1/* irq-mb93093.c: MB93093 FPGA interrupt handling
2 *
3 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#include <linux/ptrace.h>
13#include <linux/errno.h>
14#include <linux/signal.h>
15#include <linux/sched.h>
16#include <linux/ioport.h>
17#include <linux/interrupt.h>
18#include <linux/init.h>
19#include <linux/irq.h>
20#include <linux/bitops.h>
21
22#include <asm/io.h>
23#include <asm/delay.h>
24#include <asm/irq.h>
25#include <asm/irc-regs.h>
26
27#define __reg16(ADDR) (*(volatile unsigned short *)(__region_CS2 + (ADDR)))
28
29#define __get_IMR()	({ __reg16(0x0a); })
30#define __set_IMR(M)	do { __reg16(0x0a) = (M);  wmb(); } while(0)
31#define __get_IFR()	({ __reg16(0x02); })
32#define __clr_IFR(M)	do { __reg16(0x02) = ~(M); wmb(); } while(0)
33
34/*
35 * off-CPU FPGA PIC operations
36 */
37static void frv_fpga_mask(struct irq_data *d)
38{
39	uint16_t imr = __get_IMR();
40
41	imr |= 1 << (d->irq - IRQ_BASE_FPGA);
42	__set_IMR(imr);
43}
44
45static void frv_fpga_ack(struct irq_data *d)
46{
47	__clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
48}
49
50static void frv_fpga_mask_ack(struct irq_data *d)
51{
52	uint16_t imr = __get_IMR();
53
54	imr |= 1 << (d->irq - IRQ_BASE_FPGA);
55	__set_IMR(imr);
56
57	__clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
58}
59
60static void frv_fpga_unmask(struct irq_data *d)
61{
62	uint16_t imr = __get_IMR();
63
64	imr &= ~(1 << (d->irq - IRQ_BASE_FPGA));
65
66	__set_IMR(imr);
67}
68
69static struct irq_chip frv_fpga_pic = {
70	.name		= "mb93093",
71	.irq_ack	= frv_fpga_ack,
72	.irq_mask	= frv_fpga_mask,
73	.irq_mask_ack	= frv_fpga_mask_ack,
74	.irq_unmask	= frv_fpga_unmask,
75};
76
77/*
78 * FPGA PIC interrupt handler
79 */
80static irqreturn_t fpga_interrupt(int irq, void *_mask)
81{
82	uint16_t imr, mask = (unsigned long) _mask;
83
84	imr = __get_IMR();
85	mask = mask & ~imr & __get_IFR();
86
87	/* poll all the triggered IRQs */
88	while (mask) {
89		int irq;
90
91		asm("scan %1,gr0,%0" : "=r"(irq) : "r"(mask));
92		irq = 31 - irq;
93		mask &= ~(1 << irq);
94
95		generic_handle_irq(IRQ_BASE_FPGA + irq);
96	}
97
98	return IRQ_HANDLED;
99}
100
101/*
102 * define an interrupt action for each FPGA PIC output
103 * - use dev_id to indicate the FPGA PIC input to output mappings
104 */
105static struct irqaction fpga_irq[1]  = {
106	[0] = {
107		.handler	= fpga_interrupt,
108		.name		= "fpga.0",
109		.dev_id		= (void *) 0x0700UL,
110	}
111};
112
113/*
114 * initialise the motherboard FPGA's PIC
115 */
116void __init fpga_init(void)
117{
118	int irq;
119
120	/* all PIC inputs are all set to be edge triggered */
121	__set_IMR(0x0700);
122	__clr_IFR(0x0000);
123
124	for (irq = IRQ_BASE_FPGA + 8; irq <= IRQ_BASE_FPGA + 10; irq++)
125		irq_set_chip_and_handler(irq, &frv_fpga_pic, handle_edge_irq);
126
127	/* the FPGA drives external IRQ input #2 on the CPU PIC */
128	setup_irq(IRQ_CPU_EXTERNAL2, &fpga_irq[0]);
129}
130