aboutsummaryrefslogtreecommitdiff
path: root/arch/mips/mips-boards/atlas/atlas_int.c
blob: 6cfcd8fedcce653e0fa33f5e2e9054feaef7dab9 (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
266
267
268
269
270
271
/*
 * Copyright (C) 1999, 2000, 2006  MIPS Technologies, Inc.
 *	All rights reserved.
 *	Authors: Carsten Langgaard <carstenl@mips.com>
 *		 Maciej W. Rozycki <macro@mips.com>
 *
 * ########################################################################
 *
 *  This program is free software; you can distribute it and/or modify it
 *  under the terms of the GNU General Public License (Version 2) as
 *  published by the Free Software Foundation.
 *
 *  This program is distributed in the hope it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * ########################################################################
 *
 * Routines for generic manipulation of the interrupts found on the MIPS
 * Atlas board.
 *
 */
#include <linux/compiler.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>

#include <asm/gdb-stub.h>
#include <asm/io.h>
#include <asm/irq_cpu.h>
#include <asm/msc01_ic.h>

#include <asm/mips-boards/atlas.h>
#include <asm/mips-boards/atlasint.h>
#include <asm/mips-boards/generic.h>

static struct atlas_ictrl_regs *atlas_hw0_icregs;

#if 0
#define DEBUG_INT(x...) printk(x)
#else
#define DEBUG_INT(x...)
#endif

void disable_atlas_irq(unsigned int irq_nr)
{
	atlas_hw0_icregs->intrsten = 1 << (irq_nr - ATLAS_INT_BASE);
	iob();
}

void enable_atlas_irq(unsigned int irq_nr)
{
	atlas_hw0_icregs->intseten = 1 << (irq_nr - ATLAS_INT_BASE);
	iob();
}

static void end_atlas_irq(unsigned int irq)
{
	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
		enable_atlas_irq(irq);
}

static struct irq_chip atlas_irq_type = {
	.name = "Atlas",
	.ack = disable_atlas_irq,
	.mask = disable_atlas_irq,
	.mask_ack = disable_atlas_irq,
	.unmask = enable_atlas_irq,
	.eoi = enable_atlas_irq,
	.end = end_atlas_irq,
};

static inline int ls1bit32(unsigned int x)
{
	int b = 31, s;

	s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
	s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
	s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
	s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
	s =  1; if (x <<  1 == 0) s = 0; b -= s;

	return b;
}

static inline void atlas_hw0_irqdispatch(void)
{
	unsigned long int_status;
	int irq;

	int_status = atlas_hw0_icregs->intstatus;

	/* if int_status == 0, then the interrupt has already been cleared */
	if (unlikely(int_status == 0))
		return;

	irq = ATLAS_INT_BASE + ls1bit32(int_status);

	DEBUG_INT("atlas_hw0_irqdispatch: irq=%d\n", irq);

	do_IRQ(irq);
}

static inline int clz(unsigned long x)
{
	__asm__ (
	"	.set	push					\n"
	"	.set	mips32					\n"
	"	clz	%0, %1					\n"
	"	.set	pop					\n"
	: "=r" (x)
	: "r" (x));

	return x;
}

/*
 * Version of ffs that only looks at bits 12..15.
 */
static inline unsigned int irq_ffs(unsigned int pending)
{
#if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
	return -clz(pending) + 31 - CAUSEB_IP;
#else
	unsigned int a0 = 7;
	unsigned int t0;

	t0 = s0 & 0xf000;
	t0 = t0 < 1;
	t0 = t0 << 2;
	a0 = a0 - t0;
	s0 = s0 << t0;

	t0 = s0 & 0xc000;
	t0 = t0 < 1;
	t0 = t0 << 1;
	a0 = a0 - t0;
	s0 = s0 << t0;

	t0 = s0 & 0x8000;
	t0 = t0 < 1;
	//t0 = t0 << 2;
	a0 = a0 - t0;
	//s0 = s0 << t0;

	return a0;
#endif
}

/*
 * IRQs on the Atlas board look basically like (all external interrupt
 * sources are combined together on hardware interrupt 0 (MIPS IRQ 2)):
 *
 *      MIPS IRQ        Source
 *      --------        ------
 *             0        Software 0 (reschedule IPI on MT)
 *             1        Software 1 (remote call IPI on MT)
 *             2        Combined Atlas hardware interrupt (hw0)
 *             3        Hardware (ignored)
 *             4        Hardware (ignored)
 *             5        Hardware (ignored)
 *             6        Hardware (ignored)
 *             7        R4k timer (what we use)
 *
 * We handle the IRQ according to _our_ priority which is:
 *
 * Highest ----     R4k Timer
 * Lowest  ----     Software 0
 *
 * then we just return, if multiple IRQs are pending then we will just take
 * another exception, big deal.
 */
asmlinkage void plat_irq_dispatch(void)
{
	unsigned int pending = read_c0_cause() & read_c0_status() & ST0_IM;
	int irq;

	irq = irq_ffs(pending);

	if (irq == MIPSCPU_INT_ATLAS)
		atlas_hw0_irqdispatch();
	else if (irq >= 0)
		do_IRQ(MIPSCPU_INT_BASE + irq);
	else
		spurious_interrupt();
}

static inline void init_atlas_irqs (int base)
{
	int i;

	atlas_hw0_icregs = (struct atlas_ictrl_regs *)
			   ioremap(ATLAS_ICTRL_REGS_BASE,
				   sizeof(struct atlas_ictrl_regs *));

	/*
	 * Mask out all interrupt by writing "1" to all bit position in
	 * the interrupt reset reg.
	 */
	atlas_hw0_icregs->intrsten = 0xffffffff;

	for (i = ATLAS_INT_BASE; i <= ATLAS_INT_END; i++)
		set_irq_chip_and_handler(i, &atlas_irq_type, handle_level_irq);
}

static struct irqaction atlasirq = {
	.handler = no_action,
	.name = "Atlas cascade"
};

msc_irqmap_t __initdata msc_irqmap[] = {
	{MSC01C_INT_TMR,		MSC01_IRQ_EDGE, 0},
	{MSC01C_INT_PCI,		MSC01_IRQ_LEVEL, 0},
};
int __initdata msc_nr_irqs = sizeof(msc_irqmap) / sizeof(*msc_irqmap);

msc_irqmap_t __initdata msc_eicirqmap[] = {
	{MSC01E_INT_SW0,		MSC01_IRQ_LEVEL, 0},
	{MSC01E_INT_SW1,		MSC01_IRQ_LEVEL, 0},
	{MSC01E_INT_ATLAS,		MSC01_IRQ_LEVEL, 0},
	{MSC01E_INT_TMR,		MSC01_IRQ_EDGE, 0},
	{MSC01E_INT_PCI,		MSC01_IRQ_LEVEL, 0},
	{MSC01E_INT_PERFCTR,		MSC01_IRQ_LEVEL, 0},
	{MSC01E_INT_CPUCTR,		MSC01_IRQ_LEVEL, 0}
};
int __initdata msc_nr_eicirqs = sizeof(msc_eicirqmap) / sizeof(*msc_eicirqmap);

void __init arch_init_irq(void)
{
	init_atlas_irqs(ATLAS_INT_BASE);

	if (!cpu_has_veic)
		mips_cpu_irq_init();

	switch(mips_revision_corid) {
	case MIPS_REVISION_CORID_CORE_MSC:
	case MIPS_REVISION_CORID_CORE_FPGA2:
	case MIPS_REVISION_CORID_CORE_FPGA3:
	case MIPS_REVISION_CORID_CORE_24K:
	case MIPS_REVISION_CORID_CORE_EMUL_MSC:
		if (cpu_has_veic)
			init_msc_irqs (MSC01E_INT_BASE,
				       msc_eicirqmap, msc_nr_eicirqs);
		else
			init_msc_irqs (MSC01C_INT_BASE,
				       msc_irqmap, msc_nr_irqs);
	}


	if (cpu_has_veic) {
		set_vi_handler (MSC01E_INT_ATLAS, atlas_hw0_irqdispatch);
		setup_irq (MSC01E_INT_BASE + MSC01E_INT_ATLAS, &atlasirq);
	} else if (cpu_has_vint) {
		set_vi_handler (MIPSCPU_INT_ATLAS, atlas_hw0_irqdispatch);
#ifdef CONFIG_MIPS_MT_SMTC
		setup_irq_smtc (MIPSCPU_INT_BASE + MIPSCPU_INT_ATLAS,
				&atlasirq, (0x100 << MIPSCPU_INT_ATLAS));
#else /* Not SMTC */
		setup_irq(MIPSCPU_INT_BASE + MIPSCPU_INT_ATLAS, &atlasirq);
#endif /* CONFIG_MIPS_MT_SMTC */
	} else
		setup_irq(MIPSCPU_INT_BASE + MIPSCPU_INT_ATLAS, &atlasirq);
}