arch/sh/boards/harp/irq.c

   1 /*
   2  * Copyright (C) 2000 David J. Mckay (david.mckay@st.com)
   3  *
   4  * May be copied or modified under the terms of the GNU General Public
   5  * License.  See linux/COPYING for more information.
   6  *
   7  * Looks after interrupts on the HARP board.
   8  *
   9  * Bases on the IPR irq system
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/irq.h>
  14
  15 #include <asm/system.h>
  16 #include <asm/io.h>
  17 #include <asm/harp/harp.h>
  18
  19
  20 #define NUM_EXTERNAL_IRQS 16
  21
  22 // Early versions of the STB1 Overdrive required this nasty frig
  23 //#define INVERT_INTMASK_WRITES
  24
  25 static void enable_harp_irq(unsigned int irq);
  26 static void disable_harp_irq(unsigned int irq);
  27
  28 /* shutdown is same as "disable" */
  29 #define shutdown_harp_irq disable_harp_irq
  30
  31 static void mask_and_ack_harp(unsigned int);
  32 static void end_harp_irq(unsigned int irq);
  33
  34 static unsigned int startup_harp_irq(unsigned int irq)
  35 {
  36         enable_harp_irq(irq);
  37         return 0;               /* never anything pending */
  38 }
  39
  40 static struct hw_interrupt_type harp_irq_type = {
  41         .typename = "Harp-IRQ",
  42         .startup = startup_harp_irq,
  43         .shutdown = shutdown_harp_irq,
  44         .enable = enable_harp_irq,
  45         .disable = disable_harp_irq,
  46         .ack = mask_and_ack_harp,
  47         .end = end_harp_irq
  48 };
  49
  50 static void disable_harp_irq(unsigned int irq)
  51 {
  52         unsigned val, flags;
  53         unsigned maskReg;
  54         unsigned mask;
  55         int pri;
  56
  57         if (irq < 0 || irq >= NUM_EXTERNAL_IRQS)
  58                 return;
  59
  60         pri = 15 - irq;
  61
  62         if (pri < 8) {
  63                 maskReg = EPLD_INTMASK0;
  64         } else {
  65                 maskReg = EPLD_INTMASK1;
  66                 pri -= 8;
  67         }
  68
  69         local_irq_save(flags);
  70         mask = ctrl_inl(maskReg);
  71         mask &= (~(1 << pri));
  72 #if defined(INVERT_INTMASK_WRITES)
  73         mask ^= 0xff;
  74 #endif
  75         ctrl_outl(mask, maskReg);
  76         local_irq_restore(flags);
  77 }
  78
  79 static void enable_harp_irq(unsigned int irq)
  80 {
  81         unsigned flags;
  82         unsigned maskReg;
  83         unsigned mask;
  84         int pri;
  85
  86         if (irq < 0 || irq >= NUM_EXTERNAL_IRQS)
  87                 return;
  88
  89         pri = 15 - irq;
  90
  91         if (pri < 8) {
  92                 maskReg = EPLD_INTMASK0;
  93         } else {
  94                 maskReg = EPLD_INTMASK1;
  95                 pri -= 8;
  96         }
  97
  98         local_irq_save(flags);
  99         mask = ctrl_inl(maskReg);
 100
 101
 102         mask |= (1 << pri);
 103
 104 #if defined(INVERT_INTMASK_WRITES)
 105         mask ^= 0xff;
 106 #endif
 107         ctrl_outl(mask, maskReg);
 108
 109         local_irq_restore(flags);
 110 }
 111
 112 /* This functions sets the desired irq handler to be an overdrive type */
 113 static void __init make_harp_irq(unsigned int irq)
 114 {
 115         disable_irq_nosync(irq);
 116         irq_desc[irq].chip = &harp_irq_type;
 117         disable_harp_irq(irq);
 118 }
 119
 120 static void mask_and_ack_harp(unsigned int irq)
 121 {
 122         disable_harp_irq(irq);
 123 }
 124
 125 static void end_harp_irq(unsigned int irq)
 126 {
 127         enable_harp_irq(irq);
 128 }
 129
 130 void __init init_harp_irq(void)
 131 {
 132         int i;
 133
 134 #if !defined(INVERT_INTMASK_WRITES)
 135         // On the harp these are set to enable an interrupt
 136         ctrl_outl(0x00, EPLD_INTMASK0);
 137         ctrl_outl(0x00, EPLD_INTMASK1);
 138 #else
 139         // On the Overdrive the data is inverted before being stored in the reg
 140         ctrl_outl(0xff, EPLD_INTMASK0);
 141         ctrl_outl(0xff, EPLD_INTMASK1);
 142 #endif
 143
 144         for (i = 0; i < NUM_EXTERNAL_IRQS; i++) {
 145                 make_harp_irq(i);
 146         }
 147 }