arch/arm/common/gic.c - kernel/prism - Git at Google

 /*
  *  linux/arch/arm/common/gic.c
  *
  *  Copyright (C) 2002 ARM Limited, All Rights Reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * Interrupt architecture for the GIC:
  *
  * o There is one Interrupt Distributor, which receives interrupts
  *   from system devices and sends them to the Interrupt Controllers.
  *
  * o There is one CPU Interface per CPU, which sends interrupts sent
  *   by the Distributor, and interrupts generated locally, to the
  *   associated CPU. The base address of the CPU interface is usually
  *   aliased so that the same address points to different chips depending
  *   on the CPU it is accessed from.
  *
  * Note that IRQs 0-31 are special - they are local to each CPU.
  * As such, the enable set/clear, pending set/clear and active bit
  * registers are banked per-cpu for these sources.
  */
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/smp.h>
 #include <linux/cpumask.h>
 #include <linux/io.h>

 #include <asm/irq.h>
 #include <asm/mach/irq.h>
 #include <asm/hardware/gic.h>

 static DEFINE_SPINLOCK(irq_controller_lock);

 struct gic_chip_data {
 	unsigned int irq_offset;
 	void __iomem *dist_base;
 	void __iomem *cpu_base;
 };

 #ifndef MAX_GIC_NR
 #define MAX_GIC_NR	1
 #endif

 static struct gic_chip_data gic_data[MAX_GIC_NR];

 static inline void __iomem *gic_dist_base(unsigned int irq)
 {
 	struct gic_chip_data *gic_data = get_irq_chip_data(irq);
 	return gic_data->dist_base;
 }

 static inline void __iomem *gic_cpu_base(unsigned int irq)
 {
 	struct gic_chip_data *gic_data = get_irq_chip_data(irq);
 	return gic_data->cpu_base;
 }

 static inline unsigned int gic_irq(unsigned int irq)
 {
 	struct gic_chip_data *gic_data = get_irq_chip_data(irq);
 	return irq - gic_data->irq_offset;
 }

 /*
  * Routines to acknowledge, disable and enable interrupts
  *
  * Linux assumes that when we're done with an interrupt we need to
  * unmask it, in the same way we need to unmask an interrupt when
  * we first enable it.
  *
  * The GIC has a separate notion of "end of interrupt" to re-enable
  * an interrupt after handling, in order to support hardware
  * prioritisation.
  *
  * We can make the GIC behave in the way that Linux expects by making
  * our "acknowledge" routine disable the interrupt, then mark it as
  * complete.
  */
 static void gic_ack_irq(unsigned int irq)
 {
 	u32 mask = 1 << (irq % 32);

 	spin_lock(&irq_controller_lock);
 	writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_CLEAR + (gic_irq(irq) / 32) * 4);
 	writel(gic_irq(irq), gic_cpu_base(irq) + GIC_CPU_EOI);
 	spin_unlock(&irq_controller_lock);
 }

 static void gic_mask_irq(unsigned int irq)
 {
 	u32 mask = 1 << (irq % 32);

 	spin_lock(&irq_controller_lock);
 	writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_CLEAR + (gic_irq(irq) / 32) * 4);
 	spin_unlock(&irq_controller_lock);
 }

 static void gic_unmask_irq(unsigned int irq)
 {
 	u32 mask = 1 << (irq % 32);

 	spin_lock(&irq_controller_lock);
 	writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_SET + (gic_irq(irq) / 32) * 4);
 	spin_unlock(&irq_controller_lock);
 }

 #ifdef CONFIG_SMP
 static int gic_set_cpu(unsigned int irq, const struct cpumask *mask_val)
 {
 	void __iomem *reg = gic_dist_base(irq) + GIC_DIST_TARGET + (gic_irq(irq) & ~3);
 	unsigned int shift = (irq % 4) * 8;
 	unsigned int cpu = cpumask_first(mask_val);
 	u32 val;

 	spin_lock(&irq_controller_lock);
 	irq_desc[irq].node = cpu;
 	val = readl(reg) & ~(0xff << shift);
 	val |= 1 << (cpu + shift);
 	writel(val, reg);
 	spin_unlock(&irq_controller_lock);

 	return 0;
 }
 #endif

 static void gic_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
 {
 	struct gic_chip_data *chip_data = get_irq_data(irq);
 	struct irq_chip *chip = get_irq_chip(irq);
 	unsigned int cascade_irq, gic_irq;
 	unsigned long status;

 	/* primary controller ack'ing */
 	chip->ack(irq);

 	spin_lock(&irq_controller_lock);
 	status = readl(chip_data->cpu_base + GIC_CPU_INTACK);
 	spin_unlock(&irq_controller_lock);

 	gic_irq = (status & 0x3ff);
 	if (gic_irq == 1023)
 		goto out;

 	cascade_irq = gic_irq + chip_data->irq_offset;
 	if (unlikely(gic_irq < 32 || gic_irq > 1020 || cascade_irq >= NR_IRQS))
 		do_bad_IRQ(cascade_irq, desc);
 	else
 		generic_handle_irq(cascade_irq);

  out:
 	/* primary controller unmasking */
 	chip->unmask(irq);
 }

 static struct irq_chip gic_chip = {
 	.name		= "GIC",
 	.ack		= gic_ack_irq,
 	.mask		= gic_mask_irq,
 	.unmask		= gic_unmask_irq,
 #ifdef CONFIG_SMP
 	.set_affinity	= gic_set_cpu,
 #endif
 };

 void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq)
 {
 	if (gic_nr >= MAX_GIC_NR)
 		BUG();
 	if (set_irq_data(irq, &gic_data[gic_nr]) != 0)
 		BUG();
 	set_irq_chained_handler(irq, gic_handle_cascade_irq);
 }

 void __init gic_dist_init(unsigned int gic_nr, void __iomem *base,
 			  unsigned int irq_start)
 {
 	unsigned int max_irq, i;
 	u32 cpumask = 1 << smp_processor_id();

 	if (gic_nr >= MAX_GIC_NR)
 		BUG();

 	cpumask |= cpumask << 8;
 	cpumask |= cpumask << 16;

 	gic_data[gic_nr].dist_base = base;
 	gic_data[gic_nr].irq_offset = (irq_start - 1) & ~31;

 	writel(0, base + GIC_DIST_CTRL);

 	/*
 	 * Find out how many interrupts are supported.
 	 */
 	max_irq = readl(base + GIC_DIST_CTR) & 0x1f;
 	max_irq = (max_irq + 1) * 32;

 	/*
 	 * The GIC only supports up to 1020 interrupt sources.
 	 * Limit this to either the architected maximum, or the
 	 * platform maximum.
 	 */
 	if (max_irq > max(1020, NR_IRQS))
 		max_irq = max(1020, NR_IRQS);

 	/*
 	 * Set all global interrupts to be level triggered, active low.
 	 */
 	for (i = 32; i < max_irq; i += 16)
 		writel(0, base + GIC_DIST_CONFIG + i * 4 / 16);

 	/*
 	 * Set all global interrupts to this CPU only.
 	 */
 	for (i = 32; i < max_irq; i += 4)
 		writel(cpumask, base + GIC_DIST_TARGET + i * 4 / 4);

 	/*
 	 * Set priority on all interrupts.
 	 */
 	for (i = 0; i < max_irq; i += 4)
 		writel(0xa0a0a0a0, base + GIC_DIST_PRI + i * 4 / 4);

 	/*
 	 * Disable all interrupts.
 	 */
 	for (i = 0; i < max_irq; i += 32)
 		writel(0xffffffff, base + GIC_DIST_ENABLE_CLEAR + i * 4 / 32);

 	/*
 	 * Setup the Linux IRQ subsystem.
 	 */
 	for (i = irq_start; i < gic_data[gic_nr].irq_offset + max_irq; i++) {
 		set_irq_chip(i, &gic_chip);
 		set_irq_chip_data(i, &gic_data[gic_nr]);
 		set_irq_handler(i, handle_level_irq);
 		set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
 	}

 	writel(1, base + GIC_DIST_CTRL);
 }

 void __cpuinit gic_cpu_init(unsigned int gic_nr, void __iomem *base)
 {
 	if (gic_nr >= MAX_GIC_NR)
 		BUG();

 	gic_data[gic_nr].cpu_base = base;

 	writel(0xf0, base + GIC_CPU_PRIMASK);
 	writel(1, base + GIC_CPU_CTRL);
 }

 #ifdef CONFIG_SMP
 void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
 {
 	unsigned long map = *cpus_addr(*mask);

 	/* this always happens on GIC0 */
 	writel(map << 16 | irq, gic_data[0].dist_base + GIC_DIST_SOFTINT);
 }
 #endif
	/*
	* linux/arch/arm/common/gic.c
	*
	* Copyright (C) 2002 ARM Limited, All Rights Reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* Interrupt architecture for the GIC:
	*
	* o There is one Interrupt Distributor, which receives interrupts
	* from system devices and sends them to the Interrupt Controllers.
	*
	* o There is one CPU Interface per CPU, which sends interrupts sent
	* by the Distributor, and interrupts generated locally, to the
	* associated CPU. The base address of the CPU interface is usually
	* aliased so that the same address points to different chips depending
	* on the CPU it is accessed from.
	*
	* Note that IRQs 0-31 are special - they are local to each CPU.
	* As such, the enable set/clear, pending set/clear and active bit
	* registers are banked per-cpu for these sources.
	*/
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/list.h>
	#include <linux/smp.h>
	#include <linux/cpumask.h>
	#include <linux/io.h>

	#include <asm/irq.h>
	#include <asm/mach/irq.h>
	#include <asm/hardware/gic.h>

	static DEFINE_SPINLOCK(irq_controller_lock);

	struct gic_chip_data {
	unsigned int irq_offset;
	void __iomem *dist_base;
	void __iomem *cpu_base;
	};

	#ifndef MAX_GIC_NR
	#define MAX_GIC_NR 1
	#endif

	static struct gic_chip_data gic_data[MAX_GIC_NR];

	static inline void __iomem *gic_dist_base(unsigned int irq)
	{
	struct gic_chip_data *gic_data = get_irq_chip_data(irq);
	return gic_data->dist_base;
	}

	static inline void __iomem *gic_cpu_base(unsigned int irq)
	{
	struct gic_chip_data *gic_data = get_irq_chip_data(irq);
	return gic_data->cpu_base;
	}

	static inline unsigned int gic_irq(unsigned int irq)
	{
	struct gic_chip_data *gic_data = get_irq_chip_data(irq);
	return irq - gic_data->irq_offset;
	}

	/*
	* Routines to acknowledge, disable and enable interrupts
	*
	* Linux assumes that when we're done with an interrupt we need to
	* unmask it, in the same way we need to unmask an interrupt when
	* we first enable it.
	*
	* The GIC has a separate notion of "end of interrupt" to re-enable
	* an interrupt after handling, in order to support hardware
	* prioritisation.
	*
	* We can make the GIC behave in the way that Linux expects by making
	* our "acknowledge" routine disable the interrupt, then mark it as
	* complete.
	*/
	static void gic_ack_irq(unsigned int irq)
	{
	u32 mask = 1 << (irq % 32);

	spin_lock(&irq_controller_lock);
	writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_CLEAR + (gic_irq(irq) / 32) * 4);
	writel(gic_irq(irq), gic_cpu_base(irq) + GIC_CPU_EOI);
	spin_unlock(&irq_controller_lock);
	}

	static void gic_mask_irq(unsigned int irq)
	{
	u32 mask = 1 << (irq % 32);

	spin_lock(&irq_controller_lock);
	writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_CLEAR + (gic_irq(irq) / 32) * 4);
	spin_unlock(&irq_controller_lock);
	}

	static void gic_unmask_irq(unsigned int irq)
	{
	u32 mask = 1 << (irq % 32);

	spin_lock(&irq_controller_lock);
	writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_SET + (gic_irq(irq) / 32) * 4);
	spin_unlock(&irq_controller_lock);
	}

	#ifdef CONFIG_SMP
	static int gic_set_cpu(unsigned int irq, const struct cpumask *mask_val)
	{
	void __iomem *reg = gic_dist_base(irq) + GIC_DIST_TARGET + (gic_irq(irq) & ~3);
	unsigned int shift = (irq % 4) * 8;
	unsigned int cpu = cpumask_first(mask_val);
	u32 val;

	spin_lock(&irq_controller_lock);
	irq_desc[irq].node = cpu;
	val = readl(reg) & ~(0xff << shift);
	val \|= 1 << (cpu + shift);
	writel(val, reg);
	spin_unlock(&irq_controller_lock);

	return 0;
	}
	#endif

	static void gic_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
	{
	struct gic_chip_data *chip_data = get_irq_data(irq);
	struct irq_chip *chip = get_irq_chip(irq);
	unsigned int cascade_irq, gic_irq;
	unsigned long status;

	/* primary controller ack'ing */
	chip->ack(irq);

	spin_lock(&irq_controller_lock);
	status = readl(chip_data->cpu_base + GIC_CPU_INTACK);
	spin_unlock(&irq_controller_lock);

	gic_irq = (status & 0x3ff);
	if (gic_irq == 1023)
	goto out;

	cascade_irq = gic_irq + chip_data->irq_offset;
	if (unlikely(gic_irq < 32 \|\| gic_irq > 1020 \|\| cascade_irq >= NR_IRQS))
	do_bad_IRQ(cascade_irq, desc);
	else
	generic_handle_irq(cascade_irq);

	out:
	/* primary controller unmasking */
	chip->unmask(irq);
	}

	static struct irq_chip gic_chip = {
	.name = "GIC",
	.ack = gic_ack_irq,
	.mask = gic_mask_irq,
	.unmask = gic_unmask_irq,
	#ifdef CONFIG_SMP
	.set_affinity = gic_set_cpu,
	#endif
	};

	void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq)
	{
	if (gic_nr >= MAX_GIC_NR)
	BUG();
	if (set_irq_data(irq, &gic_data[gic_nr]) != 0)
	BUG();
	set_irq_chained_handler(irq, gic_handle_cascade_irq);
	}

	void __init gic_dist_init(unsigned int gic_nr, void __iomem *base,
	unsigned int irq_start)
	{
	unsigned int max_irq, i;
	u32 cpumask = 1 << smp_processor_id();

	if (gic_nr >= MAX_GIC_NR)
	BUG();

	cpumask \|= cpumask << 8;
	cpumask \|= cpumask << 16;

	gic_data[gic_nr].dist_base = base;
	gic_data[gic_nr].irq_offset = (irq_start - 1) & ~31;

	writel(0, base + GIC_DIST_CTRL);

	/*
	* Find out how many interrupts are supported.
	*/
	max_irq = readl(base + GIC_DIST_CTR) & 0x1f;
	max_irq = (max_irq + 1) * 32;

	/*
	* The GIC only supports up to 1020 interrupt sources.
	* Limit this to either the architected maximum, or the
	* platform maximum.
	*/
	if (max_irq > max(1020, NR_IRQS))
	max_irq = max(1020, NR_IRQS);

	/*
	* Set all global interrupts to be level triggered, active low.
	*/
	for (i = 32; i < max_irq; i += 16)
	writel(0, base + GIC_DIST_CONFIG + i * 4 / 16);

	/*
	* Set all global interrupts to this CPU only.
	*/
	for (i = 32; i < max_irq; i += 4)
	writel(cpumask, base + GIC_DIST_TARGET + i * 4 / 4);

	/*
	* Set priority on all interrupts.
	*/
	for (i = 0; i < max_irq; i += 4)
	writel(0xa0a0a0a0, base + GIC_DIST_PRI + i * 4 / 4);

	/*
	* Disable all interrupts.
	*/
	for (i = 0; i < max_irq; i += 32)
	writel(0xffffffff, base + GIC_DIST_ENABLE_CLEAR + i * 4 / 32);

	/*
	* Setup the Linux IRQ subsystem.
	*/
	for (i = irq_start; i < gic_data[gic_nr].irq_offset + max_irq; i++) {
	set_irq_chip(i, &gic_chip);
	set_irq_chip_data(i, &gic_data[gic_nr]);
	set_irq_handler(i, handle_level_irq);
	set_irq_flags(i, IRQF_VALID \| IRQF_PROBE);
	}

	writel(1, base + GIC_DIST_CTRL);
	}

	void __cpuinit gic_cpu_init(unsigned int gic_nr, void __iomem *base)
	{
	if (gic_nr >= MAX_GIC_NR)
	BUG();

	gic_data[gic_nr].cpu_base = base;

	writel(0xf0, base + GIC_CPU_PRIMASK);
	writel(1, base + GIC_CPU_CTRL);
	}

	#ifdef CONFIG_SMP
	void gic_raise_softirq(const struct cpumask *mask, unsigned int irq)
	{
	unsigned long map = cpus_addr(mask);

	/* this always happens on GIC0 */
	writel(map << 16 \| irq, gic_data[0].dist_base + GIC_DIST_SOFTINT);
	}
	#endif