aboutsummaryrefslogtreecommitdiff
path: root/arch/frv/kernel/irq-mb93093.c
blob: f60db7988e78418b8851c424a5576bf24a59cbf5 (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
/* irq-mb93093.c: MB93093 FPGA interrupt handling
 *
 * Copyright (C) 2006 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 <asm/io.h>
#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/delay.h>
#include <asm/irq.h>
#include <asm/irc-regs.h>

#define __reg16(ADDR) (*(volatile unsigned short *)(__region_CS2 + (ADDR)))

#define __get_IMR()	({ __reg16(0x0a); })
#define __set_IMR(M)	do { __reg16(0x0a) = (M);  wmb(); } while(0)
#define __get_IFR()	({ __reg16(0x02); })
#define __clr_IFR(M)	do { __reg16(0x02) = ~(M); wmb(); } while(0)

/*
 * off-CPU FPGA PIC operations
 */
static void frv_fpga_enable(unsigned int irq)
{
	uint16_t imr = __get_IMR();

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

	__set_IMR(imr);
}

static void frv_fpga_disable(unsigned int irq)
{
	uint16_t imr = __get_IMR();

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

	__set_IMR(imr);
}

static void frv_fpga_ack(unsigned int irq)
{
	__clr_IFR(1 << (irq - IRQ_BASE_FPGA));
}

static void frv_fpga_end(unsigned int irq)
{
}

static struct irq_chip frv_fpga_pic = {
	.name		= "mb93093",
	.enable		= frv_fpga_enable,
	.disable	= frv_fpga_disable,
	.ack		= frv_fpga_ack,
	.mask		= frv_fpga_disable,
	.unmask		= frv_fpga_enable,
	.end		= frv_fpga_end,
};

/*
 * FPGA PIC interrupt handler
 */
static irqreturn_t fpga_interrupt(int irq, void *_mask, struct pt_regs *regs)
{
	uint16_t imr, mask = (unsigned long) _mask;
	irqreturn_t iret = 0;

	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);

		if (__do_IRQ(IRQ_BASE_FPGA + irq, regs))
			iret |= IRQ_HANDLED;
	}

	return iret;
}

/*
 * 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[1]  = {
	[0] = {
		.handler	= fpga_interrupt,
		.flags		= IRQF_DISABLED,
		.mask		= CPU_MASK_NONE,
		.name		= "fpga.0",
		.dev_id		= (void *) 0x0700UL,
	}
};

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

	/* all PIC inputs are all set to be edge triggered */
	__set_IMR(0x0700);
	__clr_IFR(0x0000);

	for (irq = IRQ_BASE_FPGA + 8; irq <= IRQ_BASE_FPGA + 10; irq++)
		set_irq_chip_and_handler(irq, &frv_fpga_pic, handle_edge_irq);

	/* the FPGA drives external IRQ input #2 on the CPU PIC */
	setup_irq(IRQ_CPU_EXTERNAL2, &fpga_irq[0]);
}