tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2020, Jiaxun Yang <jiaxun.yang@flygoat.com>
4 * Loongson HTPIC IRQ support
5 */
6
7#include <linux/init.h>
8#include <linux/of_address.h>
9#include <linux/of_irq.h>
10#include <linux/irqchip.h>
11#include <linux/irqchip/chained_irq.h>
12#include <linux/irq.h>
13#include <linux/io.h>
14#include <linux/syscore_ops.h>
15
16#include <asm/i8259.h>
17
18#define HTPIC_MAX_PARENT_IRQ 4
19#define HTINT_NUM_VECTORS 8
20#define HTINT_EN_OFF 0x20
21
22struct loongson_htpic {
23 void __iomem *base;
24 struct irq_domain *domain;
25};
26
27static struct loongson_htpic *htpic;
28
29static void htpic_irq_dispatch(struct irq_desc *desc)
30{
31 struct loongson_htpic *priv = irq_desc_get_handler_data(desc);
32 struct irq_chip *chip = irq_desc_get_chip(desc);
33 uint32_t pending;
34
35 chained_irq_enter(chip, desc);
36 pending = readl(priv->base);
37 /* Ack all IRQs at once, otherwise IRQ flood might happen */
38 writel(pending, priv->base);
39
40 if (!pending)
41 spurious_interrupt();
42
43 while (pending) {
44 int bit = __ffs(pending);
45
46 if (unlikely(bit > 15)) {
47 spurious_interrupt();
48 break;
49 }
50
51 generic_handle_domain_irq(priv->domain, bit);
52 pending &= ~BIT(bit);
53 }
54 chained_irq_exit(chip, desc);
55}
56
57static void htpic_reg_init(void)
58{
59 int i;
60
61 for (i = 0; i < HTINT_NUM_VECTORS; i++) {
62 /* Disable all HT Vectors */
63 writel(0x0, htpic->base + HTINT_EN_OFF + i * 0x4);
64 /* Read back to force write */
65 (void) readl(htpic->base + i * 0x4);
66 /* Ack all possible pending IRQs */
67 writel(GENMASK(31, 0), htpic->base + i * 0x4);
68 }
69
70 /* Enable 16 vectors for PIC */
71 writel(0xffff, htpic->base + HTINT_EN_OFF);
72}
73
74static void htpic_resume(void *data)
75{
76 htpic_reg_init();
77}
78
79static const struct syscore_ops htpic_syscore_ops = {
80 .resume = htpic_resume,
81};
82
83static struct syscore htpic_syscore = {
84 .ops = &htpic_syscore_ops,
85};
86
87static int __init htpic_of_init(struct device_node *node, struct device_node *parent)
88{
89 unsigned int parent_irq[4];
90 int i, err;
91 int num_parents = 0;
92
93 if (htpic) {
94 pr_err("loongson-htpic: Only one HTPIC is allowed in the system\n");
95 return -ENODEV;
96 }
97
98 htpic = kzalloc(sizeof(*htpic), GFP_KERNEL);
99 if (!htpic)
100 return -ENOMEM;
101
102 htpic->base = of_iomap(node, 0);
103 if (!htpic->base) {
104 err = -ENODEV;
105 goto out_free;
106 }
107
108 htpic->domain = __init_i8259_irqs(node);
109 if (!htpic->domain) {
110 pr_err("loongson-htpic: Failed to initialize i8259 IRQs\n");
111 err = -ENOMEM;
112 goto out_iounmap;
113 }
114
115 /* Interrupt may come from any of the 4 interrupt line */
116 for (i = 0; i < HTPIC_MAX_PARENT_IRQ; i++) {
117 parent_irq[i] = irq_of_parse_and_map(node, i);
118 if (parent_irq[i] <= 0)
119 break;
120
121 num_parents++;
122 }
123
124 if (!num_parents) {
125 pr_err("loongson-htpic: Failed to get parent irqs\n");
126 err = -ENODEV;
127 goto out_remove_domain;
128 }
129
130 htpic_reg_init();
131
132 for (i = 0; i < num_parents; i++) {
133 irq_set_chained_handler_and_data(parent_irq[i],
134 htpic_irq_dispatch, htpic);
135 }
136
137 register_syscore(&htpic_syscore);
138
139 return 0;
140
141out_remove_domain:
142 irq_domain_remove(htpic->domain);
143out_iounmap:
144 iounmap(htpic->base);
145out_free:
146 kfree(htpic);
147 return err;
148}
149
150IRQCHIP_DECLARE(loongson_htpic, "loongson,htpic-1.0", htpic_of_init);