1 /*
2 * linux/drivers/irqchip/irq-zevio.c
3 *
4 * Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2, as
8 * published by the Free Software Foundation.
9 *
10 */
11
12 #include <linux/io.h>
13 #include <linux/irq.h>
14 #include <linux/irqchip.h>
15 #include <linux/of.h>
16 #include <linux/of_address.h>
17 #include <linux/of_irq.h>
18
19 #include <asm/mach/irq.h>
20 #include <asm/exception.h>
21
22 #define IO_STATUS 0x000
23 #define IO_RAW_STATUS 0x004
24 #define IO_ENABLE 0x008
25 #define IO_DISABLE 0x00C
26 #define IO_CURRENT 0x020
27 #define IO_RESET 0x028
28 #define IO_MAX_PRIOTY 0x02C
29
30 #define IO_IRQ_BASE 0x000
31 #define IO_FIQ_BASE 0x100
32
33 #define IO_INVERT_SEL 0x200
34 #define IO_STICKY_SEL 0x204
35 #define IO_PRIORITY_SEL 0x300
36
37 #define MAX_INTRS 32
38 #define FIQ_START MAX_INTRS
39
40 static struct irq_domain *zevio_irq_domain;
41 static void __iomem *zevio_irq_io;
42
zevio_irq_ack(struct irq_data * irqd)43 static void zevio_irq_ack(struct irq_data *irqd)
44 {
45 struct irq_chip_generic *gc = irq_data_get_irq_chip_data(irqd);
46 struct irq_chip_regs *regs = &irq_data_get_chip_type(irqd)->regs;
47
48 readl(gc->reg_base + regs->ack);
49 }
50
zevio_handle_irq(struct pt_regs * regs)51 static void __exception_irq_entry zevio_handle_irq(struct pt_regs *regs)
52 {
53 int irqnr;
54
55 while (readl(zevio_irq_io + IO_STATUS)) {
56 irqnr = readl(zevio_irq_io + IO_CURRENT);
57 handle_domain_irq(zevio_irq_domain, irqnr, regs);
58 };
59 }
60
zevio_init_irq_base(void __iomem * base)61 static void __init zevio_init_irq_base(void __iomem *base)
62 {
63 /* Disable all interrupts */
64 writel(~0, base + IO_DISABLE);
65
66 /* Accept interrupts of all priorities */
67 writel(0xF, base + IO_MAX_PRIOTY);
68
69 /* Reset existing interrupts */
70 readl(base + IO_RESET);
71 }
72
zevio_of_init(struct device_node * node,struct device_node * parent)73 static int __init zevio_of_init(struct device_node *node,
74 struct device_node *parent)
75 {
76 unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
77 struct irq_chip_generic *gc;
78 int ret;
79
80 if (WARN_ON(zevio_irq_io || zevio_irq_domain))
81 return -EBUSY;
82
83 zevio_irq_io = of_iomap(node, 0);
84 BUG_ON(!zevio_irq_io);
85
86 /* Do not invert interrupt status bits */
87 writel(~0, zevio_irq_io + IO_INVERT_SEL);
88
89 /* Disable sticky interrupts */
90 writel(0, zevio_irq_io + IO_STICKY_SEL);
91
92 /* We don't use IRQ priorities. Set each IRQ to highest priority. */
93 memset_io(zevio_irq_io + IO_PRIORITY_SEL, 0, MAX_INTRS * sizeof(u32));
94
95 /* Init IRQ and FIQ */
96 zevio_init_irq_base(zevio_irq_io + IO_IRQ_BASE);
97 zevio_init_irq_base(zevio_irq_io + IO_FIQ_BASE);
98
99 zevio_irq_domain = irq_domain_add_linear(node, MAX_INTRS,
100 &irq_generic_chip_ops, NULL);
101 BUG_ON(!zevio_irq_domain);
102
103 ret = irq_alloc_domain_generic_chips(zevio_irq_domain, MAX_INTRS, 1,
104 "zevio_intc", handle_level_irq,
105 clr, 0, IRQ_GC_INIT_MASK_CACHE);
106 BUG_ON(ret);
107
108 gc = irq_get_domain_generic_chip(zevio_irq_domain, 0);
109 gc->reg_base = zevio_irq_io;
110 gc->chip_types[0].chip.irq_ack = zevio_irq_ack;
111 gc->chip_types[0].chip.irq_mask = irq_gc_mask_disable_reg;
112 gc->chip_types[0].chip.irq_unmask = irq_gc_unmask_enable_reg;
113 gc->chip_types[0].regs.mask = IO_IRQ_BASE + IO_ENABLE;
114 gc->chip_types[0].regs.enable = IO_IRQ_BASE + IO_ENABLE;
115 gc->chip_types[0].regs.disable = IO_IRQ_BASE + IO_DISABLE;
116 gc->chip_types[0].regs.ack = IO_IRQ_BASE + IO_RESET;
117
118 set_handle_irq(zevio_handle_irq);
119
120 pr_info("TI-NSPIRE classic IRQ controller\n");
121 return 0;
122 }
123
124 IRQCHIP_DECLARE(zevio_irq, "lsi,zevio-intc", zevio_of_init);
125