1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
|
/*
* linux/arch/arm/common/gic.c
*
* Copyright (C) 2002 ARM Limited, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Interrupt architecture for the GIC:
*
* o There is one Interrupt Distributor, which receives interrupts
* from system devices and sends them to the Interrupt Controllers.
*
* o There is one CPU Interface per CPU, which sends interrupts sent
* by the Distributor, and interrupts generated locally, to the
* associated CPU.
*
* Note that IRQs 0-31 are special - they are local to each CPU.
* As such, the enable set/clear, pending set/clear and active bit
* registers are banked per-cpu for these sources.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/smp.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/mach/irq.h>
#include <asm/hardware/gic.h>
static void __iomem *gic_dist_base;
static void __iomem *gic_cpu_base;
/*
* Routines to acknowledge, disable and enable interrupts
*
* Linux assumes that when we're done with an interrupt we need to
* unmask it, in the same way we need to unmask an interrupt when
* we first enable it.
*
* The GIC has a seperate notion of "end of interrupt" to re-enable
* an interrupt after handling, in order to support hardware
* prioritisation.
*
* We can make the GIC behave in the way that Linux expects by making
* our "acknowledge" routine disable the interrupt, then mark it as
* complete.
*/
static void gic_ack_irq(unsigned int irq)
{
u32 mask = 1 << (irq % 32);
writel(mask, gic_dist_base + GIC_DIST_ENABLE_CLEAR + (irq / 32) * 4);
writel(irq, gic_cpu_base + GIC_CPU_EOI);
}
static void gic_mask_irq(unsigned int irq)
{
u32 mask = 1 << (irq % 32);
writel(mask, gic_dist_base + GIC_DIST_ENABLE_CLEAR + (irq / 32) * 4);
}
static void gic_unmask_irq(unsigned int irq)
{
u32 mask = 1 << (irq % 32);
writel(mask, gic_dist_base + GIC_DIST_ENABLE_SET + (irq / 32) * 4);
}
static void gic_set_cpu(struct irqdesc *desc, unsigned int irq, unsigned int cpu)
{
void __iomem *reg = gic_dist_base + GIC_DIST_TARGET + (irq & ~3);
unsigned int shift = (irq % 4) * 8;
u32 val;
val = readl(reg) & ~(0xff << shift);
val |= 1 << (cpu + shift);
writel(val, reg);
}
static struct irqchip gic_chip = {
.ack = gic_ack_irq,
.mask = gic_mask_irq,
.unmask = gic_unmask_irq,
#ifdef CONFIG_SMP
.set_cpu = gic_set_cpu,
#endif
};
void __init gic_dist_init(void __iomem *base)
{
unsigned int max_irq, i;
u32 cpumask = 1 << smp_processor_id();
cpumask |= cpumask << 8;
cpumask |= cpumask << 16;
gic_dist_base = base;
writel(0, base + GIC_DIST_CTRL);
/*
* Find out how many interrupts are supported.
*/
max_irq = readl(base + GIC_DIST_CTR) & 0x1f;
max_irq = (max_irq + 1) * 32;
/*
* The GIC only supports up to 1020 interrupt sources.
* Limit this to either the architected maximum, or the
* platform maximum.
*/
if (max_irq > max(1020, NR_IRQS))
max_irq = max(1020, NR_IRQS);
/*
* Set all global interrupts to be level triggered, active low.
*/
for (i = 32; i < max_irq; i += 16)
writel(0, base + GIC_DIST_CONFIG + i * 4 / 16);
/*
* Set all global interrupts to this CPU only.
*/
for (i = 32; i < max_irq; i += 4)
writel(cpumask, base + GIC_DIST_TARGET + i * 4 / 4);
/*
* Set priority on all interrupts.
*/
for (i = 0; i < max_irq; i += 4)
writel(0xa0a0a0a0, base + GIC_DIST_PRI + i * 4 / 4);
/*
* Disable all interrupts.
*/
for (i = 0; i < max_irq; i += 32)
writel(0xffffffff, base + GIC_DIST_ENABLE_CLEAR + i * 4 / 32);
/*
* Setup the Linux IRQ subsystem.
*/
for (i = 29; i < max_irq; i++) {
set_irq_chip(i, &gic_chip);
set_irq_handler(i, do_level_IRQ);
set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
}
writel(1, base + GIC_DIST_CTRL);
}
void __cpuinit gic_cpu_init(void __iomem *base)
{
gic_cpu_base = base;
writel(0xf0, base + GIC_CPU_PRIMASK);
writel(1, base + GIC_CPU_CTRL);
}
#ifdef CONFIG_SMP
void gic_raise_softirq(cpumask_t cpumask, unsigned int irq)
{
unsigned long map = *cpus_addr(cpumask);
writel(map << 16 | irq, gic_dist_base + GIC_DIST_SOFTINT);
}
#endif
|
