isa-irq.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *  linux/arch/arm/mach-footbridge/irq.c
  4 *
  5 *  Copyright (C) 1996-2000 Russell King
  6 *
  7 *  Changelog:
  8 *   22-Aug-1998 RMK	Restructured IRQ routines
  9 *   03-Sep-1998 PJB	Merged CATS support
 10 *   20-Jan-1998 RMK	Started merge of EBSA286, CATS and NetWinder
 11 *   26-Jan-1999 PJB	Don't use IACK on CATS
 12 *   16-Mar-1999 RMK	Added autodetect of ISA PICs
 13 */
 14#include <linux/ioport.h>
 15#include <linux/interrupt.h>
 16#include <linux/list.h>
 17#include <linux/init.h>
 18#include <linux/io.h>
 19#include <linux/spinlock.h>
 20
 21#include <asm/mach/irq.h>
 22
 23#include <mach/hardware.h>
 24#include <asm/hardware/dec21285.h>
 25#include <asm/irq.h>
 26#include <asm/mach-types.h>
 27
 28#include "common.h"
 29
 30static void isa_mask_pic_lo_irq(struct irq_data *d)
 31{
 32	unsigned int mask = 1 << (d->irq & 7);
 33
 34	outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
 35}
 36
 37static void isa_ack_pic_lo_irq(struct irq_data *d)
 38{
 39	unsigned int mask = 1 << (d->irq & 7);
 40
 41	outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
 42	outb(0x20, PIC_LO);
 43}
 44
 45static void isa_unmask_pic_lo_irq(struct irq_data *d)
 46{
 47	unsigned int mask = 1 << (d->irq & 7);
 48
 49	outb(inb(PIC_MASK_LO) & ~mask, PIC_MASK_LO);
 50}
 51
 52static struct irq_chip isa_lo_chip = {
 53	.irq_ack	= isa_ack_pic_lo_irq,
 54	.irq_mask	= isa_mask_pic_lo_irq,
 55	.irq_unmask	= isa_unmask_pic_lo_irq,
 56};
 57
 58static void isa_mask_pic_hi_irq(struct irq_data *d)
 59{
 60	unsigned int mask = 1 << (d->irq & 7);
 61
 62	outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
 63}
 64
 65static void isa_ack_pic_hi_irq(struct irq_data *d)
 66{
 67	unsigned int mask = 1 << (d->irq & 7);
 68
 69	outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
 70	outb(0x62, PIC_LO);
 71	outb(0x20, PIC_HI);
 72}
 73
 74static void isa_unmask_pic_hi_irq(struct irq_data *d)
 75{
 76	unsigned int mask = 1 << (d->irq & 7);
 77
 78	outb(inb(PIC_MASK_HI) & ~mask, PIC_MASK_HI);
 79}
 80
 81static struct irq_chip isa_hi_chip = {
 82	.irq_ack	= isa_ack_pic_hi_irq,
 83	.irq_mask	= isa_mask_pic_hi_irq,
 84	.irq_unmask	= isa_unmask_pic_hi_irq,
 85};
 86
 87static void isa_irq_handler(struct irq_desc *desc)
 88{
 89	unsigned int isa_irq = *(unsigned char *)PCIIACK_BASE;
 90
 91	if (isa_irq < _ISA_IRQ(0) || isa_irq >= _ISA_IRQ(16)) {
 92		do_bad_IRQ(desc);
 93		return;
 94	}
 95
 96	generic_handle_irq(isa_irq);
 97}
 98
 99static struct resource pic1_resource = {
100	.name	= "pic1",
101	.start	= 0x20,
102	.end	= 0x3f,
103};
104
105static struct resource pic2_resource = {
106	.name	= "pic2",
107	.start	= 0xa0,
108	.end	= 0xbf,
109};
110
111void __init isa_init_irq(unsigned int host_irq)
112{
113	unsigned int irq;
114
115	/*
116	 * Setup, and then probe for an ISA PIC
117	 * If the PIC is not there, then we
118	 * ignore the PIC.
119	 */
120	outb(0x11, PIC_LO);
121	outb(_ISA_IRQ(0), PIC_MASK_LO);	/* IRQ number		*/
122	outb(0x04, PIC_MASK_LO);	/* Slave on Ch2		*/
123	outb(0x01, PIC_MASK_LO);	/* x86			*/
124	outb(0xf5, PIC_MASK_LO);	/* pattern: 11110101	*/
125
126	outb(0x11, PIC_HI);
127	outb(_ISA_IRQ(8), PIC_MASK_HI);	/* IRQ number		*/
128	outb(0x02, PIC_MASK_HI);	/* Slave on Ch1		*/
129	outb(0x01, PIC_MASK_HI);	/* x86			*/
130	outb(0xfa, PIC_MASK_HI);	/* pattern: 11111010	*/
131
132	outb(0x0b, PIC_LO);
133	outb(0x0b, PIC_HI);
134
135	if (inb(PIC_MASK_LO) == 0xf5 && inb(PIC_MASK_HI) == 0xfa) {
136		outb(0xff, PIC_MASK_LO);/* mask all IRQs	*/
137		outb(0xff, PIC_MASK_HI);/* mask all IRQs	*/
138	} else {
139		printk(KERN_INFO "IRQ: ISA PIC not found\n");
140		host_irq = (unsigned int)-1;
141	}
142
143	if (host_irq != (unsigned int)-1) {
144		for (irq = _ISA_IRQ(0); irq < _ISA_IRQ(8); irq++) {
145			irq_set_chip_and_handler(irq, &isa_lo_chip,
146						 handle_level_irq);
147			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
148		}
149
150		for (irq = _ISA_IRQ(8); irq < _ISA_IRQ(16); irq++) {
151			irq_set_chip_and_handler(irq, &isa_hi_chip,
152						 handle_level_irq);
153			irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
154		}
155
156		request_resource(&ioport_resource, &pic1_resource);
157		request_resource(&ioport_resource, &pic2_resource);
158
159		irq = IRQ_ISA_CASCADE;
160		if (request_irq(irq, no_action, 0, "cascade", NULL))
161			pr_err("Failed to request irq %u (cascade)\n", irq);
162
163		irq_set_chained_handler(host_irq, isa_irq_handler);
164
165		/*
166		 * On the NetWinder, don't automatically
167		 * enable ISA IRQ11 when it is requested.
168		 * There appears to be a missing pull-up
169		 * resistor on this line.
170		 */
171		if (machine_is_netwinder())
172			irq_modify_status(_ISA_IRQ(11),
173				IRQ_NOREQUEST | IRQ_NOPROBE, IRQ_NOAUTOEN);
174	}
175}
176
177