asm/cpu-regs.h>
 #include <asm/cacheflush.h>
+#include <asm-generic/pci_iomap.h>
 
 #define mmiowb() do {} while (0)