summaryrefslogtreecommitdiffstats
path: root/arch/frv/kernel/irq-mb93091.c
blob: 091b2839be902dc488243394814d1a3c546a84b2 (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
/* irq-mb93091.c: MB93091 FPGA interrupt handling
 *
 * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/bitops.h>

#include <asm/io.h>
#include <asm/delay.h>
#include <asm/irq.h>
#include <asm/irc-regs.h>

#define __reg16(ADDR) (*(volatile unsigned short *)(ADDR))

#define __get_IMR()	({ __reg16(0xffc00004); })
#define __set_IMR(M)	do { __reg16(0xffc00004) = (M); wmb(); } while(0)
#define __get_IFR()	({ __reg16(0xffc0000c); })
#define __clr_IFR(M)	do { __reg16(0xffc0000c) = ~(M); wmb(); } while(0)


/*
 * on-motherboard FPGA PIC operations
 */
static void frv_fpga_mask(struct irq_data *d)
{
	uint16_t imr = __get_IMR();

	imr |= 1 << (d->irq - IRQ_BASE_FPGA);

	__set_IMR(imr);
}

static void frv_fpga_ack(struct irq_data *d)
{
	__clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
}

static void frv_fpga_mask_ack(struct irq_data *d)
{
	uint16_t imr = __get_IMR();

	imr |= 1 << (d->irq - IRQ_BASE_FPGA);
	__set_IMR(imr);

	__clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
}

static void frv_fpga_unmask(struct irq_data *d)
{
	uint16_t imr = __get_IMR();

	imr &= ~(1 << (d->irq - IRQ_BASE_FPGA));

	__set_IMR(imr);
}

static struct irq_chip frv_fpga_pic = {
	.name		= "mb93091",
	.irq_ack	= frv_fpga_ack,
	.irq_mask	= frv_fpga_mask,
	.irq_mask_ack	= frv_fpga_mask_ack,
	.irq_unmask	= frv_fpga_unmask,
};

/*
 * FPGA PIC interrupt handler
 */
static irqreturn_t fpga_interrupt(int irq, void *_mask)
{
	uint16_t imr, mask = (unsigned long) _mask;

	imr = __get_IMR();
	mask = mask & ~imr & __get_IFR();

	/* poll all the triggered IRQs */
	while (mask) {
		int irq;

		asm("scan %1,gr0,%0" : "=r"(irq) : "r"(mask));
		irq = 31 - irq;
		mask &= ~(1 << irq);

		generic_handle_irq(IRQ_BASE_FPGA + irq);
	}

	return IRQ_HANDLED;
}

/*
 * define an interrupt action for each FPGA PIC output
 * - use dev_id to indicate the FPGA PIC input to output mappings
 */
static struct irqaction fpga_irq[4]  = {
	[0] = {
		.handler	= fpga_interrupt,
		.flags		= IRQF_SHARED,
		.name		= "fpga.0",
		.dev_id		= (void *) 0x0028UL,
	},
	[1] = {
		.handler	= fpga_interrupt,
		.flags		= IRQF_SHARED,
		.name		= "fpga.1",
		.dev_id		= (void *) 0x0050UL,
	},
	[2] = {
		.handler	= fpga_interrupt,
		.flags		= IRQF_SHARED,
		.name		= "fpga.2",
		.dev_id		= (void *) 0x1c00UL,
	},
	[3] = {
		.handler	= fpga_interrupt,
		.flags		= IRQF_SHARED,
		.name		= "fpga.3",
		.dev_id		= (void *) 0x6386UL,
	}
};

/*
 * initialise the motherboard FPGA's PIC
 */
void __init fpga_init(void)
{
	int irq;

	/* all PIC inputs are all set to be low-level driven, apart from the
	 * NMI button (15) which is fixed at falling-edge
	 */
	__set_IMR(0x7ffe);
	__clr_IFR(0x0000);

	for (irq = IRQ_BASE_FPGA + 1; irq <= IRQ_BASE_FPGA + 14; irq++)
		irq_set_chip_and_handler(irq, &frv_fpga_pic, handle_level_irq);

	irq_set_chip_and_handler(IRQ_FPGA_NMI, &frv_fpga_pic, handle_edge_irq);

	/* the FPGA drives the first four external IRQ inputs on the CPU PIC */
	setup_irq(IRQ_CPU_EXTERNAL0, &fpga_irq[0]);
	setup_irq(IRQ_CPU_EXTERNAL1, &fpga_irq[1]);
	setup_irq(IRQ_CPU_EXTERNAL2, &fpga_irq[2]);
	setup_irq(IRQ_CPU_EXTERNAL3, &fpga_irq[3]);
}