arch/i386/kernel/irq.c

/* */
This source file includes following definitions.
disable_irq
enable_irq
get_irq_list
get_smp_prof_list
do_IRQ
do_fast_IRQ
request_irq
free_irq
math_error_irq
no_action
probe_irq_on
probe_irq_off
init_IRQ
   1 /*
   2  *      linux/arch/i386/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  * Naturally it's not a 1:1 relation, but there are similarities.
  16  */
  17 
  18 #include <linux/ptrace.h>
  19 #include <linux/errno.h>
  20 #include <linux/kernel_stat.h>
  21 #include <linux/signal.h>
  22 #include <linux/sched.h>
  23 #include <linux/ioport.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/timex.h>
  26 #include <linux/random.h>
  27 
  28 #include <asm/system.h>
  29 #include <asm/io.h>
  30 #include <asm/irq.h>
  31 #include <asm/bitops.h>
  32 #include <asm/smp.h>
  33 
  34 #define CR0_NE 32
  35 
  36 static unsigned char cache_21 = 0xff;
  37 static unsigned char cache_A1 = 0xff;
  38 
  39 #ifdef __SMP_PROF__
  40 static unsigned int int_count[NR_CPUS][NR_IRQS] = {{0},};
  41 #endif
  42 
  43 void disable_irq(unsigned int irq_nr)
     /*  */
  44 {
  45         unsigned long flags;
  46         unsigned char mask;
  47 
  48         mask = 1 << (irq_nr & 7);
  49         save_flags(flags);
  50         if (irq_nr < 8) {
  51                 cli();
  52                 cache_21 |= mask;
  53                 outb(cache_21,0x21);
  54                 restore_flags(flags);
  55                 return;
  56         }
  57         cli();
  58         cache_A1 |= mask;
  59         outb(cache_A1,0xA1);
  60         restore_flags(flags);
  61 }
  62 
  63 void enable_irq(unsigned int irq_nr)
     /*  */
  64 {
  65         unsigned long flags;
  66         unsigned char mask;
  67 
  68         mask = ~(1 << (irq_nr & 7));
  69         save_flags(flags);
  70         if (irq_nr < 8) {
  71                 cli();
  72                 cache_21 &= mask;
  73                 outb(cache_21,0x21);
  74                 restore_flags(flags);
  75                 return;
  76         }
  77         cli();
  78         cache_A1 &= mask;
  79         outb(cache_A1,0xA1);
  80         restore_flags(flags);
  81 }
  82 
  83 /*
  84  * This builds up the IRQ handler stubs using some ugly macros in irq.h
  85  *
  86  * These macros create the low-level assembly IRQ routines that do all
  87  * the operations that are needed to keep the AT interrupt-controller
  88  * happy. They are also written to be fast - and to disable interrupts
  89  * as little as humanly possible.
  90  *
  91  * NOTE! These macros expand to three different handlers for each line: one
  92  * complete handler that does all the fancy stuff (including signal handling),
  93  * and one fast handler that is meant for simple IRQ's that want to be
  94  * atomic. The specific handler is chosen depending on the SA_INTERRUPT
  95  * flag when installing a handler. Finally, one "bad interrupt" handler, that
  96  * is used when no handler is present.
  97  */
  98 BUILD_IRQ(FIRST,0,0x01)
  99 BUILD_IRQ(FIRST,1,0x02)
 100 BUILD_IRQ(FIRST,2,0x04)
 101 BUILD_IRQ(FIRST,3,0x08)
 102 BUILD_IRQ(FIRST,4,0x10)
 103 BUILD_IRQ(FIRST,5,0x20)
 104 BUILD_IRQ(FIRST,6,0x40)
 105 BUILD_IRQ(FIRST,7,0x80)
 106 BUILD_IRQ(SECOND,8,0x01)
 107 BUILD_IRQ(SECOND,9,0x02)
 108 BUILD_IRQ(SECOND,10,0x04)
 109 BUILD_IRQ(SECOND,11,0x08)
 110 BUILD_IRQ(SECOND,12,0x10)
 111 #ifdef __SMP__
 112 BUILD_MSGIRQ(SECOND,13,0x20)
 113 #else
 114 BUILD_IRQ(SECOND,13,0x20)
 115 #endif
 116 BUILD_IRQ(SECOND,14,0x40)
 117 BUILD_IRQ(SECOND,15,0x80)
 118 #ifdef __SMP__
 119 BUILD_RESCHEDIRQ(16)
 120 #endif
 121 
 122 /*
 123  * Pointers to the low-level handlers: first the general ones, then the
 124  * fast ones, then the bad ones.
 125  */
 126 static void (*interrupt[17])(void) = {
 127         IRQ0_interrupt, IRQ1_interrupt, IRQ2_interrupt, IRQ3_interrupt,
 128         IRQ4_interrupt, IRQ5_interrupt, IRQ6_interrupt, IRQ7_interrupt,
 129         IRQ8_interrupt, IRQ9_interrupt, IRQ10_interrupt, IRQ11_interrupt,
 130         IRQ12_interrupt, IRQ13_interrupt, IRQ14_interrupt, IRQ15_interrupt      
 131 #ifdef __SMP__  
 132         ,IRQ16_interrupt
 133 #endif
 134 };
 135 
 136 static void (*fast_interrupt[16])(void) = {
 137         fast_IRQ0_interrupt, fast_IRQ1_interrupt,
 138         fast_IRQ2_interrupt, fast_IRQ3_interrupt,
 139         fast_IRQ4_interrupt, fast_IRQ5_interrupt,
 140         fast_IRQ6_interrupt, fast_IRQ7_interrupt,
 141         fast_IRQ8_interrupt, fast_IRQ9_interrupt,
 142         fast_IRQ10_interrupt, fast_IRQ11_interrupt,
 143         fast_IRQ12_interrupt, fast_IRQ13_interrupt,
 144         fast_IRQ14_interrupt, fast_IRQ15_interrupt
 145 };
 146 
 147 static void (*bad_interrupt[16])(void) = {
 148         bad_IRQ0_interrupt, bad_IRQ1_interrupt,
 149         bad_IRQ2_interrupt, bad_IRQ3_interrupt,
 150         bad_IRQ4_interrupt, bad_IRQ5_interrupt,
 151         bad_IRQ6_interrupt, bad_IRQ7_interrupt,
 152         bad_IRQ8_interrupt, bad_IRQ9_interrupt,
 153         bad_IRQ10_interrupt, bad_IRQ11_interrupt,
 154         bad_IRQ12_interrupt, bad_IRQ13_interrupt,
 155         bad_IRQ14_interrupt, bad_IRQ15_interrupt
 156 };
 157 
 158 /*
 159  * Initial irq handlers.
 160  */
 161 struct irqaction {
 162         void (*handler)(int, struct pt_regs *);
 163         unsigned long flags;
 164         unsigned long mask;
 165         const char *name;
 166 };
 167 
 168 static struct irqaction irq_action[16] = {
 169         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
 170         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
 171         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
 172         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
 173         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
 174         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
 175         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL },
 176         { NULL, 0, 0, NULL }, { NULL, 0, 0, NULL }
 177 };
 178 
 179 int get_irq_list(char *buf)
     /*  */
 180 {
 181         int i, len = 0;
 182         struct irqaction * action = irq_action;
 183 
 184         for (i = 0 ; i < 16 ; i++, action++) {
 185                 if (!action->handler)
 186                         continue;
 187                 len += sprintf(buf+len, "%3d: %8d %c %s\n",
 188                         i, kstat.interrupts[i],
 189                         (action->flags & SA_INTERRUPT) ? '+' : ' ',
 190                         action->name);
 191         }
 192 /*
 193  *      Linus - should you add NMI counts here ?????
 194  */
 195 #ifdef __SMP_PROF__
 196         len+=sprintf(buf+len, "IPI: %8lu received\n",
 197                 ipi_count);
 198 #endif          
 199         return len;
 200 }
 201 
 202 #ifdef __SMP_PROF__
 203 
 204 int get_smp_prof_list(char *buf) {
     /*  */
 205         int i,j, len = 0;
 206         struct irqaction * action = irq_action;
 207         unsigned long sum_spins = 0;
 208         unsigned long sum_spins_syscall = 0;
 209         unsigned long sum_spins_sys_idle = 0;
 210         unsigned long sum_smp_idle_count = 0;
 211 
 212         for (i=0;i<=smp_num_cpus;i++) {
 213           sum_spins+=smp_spins[i];
 214           sum_spins_syscall+=smp_spins_syscall[i];
 215           sum_spins_sys_idle+=smp_spins_sys_idle[i];
 216           sum_smp_idle_count+=smp_idle_count[i];
 217         }
 218 
 219         len += sprintf(buf+len,"CPUS: %10i \n", 
 220                 0==smp_num_cpus?1:smp_num_cpus);
 221         len += sprintf(buf+len,"            SUM ");
 222         for (i=0;i<smp_num_cpus;i++)
 223           len += sprintf(buf+len,"        P%1d ",i);
 224         len += sprintf(buf+len,"\n");
 225         for (i = 0 ; i < NR_IRQS ; i++, action++) {
 226                 if (!action->handler)
 227                         continue;
 228                 len += sprintf(buf+len, "%3d: %10d ",
 229                         i, kstat.interrupts[i]);
 230                 for (j=0;j<smp_num_cpus;j++)
 231                   len+=sprintf(buf+len, "%10d ",int_count[j][i]);
 232                 len += sprintf(buf+len, "%c %s\n",
 233                         (action->flags & SA_INTERRUPT) ? '+' : ' ',
 234                         action->name);
 235         }
 236         len+=sprintf(buf+len, "LCK: %10lu",
 237                 sum_spins);
 238         for (i=0;i<smp_num_cpus;i++)
 239           len+=sprintf(buf+len," %10lu",smp_spins[i]);
 240         len +=sprintf(buf+len,"   spins from int\n");
 241 
 242         len+=sprintf(buf+len, "LCK: %10lu",
 243                 sum_spins_syscall);
 244         for (i=0;i<smp_num_cpus;i++)
 245           len+=sprintf(buf+len," %10lu",smp_spins_syscall[i]);
 246         len +=sprintf(buf+len,"   spins from syscall\n");
 247 
 248         len+=sprintf(buf+len, "LCK: %10lu",
 249                 sum_spins_sys_idle);
 250         for (i=0;i<smp_num_cpus;i++)
 251           len+=sprintf(buf+len," %10lu",smp_spins_sys_idle[i]);
 252         len +=sprintf(buf+len,"   spins from sysidle\n");
 253         len+=sprintf(buf+len,"IDLE %10lu",sum_smp_idle_count);
 254         for (i=0;i<smp_num_cpus;i++)
 255           len+=sprintf(buf+len," %10lu",smp_idle_count[i]);
 256         len +=sprintf(buf+len,"   idle ticks\n");
 257 
 258         len+=sprintf(buf+len, "IPI: %10lu   received\n",
 259                 ipi_count);
 260 
 261         return len;
 262 }
 263 #endif 
 264 
 265 
 266 
 267 /*
 268  * do_IRQ handles IRQ's that have been installed without the
 269  * SA_INTERRUPT flag: it uses the full signal-handling return
 270  * and runs with other interrupts enabled. All relatively slow
 271  * IRQ's should use this format: notably the keyboard/timer
 272  * routines.
 273  */
 274 asmlinkage void do_IRQ(int irq, struct pt_regs * regs)
     /*  */
 275 {
 276         struct irqaction * action = irq + irq_action;
 277 #ifdef __SMP__
 278         if(smp_threads_ready && active_kernel_processor!=smp_processor_id())
 279                 panic("IRQ %d: active processor set wrongly(%d not %d).\n", irq, active_kernel_processor, smp_processor_id());
 280 #endif
 281 
 282         kstat.interrupts[irq]++;
 283 #ifdef __SMP_PROF__
 284         int_count[smp_processor_id()][irq]++;
 285 #endif
 286         if (action->flags & SA_SAMPLE_RANDOM)
 287                 add_interrupt_randomness(irq);
 288         action->handler(irq, regs);
 289 }
 290 
 291 /*
 292  * do_fast_IRQ handles IRQ's that don't need the fancy interrupt return
 293  * stuff - the handler is also running with interrupts disabled unless
 294  * it explicitly enables them later.
 295  */
 296 asmlinkage void do_fast_IRQ(int irq)
     /*  */
 297 {
 298         struct irqaction * action = irq + irq_action;
 299 #ifdef __SMP__
 300         /* IRQ 13 is allowed - thats an invalidate */
 301         if(smp_threads_ready && active_kernel_processor!=smp_processor_id() && irq!=13)
 302                 panic("fast_IRQ %d: active processor set wrongly(%d not %d).\n", irq, active_kernel_processor, smp_processor_id());
 303 #endif
 304 
 305         kstat.interrupts[irq]++;
 306 #ifdef __SMP_PROF__
 307         int_count[smp_processor_id()][irq]++;
 308 #endif
 309         if (action->flags & SA_SAMPLE_RANDOM)
 310                 add_interrupt_randomness(irq);
 311         action->handler(irq, NULL);
 312 }
 313 
 314 #define SA_PROBE SA_ONESHOT
 315 
 316 int request_irq(unsigned int irq, void (*handler)(int, struct pt_regs *),
     /*  */
 317         unsigned long irqflags, const char * devname)
 318 {
 319         struct irqaction * action;
 320         unsigned long flags;
 321 
 322         if (irq > 15)
 323                 return -EINVAL;
 324         action = irq + irq_action;
 325         if (action->handler)
 326                 return -EBUSY;
 327         if (!handler)
 328                 return -EINVAL;
 329         if (irqflags & SA_SAMPLE_RANDOM)
 330                 rand_initialize_irq(irq);
 331         save_flags(flags);
 332         cli();
 333         action->handler = handler;
 334         action->flags = irqflags;
 335         action->mask = 0;
 336         action->name = devname;
 337         if (!(action->flags & SA_PROBE)) { /* SA_ONESHOT is used by probing */
 338                 if (action->flags & SA_INTERRUPT)
 339                         set_intr_gate(0x20+irq,fast_interrupt[irq]);
 340                 else
 341                         set_intr_gate(0x20+irq,interrupt[irq]);
 342         }
 343         if (irq < 8) {
 344                 cache_21 &= ~(1<<irq);
 345                 outb(cache_21,0x21);
 346         } else {
 347                 cache_21 &= ~(1<<2);
 348                 cache_A1 &= ~(1<<(irq-8));
 349                 outb(cache_21,0x21);
 350                 outb(cache_A1,0xA1);
 351         }
 352         restore_flags(flags);
 353         return 0;
 354 }
 355                 
 356 void free_irq(unsigned int irq)
     /*  */
 357 {
 358         struct irqaction * action = irq + irq_action;
 359         unsigned long flags;
 360 
 361         if (irq > 15) {
 362                 printk("Trying to free IRQ%d\n",irq);
 363                 return;
 364         }
 365         if (!action->handler) {
 366                 printk("Trying to free free IRQ%d\n",irq);
 367                 return;
 368         }
 369         save_flags(flags);
 370         cli();
 371         if (irq < 8) {
 372                 cache_21 |= 1 << irq;
 373                 outb(cache_21,0x21);
 374         } else {
 375                 cache_A1 |= 1 << (irq-8);
 376                 outb(cache_A1,0xA1);
 377         }
 378         set_intr_gate(0x20+irq,bad_interrupt[irq]);
 379         action->handler = NULL;
 380         action->flags = 0;
 381         action->mask = 0;
 382         action->name = NULL;
 383         restore_flags(flags);
 384 }
 385 
 386 #ifndef __SMP__
 387 
 388 /*
 389  * Note that on a 486, we don't want to do a SIGFPE on a irq13
 390  * as the irq is unreliable, and exception 16 works correctly
 391  * (ie as explained in the intel literature). On a 386, you
 392  * can't use exception 16 due to bad IBM design, so we have to
 393  * rely on the less exact irq13.
 394  *
 395  * Careful.. Not only is IRQ13 unreliable, but it is also
 396  * leads to races. IBM designers who came up with it should
 397  * be shot.
 398  */
 399  
 400 
 401 static void math_error_irq(int cpl, struct pt_regs *regs)
     /*  */
 402 {
 403         outb(0,0xF0);
 404         if (ignore_irq13 || !hard_math)
 405                 return;
 406         math_error();
 407 }
 408 
 409 #endif
 410 
 411 static void no_action(int cpl, struct pt_regs * regs) { }
     /*  */
 412 
 413 unsigned long probe_irq_on (void)
     /*  */
 414 {
 415         unsigned int i, irqs = 0, irqmask;
 416         unsigned long delay;
 417 
 418         /* first, snaffle up any unassigned irqs */
 419         for (i = 15; i > 0; i--) {
 420                 if (!request_irq(i, no_action, SA_PROBE, "probe")) {
 421                         enable_irq(i);
 422                         irqs |= (1 << i);
 423                 }
 424         }
 425 
 426         /* wait for spurious interrupts to mask themselves out again */
 427         for (delay = jiffies + 2; delay > jiffies; );   /* min 10ms delay */
 428 
 429         /* now filter out any obviously spurious interrupts */
 430         irqmask = (((unsigned int)cache_A1)<<8) | (unsigned int)cache_21;
 431         for (i = 15; i > 0; i--) {
 432                 if (irqs & (1 << i) & irqmask) {
 433                         irqs ^= (1 << i);
 434                         free_irq(i);
 435                 }
 436         }
 437 #ifdef DEBUG
 438         printk("probe_irq_on:  irqs=0x%04x irqmask=0x%04x\n", irqs, irqmask);
 439 #endif
 440         return irqs;
 441 }
 442 
 443 int probe_irq_off (unsigned long irqs)
     /*  */
 444 {
 445         unsigned int i, irqmask;
 446 
 447         irqmask = (((unsigned int)cache_A1)<<8) | (unsigned int)cache_21;
 448         for (i = 15; i > 0; i--) {
 449                 if (irqs & (1 << i)) {
 450                         free_irq(i);
 451                 }
 452         }
 453 #ifdef DEBUG
 454         printk("probe_irq_off: irqs=0x%04x irqmask=0x%04x\n", irqs, irqmask);
 455 #endif
 456         irqs &= irqmask;
 457         if (!irqs)
 458                 return 0;
 459         i = ffz(~irqs);
 460         if (irqs != (irqs & (1 << i)))
 461                 i = -i;
 462         return i;
 463 }
 464 
 465 void init_IRQ(void)
     /*  */
 466 {
 467         int i;
 468         static unsigned char smptrap=0;
 469         if(smptrap)
 470                 return;
 471         smptrap=1;
 472 
 473         /* set the clock to 100 Hz */
 474         outb_p(0x34,0x43);              /* binary, mode 2, LSB/MSB, ch 0 */
 475         outb_p(LATCH & 0xff , 0x40);    /* LSB */
 476         outb(LATCH >> 8 , 0x40);        /* MSB */
 477         for (i = 0; i < 16 ; i++)
 478                 set_intr_gate(0x20+i,bad_interrupt[i]);
 479         /* This bit is a hack because we don't send timer messages to all processors yet */
 480         /* It has to here .. it doesnt work if you put it down the bottom - assembler explodes 8) */
 481 #ifdef __SMP__  
 482         set_intr_gate(0x20+i, interrupt[i]);    /* IRQ '16' - IPI for rescheduling */
 483 #endif  
 484         if (request_irq(2, no_action, SA_INTERRUPT, "cascade"))
 485                 printk("Unable to get IRQ2 for cascade.\n");
 486 #ifndef __SMP__         
 487         if (request_irq(13,math_error_irq, 0, "math error"))
 488                 printk("Unable to get IRQ13 for math-error handler.\n");
 489 #else
 490         if (request_irq(13, smp_message_irq, SA_INTERRUPT, "IPI"))
 491                 printk("Unable to get IRQ13 for IPI.\n");
 492 #endif                          
 493         request_region(0x20,0x20,"pic1");
 494         request_region(0xa0,0x20,"pic2");
 495 }
/* */
root/arch/i386/kernel/irq.c

DEFINITIONS
