release/src-rt-6.x.4708/linux/linux-2.6.36/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/interrupt.h>
  23 #include <linux/irq.h>
  24
  25 #include <asm/irq_cpu.h>
  26 #include <asm/lasat/lasat.h>
  27 #include <asm/lasat/lasatint.h>
  28
  29 #include <irq.h>
  30
  31 static volatile int *lasat_int_status;
  32 static volatile int *lasat_int_mask;
  33 static volatile int lasat_int_mask_shift;
  34
  35 void disable_lasat_irq(unsigned int irq_nr)
  36 {
  37         irq_nr -= LASAT_IRQ_BASE;
  38         *lasat_int_mask &= ~(1 << irq_nr) << lasat_int_mask_shift;
  39 }
  40
  41 void enable_lasat_irq(unsigned int irq_nr)
  42 {
  43         irq_nr -= LASAT_IRQ_BASE;
  44         *lasat_int_mask |= (1 << irq_nr) << lasat_int_mask_shift;
  45 }
  46
  47 static struct irq_chip lasat_irq_type = {
  48         .name = "Lasat",
  49         .ack = disable_lasat_irq,
  50         .mask = disable_lasat_irq,
  51         .mask_ack = disable_lasat_irq,
  52         .unmask = enable_lasat_irq,
  53 };
  54
  55 static inline int ls1bit32(unsigned int x)
  56 {
  57         int b = 31, s;
  58
  59         s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
  60         s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
  61         s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
  62         s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
  63         s =  1; if (x <<  1 == 0) s = 0; b -= s;
  64
  65         return b;
  66 }
  67
  68 static unsigned long (*get_int_status)(void);
  69
  70 static unsigned long get_int_status_100(void)
  71 {
  72         return *lasat_int_status & *lasat_int_mask;
  73 }
  74
  75 static unsigned long get_int_status_200(void)
  76 {
  77         unsigned long int_status;
  78
  79         int_status = *lasat_int_status;
  80         int_status &= (int_status >> LASATINT_MASK_SHIFT_200) & 0xffff;
  81         return int_status;
  82 }
  83
  84 asmlinkage void plat_irq_dispatch(void)
  85 {
  86         unsigned long int_status;
  87         unsigned int cause = read_c0_cause();
  88         int irq;
  89
  90         if (cause & CAUSEF_IP7) {       /* R4000 count / compare IRQ */
  91                 do_IRQ(7);
  92                 return;
  93         }
  94
  95         int_status = get_int_status();
  96
  97         /* if int_status == 0, then the interrupt has already been cleared */
  98         if (int_status) {
  99                 irq = LASAT_IRQ_BASE + ls1bit32(int_status);
 100
 101                 do_IRQ(irq);
 102         }
 103 }
 104
 105 static struct irqaction cascade = {
 106         .handler        = no_action,
 107         .name           = "cascade",
 108 };
 109
 110 void __init arch_init_irq(void)
 111 {
 112         int i;
 113
 114         if (IS_LASAT_200()) {
 115                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_200;
 116                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_200;
 117                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_200;
 118                 get_int_status = get_int_status_200;
 119                 *lasat_int_mask &= 0xffff;
 120         } else {
 121                 lasat_int_status = (void *)LASAT_INT_STATUS_REG_100;
 122                 lasat_int_mask = (void *)LASAT_INT_MASK_REG_100;
 123                 lasat_int_mask_shift = LASATINT_MASK_SHIFT_100;
 124                 get_int_status = get_int_status_100;
 125                 *lasat_int_mask = 0;
 126         }
 127
 128         mips_cpu_irq_init();
 129
 130         for (i = LASAT_IRQ_BASE; i <= LASAT_IRQ_END; i++)
 131                 set_irq_chip_and_handler(i, &lasat_irq_type, handle_level_irq);
 132
 133         setup_irq(LASAT_CASCADE_IRQ, &cascade);
 134 }