| /* |
| * 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; |
| static DEFINE_SPINLOCK(irq_controller_lock); |
| |
| /* |
| * 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); |
| |
| spin_lock(&irq_controller_lock); |
| writel(mask, gic_dist_base + GIC_DIST_ENABLE_CLEAR + (irq / 32) * 4); |
| writel(irq, gic_cpu_base + 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 + GIC_DIST_ENABLE_CLEAR + (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 + GIC_DIST_ENABLE_SET + (irq / 32) * 4); |
| spin_unlock(&irq_controller_lock); |
| } |
| |
| #ifdef CONFIG_SMP |
| static void gic_set_cpu(unsigned int irq, cpumask_t mask_val) |
| { |
| void __iomem *reg = gic_dist_base + GIC_DIST_TARGET + (irq & ~3); |
| unsigned int shift = (irq % 4) * 8; |
| unsigned int cpu = first_cpu(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 struct irqchip gic_chip = { |
| .ack = gic_ack_irq, |
| .mask = gic_mask_irq, |
| .unmask = gic_unmask_irq, |
| #ifdef CONFIG_SMP |
| .set_affinity = 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 |