arch/mips/mips-boards/atlas/atlas_int.c

   1 /*
   2  * Carsten Langgaard, carstenl@mips.com
   3  * Copyright (C) 1999,2000 MIPS Technologies, Inc.  All rights reserved.
   4  *
   5  * ########################################################################
   6  *
   7  *  This program is free software; you can distribute it and/or modify it
   8  *  under the terms of the GNU General Public License (Version 2) as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope it will be useful, but WITHOUT
  12  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  *  for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License along
  17  *  with this program; if not, write to the Free Software Foundation, Inc.,
  18  *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
  19  *
  20  * ########################################################################
  21  *
  22  * Routines for generic manipulation of the interrupts found on the MIPS
  23  * Atlas board.
  24  *
  25  */
  26 #include <linux/config.h>
  27 #include <linux/compiler.h>
  28 #include <linux/init.h>
  29 #include <linux/sched.h>
  30 #include <linux/slab.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/kernel_stat.h>
  33
  34 #include <asm/irq.h>
  35 #include <asm/io.h>
  36 #include <asm/mips-boards/atlas.h>
  37 #include <asm/mips-boards/atlasint.h>
  38 #include <asm/gdb-stub.h>
  39
  40
  41 static struct atlas_ictrl_regs *atlas_hw0_icregs;
  42
  43 extern asmlinkage void mipsIRQ(void);
  44
  45 #if 0
  46 #define DEBUG_INT(x...) printk(x)
  47 #else
  48 #define DEBUG_INT(x...)
  49 #endif
  50
  51 void disable_atlas_irq(unsigned int irq_nr)
  52 {
  53         atlas_hw0_icregs->intrsten = (1 << (irq_nr-ATLASINT_BASE));
  54         iob();
  55 }
  56
  57 void enable_atlas_irq(unsigned int irq_nr)
  58 {
  59         atlas_hw0_icregs->intseten = (1 << (irq_nr-ATLASINT_BASE));
  60         iob();
  61 }
  62
  63 static unsigned int startup_atlas_irq(unsigned int irq)
  64 {
  65         enable_atlas_irq(irq);
  66         return 0; /* never anything pending */
  67 }
  68
  69 #define shutdown_atlas_irq      disable_atlas_irq
  70
  71 #define mask_and_ack_atlas_irq disable_atlas_irq
  72
  73 static void end_atlas_irq(unsigned int irq)
  74 {
  75         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
  76                 enable_atlas_irq(irq);
  77 }
  78
  79 static struct hw_interrupt_type atlas_irq_type = {
  80         "Atlas",
  81         startup_atlas_irq,
  82         shutdown_atlas_irq,
  83         enable_atlas_irq,
  84         disable_atlas_irq,
  85         mask_and_ack_atlas_irq,
  86         end_atlas_irq,
  87         NULL
  88 };
  89
  90 static inline int ls1bit32(unsigned int x)
  91 {
  92         int b = 31, s;
  93
  94         s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
  95         s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
  96         s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
  97         s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
  98         s =  1; if (x <<  1 == 0) s = 0; b -= s;
  99
 100         return b;
 101 }
 102
 103 void atlas_hw0_irqdispatch(struct pt_regs *regs)
 104 {
 105         unsigned long int_status;
 106         int irq;
 107
 108         int_status = atlas_hw0_icregs->intstatus;
 109
 110         /* if int_status == 0, then the interrupt has already been cleared */
 111         if (unlikely(int_status == 0))
 112                 return;
 113
 114         irq = ATLASINT_BASE + ls1bit32(int_status);
 115
 116         DEBUG_INT("atlas_hw0_irqdispatch: irq=%d\n", irq);
 117
 118         do_IRQ(irq, regs);
 119 }
 120
 121 #ifdef CONFIG_KGDB
 122 extern void breakpoint(void);
 123 extern int remote_debug;
 124 #endif
 125
 126 void __init init_IRQ(void)
 127 {
 128         int i;
 129
 130         atlas_hw0_icregs = (struct atlas_ictrl_regs *)ioremap (ATLAS_ICTRL_REGS_BASE, sizeof(struct atlas_ictrl_regs *));
 131
 132         /*
 133          * Mask out all interrupt by writing "1" to all bit position in
 134          * the interrupt reset reg.
 135          */
 136         atlas_hw0_icregs->intrsten = 0xffffffff;
 137
 138         /* Now safe to set the exception vector. */
 139         set_except_vector(0, mipsIRQ);
 140
 141         for (i = ATLASINT_BASE; i <= ATLASINT_END; i++) {
 142                 irq_desc[i].status      = IRQ_DISABLED;
 143                 irq_desc[i].action      = 0;
 144                 irq_desc[i].depth       = 1;
 145                 irq_desc[i].handler     = &atlas_irq_type;
 146                 spin_lock_init(&irq_desc[i].lock);
 147         }
 148
 149 #ifdef CONFIG_KGDB
 150         if (remote_debug) {
 151                 set_debug_traps();
 152                 breakpoint();
 153         }
 154 #endif
 155 }