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a93f1d90 JY |
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 | ||
22 | struct loongson_htpic { | |
23 | void __iomem *base; | |
24 | struct irq_domain *domain; | |
25 | }; | |
26 | ||
27 | static struct loongson_htpic *htpic; | |
28 | ||
29 | static 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_irq(irq_linear_revmap(priv->domain, bit)); | |
52 | pending &= ~BIT(bit); | |
53 | } | |
54 | chained_irq_exit(chip, desc); | |
55 | } | |
56 | ||
57 | static void htpic_reg_init(void) | |
58 | { | |
59 | int i; | |
60 | ||
61 | for (i = 0; i < HTINT_NUM_VECTORS; i++) { | |
62 | uint32_t val; | |
63 | ||
64 | /* Disable all HT Vectors */ | |
65 | writel(0x0, htpic->base + HTINT_EN_OFF + i * 0x4); | |
66 | val = readl(htpic->base + i * 0x4); | |
67 | /* Ack all possible pending IRQs */ | |
68 | writel(GENMASK(31, 0), htpic->base + i * 0x4); | |
69 | } | |
70 | ||
71 | /* Enable 16 vectors for PIC */ | |
72 | writel(0xffff, htpic->base + HTINT_EN_OFF); | |
73 | } | |
74 | ||
75 | static void htpic_resume(void) | |
76 | { | |
77 | htpic_reg_init(); | |
78 | } | |
79 | ||
80 | struct syscore_ops htpic_syscore_ops = { | |
81 | .resume = htpic_resume, | |
82 | }; | |
83 | ||
84 | int __init htpic_of_init(struct device_node *node, struct device_node *parent) | |
85 | { | |
86 | unsigned int parent_irq[4]; | |
87 | int i, err; | |
88 | int num_parents = 0; | |
89 | ||
90 | if (htpic) { | |
91 | pr_err("loongson-htpic: Only one HTPIC is allowed in the system\n"); | |
92 | return -ENODEV; | |
93 | } | |
94 | ||
95 | htpic = kzalloc(sizeof(*htpic), GFP_KERNEL); | |
96 | if (!htpic) { | |
97 | err = -ENOMEM; | |
98 | goto out_free; | |
99 | } | |
100 | ||
101 | htpic->base = of_iomap(node, 0); | |
102 | if (!htpic->base) { | |
103 | err = -ENODEV; | |
104 | goto out_free; | |
105 | } | |
106 | ||
107 | htpic->domain = __init_i8259_irqs(node); | |
108 | if (!htpic->domain) { | |
109 | pr_err("loongson-htpic: Failed to initialize i8259 IRQs\n"); | |
110 | err = -ENOMEM; | |
111 | goto out_iounmap; | |
112 | } | |
113 | ||
114 | /* Interrupt may come from any of the 4 interrupt line */ | |
115 | for (i = 0; i < HTPIC_MAX_PARENT_IRQ; i++) { | |
116 | parent_irq[i] = irq_of_parse_and_map(node, i); | |
117 | if (parent_irq[i] <= 0) | |
118 | break; | |
119 | ||
120 | num_parents++; | |
121 | } | |
122 | ||
123 | if (!num_parents) { | |
124 | pr_err("loongson-htpic: Failed to get parent irqs\n"); | |
125 | err = -ENODEV; | |
126 | goto out_remove_domain; | |
127 | } | |
128 | ||
129 | htpic_reg_init(); | |
130 | ||
131 | for (i = 0; i < num_parents; i++) { | |
132 | irq_set_chained_handler_and_data(parent_irq[i], | |
133 | htpic_irq_dispatch, htpic); | |
134 | } | |
135 | ||
136 | register_syscore_ops(&htpic_syscore_ops); | |
137 | ||
138 | return 0; | |
139 | ||
140 | out_remove_domain: | |
141 | irq_domain_remove(htpic->domain); | |
142 | out_iounmap: | |
143 | iounmap(htpic->base); | |
144 | out_free: | |
145 | kfree(htpic); | |
146 | return err; | |
147 | } | |
148 | ||
149 | IRQCHIP_DECLARE(loongson_htpic, "loongson,htpic-1.0", htpic_of_init); |