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/sched.h>
  23 #include <linux/slab.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/kernel_stat.h>
  26
  27 #include <asm/bootinfo.h>
  28 #include <asm/irq.h>
  29 #include <asm/lasat/lasatint.h>
  30 #include <asm/time.h>
  31 #include <asm/gdb-stub.h>
  32
  33 static volatile int *lasat_int_status = NULL;
  34 static volatile int *lasat_int_mask = NULL;
  35 static volatile int lasat_int_mask_shift;
  36
  37 void disable_lasat_irq(unsigned int irq_nr)
  38 {
  39         *lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
  40 }
  41
  42 void enable_lasat_irq(unsigned int irq_nr)
  43 {
  44         *lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
  45 }
  46
  47 static void end_lasat_irq(unsigned int irq)
  48 {
  49         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
  50                 enable_lasat_irq(irq);
  51 }
  52
  53 static struct irq_chip lasat_irq_type = {
  54         .typename = "Lasat",
  55         .ack = disable_lasat_irq,
  56         .mask = disable_lasat_irq,
  57         .mask_ack = disable_lasat_irq,
  58         .unmask = enable_lasat_irq,
  59         .end = end_lasat_irq,
  60 };
  61
  62 static inline int ls1bit32(unsigned int x)
  63 {
  64         int b = 31, s;
  65
  66         s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
  67         s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
  68         s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
  69         s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
  70         s =  1; if (x <<  1 == 0) s = 0; b -= s;
  71
  72         return b;
  73 }
  74
  75 static unsigned long (* get_int_status)(void);
  76
  77 static unsigned long get_int_status_100(void)
  78 {
  79         return *lasat_int_status & *lasat_int_mask;
  80 }
  81
  82 static unsigned long get_int_status_200(void)
  83 {
  84         unsigned long int_status;
  85
  86         int_status = *lasat_int_status;
  87         int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;
  88         return int_status;
  89 }
  90
  91 asmlinkage void plat_irq_dispatch(void)
  92 {
  93         unsigned long int_status;
  94         unsigned int cause = read_c0_cause();
  95         int irq;
  96
  97         if (cause & CAUSEF_IP7) {       /* R4000 count / compare IRQ */
  98                 ll_timer_interrupt(7);
  99                 return;
 100         }
 101
 102         int_status = get_int_status();
 103
 104         /* if int_status == 0, then the interrupt has already been cleared */
 105         if (int_status) {
 106                 irq = ls1bit32(int_status);
 107
 108                 do_IRQ(irq);
 109         }
 110 }
 111
 112 void __init arch_init_irq(void)
 113 {
 114         int i;
 115
 116         switch (mips_machtype) {
 117         case MACH_LASAT_100:
 118                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
 119                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
 120                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
 121                 get_int_status = get_int_status_100;
 122                 *lasat_int_mask = 0;
 123                 break;
 124         case MACH_LASAT_200:
 125                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
 126                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
 127                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
 128                 get_int_status = get_int_status_200;
 129                 *lasat_int_mask &= 0xffff;
 130                 break;
 131         default:
 132                 panic("arch_init_irq: mips_machtype incorrect");
 133         }
 134
 135         for (i = 0; i <= LASATINT_END; i++)
 136                 set_irq_chip_and_handler(i, &lasat_irq_type, handle_level_irq);
 137 }