arch/mips/kernel/irq.c

/* */
This source file includes following definitions.
disable_irq
enable_irq
get_irq_list
do_IRQ
do_fast_IRQ
irqaction
request_irq
free_irq
math_error_irq
no_action
probe_irq_on
probe_irq_off
init_IRQ
   1 /*
   2  *      linux/kernel/irq.c
   3  *
   4  *      Copyright (C) 1992 Linus Torvalds
   5  *
   6  * This file contains the code used by various IRQ handling routines:
   7  * asking for different IRQ's should be done through these routines
   8  * instead of just grabbing them. Thus setups with different IRQ numbers
   9  * shouldn't result in any weird surprises, and installing new handlers
  10  * should be easier.
  11  */
  12 
  13 /*
  14  * IRQ's are in fact implemented a bit like signal handlers for the kernel.
  15  * The same sigaction struct is used, and with similar semantics (ie there
  16  * is a SA_INTERRUPT flag etc). Naturally it's not a 1:1 relation, but there
  17  * are similarities.
  18  *
  19  * sa_handler(int irq_NR) is the default function called (0 if no).
  20  * sa_mask is horribly ugly (I won't even mention it)
  21  * sa_flags contains various info: SA_INTERRUPT etc
  22  * sa_restorer is the unused
  23  */
  24 
  25 #include <linux/ptrace.h>
  26 #include <linux/errno.h>
  27 #include <linux/kernel_stat.h>
  28 #include <linux/signal.h>
  29 #include <linux/sched.h>
  30 #include <linux/interrupt.h>
  31 
  32 #include <asm/system.h>
  33 #include <asm/io.h>
  34 #include <asm/irq.h>
  35 #include <asm/bitops.h>
  36 
  37 unsigned char cache_21 = 0xff;
  38 unsigned char cache_A1 = 0xff;
  39 
  40 unsigned long spurious_count = 0;
  41 
  42 void disable_irq(unsigned int irq_nr)
     /*  */
  43 {
  44         unsigned long flags;
  45         unsigned char mask;
  46 
  47         mask = 1 << (irq_nr & 7);
  48         save_flags(flags);
  49         if (irq_nr < 8) {
  50                 cli();
  51                 cache_21 |= mask;
  52                 outb(cache_21,0x21);
  53                 restore_flags(flags);
  54                 return;
  55         }
  56         cli();
  57         cache_A1 |= mask;
  58         outb(cache_A1,0xA1);
  59         restore_flags(flags);
  60 }
  61 
  62 void enable_irq(unsigned int irq_nr)
     /*  */
  63 {
  64         unsigned long flags;
  65         unsigned char mask;
  66 
  67         mask = ~(1 << (irq_nr & 7));
  68         save_flags(flags);
  69         if (irq_nr < 8) {
  70                 cli();
  71                 cache_21 &= mask;
  72                 outb(cache_21,0x21);
  73                 restore_flags(flags);
  74                 return;
  75         }
  76         cli();
  77         cache_A1 &= mask;
  78         outb(cache_A1,0xA1);
  79         restore_flags(flags);
  80 }
  81 
  82 /*
  83  * Pointers to the low-level handlers: first the general ones, then the
  84  * fast ones, then the bad ones.
  85  */
  86 extern void interrupt(void);
  87 extern void fast_interrupt(void);
  88 extern void bad_interrupt(void);
  89 
  90 /*
  91  * Initial irq handlers.
  92  */
  93 static struct sigaction irq_sigaction[16] = {
  94         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
  95         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
  96         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
  97         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
  98         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
  99         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
 100         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
 101         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }
 102 };
 103 
 104 int get_irq_list(char *buf)
     /*  */
 105 {
 106         int i, len = 0;
 107         struct sigaction * sa = irq_sigaction;
 108 
 109         for (i = 0 ; i < 16 ; i++, sa++) {
 110                 if (!sa->sa_handler)
 111                         continue;
 112                 len += sprintf(buf+len, "%2d: %8d %c %s\n",
 113                         i, kstat.interrupts[i],
 114                         (sa->sa_flags & SA_INTERRUPT) ? '+' : ' ',
 115                         (char *) sa->sa_mask);
 116         }
 117         return len;
 118 }
 119 
 120 /*
 121  * do_IRQ handles IRQ's that have been installed without the
 122  * SA_INTERRUPT flag: it uses the full signal-handling return
 123  * and runs with other interrupts enabled. All relatively slow
 124  * IRQ's should use this format: notably the keyboard/timer
 125  * routines.
 126  */
 127 asmlinkage void do_IRQ(int irq, struct pt_regs * regs)
     /*  */
 128 {
 129         struct sigaction * sa = irq + irq_sigaction;
 130 
 131         kstat.interrupts[irq]++;
 132         sa->sa_handler((int) regs);
 133 }
 134 
 135 /*
 136  * do_fast_IRQ handles IRQ's that don't need the fancy interrupt return
 137  * stuff - the handler is also running with interrupts disabled unless
 138  * it explicitly enables them later.
 139  */
 140 asmlinkage void do_fast_IRQ(int irq)
     /*  */
 141 {
 142         struct sigaction * sa = irq + irq_sigaction;
 143 
 144         kstat.interrupts[irq]++;
 145         sa->sa_handler(irq);
 146 }
 147 
 148 #define SA_PROBE SA_ONESHOT
 149 
 150 /*
 151  * Using "struct sigaction" is slightly silly, but there
 152  * are historical reasons and it works well, so..
 153  */
 154 static int irqaction(unsigned int irq, struct sigaction * new_sa)
     /*  */
 155 {
 156         struct sigaction * sa;
 157         unsigned long flags;
 158 
 159         if (irq > 15)
 160                 return -EINVAL;
 161         sa = irq + irq_sigaction;
 162         if (sa->sa_handler)
 163                 return -EBUSY;
 164         if (!new_sa->sa_handler)
 165                 return -EINVAL;
 166         save_flags(flags);
 167         cli();
 168         *sa = *new_sa;
 169         /*
 170          * FIXME: Does the SA_INTERRUPT flag make any sense on the MIPS???
 171          */
 172         if (!(sa->sa_flags & SA_PROBE)) { /* SA_ONESHOT is used by probing */
 173                 if (sa->sa_flags & SA_INTERRUPT)
 174                         set_intr_gate(irq,fast_interrupt);
 175                 else
 176                         set_intr_gate(irq,interrupt);
 177         }
 178         if (irq < 8) {
 179                 cache_21 &= ~(1<<irq);
 180                 outb(cache_21,0x21);
 181         } else {
 182                 cache_21 &= ~(1<<2);
 183                 cache_A1 &= ~(1<<(irq-8));
 184                 outb(cache_21,0x21);
 185                 outb(cache_A1,0xA1);
 186         }
 187         restore_flags(flags);
 188         return 0;
 189 }
 190 
 191 int request_irq(unsigned int irq, void (*handler)(int),
     /*  */
 192         unsigned long flags, const char * devname)
 193 {
 194         struct sigaction sa;
 195 
 196         sa.sa_handler = handler;
 197         sa.sa_flags = flags;
 198         sa.sa_mask = (unsigned long) devname;
 199         sa.sa_restorer = NULL;
 200         return irqaction(irq,&sa);
 201 }
 202 
 203 void free_irq(unsigned int irq)
     /*  */
 204 {
 205         struct sigaction * sa = irq + irq_sigaction;
 206         unsigned long flags;
 207 
 208         if (irq > 15) {
 209                 printk("Trying to free IRQ%d\n",irq);
 210                 return;
 211         }
 212         if (!sa->sa_handler) {
 213                 printk("Trying to free free IRQ%d\n",irq);
 214                 return;
 215         }
 216         save_flags(flags);
 217         cli();
 218         if (irq < 8) {
 219                 cache_21 |= 1 << irq;
 220                 outb(cache_21,0x21);
 221         } else {
 222                 cache_A1 |= 1 << (irq-8);
 223                 outb(cache_A1,0xA1);
 224         }
 225         set_intr_gate(irq,bad_interrupt);
 226         sa->sa_handler = NULL;
 227         sa->sa_flags = 0;
 228         sa->sa_mask = 0;
 229         sa->sa_restorer = NULL;
 230         restore_flags(flags);
 231 }
 232 
 233 #if 0
 234 /*
 235  * handle fpu errors
 236  */
 237 static void math_error_irq(int cpl)
     /*  */
 238 {
 239         if (!hard_math)
 240                 return;
 241         handle_fpe();
 242 }
 243 #endif
 244 
 245 static void no_action(int cpl) { }
     /*  */
 246 
 247 unsigned int probe_irq_on (void)
     /*  */
 248 {
 249         unsigned int i, irqs = 0, irqmask;
 250         unsigned long delay;
 251 
 252         /* first, snaffle up any unassigned irqs */
 253         for (i = 15; i > 0; i--) {
 254                 if (!request_irq(i, no_action, SA_PROBE, "probe")) {
 255                         enable_irq(i);
 256                         irqs |= (1 << i);
 257                 }
 258         }
 259 
 260         /* wait for spurious interrupts to mask themselves out again */
 261         for (delay = jiffies + 2; delay > jiffies; );   /* min 10ms delay */
 262 
 263         /* now filter out any obviously spurious interrupts */
 264         irqmask = (((unsigned int)cache_A1)<<8) | (unsigned int)cache_21;
 265         for (i = 15; i > 0; i--) {
 266                 if (irqs & (1 << i) & irqmask) {
 267                         irqs ^= (1 << i);
 268                         free_irq(i);
 269                 }
 270         }
 271 #ifdef DEBUG
 272         printk("probe_irq_on:  irqs=0x%04x irqmask=0x%04x\n", irqs, irqmask);
 273 #endif
 274         return irqs;
 275 }
 276 
 277 int probe_irq_off (unsigned int irqs)
     /*  */
 278 {
 279         unsigned int i, irqmask;
 280 
 281         irqmask = (((unsigned int)cache_A1)<<8) | (unsigned int)cache_21;
 282         for (i = 15; i > 0; i--) {
 283                 if (irqs & (1 << i)) {
 284                         free_irq(i);
 285                 }
 286         }
 287 #ifdef DEBUG
 288         printk("probe_irq_off: irqs=0x%04x irqmask=0x%04x\n", irqs, irqmask);
 289 #endif
 290         irqs &= irqmask;
 291         if (!irqs)
 292                 return 0;
 293         i = ffz(~irqs);
 294         if (irqs != (irqs & (1 << i)))
 295                 i = -i;
 296         return i;
 297 }
 298 
 299 void init_IRQ(void)
     /*  */
 300 {
 301         int i;
 302 
 303         for (i = 0; i < 16 ; i++)
 304                 set_intr_gate(i, bad_interrupt);
 305         if (request_irq(2, no_action, SA_INTERRUPT, "cascade"))
 306                 printk("Unable to get IRQ2 for cascade\n");
 307 
 308         /* initialize the bottom half routines. */
 309         for (i = 0; i < 32; i++) {
 310                 bh_base[i].routine = NULL;
 311                 bh_base[i].data = NULL;
 312         }
 313         bh_active = 0;
 314         intr_count = 0;
 315 }
/* */
root/arch/mips/kernel/irq.c

DEFINITIONS
