[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 627ace98d4a2..1dab0ac3f797 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 000000000000..8736f2ca8a3b
--- /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 ca187b83f897..b483deed311c 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);
         }