1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Driver for MIPS Goldfish Programmable Interrupt Controller.
4 *
5 * Author: Miodrag Dinic <miodrag.dinic@mips.com>
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/interrupt.h>
11 #include <linux/irq.h>
12 #include <linux/irqchip.h>
13 #include <linux/irqchip/chained_irq.h>
14 #include <linux/irqdomain.h>
15 #include <linux/of_address.h>
16 #include <linux/of_irq.h>
17
18 #define GFPIC_NR_IRQS 32
19
20 /* 8..39 Cascaded Goldfish PIC interrupts */
21 #define GFPIC_IRQ_BASE 8
22
23 #define GFPIC_REG_IRQ_PENDING 0x04
24 #define GFPIC_REG_IRQ_DISABLE_ALL 0x08
25 #define GFPIC_REG_IRQ_DISABLE 0x0c
26 #define GFPIC_REG_IRQ_ENABLE 0x10
27
28 struct goldfish_pic_data {
29 void __iomem *base;
30 struct irq_domain *irq_domain;
31 };
32
goldfish_pic_cascade(struct irq_desc * desc)33 static void goldfish_pic_cascade(struct irq_desc *desc)
34 {
35 struct goldfish_pic_data *gfpic = irq_desc_get_handler_data(desc);
36 struct irq_chip *host_chip = irq_desc_get_chip(desc);
37 u32 pending, hwirq;
38
39 chained_irq_enter(host_chip, desc);
40
41 pending = readl(gfpic->base + GFPIC_REG_IRQ_PENDING);
42 while (pending) {
43 hwirq = __fls(pending);
44 generic_handle_domain_irq(gfpic->irq_domain, hwirq);
45 pending &= ~(1 << hwirq);
46 }
47
48 chained_irq_exit(host_chip, desc);
49 }
50
51 static const struct irq_domain_ops goldfish_irq_domain_ops = {
52 .xlate = irq_domain_xlate_onecell,
53 };
54
goldfish_pic_of_init(struct device_node * of_node,struct device_node * parent)55 static int __init goldfish_pic_of_init(struct device_node *of_node,
56 struct device_node *parent)
57 {
58 struct goldfish_pic_data *gfpic;
59 struct irq_chip_generic *gc;
60 struct irq_chip_type *ct;
61 unsigned int parent_irq;
62 int ret = 0;
63
64 gfpic = kzalloc(sizeof(*gfpic), GFP_KERNEL);
65 if (!gfpic) {
66 ret = -ENOMEM;
67 goto out_err;
68 }
69
70 parent_irq = irq_of_parse_and_map(of_node, 0);
71 if (!parent_irq) {
72 pr_err("Failed to map parent IRQ!\n");
73 ret = -EINVAL;
74 goto out_free;
75 }
76
77 gfpic->base = of_iomap(of_node, 0);
78 if (!gfpic->base) {
79 pr_err("Failed to map base address!\n");
80 ret = -ENOMEM;
81 goto out_unmap_irq;
82 }
83
84 /* Mask interrupts. */
85 writel(1, gfpic->base + GFPIC_REG_IRQ_DISABLE_ALL);
86
87 gc = irq_alloc_generic_chip("GFPIC", 1, GFPIC_IRQ_BASE, gfpic->base,
88 handle_level_irq);
89 if (!gc) {
90 pr_err("Failed to allocate chip structures!\n");
91 ret = -ENOMEM;
92 goto out_iounmap;
93 }
94
95 ct = gc->chip_types;
96 ct->regs.enable = GFPIC_REG_IRQ_ENABLE;
97 ct->regs.disable = GFPIC_REG_IRQ_DISABLE;
98 ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
99 ct->chip.irq_mask = irq_gc_mask_disable_reg;
100
101 irq_setup_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS), 0,
102 IRQ_NOPROBE | IRQ_LEVEL, 0);
103
104 gfpic->irq_domain = irq_domain_add_legacy(of_node, GFPIC_NR_IRQS,
105 GFPIC_IRQ_BASE, 0,
106 &goldfish_irq_domain_ops,
107 NULL);
108 if (!gfpic->irq_domain) {
109 pr_err("Failed to add irqdomain!\n");
110 ret = -ENOMEM;
111 goto out_destroy_generic_chip;
112 }
113
114 irq_set_chained_handler_and_data(parent_irq,
115 goldfish_pic_cascade, gfpic);
116
117 pr_info("Successfully registered.\n");
118 return 0;
119
120 out_destroy_generic_chip:
121 irq_destroy_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS),
122 IRQ_NOPROBE | IRQ_LEVEL, 0);
123 out_iounmap:
124 iounmap(gfpic->base);
125 out_unmap_irq:
126 irq_dispose_mapping(parent_irq);
127 out_free:
128 kfree(gfpic);
129 out_err:
130 pr_err("Failed to initialize! (errno = %d)\n", ret);
131 return ret;
132 }
133
134 IRQCHIP_DECLARE(google_gf_pic, "google,goldfish-pic", goldfish_pic_of_init);
135