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/*
* Driver for MIPS Goldfish Programmable Interrupt Controller.
*
* Author: Miodrag Dinic <miodrag.dinic@mips.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irqdomain.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#define GFPIC_NR_IRQS 32
/* 8..39 Cascaded Goldfish PIC interrupts */
#define GFPIC_IRQ_BASE 8
#define GFPIC_REG_IRQ_PENDING 0x04
#define GFPIC_REG_IRQ_DISABLE_ALL 0x08
#define GFPIC_REG_IRQ_DISABLE 0x0c
#define GFPIC_REG_IRQ_ENABLE 0x10
struct goldfish_pic_data {
void __iomem *base;
struct irq_domain *irq_domain;
};
static void goldfish_pic_cascade(struct irq_desc *desc)
{
struct goldfish_pic_data *gfpic = irq_desc_get_handler_data(desc);
struct irq_chip *host_chip = irq_desc_get_chip(desc);
u32 pending, hwirq, virq;
chained_irq_enter(host_chip, desc);
pending = readl(gfpic->base + GFPIC_REG_IRQ_PENDING);
while (pending) {
hwirq = __fls(pending);
virq = irq_linear_revmap(gfpic->irq_domain, hwirq);
generic_handle_irq(virq);
pending &= ~(1 << hwirq);
}
chained_irq_exit(host_chip, desc);
}
static const struct irq_domain_ops goldfish_irq_domain_ops = {
.xlate = irq_domain_xlate_onecell,
};
static int __init goldfish_pic_of_init(struct device_node *of_node,
struct device_node *parent)
{
struct goldfish_pic_data *gfpic;
struct irq_chip_generic *gc;
struct irq_chip_type *ct;
unsigned int parent_irq;
int ret = 0;
gfpic = kzalloc(sizeof(*gfpic), GFP_KERNEL);
if (!gfpic) {
ret = -ENOMEM;
goto out_err;
}
parent_irq = irq_of_parse_and_map(of_node, 0);
if (!parent_irq) {
pr_err("Failed to map parent IRQ!\n");
ret = -EINVAL;
goto out_free;
}
gfpic->base = of_iomap(of_node, 0);
if (!gfpic->base) {
pr_err("Failed to map base address!\n");
ret = -ENOMEM;
goto out_unmap_irq;
}
/* Mask interrupts. */
writel(1, gfpic->base + GFPIC_REG_IRQ_DISABLE_ALL);
gc = irq_alloc_generic_chip("GFPIC", 1, GFPIC_IRQ_BASE, gfpic->base,
handle_level_irq);
if (!gc) {
pr_err("Failed to allocate chip structures!\n");
ret = -ENOMEM;
goto out_iounmap;
}
ct = gc->chip_types;
ct->regs.enable = GFPIC_REG_IRQ_ENABLE;
ct->regs.disable = GFPIC_REG_IRQ_DISABLE;
ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
ct->chip.irq_mask = irq_gc_mask_disable_reg;
irq_setup_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS), 0,
IRQ_NOPROBE | IRQ_LEVEL, 0);
gfpic->irq_domain = irq_domain_add_legacy(of_node, GFPIC_NR_IRQS,
GFPIC_IRQ_BASE, 0,
&goldfish_irq_domain_ops,
NULL);
if (!gfpic->irq_domain) {
pr_err("Failed to add irqdomain!\n");
ret = -ENOMEM;
goto out_iounmap;
}
irq_set_chained_handler_and_data(parent_irq,
goldfish_pic_cascade, gfpic);
pr_info("Successfully registered.\n");
return 0;
out_iounmap:
iounmap(gfpic->base);
out_unmap_irq:
irq_dispose_mapping(parent_irq);
out_free:
kfree(gfpic);
out_err:
pr_err("Failed to initialize! (errno = %d)\n", ret);
return ret;
}
IRQCHIP_DECLARE(google_gf_pic, "google,goldfish-pic", goldfish_pic_of_init);
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