arch/arm/mach-footbridge/isa-irq.c

   1 /*
   2  *  linux/arch/arm/mach-footbridge/irq.c
   3  *
   4  *  Copyright (C) 1996-2000 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  *  Changelog:
  11  *   22-Aug-1998 RMK    Restructured IRQ routines
  12  *   03-Sep-1998 PJB    Merged CATS support
  13  *   20-Jan-1998 RMK    Started merge of EBSA286, CATS and NetWinder
  14  *   26-Jan-1999 PJB    Don't use IACK on CATS
  15  *   16-Mar-1999 RMK    Added autodetect of ISA PICs
  16  */
  17 #include <linux/ioport.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/list.h>
  20 #include <linux/init.h>
  21
  22 #include <asm/mach/irq.h>
  23
  24 #include <asm/hardware.h>
  25 #include <asm/hardware/dec21285.h>
  26 #include <asm/irq.h>
  27 #include <asm/io.h>
  28 #include <asm/mach-types.h>
  29
  30 static void isa_mask_pic_lo_irq(unsigned int irq)
  31 {
  32         unsigned int mask = 1 << (irq & 7);
  33
  34         outb(inb(PIC_MASK_LO) | mask, PIC_MASK_LO);
  35 }
  36
  37 static void isa_ack_pic_lo_irq(unsigned int irq)
  38 {
  39         unsigned int mask = 1 << (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(unsigned int irq)
  46 {
  47         unsigned int mask = 1 << (irq & 7);
  48
  49         outb(inb(PIC_MASK_LO) & ~mask, PIC_MASK_LO);
  50 }
  51
  52 static struct irqchip isa_lo_chip = {
  53         .ack    = isa_ack_pic_lo_irq,
  54         .mask   = isa_mask_pic_lo_irq,
  55         .unmask = isa_unmask_pic_lo_irq,
  56 };
  57
  58 static void isa_mask_pic_hi_irq(unsigned int irq)
  59 {
  60         unsigned int mask = 1 << (irq & 7);
  61
  62         outb(inb(PIC_MASK_HI) | mask, PIC_MASK_HI);
  63 }
  64
  65 static void isa_ack_pic_hi_irq(unsigned int irq)
  66 {
  67         unsigned int mask = 1 << (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(unsigned int irq)
  75 {
  76         unsigned int mask = 1 << (irq & 7);
  77
  78         outb(inb(PIC_MASK_HI) & ~mask, PIC_MASK_HI);
  79 }
  80
  81 static struct irqchip isa_hi_chip = {
  82         .ack    = isa_ack_pic_hi_irq,
  83         .mask   = isa_mask_pic_hi_irq,
  84         .unmask = isa_unmask_pic_hi_irq,
  85 };
  86
  87 static void
  88 isa_irq_handler(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
  89 {
  90         unsigned int isa_irq = *(unsigned char *)PCIIACK_BASE;
  91
  92         if (isa_irq < _ISA_IRQ(0) || isa_irq >= _ISA_IRQ(16)) {
  93                 do_bad_IRQ(isa_irq, desc, regs);
  94                 return;
  95         }
  96
  97         desc = irq_desc + isa_irq;
  98         desc->handle(isa_irq, desc, regs);
  99 }
 100
 101 static struct irqaction irq_cascade = { .handler = no_action, .name = "cascade", };
 102 static struct resource pic1_resource = { "pic1", 0x20, 0x3f };
 103 static struct resource pic2_resource = { "pic2", 0xa0, 0xbf };
 104
 105 void __init isa_init_irq(unsigned int host_irq)
 106 {
 107         unsigned int irq;
 108
 109         /*
 110          * Setup, and then probe for an ISA PIC
 111          * If the PIC is not there, then we
 112          * ignore the PIC.
 113          */
 114         outb(0x11, PIC_LO);
 115         outb(_ISA_IRQ(0), PIC_MASK_LO); /* IRQ number           */
 116         outb(0x04, PIC_MASK_LO);        /* Slave on Ch2         */
 117         outb(0x01, PIC_MASK_LO);        /* x86                  */
 118         outb(0xf5, PIC_MASK_LO);        /* pattern: 11110101    */
 119
 120         outb(0x11, PIC_HI);
 121         outb(_ISA_IRQ(8), PIC_MASK_HI); /* IRQ number           */
 122         outb(0x02, PIC_MASK_HI);        /* Slave on Ch1         */
 123         outb(0x01, PIC_MASK_HI);        /* x86                  */
 124         outb(0xfa, PIC_MASK_HI);        /* pattern: 11111010    */
 125
 126         outb(0x0b, PIC_LO);
 127         outb(0x0b, PIC_HI);
 128
 129         if (inb(PIC_MASK_LO) == 0xf5 && inb(PIC_MASK_HI) == 0xfa) {
 130                 outb(0xff, PIC_MASK_LO);/* mask all IRQs        */
 131                 outb(0xff, PIC_MASK_HI);/* mask all IRQs        */
 132         } else {
 133                 printk(KERN_INFO "IRQ: ISA PIC not found\n");
 134                 host_irq = (unsigned int)-1;
 135         }
 136
 137         if (host_irq != (unsigned int)-1) {
 138                 for (irq = _ISA_IRQ(0); irq < _ISA_IRQ(8); irq++) {
 139                         set_irq_chip(irq, &isa_lo_chip);
 140                         set_irq_handler(irq, do_level_IRQ);
 141                         set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
 142                 }
 143
 144                 for (irq = _ISA_IRQ(8); irq < _ISA_IRQ(16); irq++) {
 145                         set_irq_chip(irq, &isa_hi_chip);
 146                         set_irq_handler(irq, do_level_IRQ);
 147                         set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
 148                 }
 149
 150                 request_resource(&ioport_resource, &pic1_resource);
 151                 request_resource(&ioport_resource, &pic2_resource);
 152                 setup_irq(IRQ_ISA_CASCADE, &irq_cascade);
 153
 154                 set_irq_chained_handler(host_irq, isa_irq_handler);
 155
 156                 /*
 157                  * On the NetWinder, don't automatically
 158                  * enable ISA IRQ11 when it is requested.
 159                  * There appears to be a missing pull-up
 160                  * resistor on this line.
 161                  */
 162                 if (machine_is_netwinder())
 163                         set_irq_flags(_ISA_IRQ(11), IRQF_VALID |
 164                                       IRQF_PROBE | IRQF_NOAUTOEN);
 165         }
 166 }
 167
 168