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/compiler.h>
  27 #include <linux/init.h>
  28 #include <linux/sched.h>
  29 #include <linux/slab.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/kernel_stat.h>
  32
  33 #include <asm/irq.h>
  34 #include <asm/io.h>
  35 #include <asm/mips-boards/atlas.h>
  36 #include <asm/mips-boards/atlasint.h>
  37 #include <asm/gdb-stub.h>
  38
  39
  40 static struct atlas_ictrl_regs *atlas_hw0_icregs;
  41
  42 extern asmlinkage void mipsIRQ(void);
  43
  44 #if 0
  45 #define DEBUG_INT(x...) printk(x)
  46 #else
  47 #define DEBUG_INT(x...)
  48 #endif
  49
  50 void disable_atlas_irq(unsigned int irq_nr)
  51 {
  52         atlas_hw0_icregs->intrsten = (1 << (irq_nr-ATLASINT_BASE));
  53         iob();
  54 }
  55
  56 void enable_atlas_irq(unsigned int irq_nr)
  57 {
  58         atlas_hw0_icregs->intseten = (1 << (irq_nr-ATLASINT_BASE));
  59         iob();
  60 }
  61
  62 static unsigned int startup_atlas_irq(unsigned int irq)
  63 {
  64         enable_atlas_irq(irq);
  65         return 0; /* never anything pending */
  66 }
  67
  68 #define shutdown_atlas_irq      disable_atlas_irq
  69
  70 #define mask_and_ack_atlas_irq disable_atlas_irq
  71
  72 static void end_atlas_irq(unsigned int irq)
  73 {
  74         if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
  75                 enable_atlas_irq(irq);
  76 }
  77
  78 static struct hw_interrupt_type atlas_irq_type = {
  79         "Atlas",
  80         startup_atlas_irq,
  81         shutdown_atlas_irq,
  82         enable_atlas_irq,
  83         disable_atlas_irq,
  84         mask_and_ack_atlas_irq,
  85         end_atlas_irq,
  86         NULL
  87 };
  88
  89 static inline int ls1bit32(unsigned int x)
  90 {
  91         int b = 31, s;
  92
  93         s = 16; if (x << 16 == 0) s = 0; b -= s; x <<= s;
  94         s =  8; if (x <<  8 == 0) s = 0; b -= s; x <<= s;
  95         s =  4; if (x <<  4 == 0) s = 0; b -= s; x <<= s;
  96         s =  2; if (x <<  2 == 0) s = 0; b -= s; x <<= s;
  97         s =  1; if (x <<  1 == 0) s = 0; b -= s;
  98
  99         return b;
 100 }
 101
 102 void atlas_hw0_irqdispatch(struct pt_regs *regs)
 103 {
 104         unsigned long int_status;
 105         int irq;
 106
 107         int_status = atlas_hw0_icregs->intstatus;
 108
 109         /* if int_status == 0, then the interrupt has already been cleared */
 110         if (unlikely(int_status == 0))
 111                 return;
 112
 113         irq = ATLASINT_BASE + ls1bit32(int_status);
 114
 115         DEBUG_INT("atlas_hw0_irqdispatch: irq=%d\n", irq);
 116
 117         do_IRQ(irq, regs);
 118 }
 119
 120 void __init arch_init_irq(void)
 121 {
 122         int i;
 123
 124         atlas_hw0_icregs = (struct atlas_ictrl_regs *)ioremap (ATLAS_ICTRL_REGS_BASE, sizeof(struct atlas_ictrl_regs *));
 125
 126         /*
 127          * Mask out all interrupt by writing "1" to all bit position in
 128          * the interrupt reset reg.
 129          */
 130         atlas_hw0_icregs->intrsten = 0xffffffff;
 131
 132         /* Now safe to set the exception vector. */
 133         set_except_vector(0, mipsIRQ);
 134
 135         for (i = ATLASINT_BASE; i <= ATLASINT_END; i++) {
 136                 irq_desc[i].status      = IRQ_DISABLED;
 137                 irq_desc[i].action      = 0;
 138                 irq_desc[i].depth       = 1;
 139                 irq_desc[i].handler     = &atlas_irq_type;
 140                 spin_lock_init(&irq_desc[i].lock);
 141         }
 142 }