[PATCH] genirq: add irq-chip support

Enable platforms to use the irq-chip and irq-flow abstractions: allow setting
of the chip, the type and provide highlevel handlers for common irq-flows.

[rostedt@goodmis.org: misroute-irq: Don't call desc->chip->end because of edge interrupts]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 527 insertions, 2 deletions

diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index 627ace9..1dab0ac 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -1,5 +1,5 @@
 
-obj-y := handle.o manage.o spurious.o resend.o
+obj-y := handle.o manage.o spurious.o resend.o chip.o
 obj-$(CONFIG_GENERIC_IRQ_PROBE) += autoprobe.o
 obj-$(CONFIG_PROC_FS) += proc.o
 obj-$(CONFIG_GENERIC_PENDING_IRQ) += migration.o
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
new file mode 100644
index 0000000..8736f2c
--- /dev/null
+++ b/kernel/irq/chip.c
@@ -0,0 +1,525 @@
+/*
+ * linux/kernel/irq/chip.c
+ *
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
+ *
+ * This file contains the core interrupt handling code, for irq-chip
+ * based architectures.
+ *
+ * Detailed information is available in Documentation/DocBook/genericirq
+ */
+
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+
+#include "internals.h"
+
+/**
+ *	set_irq_chip - set the irq chip for an irq
+ *	@irq:	irq number
+ *	@chip:	pointer to irq chip description structure
+ */
+int set_irq_chip(unsigned int irq, struct irq_chip *chip)
+{
+	struct irq_desc *desc;
+	unsigned long flags;
+
+	if (irq >= NR_IRQS) {
+		printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
+	if (!chip)
+		chip = &no_irq_chip;
+
+	desc = irq_desc + irq;
+	spin_lock_irqsave(&desc->lock, flags);
+	irq_chip_set_defaults(chip);
+	desc->chip = chip;
+	/*
+	 * For compatibility only:
+	 */
+	desc->chip = chip;
+	spin_unlock_irqrestore(&desc->lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL(set_irq_chip);
+
+/**
+ *	set_irq_type - set the irq type for an irq
+ *	@irq:	irq number
+ *	@type:	interrupt type - see include/linux/interrupt.h
+ */
+int set_irq_type(unsigned int irq, unsigned int type)
+{
+	struct irq_desc *desc;
+	unsigned long flags;
+	int ret = -ENXIO;
+
+	if (irq >= NR_IRQS) {
+		printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
+		return -ENODEV;
+	}
+
+	desc = irq_desc + irq;
+	if (desc->chip->set_type) {
+		spin_lock_irqsave(&desc->lock, flags);
+		ret = desc->chip->set_type(irq, type);
+		spin_unlock_irqrestore(&desc->lock, flags);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(set_irq_type);
+
+/**
+ *	set_irq_data - set irq type data for an irq
+ *	@irq:	Interrupt number
+ *	@data:	Pointer to interrupt specific data
+ *
+ *	Set the hardware irq controller data for an irq
+ */
+int set_irq_data(unsigned int irq, void *data)
+{
+	struct irq_desc *desc;
+	unsigned long flags;
+
+	if (irq >= NR_IRQS) {
+		printk(KERN_ERR
+		       "Trying to install controller data for IRQ%d\n", irq);
+		return -EINVAL;
+	}
+
+	desc = irq_desc + irq;
+	spin_lock_irqsave(&desc->lock, flags);
+	desc->handler_data = data;
+	spin_unlock_irqrestore(&desc->lock, flags);
+	return 0;
+}
+EXPORT_SYMBOL(set_irq_data);
+
+/**
+ *	set_irq_chip_data - set irq chip data for an irq
+ *	@irq:	Interrupt number
+ *	@data:	Pointer to chip specific data
+ *
+ *	Set the hardware irq chip data for an irq
+ */
+int set_irq_chip_data(unsigned int irq, void *data)
+{
+	struct irq_desc *desc = irq_desc + irq;
+	unsigned long flags;
+
+	if (irq >= NR_IRQS || !desc->chip) {
+		printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
+		return -EINVAL;
+	}
+
+	spin_lock_irqsave(&desc->lock, flags);
+	desc->chip_data = data;
+	spin_unlock_irqrestore(&desc->lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL(set_irq_chip_data);
+
+/*
+ * default enable function
+ */
+static void default_enable(unsigned int irq)
+{
+	struct irq_desc *desc = irq_desc + irq;
+
+	desc->chip->unmask(irq);
+	desc->status &= ~IRQ_MASKED;
+}
+
+/*
+ * default disable function
+ */
+static void default_disable(unsigned int irq)
+{
+	struct irq_desc *desc = irq_desc + irq;
+
+	if (!(desc->status & IRQ_DELAYED_DISABLE))
+		irq_desc[irq].chip->mask(irq);
+}
+
+/*
+ * default startup function
+ */
+static unsigned int default_startup(unsigned int irq)
+{
+	irq_desc[irq].chip->enable(irq);
+
+	return 0;
+}
+
+/*
+ * Fixup enable/disable function pointers
+ */
+void irq_chip_set_defaults(struct irq_chip *chip)
+{
+	if (!chip->enable)
+		chip->enable = default_enable;
+	if (!chip->disable)
+		chip->disable = default_disable;
+	if (!chip->startup)
+		chip->startup = default_startup;
+	if (!chip->shutdown)
+		chip->shutdown = chip->disable;
+	if (!chip->name)
+		chip->name = chip->typename;
+}
+
+static inline void mask_ack_irq(struct irq_desc *desc, int irq)
+{
+	if (desc->chip->mask_ack)
+		desc->chip->mask_ack(irq);
+	else {
+		desc->chip->mask(irq);
+		desc->chip->ack(irq);
+	}
+}
+
+/**
+ *	handle_simple_irq - Simple and software-decoded IRQs.
+ *	@irq:	the interrupt number
+ *	@desc:	the interrupt description structure for this irq
+ *	@regs:	pointer to a register structure
+ *
+ *	Simple interrupts are either sent from a demultiplexing interrupt
+ *	handler or come from hardware, where no interrupt hardware control
+ *	is necessary.
+ *
+ *	Note: The caller is expected to handle the ack, clear, mask and
+ *	unmask issues if necessary.
+ */
+void fastcall
+handle_simple_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
+{
+	struct irqaction *action;
+	irqreturn_t action_ret;
+	const unsigned int cpu = smp_processor_id();
+
+	spin_lock(&desc->lock);
+
+	if (unlikely(desc->status & IRQ_INPROGRESS))
+		goto out_unlock;
+	desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
+	kstat_cpu(cpu).irqs[irq]++;
+
+	action = desc->action;
+	if (unlikely(!action || (desc->status & IRQ_DISABLED)))
+		goto out_unlock;
+
+	desc->status |= IRQ_INPROGRESS;
+	spin_unlock(&desc->lock);
+
+	action_ret = handle_IRQ_event(irq, regs, action);
+	if (!noirqdebug)
+		note_interrupt(irq, desc, action_ret, regs);
+
+	spin_lock(&desc->lock);
+	desc->status &= ~IRQ_INPROGRESS;
+out_unlock:
+	spin_unlock(&desc->lock);
+}
+
+/**
+ *	handle_level_irq - Level type irq handler
+ *	@irq:	the interrupt number
+ *	@desc:	the interrupt description structure for this irq
+ *	@regs:	pointer to a register structure
+ *
+ *	Level type interrupts are active as long as the hardware line has
+ *	the active level. This may require to mask the interrupt and unmask
+ *	it after the associated handler has acknowledged the device, so the
+ *	interrupt line is back to inactive.
+ */
+void fastcall
+handle_level_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
+{
+	unsigned int cpu = smp_processor_id();
+	struct irqaction *action;
+	irqreturn_t action_ret;
+
+	spin_lock(&desc->lock);
+	mask_ack_irq(desc, irq);
+
+	if (unlikely(desc->status & IRQ_INPROGRESS))
+		goto out;
+	desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
+	kstat_cpu(cpu).irqs[irq]++;
+
+	/*
+	 * If its disabled or no action available
+	 * keep it masked and get out of here
+	 */
+	action = desc->action;
+	if (unlikely(!action || (desc->status & IRQ_DISABLED)))
+		goto out;
+
+	desc->status |= IRQ_INPROGRESS;
+	spin_unlock(&desc->lock);
+
+	action_ret = handle_IRQ_event(irq, regs, action);
+	if (!noirqdebug)
+		note_interrupt(irq, desc, action_ret, regs);
+
+	spin_lock(&desc->lock);
+	desc->status &= ~IRQ_INPROGRESS;
+out:
+	if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
+		desc->chip->unmask(irq);
+	spin_unlock(&desc->lock);
+}
+
+/**
+ *	handle_fastack_irq - irq handler for transparent controllers
+ *	@irq:	the interrupt number
+ *	@desc:	the interrupt description structure for this irq
+ *	@regs:	pointer to a register structure
+ *
+ *	Only a single callback will be issued to the chip: an ->ack()
+ *	call when the interrupt has been serviced. This enables support
+ *	for modern forms of interrupt handlers, which handle the flow
+ *	details in hardware, transparently.
+ */
+void fastcall
+handle_fastack_irq(unsigned int irq, struct irq_desc *desc,
+		   struct pt_regs *regs)
+{
+	unsigned int cpu = smp_processor_id();
+	struct irqaction *action;
+	irqreturn_t action_ret;
+
+	spin_lock(&desc->lock);
+
+	if (unlikely(desc->status & IRQ_INPROGRESS))
+		goto out;
+
+	desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
+	kstat_cpu(cpu).irqs[irq]++;
+
+	/*
+	 * If its disabled or no action available
+	 * keep it masked and get out of here
+	 */
+	action = desc->action;
+	if (unlikely(!action || (desc->status & IRQ_DISABLED)))
+		goto out;
+
+	desc->status |= IRQ_INPROGRESS;
+	spin_unlock(&desc->lock);
+
+	action_ret = handle_IRQ_event(irq, regs, action);
+	if (!noirqdebug)
+		note_interrupt(irq, desc, action_ret, regs);
+
+	spin_lock(&desc->lock);
+	desc->status &= ~IRQ_INPROGRESS;
+out:
+	if (!(desc->status & IRQ_DISABLED))
+		desc->chip->ack(irq);
+	else
+		desc->chip->mask(irq);
+
+	spin_unlock(&desc->lock);
+}
+
+/**
+ *	handle_edge_irq - edge type IRQ handler
+ *	@irq:	the interrupt number
+ *	@desc:	the interrupt description structure for this irq
+ *	@regs:	pointer to a register structure
+ *
+ *	Interrupt occures on the falling and/or rising edge of a hardware
+ *	signal. The occurence is latched into the irq controller hardware
+ *	and must be acked in order to be reenabled. After the ack another
+ *	interrupt can happen on the same source even before the first one
+ *	is handled by the assosiacted event handler. If this happens it
+ *	might be necessary to disable (mask) the interrupt depending on the
+ *	controller hardware. This requires to reenable the interrupt inside
+ *	of the loop which handles the interrupts which have arrived while
+ *	the handler was running. If all pending interrupts are handled, the
+ *	loop is left.
+ */
+void fastcall
+handle_edge_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
+{
+	const unsigned int cpu = smp_processor_id();
+
+	spin_lock(&desc->lock);
+
+	desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
+
+	/*
+	 * If we're currently running this IRQ, or its disabled,
+	 * we shouldn't process the IRQ. Mark it pending, handle
+	 * the necessary masking and go out
+	 */
+	if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
+		    !desc->action)) {
+		desc->status |= (IRQ_PENDING | IRQ_MASKED);
+		mask_ack_irq(desc, irq);
+		goto out_unlock;
+	}
+
+	kstat_cpu(cpu).irqs[irq]++;
+
+	/* Start handling the irq */
+	desc->chip->ack(irq);
+
+	/* Mark the IRQ currently in progress.*/
+	desc->status |= IRQ_INPROGRESS;
+
+	do {
+		struct irqaction *action = desc->action;
+		irqreturn_t action_ret;
+
+		if (unlikely(!action)) {
+			desc->chip->mask(irq);
+			goto out_unlock;
+		}
+
+		/*
+		 * When another irq arrived while we were handling
+		 * one, we could have masked the irq.
+		 * Renable it, if it was not disabled in meantime.
+		 */
+		if (unlikely((desc->status &
+			       (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
+			      (IRQ_PENDING | IRQ_MASKED))) {
+			desc->chip->unmask(irq);
+			desc->status &= ~IRQ_MASKED;
+		}
+
+		desc->status &= ~IRQ_PENDING;
+		spin_unlock(&desc->lock);
+		action_ret = handle_IRQ_event(irq, regs, action);
+		if (!noirqdebug)
+			note_interrupt(irq, desc, action_ret, regs);
+		spin_lock(&desc->lock);
+
+	} while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
+
+	desc->status &= ~IRQ_INPROGRESS;
+out_unlock:
+	spin_unlock(&desc->lock);
+}
+
+#ifdef CONFIG_SMP
+/**
+ *	handle_percpu_IRQ - Per CPU local irq handler
+ *	@irq:	the interrupt number
+ *	@desc:	the interrupt description structure for this irq
+ *	@regs:	pointer to a register structure
+ *
+ *	Per CPU interrupts on SMP machines without locking requirements
+ */
+void fastcall
+handle_percpu_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
+{
+	irqreturn_t action_ret;
+
+	kstat_this_cpu.irqs[irq]++;
+
+	if (desc->chip->ack)
+		desc->chip->ack(irq);
+
+	action_ret = handle_IRQ_event(irq, regs, desc->action);
+	if (!noirqdebug)
+		note_interrupt(irq, desc, action_ret, regs);
+
+	if (desc->chip->eoi)
+		desc->chip->eoi(irq);
+}
+
+#endif /* CONFIG_SMP */
+
+void
+__set_irq_handler(unsigned int irq,
+		  void fastcall (*handle)(unsigned int, irq_desc_t *,
+					  struct pt_regs *),
+		  int is_chained)
+{
+	struct irq_desc *desc;
+	unsigned long flags;
+
+	if (irq >= NR_IRQS) {
+		printk(KERN_ERR
+		       "Trying to install type control for IRQ%d\n", irq);
+		return;
+	}
+
+	desc = irq_desc + irq;
+
+	if (!handle)
+		handle = handle_bad_irq;
+
+	if (is_chained && desc->chip == &no_irq_chip)
+		printk(KERN_WARNING "Trying to install "
+		       "chained interrupt type for IRQ%d\n", irq);
+
+	spin_lock_irqsave(&desc->lock, flags);
+
+	/* Uninstall? */
+	if (handle == handle_bad_irq) {
+		if (desc->chip != &no_irq_chip) {
+			desc->chip->mask(irq);
+			desc->chip->ack(irq);
+		}
+		desc->status |= IRQ_DISABLED;
+		desc->depth = 1;
+	}
+	desc->handle_irq = handle;
+
+	if (handle != handle_bad_irq && is_chained) {
+		desc->status &= ~IRQ_DISABLED;
+		desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
+		desc->depth = 0;
+		desc->chip->unmask(irq);
+	}
+	spin_unlock_irqrestore(&desc->lock, flags);
+}
+
+void
+set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
+			 void fastcall (*handle)(unsigned int,
+						 struct irq_desc *,
+						 struct pt_regs *))
+{
+	set_irq_chip(irq, chip);
+	__set_irq_handler(irq, handle, 0);
+}
+
+/*
+ * Get a descriptive string for the highlevel handler, for
+ * /proc/interrupts output:
+ */
+const char *
+handle_irq_name(void fastcall (*handle)(unsigned int, struct irq_desc *,
+					struct pt_regs *))
+{
+	if (handle == handle_level_irq)
+		return "level ";
+	if (handle == handle_fastack_irq)
+		return "level ";
+	if (handle == handle_edge_irq)
+		return "edge  ";
+	if (handle == handle_simple_irq)
+		return "simple";
+#ifdef CONFIG_SMP
+	if (handle == handle_percpu_irq)
+		return "percpu";
+#endif
+	if (handle == handle_bad_irq)
+		return "bad   ";
+
+	return NULL;
+}
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
index ca187b8..b483dee 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -79,7 +79,7 @@ static int misrouted_irq(int irq, struct pt_regs *regs)
 		 * If we did actual work for the real IRQ line we must let the
 		 * IRQ controller clean up too
 		 */
-		if (work)
+		if (work && desc->chip && desc->chip->end)
 			desc->chip->end(i);
 		spin_unlock(&desc->lock);
 	}