Merge git://bedivere.hansenpartnership.com/git/scsi-rc-fixes-2.6
[linux-2.6.git] / arch / arm / mach-exynos4 / irq-combiner.c
1 /* linux/arch/arm/mach-exynos4/irq-combiner.c
2  *
3  * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
4  *              http://www.samsung.com
5  *
6  * Based on arch/arm/common/gic.c
7  *
8  * IRQ COMBINER support
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13 */
14
15 #include <linux/io.h>
16
17 #include <asm/mach/irq.h>
18
19 #define COMBINER_ENABLE_SET     0x0
20 #define COMBINER_ENABLE_CLEAR   0x4
21 #define COMBINER_INT_STATUS     0xC
22
23 static DEFINE_SPINLOCK(irq_controller_lock);
24
25 struct combiner_chip_data {
26         unsigned int irq_offset;
27         unsigned int irq_mask;
28         void __iomem *base;
29 };
30
31 static struct combiner_chip_data combiner_data[MAX_COMBINER_NR];
32
33 static inline void __iomem *combiner_base(struct irq_data *data)
34 {
35         struct combiner_chip_data *combiner_data =
36                 irq_data_get_irq_chip_data(data);
37
38         return combiner_data->base;
39 }
40
41 static void combiner_mask_irq(struct irq_data *data)
42 {
43         u32 mask = 1 << (data->irq % 32);
44
45         __raw_writel(mask, combiner_base(data) + COMBINER_ENABLE_CLEAR);
46 }
47
48 static void combiner_unmask_irq(struct irq_data *data)
49 {
50         u32 mask = 1 << (data->irq % 32);
51
52         __raw_writel(mask, combiner_base(data) + COMBINER_ENABLE_SET);
53 }
54
55 static void combiner_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
56 {
57         struct combiner_chip_data *chip_data = irq_get_handler_data(irq);
58         struct irq_chip *chip = irq_get_chip(irq);
59         unsigned int cascade_irq, combiner_irq;
60         unsigned long status;
61
62         chained_irq_enter(chip, desc);
63
64         spin_lock(&irq_controller_lock);
65         status = __raw_readl(chip_data->base + COMBINER_INT_STATUS);
66         spin_unlock(&irq_controller_lock);
67         status &= chip_data->irq_mask;
68
69         if (status == 0)
70                 goto out;
71
72         combiner_irq = __ffs(status);
73
74         cascade_irq = combiner_irq + (chip_data->irq_offset & ~31);
75         if (unlikely(cascade_irq >= NR_IRQS))
76                 do_bad_IRQ(cascade_irq, desc);
77         else
78                 generic_handle_irq(cascade_irq);
79
80  out:
81         chained_irq_exit(chip, desc);
82 }
83
84 static struct irq_chip combiner_chip = {
85         .name           = "COMBINER",
86         .irq_mask       = combiner_mask_irq,
87         .irq_unmask     = combiner_unmask_irq,
88 };
89
90 void __init combiner_cascade_irq(unsigned int combiner_nr, unsigned int irq)
91 {
92         if (combiner_nr >= MAX_COMBINER_NR)
93                 BUG();
94         if (irq_set_handler_data(irq, &combiner_data[combiner_nr]) != 0)
95                 BUG();
96         irq_set_chained_handler(irq, combiner_handle_cascade_irq);
97 }
98
99 void __init combiner_init(unsigned int combiner_nr, void __iomem *base,
100                           unsigned int irq_start)
101 {
102         unsigned int i;
103
104         if (combiner_nr >= MAX_COMBINER_NR)
105                 BUG();
106
107         combiner_data[combiner_nr].base = base;
108         combiner_data[combiner_nr].irq_offset = irq_start;
109         combiner_data[combiner_nr].irq_mask = 0xff << ((combiner_nr % 4) << 3);
110
111         /* Disable all interrupts */
112
113         __raw_writel(combiner_data[combiner_nr].irq_mask,
114                      base + COMBINER_ENABLE_CLEAR);
115
116         /* Setup the Linux IRQ subsystem */
117
118         for (i = irq_start; i < combiner_data[combiner_nr].irq_offset
119                                 + MAX_IRQ_IN_COMBINER; i++) {
120                 irq_set_chip_and_handler(i, &combiner_chip, handle_level_irq);
121                 irq_set_chip_data(i, &combiner_data[combiner_nr]);
122                 set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
123         }
124 }