[PATCH] powerpc: fix trigger handling in the new irq code

This patch slightly reworks the new irq code to fix a small design error.  I
removed the passing of the trigger to the map() calls entirely, it was not a
good idea to have one call do two different things.  It also fixes a couple of
corner cases.

Mapping a linux virtual irq to a physical irq now does only that.  Setting the
trigger is a different action which has a different call.

The main changes are:

- I no longer call host->ops->map() for an already mapped irq, I just return
  the virtual number that was already mapped.  It was called before to give an
  opportunity to change the trigger, but that was causing issues as that could
  happen while the interrupt was in use by a device, and because of the
  trigger change, map would potentially muck around with things in a racy way.
   That was causing much burden on a given's controller implementation of
  map() to get it right.  This is much simpler now.  map() is only called on
  the initial mapping of an irq, meaning that you know that this irq is _not_
  being used.  You can initialize the hardware if you want (though you don't
  have to).

- Controllers that can handle different type of triggers (level/edge/etc...)
  now implement the standard irq_chip->set_type() call as defined by the
  generic code.  That means that you can use the standard set_irq_type() to
  configure an irq line manually if you wish or (though I don't like that
  interface), pass explicit trigger flags to request_irq() as defined by the
  generic kernel interfaces.  Also, using those interfaces guarantees that
  your controller set_type callback is called with the descriptor lock held,
  thus providing locking against activity on the same interrupt (including
  mask/unmask/etc...) automatically.  A result is that, for example, MPIC's
  own map() implementation calls irq_set_type(NONE) to configure the hardware
  to the default triggers.

- To allow the above, the irq_map array entry for the new mapped interrupt
  is now set before map() callback is called for the controller.

- The irq_create_of_mapping() (also used by irq_of_parse_and_map()) function
  for mapping interrupts from the device-tree now also call the separate
  set_irq_type(), and only does so if there is a change in the trigger type.

- While I was at it, I changed pci_read_irq_line() (which is the helper I
  would expect most archs to use in their pcibios_fixup() to get the PCI
  interrupt routing from the device tree) to also handle a fallback when the
  DT mapping fails consisting of reading the PCI_INTERRUPT_PIN to know wether
  the device has an interrupt at all, and the the PCI_INTERRUPT_LINE to get an
  interrupt number from the device.  That number is then mapped using the
  default controller, and the trigger is set to level low.  That default
  behaviour works for several platforms that don't have a proper interrupt
  tree like Pegasos.  If it doesn't work for your platform, then either
  provide a proper interrupt tree from the firmware so that fallback isn't
  needed, or don't call pci_read_irq_line()

- Add back a bit that got dropped by my main rework patch for properly
  clearing pending IPIs on pSeries when using a kexec

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 82 insertions, 102 deletions

diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c
index 72c73a6105c..9855820b954 100644
--- a/arch/powerpc/sysdev/i8259.c
+++ b/arch/powerpc/sysdev/i8259.c
@@ -169,7 +169,7 @@ static int i8259_host_match(struct irq_host *h, struct device_node *node)
 }
 
 static int i8259_host_map(struct irq_host *h, unsigned int virq,
-			  irq_hw_number_t hw, unsigned int flags)
+			  irq_hw_number_t hw)
 {
 	pr_debug("i8259_host_map(%d, 0x%lx)\n", virq, hw);
 
@@ -177,7 +177,7 @@ static int i8259_host_map(struct irq_host *h, unsigned int virq,
 	if (hw == 2)
 		get_irq_desc(virq)->status |= IRQ_NOREQUEST;
 
-	/* We use the level stuff only for now, we might want to
+	/* We use the level handler only for now, we might want to
 	 * be more cautious here but that works for now
 	 */
 	get_irq_desc(virq)->status |= IRQ_LEVEL;
diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
index 9cecebaa036..c39c4a0b1cd 100644
--- a/arch/powerpc/sysdev/mpic.c
+++ b/arch/powerpc/sysdev/mpic.c
@@ -337,6 +337,17 @@ static void __init mpic_scan_ht_pics(struct mpic *mpic)
 	}
 }
 
+#else /* CONFIG_MPIC_BROKEN_U3 */
+
+static inline int mpic_is_ht_interrupt(struct mpic *mpic, unsigned int source)
+{
+	return 0;
+}
+
+static void __init mpic_scan_ht_pics(struct mpic *mpic)
+{
+}
+
 #endif /* CONFIG_MPIC_BROKEN_U3 */
 
 
@@ -405,11 +416,9 @@ static void mpic_unmask_irq(unsigned int irq)
 	unsigned int loops = 100000;
 	struct mpic *mpic = mpic_from_irq(irq);
 	unsigned int src = mpic_irq_to_hw(irq);
-	unsigned long flags;
 
 	DBG("%p: %s: enable_irq: %d (src %d)\n", mpic, mpic->name, irq, src);
 
-	spin_lock_irqsave(&mpic_lock, flags);
 	mpic_irq_write(src, MPIC_IRQ_VECTOR_PRI,
 		       mpic_irq_read(src, MPIC_IRQ_VECTOR_PRI) &
 		       ~MPIC_VECPRI_MASK);
@@ -420,7 +429,6 @@ static void mpic_unmask_irq(unsigned int irq)
 			break;
 		}
 	} while(mpic_irq_read(src, MPIC_IRQ_VECTOR_PRI) & MPIC_VECPRI_MASK);
-	spin_unlock_irqrestore(&mpic_lock, flags);
 }
 
 static void mpic_mask_irq(unsigned int irq)
@@ -428,11 +436,9 @@ static void mpic_mask_irq(unsigned int irq)
 	unsigned int loops = 100000;
 	struct mpic *mpic = mpic_from_irq(irq);
 	unsigned int src = mpic_irq_to_hw(irq);
-	unsigned long flags;
 
 	DBG("%s: disable_irq: %d (src %d)\n", mpic->name, irq, src);
 
-	spin_lock_irqsave(&mpic_lock, flags);
 	mpic_irq_write(src, MPIC_IRQ_VECTOR_PRI,
 		       mpic_irq_read(src, MPIC_IRQ_VECTOR_PRI) |
 		       MPIC_VECPRI_MASK);
@@ -444,7 +450,6 @@ static void mpic_mask_irq(unsigned int irq)
 			break;
 		}
 	} while(!(mpic_irq_read(src, MPIC_IRQ_VECTOR_PRI) & MPIC_VECPRI_MASK));
-	spin_unlock_irqrestore(&mpic_lock, flags);
 }
 
 static void mpic_end_irq(unsigned int irq)
@@ -512,8 +517,7 @@ static void mpic_end_ht_irq(unsigned int irq)
 		mpic_ht_end_irq(mpic, src);
 	mpic_eoi(mpic);
 }
-
-#endif /* CONFIG_MPIC_BROKEN_U3 */
+#endif /* !CONFIG_MPIC_BROKEN_U3 */
 
 #ifdef CONFIG_SMP
 
@@ -560,47 +564,74 @@ static void mpic_set_affinity(unsigned int irq, cpumask_t cpumask)
 		       mpic_physmask(cpus_addr(tmp)[0]));	
 }
 
-static unsigned int mpic_flags_to_vecpri(unsigned int flags, int *level)
+static unsigned int mpic_type_to_vecpri(unsigned int type)
 {
-	unsigned int vecpri;
-
 	/* Now convert sense value */
-	switch(flags & IRQ_TYPE_SENSE_MASK) {
+	switch(type & IRQ_TYPE_SENSE_MASK) {
 	case IRQ_TYPE_EDGE_RISING:
-		vecpri = MPIC_VECPRI_SENSE_EDGE |
-			MPIC_VECPRI_POLARITY_POSITIVE;
-		*level = 0;
-		break;
+		return MPIC_VECPRI_SENSE_EDGE | MPIC_VECPRI_POLARITY_POSITIVE;
 	case IRQ_TYPE_EDGE_FALLING:
-		vecpri = MPIC_VECPRI_SENSE_EDGE |
-			MPIC_VECPRI_POLARITY_NEGATIVE;
-		*level = 0;
-		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		return MPIC_VECPRI_SENSE_EDGE | MPIC_VECPRI_POLARITY_NEGATIVE;
 	case IRQ_TYPE_LEVEL_HIGH:
-		vecpri = MPIC_VECPRI_SENSE_LEVEL |
-			MPIC_VECPRI_POLARITY_POSITIVE;
-		*level = 1;
-		break;
+		return MPIC_VECPRI_SENSE_LEVEL | MPIC_VECPRI_POLARITY_POSITIVE;
 	case IRQ_TYPE_LEVEL_LOW:
 	default:
-		vecpri = MPIC_VECPRI_SENSE_LEVEL |
-			MPIC_VECPRI_POLARITY_NEGATIVE;
-		*level = 1;
+		return MPIC_VECPRI_SENSE_LEVEL | MPIC_VECPRI_POLARITY_NEGATIVE;
 	}
-	return vecpri;
+}
+
+static int mpic_set_irq_type(unsigned int virq, unsigned int flow_type)
+{
+	struct mpic *mpic = mpic_from_irq(virq);
+	unsigned int src = mpic_irq_to_hw(virq);
+	struct irq_desc *desc = get_irq_desc(virq);
+	unsigned int vecpri, vold, vnew;
+
+	pr_debug("mpic: set_irq_type(mpic:@%p,virq:%d,src:%d,type:0x%x)\n",
+		 mpic, virq, src, flow_type);
+
+	if (src >= mpic->irq_count)
+		return -EINVAL;
+
+	if (flow_type == IRQ_TYPE_NONE)
+		if (mpic->senses && src < mpic->senses_count)
+			flow_type = mpic->senses[src];
+	if (flow_type == IRQ_TYPE_NONE)
+		flow_type = IRQ_TYPE_LEVEL_LOW;
+
+	desc->status &= ~(IRQ_TYPE_SENSE_MASK | IRQ_LEVEL);
+	desc->status |= flow_type & IRQ_TYPE_SENSE_MASK;
+	if (flow_type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
+		desc->status |= IRQ_LEVEL;
+
+	if (mpic_is_ht_interrupt(mpic, src))
+		vecpri = MPIC_VECPRI_POLARITY_POSITIVE |
+			MPIC_VECPRI_SENSE_EDGE;
+	else
+		vecpri = mpic_type_to_vecpri(flow_type);
+
+	vold = mpic_irq_read(src, MPIC_IRQ_VECTOR_PRI);
+	vnew = vold & ~(MPIC_VECPRI_POLARITY_MASK | MPIC_VECPRI_SENSE_MASK);
+	vnew |= vecpri;
+	if (vold != vnew)
+		mpic_irq_write(src, MPIC_IRQ_VECTOR_PRI, vnew);
+
+	return 0;
 }
 
 static struct irq_chip mpic_irq_chip = {
-	.mask	= mpic_mask_irq,
-	.unmask	= mpic_unmask_irq,
-	.eoi	= mpic_end_irq,
+	.mask		= mpic_mask_irq,
+	.unmask		= mpic_unmask_irq,
+	.eoi		= mpic_end_irq,
+	.set_type	= mpic_set_irq_type,
 };
 
 #ifdef CONFIG_SMP
 static struct irq_chip mpic_ipi_chip = {
-	.mask	= mpic_mask_ipi,
-	.unmask	= mpic_unmask_ipi,
-	.eoi	= mpic_end_ipi,
+	.mask		= mpic_mask_ipi,
+	.unmask		= mpic_unmask_ipi,
+	.eoi		= mpic_end_ipi,
 };
 #endif /* CONFIG_SMP */
 
@@ -611,6 +642,7 @@ static struct irq_chip mpic_irq_ht_chip = {
 	.mask		= mpic_mask_irq,
 	.unmask		= mpic_unmask_ht_irq,
 	.eoi		= mpic_end_ht_irq,
+	.set_type	= mpic_set_irq_type,
 };
 #endif /* CONFIG_MPIC_BROKEN_U3 */
 
@@ -624,18 +656,12 @@ static int mpic_host_match(struct irq_host *h, struct device_node *node)
 }
 
 static int mpic_host_map(struct irq_host *h, unsigned int virq,
-			 irq_hw_number_t hw, unsigned int flags)
+			 irq_hw_number_t hw)
 {
-	struct irq_desc *desc = get_irq_desc(virq);
-	struct irq_chip *chip;
 	struct mpic *mpic = h->host_data;
-	u32 v, vecpri = MPIC_VECPRI_SENSE_LEVEL |
-		MPIC_VECPRI_POLARITY_NEGATIVE;
-	int level;
-	unsigned long iflags;
+	struct irq_chip *chip;
 
-	pr_debug("mpic: map virq %d, hwirq 0x%lx, flags: 0x%x\n",
-		 virq, hw, flags);
+	pr_debug("mpic: map virq %d, hwirq 0x%lx\n", virq, hw);
 
 	if (hw == MPIC_VEC_SPURRIOUS)
 		return -EINVAL;
@@ -654,44 +680,23 @@ static int mpic_host_map(struct irq_host *h, unsigned int virq,
 	if (hw >= mpic->irq_count)
 		return -EINVAL;
 
-	/* If no sense provided, check default sense array */
-	if (((flags & IRQ_TYPE_SENSE_MASK) == IRQ_TYPE_NONE) &&
-	    mpic->senses && hw < mpic->senses_count)
-		flags |= mpic->senses[hw];
-
-	vecpri = mpic_flags_to_vecpri(flags, &level);
-	if (level)
-		desc->status |= IRQ_LEVEL;
+	/* Default chip */
 	chip = &mpic->hc_irq;
 
 #ifdef CONFIG_MPIC_BROKEN_U3
 	/* Check for HT interrupts, override vecpri */
-	if (mpic_is_ht_interrupt(mpic, hw)) {
-		vecpri &= ~(MPIC_VECPRI_SENSE_MASK |
-			    MPIC_VECPRI_POLARITY_MASK);
-		vecpri |= MPIC_VECPRI_POLARITY_POSITIVE;
+	if (mpic_is_ht_interrupt(mpic, hw))
 		chip = &mpic->hc_ht_irq;
-	}
-#endif
+#endif /* CONFIG_MPIC_BROKEN_U3 */
 
-	/* Reconfigure irq. We must preserve the mask bit as we can be called
-	 * while the interrupt is still active (This may change in the future
-	 * but for now, it is the case).
-	 */
-	spin_lock_irqsave(&mpic_lock, iflags);
-	v = mpic_irq_read(hw, MPIC_IRQ_VECTOR_PRI);
-	vecpri = (v &
-		~(MPIC_VECPRI_POLARITY_MASK | MPIC_VECPRI_SENSE_MASK)) |
-		vecpri;
-	if (vecpri != v)
-		mpic_irq_write(hw, MPIC_IRQ_VECTOR_PRI, vecpri);
-	spin_unlock_irqrestore(&mpic_lock, iflags);
-
-	pr_debug("mpic: mapping as IRQ, vecpri = 0x%08x (was 0x%08x)\n",
-		 vecpri, v);
+	pr_debug("mpic: mapping to irq chip @%p\n", chip);
 
 	set_irq_chip_data(virq, mpic);
 	set_irq_chip_and_handler(virq, chip, handle_fasteoi_irq);
+
+	/* Set default irq type */
+	set_irq_type(virq, IRQ_TYPE_NONE);
+
 	return 0;
 }
 
@@ -906,41 +911,16 @@ void __init mpic_init(struct mpic *mpic)
 	if (mpic->irq_count == 0)
 		mpic->irq_count = mpic->num_sources;
 
-#ifdef CONFIG_MPIC_BROKEN_U3
 	/* Do the HT PIC fixups on U3 broken mpic */
 	DBG("MPIC flags: %x\n", mpic->flags);
 	if ((mpic->flags & MPIC_BROKEN_U3) && (mpic->flags & MPIC_PRIMARY))
  		mpic_scan_ht_pics(mpic);
-#endif /* CONFIG_MPIC_BROKEN_U3 */
 
 	for (i = 0; i < mpic->num_sources; i++) {
 		/* start with vector = source number, and masked */
-		u32 vecpri = MPIC_VECPRI_MASK | i | (8 << MPIC_VECPRI_PRIORITY_SHIFT);
-		int level = 1;
+		u32 vecpri = MPIC_VECPRI_MASK | i |
+			(8 << MPIC_VECPRI_PRIORITY_SHIFT);
 		
-		/* do senses munging */
-		if (mpic->senses && i < mpic->senses_count)
-			vecpri |= mpic_flags_to_vecpri(mpic->senses[i],
-						       &level);
-		else
-			vecpri |= MPIC_VECPRI_SENSE_LEVEL;
-
-		/* deal with broken U3 */
-		if (mpic->flags & MPIC_BROKEN_U3) {
-#ifdef CONFIG_MPIC_BROKEN_U3
-			if (mpic_is_ht_interrupt(mpic, i)) {
-				vecpri &= ~(MPIC_VECPRI_SENSE_MASK |
-					    MPIC_VECPRI_POLARITY_MASK);
-				vecpri |= MPIC_VECPRI_POLARITY_POSITIVE;
-			}
-#else
-			printk(KERN_ERR "mpic: BROKEN_U3 set, but CONFIG doesn't match\n");
-#endif
-		}
-
-		DBG("setup source %d, vecpri: %08x, level: %d\n", i, vecpri,
-		    (level != 0));
-
 		/* init hw */
 		mpic_irq_write(i, MPIC_IRQ_VECTOR_PRI, vecpri);
 		mpic_irq_write(i, MPIC_IRQ_DESTINATION,
@@ -1154,7 +1134,7 @@ void mpic_request_ipis(void)
 
 	for (i = 0; i < 4; i++) {
 		unsigned int vipi = irq_create_mapping(mpic->irqhost,
-						       MPIC_VEC_IPI_0 + i, 0);
+						       MPIC_VEC_IPI_0 + i);
 		if (vipi == NO_IRQ) {
 			printk(KERN_ERR "Failed to map IPI %d\n", i);
 			break;