C6X: interrupt handling

Original port to early 2.6 kernel using TI COFF toolchain.
Brought up to date by Mark Salter <msalter@redhat.com>

Signed-off-by: Aurelien Jacquiot <a-jacquiot@ti.com>
Signed-off-by: Mark Salter <msalter@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 728 insertions, 0 deletions

diff --git a/arch/c6x/kernel/irq.c b/arch/c6x/kernel/irq.c
new file mode 100644
index 0000000..0929e4b
--- /dev/null
+++ b/arch/c6x/kernel/irq.c
@@ -0,0 +1,728 @@
+/*
+ *  Copyright (C) 2011 Texas Instruments Incorporated
+ *
+ *  This borrows heavily from powerpc version, which is:
+ *
+ *  Derived from arch/i386/kernel/irq.c
+ *    Copyright (C) 1992 Linus Torvalds
+ *  Adapted from arch/i386 by Gary Thomas
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
+ *    Copyright (C) 1996-2001 Cort Dougan
+ *  Adapted for Power Macintosh by Paul Mackerras
+ *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/radix-tree.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_irq.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+
+#include <asm/megamod-pic.h>
+
+unsigned long irq_err_count;
+
+static DEFINE_RAW_SPINLOCK(core_irq_lock);
+
+static void mask_core_irq(struct irq_data *data)
+{
+	unsigned int prio = data->irq;
+
+	BUG_ON(prio < 4 || prio >= NR_PRIORITY_IRQS);
+
+	raw_spin_lock(&core_irq_lock);
+	and_creg(IER, ~(1 << prio));
+	raw_spin_unlock(&core_irq_lock);
+}
+
+static void unmask_core_irq(struct irq_data *data)
+{
+	unsigned int prio = data->irq;
+
+	raw_spin_lock(&core_irq_lock);
+	or_creg(IER, 1 << prio);
+	raw_spin_unlock(&core_irq_lock);
+}
+
+static struct irq_chip core_chip = {
+	.name		= "core",
+	.irq_mask	= mask_core_irq,
+	.irq_unmask	= unmask_core_irq,
+};
+
+asmlinkage void c6x_do_IRQ(unsigned int prio, struct pt_regs *regs)
+{
+	struct pt_regs *old_regs = set_irq_regs(regs);
+
+	irq_enter();
+
+	BUG_ON(prio < 4 || prio >= NR_PRIORITY_IRQS);
+
+	generic_handle_irq(prio);
+
+	irq_exit();
+
+	set_irq_regs(old_regs);
+}
+
+static struct irq_host *core_host;
+
+static int core_host_map(struct irq_host *h, unsigned int virq,
+			 irq_hw_number_t hw)
+{
+	if (hw < 4 || hw >= NR_PRIORITY_IRQS)
+		return -EINVAL;
+
+	irq_set_status_flags(virq, IRQ_LEVEL);
+	irq_set_chip_and_handler(virq, &core_chip, handle_level_irq);
+	return 0;
+}
+
+static struct irq_host_ops core_host_ops = {
+	.map = core_host_map,
+};
+
+void __init init_IRQ(void)
+{
+	struct device_node *np;
+
+	/* Mask all priority IRQs */
+	and_creg(IER, ~0xfff0);
+
+	np = of_find_compatible_node(NULL, NULL, "ti,c64x+core-pic");
+	if (np != NULL) {
+		/* create the core host */
+		core_host = irq_alloc_host(np, IRQ_HOST_MAP_PRIORITY, 0,
+					   &core_host_ops, 0);
+		if (core_host)
+			irq_set_default_host(core_host);
+		of_node_put(np);
+	}
+
+	printk(KERN_INFO "Core interrupt controller initialized\n");
+
+	/* now we're ready for other SoC controllers */
+	megamod_pic_init();
+
+	/* Clear all general IRQ flags */
+	set_creg(ICR, 0xfff0);
+}
+
+void ack_bad_irq(int irq)
+{
+	printk(KERN_ERR "IRQ: spurious interrupt %d\n", irq);
+	irq_err_count++;
+}
+
+int arch_show_interrupts(struct seq_file *p, int prec)
+{
+	seq_printf(p, "%*s: %10lu\n", prec, "Err", irq_err_count);
+	return 0;
+}
+
+/*
+ * IRQ controller and virtual interrupts
+ */
+
+/* The main irq map itself is an array of NR_IRQ entries containing the
+ * associate host and irq number. An entry with a host of NULL is free.
+ * An entry can be allocated if it's free, the allocator always then sets
+ * hwirq first to the host's invalid irq number and then fills ops.
+ */
+struct irq_map_entry {
+	irq_hw_number_t	hwirq;
+	struct irq_host	*host;
+};
+
+static LIST_HEAD(irq_hosts);
+static DEFINE_RAW_SPINLOCK(irq_big_lock);
+static DEFINE_MUTEX(revmap_trees_mutex);
+static struct irq_map_entry irq_map[NR_IRQS];
+static unsigned int irq_virq_count = NR_IRQS;
+static struct irq_host *irq_default_host;
+
+irq_hw_number_t irqd_to_hwirq(struct irq_data *d)
+{
+	return irq_map[d->irq].hwirq;
+}
+EXPORT_SYMBOL_GPL(irqd_to_hwirq);
+
+irq_hw_number_t virq_to_hw(unsigned int virq)
+{
+	return irq_map[virq].hwirq;
+}
+EXPORT_SYMBOL_GPL(virq_to_hw);
+
+bool virq_is_host(unsigned int virq, struct irq_host *host)
+{
+	return irq_map[virq].host == host;
+}
+EXPORT_SYMBOL_GPL(virq_is_host);
+
+static int default_irq_host_match(struct irq_host *h, struct device_node *np)
+{
+	return h->of_node != NULL && h->of_node == np;
+}
+
+struct irq_host *irq_alloc_host(struct device_node *of_node,
+				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);
+	host = kzalloc(size, GFP_KERNEL);
+	if (host == NULL)
+		return NULL;
+
+	/* Fill structure */
+	host->revmap_type = revmap_type;
+	host->inval_irq = inval_irq;
+	host->ops = ops;
+	host->of_node = of_node_get(of_node);
+
+	if (host->ops->match == NULL)
+		host->ops->match = default_irq_host_match;
+
+	raw_spin_lock_irqsave(&irq_big_lock, flags);
+
+	/* Check for the priority controller. */
+	if (revmap_type == IRQ_HOST_MAP_PRIORITY) {
+		if (irq_map[0].host != NULL) {
+			raw_spin_unlock_irqrestore(&irq_big_lock, flags);
+			of_node_put(host->of_node);
+			kfree(host);
+			return NULL;
+		}
+		irq_map[0].host = host;
+	}
+
+	list_add(&host->link, &irq_hosts);
+	raw_spin_unlock_irqrestore(&irq_big_lock, flags);
+
+	/* Additional setups per revmap type */
+	switch (revmap_type) {
+	case IRQ_HOST_MAP_PRIORITY:
+		/* 0 is always the invalid number for priority */
+		host->inval_irq = 0;
+		/* setup us as the host for all priority interrupts */
+		for (i = 1; i < NR_PRIORITY_IRQS; i++) {
+			irq_map[i].hwirq = i;
+			smp_wmb();
+			irq_map[i].host = host;
+			smp_wmb();
+
+			ops->map(host, i, i);
+		}
+		break;
+	case IRQ_HOST_MAP_LINEAR:
+		rmap = (unsigned int *)(host + 1);
+		for (i = 0; i < revmap_arg; i++)
+			rmap[i] = NO_IRQ;
+		host->revmap_data.linear.size = revmap_arg;
+		smp_wmb();
+		host->revmap_data.linear.revmap = rmap;
+		break;
+	case IRQ_HOST_MAP_TREE:
+		INIT_RADIX_TREE(&host->revmap_data.tree, GFP_KERNEL);
+		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...
+	 */
+	raw_spin_lock_irqsave(&irq_big_lock, flags);
+	list_for_each_entry(h, &irq_hosts, link)
+		if (h->ops->match(h, node)) {
+			found = h;
+			break;
+		}
+	raw_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 < NR_PRIORITY_IRQS);
+	if (count < NR_IRQS)
+		irq_virq_count = count;
+}
+
+static int irq_setup_virq(struct irq_host *host, unsigned int virq,
+			    irq_hw_number_t hwirq)
+{
+	int res;
+
+	res = irq_alloc_desc_at(virq, 0);
+	if (res != virq) {
+		pr_debug("irq: -> allocating desc failed\n");
+		goto error;
+	}
+
+	/* map it */
+	smp_wmb();
+	irq_map[virq].hwirq = hwirq;
+	smp_mb();
+
+	if (host->ops->map(host, virq, hwirq)) {
+		pr_debug("irq: -> mapping failed, freeing\n");
+		goto errdesc;
+	}
+
+	irq_clear_status_flags(virq, IRQ_NOREQUEST);
+
+	return 0;
+
+errdesc:
+	irq_free_descs(virq, 1);
+error:
+	irq_free_virt(virq, 1);
+	return -1;
+}
+
+unsigned int irq_create_direct_mapping(struct irq_host *host)
+{
+	unsigned int virq;
+
+	if (host == NULL)
+		host = irq_default_host;
+
+	BUG_ON(host == NULL);
+	WARN_ON(host->revmap_type != IRQ_HOST_MAP_NOMAP);
+
+	virq = irq_alloc_virt(host, 1, 0);
+	if (virq == NO_IRQ) {
+		pr_debug("irq: create_direct virq allocation failed\n");
+		return NO_IRQ;
+	}
+
+	pr_debug("irq: create_direct obtained virq %d\n", virq);
+
+	if (irq_setup_virq(host, virq, virq))
+		return NO_IRQ;
+
+	return virq;
+}
+
+unsigned int irq_create_mapping(struct irq_host *host,
+				irq_hw_number_t hwirq)
+{
+	unsigned int virq, hint;
+
+	pr_debug("irq: irq_create_mapping(0x%p, 0x%lx)\n", host, hwirq);
+
+	/* 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 exists */
+	virq = irq_find_mapping(host, hwirq);
+	if (virq != NO_IRQ) {
+		pr_debug("irq: -> existing mapping on virq %d\n", virq);
+		return virq;
+	}
+
+	/* 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;
+	}
+
+	if (irq_setup_virq(host, virq, hwirq))
+		return NO_IRQ;
+
+	pr_debug("irq: irq %lu on host %s mapped to virtual irq %u\n",
+		hwirq, host->of_node ? host->of_node->full_name : "null", virq);
+
+	return virq;
+}
+EXPORT_SYMBOL_GPL(irq_create_mapping);
+
+unsigned int irq_create_of_mapping(struct device_node *controller,
+				   const u32 *intspec, unsigned int intsize)
+{
+	struct irq_host *host;
+	irq_hw_number_t hwirq;
+	unsigned int type = IRQ_TYPE_NONE;
+	unsigned int virq;
+
+	if (controller == NULL)
+		host = irq_default_host;
+	else
+		host = irq_find_host(controller);
+	if (host == NULL) {
+		printk(KERN_WARNING "irq: no irq host found for %s !\n",
+		       controller->full_name);
+		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, &type))
+			return NO_IRQ;
+	}
+
+	/* Create mapping */
+	virq = irq_create_mapping(host, hwirq);
+	if (virq == NO_IRQ)
+		return virq;
+
+	/* Set type if specified and different than the current one */
+	if (type != IRQ_TYPE_NONE &&
+	    type != (irqd_get_trigger_type(irq_get_irq_data(virq))))
+		irq_set_irq_type(virq, type);
+	return virq;
+}
+EXPORT_SYMBOL_GPL(irq_create_of_mapping);
+
+void irq_dispose_mapping(unsigned int virq)
+{
+	struct irq_host *host;
+	irq_hw_number_t hwirq;
+
+	if (virq == NO_IRQ)
+		return;
+
+	/* Never unmap priority interrupts */
+	if (virq < NR_PRIORITY_IRQS)
+		return;
+
+	host = irq_map[virq].host;
+	if (WARN_ON(host == NULL))
+		return;
+
+	irq_set_status_flags(virq, IRQ_NOREQUEST);
+
+	/* remove chip and handler */
+	irq_set_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] = NO_IRQ;
+		break;
+	case IRQ_HOST_MAP_TREE:
+		mutex_lock(&revmap_trees_mutex);
+		radix_tree_delete(&host->revmap_data.tree, hwirq);
+		mutex_unlock(&revmap_trees_mutex);
+		break;
+	}
+
+	/* Destroy map */
+	smp_mb();
+	irq_map[virq].hwirq = host->inval_irq;
+
+	irq_free_descs(virq, 1);
+	/* 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;
+
+	/* Slow path does a linear search of the map */
+	i = hint;
+	do  {
+		if (irq_map[i].host == host &&
+		    irq_map[i].hwirq == hwirq)
+			return i;
+		i++;
+		if (i >= irq_virq_count)
+			i = 4;
+	} while (i != hint);
+	return NO_IRQ;
+}
+EXPORT_SYMBOL_GPL(irq_find_mapping);
+
+unsigned int irq_radix_revmap_lookup(struct irq_host *host,
+				     irq_hw_number_t hwirq)
+{
+	struct irq_map_entry *ptr;
+	unsigned int virq;
+
+	if (WARN_ON_ONCE(host->revmap_type != IRQ_HOST_MAP_TREE))
+		return irq_find_mapping(host, hwirq);
+
+	/*
+	 * The ptr returned references the static global irq_map.
+	 * but freeing an irq can delete nodes along the path to
+	 * do the lookup via call_rcu.
+	 */
+	rcu_read_lock();
+	ptr = radix_tree_lookup(&host->revmap_data.tree, hwirq);
+	rcu_read_unlock();
+
+	/*
+	 * If found in radix tree, then fine.
+	 * Else fallback to linear lookup - this should not happen in practice
+	 * as it means that we failed to insert the node in the radix tree.
+	 */
+	if (ptr)
+		virq = ptr - irq_map;
+	else
+		virq = irq_find_mapping(host, hwirq);
+
+	return virq;
+}
+
+void irq_radix_revmap_insert(struct irq_host *host, unsigned int virq,
+			     irq_hw_number_t hwirq)
+{
+	if (WARN_ON(host->revmap_type != IRQ_HOST_MAP_TREE))
+		return;
+
+	if (virq != NO_IRQ) {
+		mutex_lock(&revmap_trees_mutex);
+		radix_tree_insert(&host->revmap_data.tree, hwirq,
+				  &irq_map[virq]);
+		mutex_unlock(&revmap_trees_mutex);
+	}
+}
+
+unsigned int irq_linear_revmap(struct irq_host *host,
+			       irq_hw_number_t hwirq)
+{
+	unsigned int *revmap;
+
+	if (WARN_ON_ONCE(host->revmap_type != IRQ_HOST_MAP_LINEAR))
+		return irq_find_mapping(host, hwirq);
+
+	/* 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;
+
+	if (count == 0 || count > (irq_virq_count - NR_PRIORITY_IRQS))
+		return NO_IRQ;
+
+	raw_spin_lock_irqsave(&irq_big_lock, flags);
+
+	/* Use hint for 1 interrupt if any */
+	if (count == 1 && hint >= NR_PRIORITY_IRQS &&
+	    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 = NR_PRIORITY_IRQS, j = 0; i < irq_virq_count; i++) {
+		if (irq_map[i].host != NULL)
+			j = 0;
+		else
+			j++;
+
+		if (j == count) {
+			found = i - count + 1;
+			break;
+		}
+	}
+	if (found == NO_IRQ) {
+		raw_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;
+	}
+	raw_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 < NR_PRIORITY_IRQS);
+	WARN_ON(count == 0 || (virq + count) > irq_virq_count);
+
+	if (virq < NR_PRIORITY_IRQS) {
+		if (virq + count < NR_PRIORITY_IRQS)
+			return;
+		count  -= NR_PRIORITY_IRQS - virq;
+		virq = NR_PRIORITY_IRQS;
+	}
+
+	if (count > irq_virq_count || virq > irq_virq_count - count) {
+		if (virq > irq_virq_count)
+			return;
+		count = irq_virq_count - virq;
+	}
+
+	raw_spin_lock_irqsave(&irq_big_lock, flags);
+	for (i = virq; i < (virq + count); i++) {
+		struct irq_host *host;
+
+		host = irq_map[i].host;
+		irq_map[i].hwirq = host->inval_irq;
+		smp_wmb();
+		irq_map[i].host = NULL;
+	}
+	raw_spin_unlock_irqrestore(&irq_big_lock, flags);
+}
+
+#ifdef CONFIG_VIRQ_DEBUG
+static int virq_debug_show(struct seq_file *m, void *private)
+{
+	unsigned long flags;
+	struct irq_desc *desc;
+	const char *p;
+	static const char none[] = "none";
+	void *data;
+	int i;
+
+	seq_printf(m, "%-5s  %-7s  %-15s  %-18s  %s\n", "virq", "hwirq",
+		      "chip name", "chip data", "host name");
+
+	for (i = 1; i < nr_irqs; i++) {
+		desc = irq_to_desc(i);
+		if (!desc)
+			continue;
+
+		raw_spin_lock_irqsave(&desc->lock, flags);
+
+		if (desc->action && desc->action->handler) {
+			struct irq_chip *chip;
+
+			seq_printf(m, "%5d  ", i);
+			seq_printf(m, "0x%05lx  ", irq_map[i].hwirq);
+
+			chip = irq_desc_get_chip(desc);
+			if (chip && chip->name)
+				p = chip->name;
+			else
+				p = none;
+			seq_printf(m, "%-15s  ", p);
+
+			data = irq_desc_get_chip_data(desc);
+			seq_printf(m, "0x%16p  ", data);
+
+			if (irq_map[i].host && irq_map[i].host->of_node)
+				p = irq_map[i].host->of_node->full_name;
+			else
+				p = none;
+			seq_printf(m, "%s\n", p);
+		}
+
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+	}
+
+	return 0;
+}
+
+static int virq_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, virq_debug_show, inode->i_private);
+}
+
+static const struct file_operations virq_debug_fops = {
+	.open = virq_debug_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int __init irq_debugfs_init(void)
+{
+	if (debugfs_create_file("virq_mapping", S_IRUGO, powerpc_debugfs_root,
+				 NULL, &virq_debug_fops) == NULL)
+		return -ENOMEM;
+
+	return 0;
+}
+device_initcall(irq_debugfs_init);
+#endif /* CONFIG_VIRQ_DEBUG */