irq-nvic.c
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/*
* drivers/irq/irq-nvic.c
*
* Copyright (C) 2008 ARM Limited, All Rights Reserved.
* Copyright (C) 2013 Pengutronix
*
* 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.
*
* Support for the Nested Vectored Interrupt Controller found on the
* ARMv7-M CPUs (Cortex-M3/M4)
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <asm/v7m.h>
#include <asm/exception.h>
#include "irqchip.h"
#define NVIC_ISER 0x000
#define NVIC_ICER 0x080
#define NVIC_IPR 0x300
#define NVIC_MAX_BANKS 16
/*
* Each bank handles 32 irqs. Only the 16th (= last) bank handles only
* 16 irqs.
*/
#define NVIC_MAX_IRQ ((NVIC_MAX_BANKS - 1) * 32 + 16)
static struct irq_domain *nvic_irq_domain;
asmlinkage void __exception_irq_entry
nvic_handle_irq(irq_hw_number_t hwirq, struct pt_regs *regs)
{
unsigned int irq = irq_linear_revmap(nvic_irq_domain, hwirq);
handle_IRQ(irq, regs);
}
static void nvic_eoi(struct irq_data *d)
{
/*
* This is a no-op as end of interrupt is signaled by the exception
* return sequence.
*/
}
static int __init nvic_of_init(struct device_node *node,
struct device_node *parent)
{
unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
unsigned int irqs, i, ret, numbanks;
void __iomem *nvic_base;
numbanks = (readl_relaxed(V7M_SCS_ICTR) &
V7M_SCS_ICTR_INTLINESNUM_MASK) + 1;
nvic_base = of_iomap(node, 0);
if (!nvic_base) {
pr_warn("unable to map nvic registers\n");
return -ENOMEM;
}
irqs = numbanks * 32;
if (irqs > NVIC_MAX_IRQ)
irqs = NVIC_MAX_IRQ;
nvic_irq_domain =
irq_domain_add_linear(node, irqs, &irq_generic_chip_ops, NULL);
if (!nvic_irq_domain) {
pr_warn("Failed to allocate irq domain\n");
return -ENOMEM;
}
ret = irq_alloc_domain_generic_chips(nvic_irq_domain, 32, 1,
"nvic_irq", handle_fasteoi_irq,
clr, 0, IRQ_GC_INIT_MASK_CACHE);
if (ret) {
pr_warn("Failed to allocate irq chips\n");
irq_domain_remove(nvic_irq_domain);
return ret;
}
for (i = 0; i < numbanks; ++i) {
struct irq_chip_generic *gc;
gc = irq_get_domain_generic_chip(nvic_irq_domain, 32 * i);
gc->reg_base = nvic_base + 4 * i;
gc->chip_types[0].regs.enable = NVIC_ISER;
gc->chip_types[0].regs.disable = NVIC_ICER;
gc->chip_types[0].chip.irq_mask = irq_gc_mask_disable_reg;
gc->chip_types[0].chip.irq_unmask = irq_gc_unmask_enable_reg;
gc->chip_types[0].chip.irq_eoi = nvic_eoi;
/* disable interrupts */
writel_relaxed(~0, gc->reg_base + NVIC_ICER);
}
/* Set priority on all interrupts */
for (i = 0; i < irqs; i += 4)
writel_relaxed(0, nvic_base + NVIC_IPR + i);
return 0;
}
IRQCHIP_DECLARE(armv7m_nvic, "arm,armv7m-nvic", nvic_of_init);