arch/arm/mach-footbridge/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
  30 static 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
  37 static 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
  45 static 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
  52 static 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
  58 static 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
  65 static 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
  74 static 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
  81 static 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
  87 static 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
  99 static struct resource pic1_resource = {
 100         .name   = "pic1",
 101         .start  = 0x20,
 102         .end    = 0x3f,
 103 };
 104
 105 static struct resource pic2_resource = {
 106         .name   = "pic2",
 107         .start  = 0xa0,
 108         .end    = 0xbf,
 109 };
 110
 111 void __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