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/*
* 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.
*
* 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 <asm/irq.h>
#include <asm/io.h>
#include <asm/mach/irq.h>
#include <asm/hardware/gic.h>
static void __iomem *gic_dist_base;
static void __iomem *gic_cpu_base;
/*
* 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 seperate 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);
writel(mask, gic_dist_base + GIC_DIST_ENABLE_CLEAR + (irq / 32) * 4);
writel(irq, gic_cpu_base + GIC_CPU_EOI);
}
static void gic_mask_irq(unsigned int irq)
{
u32 mask = 1 << (irq % 32);
writel(mask, gic_dist_base + GIC_DIST_ENABLE_CLEAR + (irq / 32) * 4);
}
static void gic_unmask_irq(unsigned int irq)
{
u32 mask = 1 << (irq % 32);
writel(mask, gic_dist_base + GIC_DIST_ENABLE_SET + (irq / 32) * 4);
}
static void gic_set_cpu(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
{
void __iomem *reg = gic_dist_base + GIC_DIST_TARGET + (irq & ~3);
unsigned int shift = (irq % 4) * 8;
u32 val;
val = readl(reg) & ~(0xff << shift);
val |= 1 << (cpu + shift);
writel(val, reg);
}
static struct irqchip gic_chip = {
.ack = gic_ack_irq,
.mask = gic_mask_irq,
.unmask = gic_unmask_irq,
#ifdef CONFIG_SMP
.set_cpu = gic_set_cpu,
#endif
};
void __init gic_dist_init(void __iomem *base)
{
unsigned int max_irq, i;
u32 cpumask = 1 << smp_processor_id();
cpumask |= cpumask << 8;
cpumask |= cpumask << 16;
gic_dist_base = base;
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 = 29; i < max_irq; i++) {
set_irq_chip(i, &gic_chip);
set_irq_handler(i, do_level_IRQ);
set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
}
writel(1, base + GIC_DIST_CTRL);
}
void __cpuinit gic_cpu_init(void __iomem *base)
{
gic_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);
writel(map << 16 | irq, gic_dist_base + GIC_DIST_SOFTINT);
}
#endif
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