1 /*
2 * Driver for MIPS Goldfish Programmable Interrupt Controller.
3 *
4 * Author: Miodrag Dinic <miodrag.dinic@mips.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 */
11
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14 #include <linux/interrupt.h>
15 #include <linux/irq.h>
16 #include <linux/irqchip.h>
17 #include <linux/irqchip/chained_irq.h>
18 #include <linux/irqdomain.h>
19 #include <linux/of_address.h>
20 #include <linux/of_irq.h>
21
22 #define GFPIC_NR_IRQS 32
23
24 /* 8..39 Cascaded Goldfish PIC interrupts */
25 #define GFPIC_IRQ_BASE 8
26
27 #define GFPIC_REG_IRQ_PENDING 0x04
28 #define GFPIC_REG_IRQ_DISABLE_ALL 0x08
29 #define GFPIC_REG_IRQ_DISABLE 0x0c
30 #define GFPIC_REG_IRQ_ENABLE 0x10
31
32 struct goldfish_pic_data {
33 void __iomem *base;
34 struct irq_domain *irq_domain;
35 };
36
goldfish_pic_cascade(struct irq_desc * desc)37 static void goldfish_pic_cascade(struct irq_desc *desc)
38 {
39 struct goldfish_pic_data *gfpic = irq_desc_get_handler_data(desc);
40 struct irq_chip *host_chip = irq_desc_get_chip(desc);
41 u32 pending, hwirq, virq;
42
43 chained_irq_enter(host_chip, desc);
44
45 pending = readl(gfpic->base + GFPIC_REG_IRQ_PENDING);
46 while (pending) {
47 hwirq = __fls(pending);
48 virq = irq_linear_revmap(gfpic->irq_domain, hwirq);
49 generic_handle_irq(virq);
50 pending &= ~(1 << hwirq);
51 }
52
53 chained_irq_exit(host_chip, desc);
54 }
55
56 static const struct irq_domain_ops goldfish_irq_domain_ops = {
57 .xlate = irq_domain_xlate_onecell,
58 };
59
goldfish_pic_of_init(struct device_node * of_node,struct device_node * parent)60 static int __init goldfish_pic_of_init(struct device_node *of_node,
61 struct device_node *parent)
62 {
63 struct goldfish_pic_data *gfpic;
64 struct irq_chip_generic *gc;
65 struct irq_chip_type *ct;
66 unsigned int parent_irq;
67 int ret = 0;
68
69 gfpic = kzalloc(sizeof(*gfpic), GFP_KERNEL);
70 if (!gfpic) {
71 ret = -ENOMEM;
72 goto out_err;
73 }
74
75 parent_irq = irq_of_parse_and_map(of_node, 0);
76 if (!parent_irq) {
77 pr_err("Failed to map parent IRQ!\n");
78 ret = -EINVAL;
79 goto out_free;
80 }
81
82 gfpic->base = of_iomap(of_node, 0);
83 if (!gfpic->base) {
84 pr_err("Failed to map base address!\n");
85 ret = -ENOMEM;
86 goto out_unmap_irq;
87 }
88
89 /* Mask interrupts. */
90 writel(1, gfpic->base + GFPIC_REG_IRQ_DISABLE_ALL);
91
92 gc = irq_alloc_generic_chip("GFPIC", 1, GFPIC_IRQ_BASE, gfpic->base,
93 handle_level_irq);
94 if (!gc) {
95 pr_err("Failed to allocate chip structures!\n");
96 ret = -ENOMEM;
97 goto out_iounmap;
98 }
99
100 ct = gc->chip_types;
101 ct->regs.enable = GFPIC_REG_IRQ_ENABLE;
102 ct->regs.disable = GFPIC_REG_IRQ_DISABLE;
103 ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
104 ct->chip.irq_mask = irq_gc_mask_disable_reg;
105
106 irq_setup_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS), 0,
107 IRQ_NOPROBE | IRQ_LEVEL, 0);
108
109 gfpic->irq_domain = irq_domain_add_legacy(of_node, GFPIC_NR_IRQS,
110 GFPIC_IRQ_BASE, 0,
111 &goldfish_irq_domain_ops,
112 NULL);
113 if (!gfpic->irq_domain) {
114 pr_err("Failed to add irqdomain!\n");
115 ret = -ENOMEM;
116 goto out_destroy_generic_chip;
117 }
118
119 irq_set_chained_handler_and_data(parent_irq,
120 goldfish_pic_cascade, gfpic);
121
122 pr_info("Successfully registered.\n");
123 return 0;
124
125 out_destroy_generic_chip:
126 irq_destroy_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS),
127 IRQ_NOPROBE | IRQ_LEVEL, 0);
128 out_iounmap:
129 iounmap(gfpic->base);
130 out_unmap_irq:
131 irq_dispose_mapping(parent_irq);
132 out_free:
133 kfree(gfpic);
134 out_err:
135 pr_err("Failed to initialize! (errno = %d)\n", ret);
136 return ret;
137 }
138
139 IRQCHIP_DECLARE(google_gf_pic, "google,goldfish-pic", goldfish_pic_of_init);
140