arch/mips/lasat/interrupt.c

   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/irq.h>
  23 #include <linux/sched.h>
  24 #include <linux/slab.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/kernel_stat.h>
  27
  28 #include <asm/bootinfo.h>
  29 #include <asm/irq_cpu.h>
  30 #include <asm/lasat/lasatint.h>
  31 #include <asm/time.h>
  32 #include <asm/gdb-stub.h>
  33
  34 static volatile int *lasat_int_status;
  35 static volatile int *lasat_int_mask;
  36 static volatile int lasat_int_mask_shift;
  37
  38 void disable_lasat_irq(unsigned int irq_nr)
  39 {
  40         *lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
  41 }
  42
  43 void enable_lasat_irq(unsigned int irq_nr)
  44 {
  45         *lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
  46 }
  47
  48 static struct irq_chip lasat_irq_type = {
  49         .name = "Lasat",
  50         .ack = disable_lasat_irq,
  51         .mask = disable_lasat_irq,
  52         .mask_ack = disable_lasat_irq,
  53         .unmask = enable_lasat_irq,
  54 };
  55
  56 static inline int ls1bit32(unsigned int x)
  57 {
  58         int b = 31, s;
  59
  60         s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
  61         s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
  62         s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
  63         s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
  64         s =  1; if (x <<  1 == 0) s = 0; b -= s;
  65
  66         return b;
  67 }
  68
  69 static unsigned long (*get_int_status)(void);
  70
  71 static unsigned long get_int_status_100(void)
  72 {
  73         return *lasat_int_status & *lasat_int_mask;
  74 }
  75
  76 static unsigned long get_int_status_200(void)
  77 {
  78         unsigned long int_status;
  79
  80         int_status = *lasat_int_status;
  81         int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;
  82         return int_status;
  83 }
  84
  85 asmlinkage void plat_irq_dispatch(void)
  86 {
  87         unsigned long int_status;
  88         unsigned int cause = read_c0_cause();
  89         int irq;
  90
  91         if (cause & CAUSEF_IP7) {       /* R4000 count / compare IRQ */
  92                 do_IRQ(7);
  93                 return;
  94         }
  95
  96         int_status = get_int_status();
  97
  98         /* if int_status == 0, then the interrupt has already been cleared */
  99         if (int_status) {
 100                 irq = LASATINT_BASE + ls1bit32(int_status);
 101
 102                 do_IRQ(irq);
 103         }
 104 }
 105
 106 void __init arch_init_irq(void)
 107 {
 108         int i;
 109
 110         switch (mips_machtype) {
 111         case MACH_LASAT_100:
 112                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
 113                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
 114                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
 115                 get_int_status = get_int_status_100;
 116                 *lasat_int_mask = 0;
 117                 break;
 118         case MACH_LASAT_200:
 119                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
 120                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
 121                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
 122                 get_int_status = get_int_status_200;
 123                 *lasat_int_mask &= 0xffff;
 124                 break;
 125         default:
 126                 panic("arch_init_irq: mips_machtype incorrect");
 127         }
 128
 129         mips_cpu_irq_init();
 130         for (i = LASATINT_BASE; i <= LASATINT_END; i++)
 131                 set_irq_chip_and_handler(i, &lasat_irq_type, handle_level_irq);
 132 }