[POWERPC] Add new interrupt mapping core and change platforms to use it

This adds the new irq remapper core and removes the old one.  Because
there are some fundamental conflicts with the old code, like the value
of NO_IRQ which I'm now setting to 0 (as per discussions with Linus),
etc..., this commit also changes the relevant platform and driver code
over to use the new remapper (so as not to cause difficulties later
in bisecting).

This patch removes the old pre-parsing of the open firmware interrupt
tree along with all the bogus assumptions it made to try to renumber
interrupts according to the platform. This is all to be handled by the
new code now.

For the pSeries XICS interrupt controller, a single remapper host is
created for the whole machine regardless of how many interrupt
presentation and source controllers are found, and it's set to match
any device node that isn't a 8259.  That works fine on pSeries and
avoids having to deal with some of the complexities of split source
controllers vs. presentation controllers in the pSeries device trees.

The powerpc i8259 PIC driver now always requests the legacy interrupt
range. It also has the feature of being able to match any device node
(including NULL) if passed no device node as an input. That will help
porting over platforms with broken device-trees like Pegasos who don't
have a proper interrupt tree.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 507 insertions, 122 deletions

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 91248559099..05a700940f6 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -29,6 +29,8 @@
  * to reduce code space and undefined function references.
  */
 
+#undef DEBUG
+
 #include <linux/module.h>
 #include <linux/threads.h>
 #include <linux/kernel_stat.h>
@@ -46,7 +48,10 @@
 #include <linux/cpumask.h>
 #include <linux/profile.h>
 #include <linux/bitops.h>
-#include <linux/pci.h>
+#include <linux/list.h>
+#include <linux/radix-tree.h>
+#include <linux/mutex.h>
+#include <linux/bootmem.h>
 
 #include <asm/uaccess.h>
 #include <asm/system.h>
@@ -57,6 +62,7 @@
 #include <asm/prom.h>
 #include <asm/ptrace.h>
 #include <asm/machdep.h>
+#include <asm/udbg.h>
 #ifdef CONFIG_PPC_ISERIES
 #include <asm/paca.h>
 #endif
@@ -88,7 +94,6 @@ extern atomic_t ipi_sent;
 EXPORT_SYMBOL(irq_desc);
 
 int distribute_irqs = 1;
-u64 ppc64_interrupt_controller;
 #endif /* CONFIG_PPC64 */
 
 int show_interrupts(struct seq_file *p, void *v)
@@ -181,7 +186,7 @@ void fixup_irqs(cpumask_t map)
 
 void do_IRQ(struct pt_regs *regs)
 {
-	int irq;
+	unsigned int irq;
 #ifdef CONFIG_IRQSTACKS
 	struct thread_info *curtp, *irqtp;
 #endif
@@ -212,7 +217,7 @@ void do_IRQ(struct pt_regs *regs)
 	 */
 	irq = ppc_md.get_irq(regs);
 
-	if (irq >= 0) {
+	if (irq != NO_IRQ && irq != NO_IRQ_IGNORE) {
 #ifdef CONFIG_IRQSTACKS
 		/* Switch to the irq stack to handle this */
 		curtp = current_thread_info();
@@ -231,7 +236,7 @@ void do_IRQ(struct pt_regs *regs)
 		} else
 #endif
 			generic_handle_irq(irq, regs);
-	} else if (irq != -2)
+	} else if (irq != NO_IRQ_IGNORE)
 		/* That's not SMP safe ... but who cares ? */
 		ppc_spurious_interrupts++;
 
@@ -254,123 +259,6 @@ void __init init_IRQ(void)
 #endif
 }
 
-#ifdef CONFIG_PPC64
-/*
- * Virtual IRQ mapping code, used on systems with XICS interrupt controllers.
- */
-
-#define UNDEFINED_IRQ 0xffffffff
-unsigned int virt_irq_to_real_map[NR_IRQS];
-
-/*
- * Don't use virtual irqs 0, 1, 2 for devices.
- * The pcnet32 driver considers interrupt numbers < 2 to be invalid,
- * and 2 is the XICS IPI interrupt.
- * We limit virtual irqs to __irq_offet_value less than virt_irq_max so
- * that when we offset them we don't end up with an interrupt
- * number >= virt_irq_max.
- */
-#define MIN_VIRT_IRQ	3
-
-unsigned int virt_irq_max;
-static unsigned int max_virt_irq;
-static unsigned int nr_virt_irqs;
-
-void
-virt_irq_init(void)
-{
-	int i;
-
-	if ((virt_irq_max == 0) || (virt_irq_max > (NR_IRQS - 1)))
-		virt_irq_max = NR_IRQS - 1;
-	max_virt_irq = virt_irq_max - __irq_offset_value;
-	nr_virt_irqs = max_virt_irq - MIN_VIRT_IRQ + 1;
-
-	for (i = 0; i < NR_IRQS; i++)
-		virt_irq_to_real_map[i] = UNDEFINED_IRQ;
-}
-
-/* Create a mapping for a real_irq if it doesn't already exist.
- * Return the virtual irq as a convenience.
- */
-int virt_irq_create_mapping(unsigned int real_irq)
-{
-	unsigned int virq, first_virq;
-	static int warned;
-
-	if (ppc64_interrupt_controller == IC_OPEN_PIC)
-		return real_irq;	/* no mapping for openpic (for now) */
-
-	if (ppc64_interrupt_controller == IC_CELL_PIC)
-		return real_irq;	/* no mapping for iic either */
-
-	/* don't map interrupts < MIN_VIRT_IRQ */
-	if (real_irq < MIN_VIRT_IRQ) {
-		virt_irq_to_real_map[real_irq] = real_irq;
-		return real_irq;
-	}
-
-	/* map to a number between MIN_VIRT_IRQ and max_virt_irq */
-	virq = real_irq;
-	if (virq > max_virt_irq)
-		virq = (virq % nr_virt_irqs) + MIN_VIRT_IRQ;
-
-	/* search for this number or a free slot */
-	first_virq = virq;
-	while (virt_irq_to_real_map[virq] != UNDEFINED_IRQ) {
-		if (virt_irq_to_real_map[virq] == real_irq)
-			return virq;
-		if (++virq > max_virt_irq)
-			virq = MIN_VIRT_IRQ;
-		if (virq == first_virq)
-			goto nospace;	/* oops, no free slots */
-	}
-
-	virt_irq_to_real_map[virq] = real_irq;
-	return virq;
-
- nospace:
-	if (!warned) {
-		printk(KERN_CRIT "Interrupt table is full\n");
-		printk(KERN_CRIT "Increase virt_irq_max (currently %d) "
-		       "in your kernel sources and rebuild.\n", virt_irq_max);
-		warned = 1;
-	}
-	return NO_IRQ;
-}
-
-/*
- * In most cases will get a hit on the very first slot checked in the
- * virt_irq_to_real_map.  Only when there are a large number of
- * IRQs will this be expensive.
- */
-unsigned int real_irq_to_virt_slowpath(unsigned int real_irq)
-{
-	unsigned int virq;
-	unsigned int first_virq;
-
-	virq = real_irq;
-
-	if (virq > max_virt_irq)
-		virq = (virq % nr_virt_irqs) + MIN_VIRT_IRQ;
-
-	first_virq = virq;
-
-	do {
-		if (virt_irq_to_real_map[virq] == real_irq)
-			return virq;
-
-		virq++;
-
-		if (virq >= max_virt_irq)
-			virq = 0;
-
-	} while (first_virq != virq);
-
-	return NO_IRQ;
-
-}
-#endif /* CONFIG_PPC64 */
 
 #ifdef CONFIG_IRQSTACKS
 struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;
@@ -430,6 +318,503 @@ void do_softirq(void)
 }
 EXPORT_SYMBOL(do_softirq);
 
+
+/*
+ * IRQ controller and virtual interrupts
+ */
+
+#ifdef CONFIG_PPC_MERGE
+
+static LIST_HEAD(irq_hosts);
+static spinlock_t irq_big_lock = SPIN_LOCK_UNLOCKED;
+
+struct irq_map_entry irq_map[NR_IRQS];
+static unsigned int irq_virq_count = NR_IRQS;
+static struct irq_host *irq_default_host;
+
+struct irq_host *irq_alloc_host(unsigned int revmap_type,
+				unsigned int revmap_arg,
+				struct irq_host_ops *ops,
+				irq_hw_number_t inval_irq)
+{
+	struct irq_host *host;
+	unsigned int size = sizeof(struct irq_host);
+	unsigned int i;
+	unsigned int *rmap;
+	unsigned long flags;
+
+	/* Allocate structure and revmap table if using linear mapping */
+	if (revmap_type == IRQ_HOST_MAP_LINEAR)
+		size += revmap_arg * sizeof(unsigned int);
+	if (mem_init_done)
+		host = kzalloc(size, GFP_KERNEL);
+	else {
+		host = alloc_bootmem(size);
+		if (host)
+			memset(host, 0, size);
+	}
+	if (host == NULL)
+		return NULL;
+
+	/* Fill structure */
+	host->revmap_type = revmap_type;
+	host->inval_irq = inval_irq;
+	host->ops = ops;
+
+	spin_lock_irqsave(&irq_big_lock, flags);
+
+	/* If it's a legacy controller, check for duplicates and
+	 * mark it as allocated (we use irq 0 host pointer for that
+	 */
+	if (revmap_type == IRQ_HOST_MAP_LEGACY) {
+		if (irq_map[0].host != NULL) {
+			spin_unlock_irqrestore(&irq_big_lock, flags);
+			/* If we are early boot, we can't free the structure,
+			 * too bad...
+			 * this will be fixed once slab is made available early
+			 * instead of the current cruft
+			 */
+			if (mem_init_done)
+				kfree(host);
+			return NULL;
+		}
+		irq_map[0].host = host;
+	}
+
+	list_add(&host->link, &irq_hosts);
+	spin_unlock_irqrestore(&irq_big_lock, flags);
+
+	/* Additional setups per revmap type */
+	switch(revmap_type) {
+	case IRQ_HOST_MAP_LEGACY:
+		/* 0 is always the invalid number for legacy */
+		host->inval_irq = 0;
+		/* setup us as the host for all legacy interrupts */
+		for (i = 1; i < NUM_ISA_INTERRUPTS; i++) {
+			irq_map[i].hwirq = 0;
+			smp_wmb();
+			irq_map[i].host = host;
+			smp_wmb();
+
+			/* Clear some flags */
+			get_irq_desc(i)->status
+				&= ~(IRQ_NOREQUEST | IRQ_LEVEL);
+
+			/* Legacy flags are left to default at this point,
+			 * one can then use irq_create_mapping() to
+			 * explicitely change them
+			 */
+			ops->map(host, i, i, 0);
+		}
+		break;
+	case IRQ_HOST_MAP_LINEAR:
+		rmap = (unsigned int *)(host + 1);
+		for (i = 0; i < revmap_arg; i++)
+			rmap[i] = IRQ_NONE;
+		host->revmap_data.linear.size = revmap_arg;
+		smp_wmb();
+		host->revmap_data.linear.revmap = rmap;
+		break;
+	default:
+		break;
+	}
+
+	pr_debug("irq: Allocated host of type %d @0x%p\n", revmap_type, host);
+
+	return host;
+}
+
+struct irq_host *irq_find_host(struct device_node *node)
+{
+	struct irq_host *h, *found = NULL;
+	unsigned long flags;
+
+	/* We might want to match the legacy controller last since
+	 * it might potentially be set to match all interrupts in
+	 * the absence of a device node. This isn't a problem so far
+	 * yet though...
+	 */
+	spin_lock_irqsave(&irq_big_lock, flags);
+	list_for_each_entry(h, &irq_hosts, link)
+		if (h->ops->match == NULL || h->ops->match(h, node)) {
+			found = h;
+			break;
+		}
+	spin_unlock_irqrestore(&irq_big_lock, flags);
+	return found;
+}
+EXPORT_SYMBOL_GPL(irq_find_host);
+
+void irq_set_default_host(struct irq_host *host)
+{
+	pr_debug("irq: Default host set to @0x%p\n", host);
+
+	irq_default_host = host;
+}
+
+void irq_set_virq_count(unsigned int count)
+{
+	pr_debug("irq: Trying to set virq count to %d\n", count);
+
+	BUG_ON(count < NUM_ISA_INTERRUPTS);
+	if (count < NR_IRQS)
+		irq_virq_count = count;
+}
+
+unsigned int irq_create_mapping(struct irq_host *host,
+				irq_hw_number_t hwirq,
+				unsigned int flags)
+{
+	unsigned int virq, hint;
+
+	pr_debug("irq: irq_create_mapping(0x%p, 0x%lx, 0x%x)\n",
+		 host, hwirq, flags);
+
+	/* Look for default host if nececssary */
+	if (host == NULL)
+		host = irq_default_host;
+	if (host == NULL) {
+		printk(KERN_WARNING "irq_create_mapping called for"
+		       " NULL host, hwirq=%lx\n", hwirq);
+		WARN_ON(1);
+		return NO_IRQ;
+	}
+	pr_debug("irq: -> using host @%p\n", host);
+
+	/* Check if mapping already exist, if it does, call
+	 * host->ops->map() to update the flags
+	 */
+	virq = irq_find_mapping(host, hwirq);
+	if (virq != IRQ_NONE) {
+		pr_debug("irq: -> existing mapping on virq %d\n", virq);
+		host->ops->map(host, virq, hwirq, flags);
+		return virq;
+	}
+
+	/* Get a virtual interrupt number */
+	if (host->revmap_type == IRQ_HOST_MAP_LEGACY) {
+		/* Handle legacy */
+		virq = (unsigned int)hwirq;
+		if (virq == 0 || virq >= NUM_ISA_INTERRUPTS)
+			return NO_IRQ;
+		return virq;
+	} else {
+		/* Allocate a virtual interrupt number */
+		hint = hwirq % irq_virq_count;
+		virq = irq_alloc_virt(host, 1, hint);
+		if (virq == NO_IRQ) {
+			pr_debug("irq: -> virq allocation failed\n");
+			return NO_IRQ;
+		}
+	}
+	pr_debug("irq: -> obtained virq %d\n", virq);
+
+	/* Clear some flags */
+	get_irq_desc(virq)->status &= ~(IRQ_NOREQUEST | IRQ_LEVEL);
+
+	/* map it */
+	if (host->ops->map(host, virq, hwirq, flags)) {
+		pr_debug("irq: -> mapping failed, freeing\n");
+		irq_free_virt(virq, 1);
+		return NO_IRQ;
+	}
+	smp_wmb();
+	irq_map[virq].hwirq = hwirq;
+	smp_mb();
+	return virq;
+}
+EXPORT_SYMBOL_GPL(irq_create_mapping);
+
+extern unsigned int irq_create_of_mapping(struct device_node *controller,
+					  u32 *intspec, unsigned int intsize)
+{
+	struct irq_host *host;
+	irq_hw_number_t hwirq;
+	unsigned int flags = IRQ_TYPE_NONE;
+
+	if (controller == NULL)
+		host = irq_default_host;
+	else
+		host = irq_find_host(controller);
+	if (host == NULL)
+		return NO_IRQ;
+
+	/* If host has no translation, then we assume interrupt line */
+	if (host->ops->xlate == NULL)
+		hwirq = intspec[0];
+	else {
+		if (host->ops->xlate(host, controller, intspec, intsize,
+				     &hwirq, &flags))
+			return NO_IRQ;
+	}
+
+	return irq_create_mapping(host, hwirq, flags);
+}
+EXPORT_SYMBOL_GPL(irq_create_of_mapping);
+
+unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
+{
+	struct of_irq oirq;
+
+	if (of_irq_map_one(dev, index, &oirq))
+		return NO_IRQ;
+
+	return irq_create_of_mapping(oirq.controller, oirq.specifier,
+				     oirq.size);
+}
+EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
+
+void irq_dispose_mapping(unsigned int virq)
+{
+	struct irq_host *host = irq_map[virq].host;
+	irq_hw_number_t hwirq;
+	unsigned long flags;
+
+	WARN_ON (host == NULL);
+	if (host == NULL)
+		return;
+
+	/* Never unmap legacy interrupts */
+	if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
+		return;
+
+	/* remove chip and handler */
+	set_irq_chip_and_handler(virq, NULL, NULL);
+
+	/* Make sure it's completed */
+	synchronize_irq(virq);
+
+	/* Tell the PIC about it */
+	if (host->ops->unmap)
+		host->ops->unmap(host, virq);
+	smp_mb();
+
+	/* Clear reverse map */
+	hwirq = irq_map[virq].hwirq;
+	switch(host->revmap_type) {
+	case IRQ_HOST_MAP_LINEAR:
+		if (hwirq < host->revmap_data.linear.size)
+			host->revmap_data.linear.revmap[hwirq] = IRQ_NONE;
+		break;
+	case IRQ_HOST_MAP_TREE:
+		/* Check if radix tree allocated yet */
+		if (host->revmap_data.tree.gfp_mask == 0)
+			break;
+		/* XXX radix tree not safe ! remove lock whem it becomes safe
+		 * and use some RCU sync to make sure everything is ok before we
+		 * can re-use that map entry
+		 */
+		spin_lock_irqsave(&irq_big_lock, flags);
+		radix_tree_delete(&host->revmap_data.tree, hwirq);
+		spin_unlock_irqrestore(&irq_big_lock, flags);
+		break;
+	}
+
+	/* Destroy map */
+	smp_mb();
+	irq_map[virq].hwirq = host->inval_irq;
+
+	/* Set some flags */
+	get_irq_desc(virq)->status |= IRQ_NOREQUEST;
+
+	/* Free it */
+	irq_free_virt(virq, 1);
+}
+EXPORT_SYMBOL_GPL(irq_dispose_mapping);
+
+unsigned int irq_find_mapping(struct irq_host *host,
+			      irq_hw_number_t hwirq)
+{
+	unsigned int i;
+	unsigned int hint = hwirq % irq_virq_count;
+
+	/* Look for default host if nececssary */
+	if (host == NULL)
+		host = irq_default_host;
+	if (host == NULL)
+		return NO_IRQ;
+
+	/* legacy -> bail early */
+	if (host->revmap_type == IRQ_HOST_MAP_LEGACY)
+		return hwirq;
+
+	/* Slow path does a linear search of the map */
+	if (hint < NUM_ISA_INTERRUPTS)
+		hint = NUM_ISA_INTERRUPTS;
+	i = hint;
+	do  {
+		if (irq_map[i].host == host &&
+		    irq_map[i].hwirq == hwirq)
+			return i;
+		i++;
+		if (i >= irq_virq_count)
+			i = NUM_ISA_INTERRUPTS;
+	} while(i != hint);
+	return NO_IRQ;
+}
+EXPORT_SYMBOL_GPL(irq_find_mapping);
+
+
+unsigned int irq_radix_revmap(struct irq_host *host,
+			      irq_hw_number_t hwirq)
+{
+	struct radix_tree_root *tree;
+	struct irq_map_entry *ptr;
+	unsigned int virq;
+	unsigned long flags;
+
+	WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE);
+
+	/* Check if the radix tree exist yet. We test the value of
+	 * the gfp_mask for that. Sneaky but saves another int in the
+	 * structure. If not, we fallback to slow mode
+	 */
+	tree = &host->revmap_data.tree;
+	if (tree->gfp_mask == 0)
+		return irq_find_mapping(host, hwirq);
+
+	/* XXX Current radix trees are NOT SMP safe !!! Remove that lock
+	 * when that is fixed (when Nick's patch gets in
+	 */
+	spin_lock_irqsave(&irq_big_lock, flags);
+
+	/* Now try to resolve */
+	ptr = radix_tree_lookup(tree, hwirq);
+	/* Found it, return */
+	if (ptr) {
+		virq = ptr - irq_map;
+		goto bail;
+	}
+
+	/* If not there, try to insert it */
+	virq = irq_find_mapping(host, hwirq);
+	if (virq != NO_IRQ)
+		radix_tree_insert(tree, virq, &irq_map[virq]);
+ bail:
+	spin_unlock_irqrestore(&irq_big_lock, flags);
+	return virq;
+}
+
+unsigned int irq_linear_revmap(struct irq_host *host,
+			       irq_hw_number_t hwirq)
+{
+	unsigned int *revmap;
+
+	WARN_ON(host->revmap_type != IRQ_HOST_MAP_LINEAR);
+
+	/* Check revmap bounds */
+	if (unlikely(hwirq >= host->revmap_data.linear.size))
+		return irq_find_mapping(host, hwirq);
+
+	/* Check if revmap was allocated */
+	revmap = host->revmap_data.linear.revmap;
+	if (unlikely(revmap == NULL))
+		return irq_find_mapping(host, hwirq);
+
+	/* Fill up revmap with slow path if no mapping found */
+	if (unlikely(revmap[hwirq] == NO_IRQ))
+		revmap[hwirq] = irq_find_mapping(host, hwirq);
+
+	return revmap[hwirq];
+}
+
+unsigned int irq_alloc_virt(struct irq_host *host,
+			    unsigned int count,
+			    unsigned int hint)
+{
+	unsigned long flags;
+	unsigned int i, j, found = NO_IRQ;
+	unsigned int limit = irq_virq_count - count;
+
+	if (count == 0 || count > (irq_virq_count - NUM_ISA_INTERRUPTS))
+		return NO_IRQ;
+
+	spin_lock_irqsave(&irq_big_lock, flags);
+
+	/* Use hint for 1 interrupt if any */
+	if (count == 1 && hint >= NUM_ISA_INTERRUPTS &&
+	    hint < irq_virq_count && irq_map[hint].host == NULL) {
+		found = hint;
+		goto hint_found;
+	}
+
+	/* Look for count consecutive numbers in the allocatable
+	 * (non-legacy) space
+	 */
+	for (i = NUM_ISA_INTERRUPTS; i <= limit; ) {
+		for (j = i; j < (i + count); j++)
+			if (irq_map[j].host != NULL) {
+				i = j + 1;
+				continue;
+			}
+		found = i;
+		break;
+	}
+	if (found == NO_IRQ) {
+		spin_unlock_irqrestore(&irq_big_lock, flags);
+		return NO_IRQ;
+	}
+ hint_found:
+	for (i = found; i < (found + count); i++) {
+		irq_map[i].hwirq = host->inval_irq;
+		smp_wmb();
+		irq_map[i].host = host;
+	}
+	spin_unlock_irqrestore(&irq_big_lock, flags);
+	return found;
+}
+
+void irq_free_virt(unsigned int virq, unsigned int count)
+{
+	unsigned long flags;
+	unsigned int i;
+
+	WARN_ON (virq < NUM_ISA_INTERRUPTS);
+	WARN_ON (count == 0 || (virq + count) > irq_virq_count);
+
+	spin_lock_irqsave(&irq_big_lock, flags);
+	for (i = virq; i < (virq + count); i++) {
+		struct irq_host *host;
+
+		if (i < NUM_ISA_INTERRUPTS ||
+		    (virq + count) > irq_virq_count)
+			continue;
+
+		host = irq_map[i].host;
+		irq_map[i].hwirq = host->inval_irq;
+		smp_wmb();
+		irq_map[i].host = NULL;
+	}
+	spin_unlock_irqrestore(&irq_big_lock, flags);
+}
+
+void irq_early_init(void)
+{
+	unsigned int i;
+
+	for (i = 0; i < NR_IRQS; i++)
+		get_irq_desc(i)->status |= IRQ_NOREQUEST;
+}
+
+/* We need to create the radix trees late */
+static int irq_late_init(void)
+{
+	struct irq_host *h;
+	unsigned long flags;
+
+	spin_lock_irqsave(&irq_big_lock, flags);
+	list_for_each_entry(h, &irq_hosts, link) {
+		if (h->revmap_type == IRQ_HOST_MAP_TREE)
+			INIT_RADIX_TREE(&h->revmap_data.tree, GFP_ATOMIC);
+	}
+	spin_unlock_irqrestore(&irq_big_lock, flags);
+
+	return 0;
+}
+arch_initcall(irq_late_init);
+
+#endif /* CONFIG_PPC_MERGE */
+
 #ifdef CONFIG_PCI_MSI
 int pci_enable_msi(struct pci_dev * pdev)
 {