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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
* Loongson HTPIC IRQ support
*/
#include <linux/init.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/irq.h>
#include <linux/io.h>
#include <linux/syscore_ops.h>
#include <asm/i8259.h>
#define HTPIC_MAX_PARENT_IRQ 4
#define HTINT_NUM_VECTORS 8
#define HTINT_EN_OFF 0x20
struct loongson_htpic {
void __iomem *base;
struct irq_domain *domain;
};
static struct loongson_htpic *htpic;
static void htpic_irq_dispatch(struct irq_desc *desc)
{
struct loongson_htpic *priv = irq_desc_get_handler_data(desc);
struct irq_chip *chip = irq_desc_get_chip(desc);
uint32_t pending;
chained_irq_enter(chip, desc);
pending = readl(priv->base);
/* Ack all IRQs at once, otherwise IRQ flood might happen */
writel(pending, priv->base);
if (!pending)
spurious_interrupt();
while (pending) {
int bit = __ffs(pending);
if (unlikely(bit > 15)) {
spurious_interrupt();
break;
}
generic_handle_domain_irq(priv->domain, bit);
pending &= ~BIT(bit);
}
chained_irq_exit(chip, desc);
}
static void htpic_reg_init(void)
{
int i;
for (i = 0; i < HTINT_NUM_VECTORS; i++) {
/* Disable all HT Vectors */
writel(0x0, htpic->base + HTINT_EN_OFF + i * 0x4);
/* Read back to force write */
(void) readl(htpic->base + i * 0x4);
/* Ack all possible pending IRQs */
writel(GENMASK(31, 0), htpic->base + i * 0x4);
}
/* Enable 16 vectors for PIC */
writel(0xffff, htpic->base + HTINT_EN_OFF);
}
static void htpic_resume(void)
{
htpic_reg_init();
}
struct syscore_ops htpic_syscore_ops = {
.resume = htpic_resume,
};
static int __init htpic_of_init(struct device_node *node, struct device_node *parent)
{
unsigned int parent_irq[4];
int i, err;
int num_parents = 0;
if (htpic) {
pr_err("loongson-htpic: Only one HTPIC is allowed in the system\n");
return -ENODEV;
}
htpic = kzalloc(sizeof(*htpic), GFP_KERNEL);
if (!htpic)
return -ENOMEM;
htpic->base = of_iomap(node, 0);
if (!htpic->base) {
err = -ENODEV;
goto out_free;
}
htpic->domain = __init_i8259_irqs(node);
if (!htpic->domain) {
pr_err("loongson-htpic: Failed to initialize i8259 IRQs\n");
err = -ENOMEM;
goto out_iounmap;
}
/* Interrupt may come from any of the 4 interrupt line */
for (i = 0; i < HTPIC_MAX_PARENT_IRQ; i++) {
parent_irq[i] = irq_of_parse_and_map(node, i);
if (parent_irq[i] <= 0)
break;
num_parents++;
}
if (!num_parents) {
pr_err("loongson-htpic: Failed to get parent irqs\n");
err = -ENODEV;
goto out_remove_domain;
}
htpic_reg_init();
for (i = 0; i < num_parents; i++) {
irq_set_chained_handler_and_data(parent_irq[i],
htpic_irq_dispatch, htpic);
}
register_syscore_ops(&htpic_syscore_ops);
return 0;
out_remove_domain:
irq_domain_remove(htpic->domain);
out_iounmap:
iounmap(htpic->base);
out_free:
kfree(htpic);
return err;
}
IRQCHIP_DECLARE(loongson_htpic, "loongson,htpic-1.0", htpic_of_init);
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