/*
* 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 void 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].cpu = cpu;
val = readl(reg) & ~(0xff << shift);
val |= 1 << (cpu + shift);
writel(val, reg);
spin_unlock(&irq_controller_lock);
}
#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(cpumask_t cpumask, unsigned int irq)
{
unsigned long map = *cpus_addr(cpumask);
/* this always happens on GIC0 */
writel(map << 16 | irq, gic_data[0].dist_base + GIC_DIST_SOFTINT);
}
#endif
