genirq: Implement a generic interrupt chip

Implement a generic interrupt chip, which is configurable and is able
to handle the most common irq chip implementations.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Tested-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by; Kevin Hilman <khilman@ti.com>

2 files changed, 262 insertions, 0 deletions

diff --git a/kernel/irq/Makefile b/kernel/irq/Makefile
index 54329cd..e7a13bd 100644
--- a/kernel/irq/Makefile
+++ b/kernel/irq/Makefile
@@ -1,5 +1,6 @@
 
 obj-y := irqdesc.o handle.o manage.o spurious.o resend.o chip.o dummychip.o devres.o
+obj-y += generic-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/generic-chip.c b/kernel/irq/generic-chip.c
new file mode 100644
index 0000000..eb23e59
--- /dev/null
+++ b/kernel/irq/generic-chip.c
@@ -0,0 +1,261 @@
+/*
+ * Library implementing the most common irq chip callback functions
+ *
+ * Copyright (C) 2011, Thomas Gleixner
+ */
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/kernel_stat.h>
+
+#include "internals.h"
+
+static inline struct irq_chip_regs *cur_regs(struct irq_data *d)
+{
+	return &container_of(d->chip, struct irq_chip_type, chip)->regs;
+}
+
+/**
+ * irq_gc_noop - NOOP function
+ * @d: irq_data
+ */
+void irq_gc_noop(struct irq_data *d)
+{
+}
+
+/**
+ * irq_gc_mask_disable_reg - Mask chip via disable register
+ * @d: irq_data
+ *
+ * Chip has separate enable/disable registers instead of a single mask
+ * register.
+ */
+void irq_gc_mask_disable_reg(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = 1 << (d->irq - gc->irq_base);
+
+	irq_gc_lock(gc);
+	irq_reg_writel(mask, gc->reg_base + cur_regs(d)->disable);
+	gc->mask_cache &= ~mask;
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_mask_set_mask_bit - Mask chip via setting bit in mask register
+ * @d: irq_data
+ *
+ * Chip has a single mask register. Values of this register are cached
+ * and protected by gc->lock
+ */
+void irq_gc_mask_set_bit(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = 1 << (d->irq - gc->irq_base);
+
+	irq_gc_lock(gc);
+	gc->mask_cache |= mask;
+	irq_reg_writel(gc->mask_cache, gc->reg_base + cur_regs(d)->mask);
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_mask_set_mask_bit - Mask chip via clearing bit in mask register
+ * @d: irq_data
+ *
+ * Chip has a single mask register. Values of this register are cached
+ * and protected by gc->lock
+ */
+void irq_gc_mask_clr_bit(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = 1 << (d->irq - gc->irq_base);
+
+	irq_gc_lock(gc);
+	gc->mask_cache &= ~mask;
+	irq_reg_writel(gc->mask_cache, gc->reg_base + cur_regs(d)->mask);
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_unmask_enable_reg - Unmask chip via enable register
+ * @d: irq_data
+ *
+ * Chip has separate enable/disable registers instead of a single mask
+ * register.
+ */
+void irq_gc_unmask_enable_reg(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = 1 << (d->irq - gc->irq_base);
+
+	irq_gc_lock(gc);
+	irq_reg_writel(mask, gc->reg_base + cur_regs(d)->enable);
+	gc->mask_cache |= mask;
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_ack - Ack pending interrupt
+ * @d: irq_data
+ */
+void irq_gc_ack(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = 1 << (d->irq - gc->irq_base);
+
+	irq_gc_lock(gc);
+	irq_reg_writel(mask, gc->reg_base + cur_regs(d)->ack);
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_mask_disable_reg_and_ack- Mask and ack pending interrupt
+ * @d: irq_data
+ */
+void irq_gc_mask_disable_reg_and_ack(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = 1 << (d->irq - gc->irq_base);
+
+	irq_gc_lock(gc);
+	irq_reg_writel(mask, gc->reg_base + cur_regs(d)->mask);
+	irq_reg_writel(mask, gc->reg_base + cur_regs(d)->ack);
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_eoi - EOI interrupt
+ * @d: irq_data
+ */
+void irq_gc_eoi(struct irq_data *d)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = 1 << (d->irq - gc->irq_base);
+
+	irq_gc_lock(gc);
+	irq_reg_writel(mask, gc->reg_base + cur_regs(d)->eoi);
+	irq_gc_unlock(gc);
+}
+
+/**
+ * irq_gc_set_wake - Set/clr wake bit for an interrupt
+ * @d: irq_data
+ *
+ * For chips where the wake from suspend functionality is not
+ * configured in a separate register and the wakeup active state is
+ * just stored in a bitmask.
+ */
+int irq_gc_set_wake(struct irq_data *d, unsigned int on)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	u32 mask = 1 << (d->irq - gc->irq_base);
+
+	if (!(mask & gc->wake_enabled))
+		return -EINVAL;
+
+	irq_gc_lock(gc);
+	if (on)
+		gc->wake_active |= mask;
+	else
+		gc->wake_active &= ~mask;
+	irq_gc_unlock(gc);
+	return 0;
+}
+
+/**
+ * irq_alloc_generic_chip - Allocate a generic chip and initialize it
+ * @name:	Name of the irq chip
+ * @num_ct:	Number of irq_chip_type instances associated with this
+ * @irq_base:	Interrupt base nr for this chip
+ * @reg_base:	Register base address (virtual)
+ * @handler:	Default flow handler associated with this chip
+ *
+ * Returns an initialized irq_chip_generic structure. The chip defaults
+ * to the primary (index 0) irq_chip_type and @handler
+ */
+struct irq_chip_generic *
+irq_alloc_generic_chip(const char *name, int num_ct, unsigned int irq_base,
+		       void __iomem *reg_base, irq_flow_handler_t handler)
+{
+	struct irq_chip_generic *gc;
+	unsigned long sz = sizeof(*gc) + num_ct * sizeof(struct irq_chip_type);
+
+	gc = kzalloc(sz, GFP_KERNEL);
+	if (gc) {
+		raw_spin_lock_init(&gc->lock);
+		gc->num_ct = num_ct;
+		gc->irq_base = irq_base;
+		gc->reg_base = reg_base;
+		gc->chip_types->chip.name = name;
+		gc->chip_types->handler = handler;
+	}
+	return gc;
+}
+
+/*
+ * Separate lockdep class for interrupt chip which can nest irq_desc
+ * lock.
+ */
+static struct lock_class_key irq_nested_lock_class;
+
+/**
+ * irq_setup_generic_chip - Setup a range of interrupts with a generic chip
+ * @gc:		Generic irq chip holding all data
+ * @msk:	Bitmask holding the irqs to initialize relative to gc->irq_base
+ * @flags:	Flags for initialization
+ * @clr:	IRQ_* bits to clear
+ * @set:	IRQ_* bits to set
+ *
+ * Set up max. 32 interrupts starting from gc->irq_base. Note, this
+ * initializes all interrupts to the primary irq_chip_type and its
+ * associated handler.
+ */
+void irq_setup_generic_chip(struct irq_chip_generic *gc, u32 msk,
+			    enum irq_gc_flags flags, unsigned int clr,
+			    unsigned int set)
+{
+	struct irq_chip_type *ct = gc->chip_types;
+	unsigned int i;
+
+	/* Init mask cache ? */
+	if (flags & IRQ_GC_INIT_MASK_CACHE)
+		gc->mask_cache = irq_reg_readl(gc->reg_base + ct->regs.mask);
+
+	for (i = gc->irq_base; msk; msk >>= 1, i++) {
+		if (!msk & 0x01)
+			continue;
+
+		if (flags & IRQ_GC_INIT_NESTED_LOCK)
+			irq_set_lockdep_class(i, &irq_nested_lock_class);
+
+		irq_set_chip_and_handler(i, &ct->chip, ct->handler);
+		irq_set_chip_data(i, gc);
+		irq_modify_status(i, clr, set);
+	}
+	gc->irq_cnt = i - gc->irq_base;
+}
+
+/**
+ * irq_setup_alt_chip - Switch to alternative chip
+ * @d:		irq_data for this interrupt
+ * @type	Flow type to be initialized
+ *
+ * Only to be called from chip->irq_set_type() callbacks.
+ */
+int irq_setup_alt_chip(struct irq_data *d, unsigned int type)
+{
+	struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
+	struct irq_chip_type *ct = gc->chip_types;
+	unsigned int i;
+
+	for (i = 0; i < gc->num_ct; i++, ct++) {
+		if (ct->type & type) {
+			d->chip = &ct->chip;
+			irq_data_to_desc(d)->handle_irq = ct->handler;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}