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         unsigned long flags;
  40
  41         local_irq_save(flags);
  42         *lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
  43         local_irq_restore(flags);
  44 }
  45
  46 void enable_lasat_irq(unsigned int irq_nr)
  47 {
  48         unsigned long flags;
  49
  50         local_irq_save(flags);
  51         *lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
  52         local_irq_restore(flags);
  53 }
  54
  55 static unsigned int startup_lasat_irq(unsigned int irq)
  56 {
  57         enable_lasat_irq(irq);
  58
  59         return 0; /* never anything pending */
  60 }
  61
  62 #define shutdown_lasat_irq      disable_lasat_irq
  63
  64 #define mask_and_ack_lasat_irq disable_lasat_irq
  65
  66 static void end_lasat_irq(unsigned int irq)
  67 {
  68         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
  69                 enable_lasat_irq(irq);
  70 }
  71
  72 static struct irq_chip lasat_irq_type = {
  73         .typename = "Lasat",
  74         .startup = startup_lasat_irq,
  75         .shutdown = shutdown_lasat_irq,
  76         .enable = enable_lasat_irq,
  77         .disable = disable_lasat_irq,
  78         .ack = mask_and_ack_lasat_irq,
  79         .end = end_lasat_irq,
  80 };
  81
  82 static inline int ls1bit32(unsigned int x)
  83 {
  84         int b = 31, s;
  85
  86         s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
  87         s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
  88         s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
  89         s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
  90         s =  1; if (x <<  1 == 0) s = 0; b -= s;
  91
  92         return b;
  93 }
  94
  95 static unsigned long (* get_int_status)(void);
  96
  97 static unsigned long get_int_status_100(void)
  98 {
  99         return *lasat_int_status & *lasat_int_mask;
 100 }
 101
 102 static unsigned long get_int_status_200(void)
 103 {
 104         unsigned long int_status;
 105
 106         int_status = *lasat_int_status;
 107         int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;
 108         return int_status;
 109 }
 110
 111 asmlinkage void plat_irq_dispatch(void)
 112 {
 113         unsigned long int_status;
 114         unsigned int cause = read_c0_cause();
 115         int irq;
 116
 117         if (cause & CAUSEF_IP7) {       /* R4000 count / compare IRQ */
 118                 ll_timer_interrupt(7);
 119                 return;
 120         }
 121
 122         int_status = get_int_status();
 123
 124         /* if int_status == 0, then the interrupt has already been cleared */
 125         if (int_status) {
 126                 irq = ls1bit32(int_status);
 127
 128                 do_IRQ(irq);
 129         }
 130 }
 131
 132 void __init arch_init_irq(void)
 133 {
 134         int i;
 135
 136         switch (mips_machtype) {
 137         case MACH_LASAT_100:
 138                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
 139                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
 140                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
 141                 get_int_status = get_int_status_100;
 142                 *lasat_int_mask = 0;
 143                 break;
 144         case MACH_LASAT_200:
 145                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
 146                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
 147                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
 148                 get_int_status = get_int_status_200;
 149                 *lasat_int_mask &= 0xffff;
 150                 break;
 151         default:
 152                 panic("arch_init_irq: mips_machtype incorrect");
 153         }
 154
 155         for (i = 0; i <= LASATINT_END; i++) {
 156                 irq_desc[i].status      = IRQ_DISABLED;
 157                 irq_desc[i].action      = 0;
 158                 irq_desc[i].depth       = 1;
 159                 irq_desc[i].chip        = &lasat_irq_type;
 160         }
 161 }