summaryrefslogtreecommitdiff
path: root/arch/arm/common/gic.c
blob: 4deece5fbdf467ac1161a24dff612f0b973d3fbb (plain)
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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
/*
 *  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. The base address of the CPU interface is usually
 *   aliased so that the same address points to different chips depending
 *   on the CPU it is accessed from.
 *
 * 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 <linux/cpumask.h>

#include <asm/irq.h>
#include <asm/io.h>
#include <asm/mach/irq.h>
#include <asm/hardware/gic.h>

static DEFINE_SPINLOCK(irq_controller_lock);

struct gic_chip_data {
	unsigned int irq_offset;
	void __iomem *dist_base;
	void __iomem *cpu_base;
};

#ifndef MAX_GIC_NR
#define MAX_GIC_NR	1
#endif

static struct gic_chip_data gic_data[MAX_GIC_NR];

static inline void __iomem *gic_dist_base(unsigned int irq)
{
	struct gic_chip_data *gic_data = get_irq_chip_data(irq);
	return gic_data->dist_base;
}

static inline void __iomem *gic_cpu_base(unsigned int irq)
{
	struct gic_chip_data *gic_data = get_irq_chip_data(irq);
	return gic_data->cpu_base;
}

static inline unsigned int gic_irq(unsigned int irq)
{
	struct gic_chip_data *gic_data = get_irq_chip_data(irq);
	return irq - gic_data->irq_offset;
}

/*
 * 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);

	spin_lock(&irq_controller_lock);
	writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_CLEAR + (gic_irq(irq) / 32) * 4);
	writel(gic_irq(irq), gic_cpu_base(irq) + GIC_CPU_EOI);
	spin_unlock(&irq_controller_lock);
}

static void gic_mask_irq(unsigned int irq)
{
	u32 mask = 1 << (irq % 32);

	spin_lock(&irq_controller_lock);
	writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_CLEAR + (gic_irq(irq) / 32) * 4);
	spin_unlock(&irq_controller_lock);
}

static void gic_unmask_irq(unsigned int irq)
{
	u32 mask = 1 << (irq % 32);

	spin_lock(&irq_controller_lock);
	writel(mask, gic_dist_base(irq) + GIC_DIST_ENABLE_SET + (gic_irq(irq) / 32) * 4);
	spin_unlock(&irq_controller_lock);
}

#ifdef CONFIG_SMP
static void gic_set_cpu(unsigned int irq, cpumask_t mask_val)
{
	void __iomem *reg = gic_dist_base(irq) + GIC_DIST_TARGET + (gic_irq(irq) & ~3);
	unsigned int shift = (irq % 4) * 8;
	unsigned int cpu = first_cpu(mask_val);
	u32 val;

	spin_lock(&irq_controller_lock);
	irq_desc[irq].cpu = cpu;
	val = readl(reg) & ~(0xff << shift);
	val |= 1 << (cpu + shift);
	writel(val, reg);
	spin_unlock(&irq_controller_lock);
}
#endif

static void fastcall gic_handle_cascade_irq(unsigned int irq,
					    struct irq_desc *desc)
{
	struct gic_chip_data *chip_data = get_irq_data(irq);
	struct irq_chip *chip = get_irq_chip(irq);
	unsigned int cascade_irq;
	unsigned long status;

	/* primary controller ack'ing */
	chip->ack(irq);

	spin_lock(&irq_controller_lock);
	status = readl(chip_data->cpu_base + GIC_CPU_INTACK);
	spin_unlock(&irq_controller_lock);

	cascade_irq = (status & 0x3ff);
	if (cascade_irq > 1020)
		goto out;
	if (cascade_irq < 32 || cascade_irq >= NR_IRQS) {
		do_bad_IRQ(cascade_irq, desc);
		goto out;
	}

	cascade_irq += chip_data->irq_offset;
	generic_handle_irq(cascade_irq);

 out:
	/* primary controller unmasking */
	chip->unmask(irq);
}

static struct irq_chip gic_chip = {
	.name		= "GIC",
	.ack		= gic_ack_irq,
	.mask		= gic_mask_irq,
	.unmask		= gic_unmask_irq,
#ifdef CONFIG_SMP
	.set_affinity	= gic_set_cpu,
#endif
};

void __init gic_cascade_irq(unsigned int gic_nr, unsigned int irq)
{
	if (gic_nr >= MAX_GIC_NR)
		BUG();
	if (set_irq_data(irq, &gic_data[gic_nr]) != 0)
		BUG();
	set_irq_chained_handler(irq, gic_handle_cascade_irq);
}

void __init gic_dist_init(unsigned int gic_nr, void __iomem *base,
			  unsigned int irq_start)
{
	unsigned int max_irq, i;
	u32 cpumask = 1 << smp_processor_id();

	if (gic_nr >= MAX_GIC_NR)
		BUG();

	cpumask |= cpumask << 8;
	cpumask |= cpumask << 16;

	gic_data[gic_nr].dist_base = base;
	gic_data[gic_nr].irq_offset = (irq_start - 1) & ~31;

	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 = irq_start; i < gic_data[gic_nr].irq_offset + max_irq; i++) {
		set_irq_chip(i, &gic_chip);
		set_irq_chip_data(i, &gic_data[gic_nr]);
		set_irq_handler(i, handle_level_irq);
		set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
	}

	writel(1, base + GIC_DIST_CTRL);
}

void __cpuinit gic_cpu_init(unsigned int gic_nr, void __iomem *base)
{
	if (gic_nr >= MAX_GIC_NR)
		BUG();

	gic_data[gic_nr].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);

	/* this always happens on GIC0 */
	writel(map << 16 | irq, gic_data[0].dist_base + GIC_DIST_SOFTINT);
}
#endif