1/*
  2 * Carsten Langgaard, carstenl@mips.com
  3 * Copyright (C) 1999,2000 MIPS Technologies, Inc.  All rights reserved.
  4 *
  5 *  This program is free software; you can distribute it and/or modify it
  6 *  under the terms of the GNU General Public License (Version 2) as
  7 *  published by the Free Software Foundation.
  8 *
  9 *  This program is distributed in the hope it will be useful, but WITHOUT
 10 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12 *  for more details.
 13 *
 14 *  You should have received a copy of the GNU General Public License along
 15 *  with this program; if not, write to the Free Software Foundation, Inc.,
 16 *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
 17 *
 18 * Routines for generic manipulation of the interrupts found on the
 19 * Lasat boards.
 20 */
 21#include <linux/init.h>
 22#include <linux/interrupt.h>
 23#include <linux/irq.h>
 24
 25#include <asm/irq_cpu.h>
 26#include <asm/lasat/lasat.h>
 27#include <asm/lasat/lasatint.h>
 28
 29#include <irq.h>
 30
 31static volatile int *lasat_int_status;
 32static volatile int *lasat_int_mask;
 33static volatile int lasat_int_mask_shift;
 34
 35void disable_lasat_irq(struct irq_data *d)
 36{
 37	unsigned int irq_nr = d->irq - LASAT_IRQ_BASE;
 38
 39	*lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
 40}
 41
 42void enable_lasat_irq(struct irq_data *d)
 43{
 44	unsigned int irq_nr = d->irq - LASAT_IRQ_BASE;
 45
 46	*lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
 47}
 48
 49static struct irq_chip lasat_irq_type = {
 50	.name = "Lasat",
 51	.irq_mask = disable_lasat_irq,
 52	.irq_unmask = enable_lasat_irq,
 53};
 54
 55static inline int ls1bit32(unsigned int x)
 56{
 57	int b = 31, s;
 58
 59	s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
 60	s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
 61	s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
 62	s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
 63	s =  1; if (x <<  1 == 0) s = 0; b -= s;
 64
 65	return b;
 66}
 67
 68static unsigned long (*get_int_status)(void);
 69
 70static unsigned long get_int_status_100(void)
 71{
 72	return *lasat_int_status & *lasat_int_mask;
 73}
 74
 75static unsigned long get_int_status_200(void)
 76{
 77	unsigned long int_status;
 78
 79	int_status = *lasat_int_status;
 80	int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;
 81	return int_status;
 82}
 83
 84asmlinkage void plat_irq_dispatch(void)
 85{
 86	unsigned long int_status;
 87	unsigned int cause = read_c0_cause();
 88	int irq;
 89
 90	if (cause & CAUSEF_IP7) {	/* R4000 count / compare IRQ */
 91		do_IRQ(7);
 92		return;
 93	}
 94
 95	int_status = get_int_status();
 96
 97	/* if int_status == 0, then the interrupt has already been cleared */
 98	if (int_status) {
 99		irq = LASAT_IRQ_BASE + ls1bit32(int_status);
100
101		do_IRQ(irq);
102	}
103}
104
105static struct irqaction cascade = {
106	.handler	= no_action,
107	.name		= "cascade",
108	.flags		= IRQF_NO_THREAD,
109};
110
111void __init arch_init_irq(void)
112{
113	int i;
114
115	if (IS_LASAT_200()) {
116		lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
117		lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
118		lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
119		get_int_status = get_int_status_200;
120		*lasat_int_mask &= 0xffff;
121	} else {
122		lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
123		lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
124		lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
125		get_int_status = get_int_status_100;
126		*lasat_int_mask = 0;
127	}
128
129	mips_cpu_irq_init();
130
131	for (i = LASAT_IRQ_BASE; i <= LASAT_IRQ_END; i++)
132		irq_set_chip_and_handler(i, &lasat_irq_type, handle_level_irq);
133
134	setup_irq(LASAT_CASCADE_IRQ, &cascade);
135}