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   1 /*
   2  * linux/kernel/irq/chip.c
   3  *
   4  * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
   5  * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
   6  *
   7  * This file contains the core interrupt handling code, for irq-chip
   8  * based architectures.
   9  *
  10  * Detailed information is available in Documentation/DocBook/genericirq
  11  */
  12
  13 #include <linux/irq.h>
  14 #include <linux/module.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/kernel_stat.h>
  17
  18 #include "internals.h"
  19
  20 /**
  21  *      set_irq_chip - set the irq chip for an irq
  22  *      @irq:   irq number
  23  *      @chip:  pointer to irq chip description structure
  24  */
  25 int set_irq_chip(unsigned int irq, struct irq_chip *chip)
  26 {
  27         struct irq_desc *desc;
  28         unsigned long flags;
  29
  30         if (irq >= NR_IRQS) {
  31                 printk(KERN_ERR "Trying to install chip for IRQ%d\n", irq);
  32                 WARN_ON(1);
  33                 return -EINVAL;
  34         }
  35
  36         if (!chip)
  37                 chip = &no_irq_chip;
  38
  39         desc = irq_desc + irq;
  40         spin_lock_irqsave(&desc->lock, flags);
  41         irq_chip_set_defaults(chip);
  42         desc->chip = chip;
  43         /*
  44          * For compatibility only:
  45          */
  46         desc->chip = chip;
  47         spin_unlock_irqrestore(&desc->lock, flags);
  48
  49         return 0;
  50 }
  51 EXPORT_SYMBOL(set_irq_chip);
  52
  53 /**
  54  *      set_irq_type - set the irq type for an irq
  55  *      @irq:   irq number
  56  *      @type:  interrupt type - see include/linux/interrupt.h
  57  */
  58 int set_irq_type(unsigned int irq, unsigned int type)
  59 {
  60         struct irq_desc *desc;
  61         unsigned long flags;
  62         int ret = -ENXIO;
  63
  64         if (irq >= NR_IRQS) {
  65                 printk(KERN_ERR "Trying to set irq type for IRQ%d\n", irq);
  66                 return -ENODEV;
  67         }
  68
  69         desc = irq_desc + irq;
  70         if (desc->chip->set_type) {
  71                 spin_lock_irqsave(&desc->lock, flags);
  72                 ret = desc->chip->set_type(irq, type);
  73                 spin_unlock_irqrestore(&desc->lock, flags);
  74         }
  75         return ret;
  76 }
  77 EXPORT_SYMBOL(set_irq_type);
  78
  79 /**
  80  *      set_irq_data - set irq type data for an irq
  81  *      @irq:   Interrupt number
  82  *      @data:  Pointer to interrupt specific data
  83  *
  84  *      Set the hardware irq controller data for an irq
  85  */
  86 int set_irq_data(unsigned int irq, void *data)
  87 {
  88         struct irq_desc *desc;
  89         unsigned long flags;
  90
  91         if (irq >= NR_IRQS) {
  92                 printk(KERN_ERR
  93                        "Trying to install controller data for IRQ%d\n", irq);
  94                 return -EINVAL;
  95         }
  96
  97         desc = irq_desc + irq;
  98         spin_lock_irqsave(&desc->lock, flags);
  99         desc->handler_data = data;
 100         spin_unlock_irqrestore(&desc->lock, flags);
 101         return 0;
 102 }
 103 EXPORT_SYMBOL(set_irq_data);
 104
 105 /**
 106  *      set_irq_chip_data - set irq chip data for an irq
 107  *      @irq:   Interrupt number
 108  *      @data:  Pointer to chip specific data
 109  *
 110  *      Set the hardware irq chip data for an irq
 111  */
 112 int set_irq_chip_data(unsigned int irq, void *data)
 113 {
 114         struct irq_desc *desc = irq_desc + irq;
 115         unsigned long flags;
 116
 117         if (irq >= NR_IRQS || !desc->chip) {
 118                 printk(KERN_ERR "BUG: bad set_irq_chip_data(IRQ#%d)\n", irq);
 119                 return -EINVAL;
 120         }
 121
 122         spin_lock_irqsave(&desc->lock, flags);
 123         desc->chip_data = data;
 124         spin_unlock_irqrestore(&desc->lock, flags);
 125
 126         return 0;
 127 }
 128 EXPORT_SYMBOL(set_irq_chip_data);
 129
 130 /*
 131  * default enable function
 132  */
 133 static void default_enable(unsigned int irq)
 134 {
 135         struct irq_desc *desc = irq_desc + irq;
 136
 137         desc->chip->unmask(irq);
 138         desc->status &= ~IRQ_MASKED;
 139 }
 140
 141 /*
 142  * default disable function
 143  */
 144 static void default_disable(unsigned int irq)
 145 {
 146         struct irq_desc *desc = irq_desc + irq;
 147
 148         if (!(desc->status & IRQ_DELAYED_DISABLE))
 149                 irq_desc[irq].chip->mask(irq);
 150 }
 151
 152 /*
 153  * default startup function
 154  */
 155 static unsigned int default_startup(unsigned int irq)
 156 {
 157         irq_desc[irq].chip->enable(irq);
 158
 159         return 0;
 160 }
 161
 162 /*
 163  * Fixup enable/disable function pointers
 164  */
 165 void irq_chip_set_defaults(struct irq_chip *chip)
 166 {
 167         if (!chip->enable)
 168                 chip->enable = default_enable;
 169         if (!chip->disable)
 170                 chip->disable = default_disable;
 171         if (!chip->startup)
 172                 chip->startup = default_startup;
 173         if (!chip->shutdown)
 174                 chip->shutdown = chip->disable;
 175         if (!chip->name)
 176                 chip->name = chip->typename;
 177 }
 178
 179 static inline void mask_ack_irq(struct irq_desc *desc, int irq)
 180 {
 181         if (desc->chip->mask_ack)
 182                 desc->chip->mask_ack(irq);
 183         else {
 184                 desc->chip->mask(irq);
 185                 desc->chip->ack(irq);
 186         }
 187 }
 188
 189 /**
 190  *      handle_simple_irq - Simple and software-decoded IRQs.
 191  *      @irq:   the interrupt number
 192  *      @desc:  the interrupt description structure for this irq
 193  *      @regs:  pointer to a register structure
 194  *
 195  *      Simple interrupts are either sent from a demultiplexing interrupt
 196  *      handler or come from hardware, where no interrupt hardware control
 197  *      is necessary.
 198  *
 199  *      Note: The caller is expected to handle the ack, clear, mask and
 200  *      unmask issues if necessary.
 201  */
 202 void fastcall
 203 handle_simple_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 204 {
 205         struct irqaction *action;
 206         irqreturn_t action_ret;
 207         const unsigned int cpu = smp_processor_id();
 208
 209         spin_lock(&desc->lock);
 210
 211         if (unlikely(desc->status & IRQ_INPROGRESS))
 212                 goto out_unlock;
 213         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 214         kstat_cpu(cpu).irqs[irq]++;
 215
 216         action = desc->action;
 217         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 218                 goto out_unlock;
 219
 220         desc->status |= IRQ_INPROGRESS;
 221         spin_unlock(&desc->lock);
 222
 223         action_ret = handle_IRQ_event(irq, regs, action);
 224         if (!noirqdebug)
 225                 note_interrupt(irq, desc, action_ret, regs);
 226
 227         spin_lock(&desc->lock);
 228         desc->status &= ~IRQ_INPROGRESS;
 229 out_unlock:
 230         spin_unlock(&desc->lock);
 231 }
 232
 233 /**
 234  *      handle_level_irq - Level type irq handler
 235  *      @irq:   the interrupt number
 236  *      @desc:  the interrupt description structure for this irq
 237  *      @regs:  pointer to a register structure
 238  *
 239  *      Level type interrupts are active as long as the hardware line has
 240  *      the active level. This may require to mask the interrupt and unmask
 241  *      it after the associated handler has acknowledged the device, so the
 242  *      interrupt line is back to inactive.
 243  */
 244 void fastcall
 245 handle_level_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 246 {
 247         unsigned int cpu = smp_processor_id();
 248         struct irqaction *action;
 249         irqreturn_t action_ret;
 250
 251         spin_lock(&desc->lock);
 252         mask_ack_irq(desc, irq);
 253
 254         if (unlikely(desc->status & IRQ_INPROGRESS))
 255                 goto out;
 256         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 257         kstat_cpu(cpu).irqs[irq]++;
 258
 259         /*
 260          * If its disabled or no action available
 261          * keep it masked and get out of here
 262          */
 263         action = desc->action;
 264         if (unlikely(!action || (desc->status & IRQ_DISABLED)))
 265                 goto out;
 266
 267         desc->status |= IRQ_INPROGRESS;
 268         spin_unlock(&desc->lock);
 269
 270         action_ret = handle_IRQ_event(irq, regs, action);
 271         if (!noirqdebug)
 272                 note_interrupt(irq, desc, action_ret, regs);
 273
 274         spin_lock(&desc->lock);
 275         desc->status &= ~IRQ_INPROGRESS;
 276 out:
 277         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 278                 desc->chip->unmask(irq);
 279         spin_unlock(&desc->lock);
 280 }
 281
 282 /**
 283  *      handle_fasteoi_irq - irq handler for transparent controllers
 284  *      @irq:   the interrupt number
 285  *      @desc:  the interrupt description structure for this irq
 286  *      @regs:  pointer to a register structure
 287  *
 288  *      Only a single callback will be issued to the chip: an ->eoi()
 289  *      call when the interrupt has been serviced. This enables support
 290  *      for modern forms of interrupt handlers, which handle the flow
 291  *      details in hardware, transparently.
 292  */
 293 void fastcall
 294 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc,
 295                    struct pt_regs *regs)
 296 {
 297         unsigned int cpu = smp_processor_id();
 298         struct irqaction *action;
 299         irqreturn_t action_ret;
 300
 301         spin_lock(&desc->lock);
 302
 303         if (unlikely(desc->status & IRQ_INPROGRESS))
 304                 goto out;
 305
 306         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 307         kstat_cpu(cpu).irqs[irq]++;
 308
 309         /*
 310          * If its disabled or no action available
 311          * keep it masked and get out of here
 312          */
 313         action = desc->action;
 314         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 315                 desc->status |= IRQ_PENDING;
 316                 goto out;
 317         }
 318
 319         desc->status |= IRQ_INPROGRESS;
 320         desc->status &= ~IRQ_PENDING;
 321         spin_unlock(&desc->lock);
 322
 323         action_ret = handle_IRQ_event(irq, regs, action);
 324         if (!noirqdebug)
 325                 note_interrupt(irq, desc, action_ret, regs);
 326
 327         spin_lock(&desc->lock);
 328         desc->status &= ~IRQ_INPROGRESS;
 329 out:
 330         desc->chip->eoi(irq);
 331
 332         spin_unlock(&desc->lock);
 333 }
 334
 335 /**
 336  *      handle_edge_irq - edge type IRQ handler
 337  *      @irq:   the interrupt number
 338  *      @desc:  the interrupt description structure for this irq
 339  *      @regs:  pointer to a register structure
 340  *
 341  *      Interrupt occures on the falling and/or rising edge of a hardware
 342  *      signal. The occurence is latched into the irq controller hardware
 343  *      and must be acked in order to be reenabled. After the ack another
 344  *      interrupt can happen on the same source even before the first one
 345  *      is handled by the assosiacted event handler. If this happens it
 346  *      might be necessary to disable (mask) the interrupt depending on the
 347  *      controller hardware. This requires to reenable the interrupt inside
 348  *      of the loop which handles the interrupts which have arrived while
 349  *      the handler was running. If all pending interrupts are handled, the
 350  *      loop is left.
 351  */
 352 void fastcall
 353 handle_edge_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 354 {
 355         const unsigned int cpu = smp_processor_id();
 356
 357         spin_lock(&desc->lock);
 358
 359         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 360
 361         /*
 362          * If we're currently running this IRQ, or its disabled,
 363          * we shouldn't process the IRQ. Mark it pending, handle
 364          * the necessary masking and go out
 365          */
 366         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 367                     !desc->action)) {
 368                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 369                 mask_ack_irq(desc, irq);
 370                 goto out_unlock;
 371         }
 372
 373         kstat_cpu(cpu).irqs[irq]++;
 374
 375         /* Start handling the irq */
 376         desc->chip->ack(irq);
 377
 378         /* Mark the IRQ currently in progress.*/
 379         desc->status |= IRQ_INPROGRESS;
 380
 381         do {
 382                 struct irqaction *action = desc->action;
 383                 irqreturn_t action_ret;
 384
 385                 if (unlikely(!action)) {
 386                         desc->chip->mask(irq);
 387                         goto out_unlock;
 388                 }
 389
 390                 /*
 391                  * When another irq arrived while we were handling
 392                  * one, we could have masked the irq.
 393                  * Renable it, if it was not disabled in meantime.
 394                  */
 395                 if (unlikely((desc->status &
 396                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 397                               (IRQ_PENDING | IRQ_MASKED))) {
 398                         desc->chip->unmask(irq);
 399                         desc->status &= ~IRQ_MASKED;
 400                 }
 401
 402                 desc->status &= ~IRQ_PENDING;
 403                 spin_unlock(&desc->lock);
 404                 action_ret = handle_IRQ_event(irq, regs, action);
 405                 if (!noirqdebug)
 406                         note_interrupt(irq, desc, action_ret, regs);
 407                 spin_lock(&desc->lock);
 408
 409         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 410
 411         desc->status &= ~IRQ_INPROGRESS;
 412 out_unlock:
 413         spin_unlock(&desc->lock);
 414 }
 415
 416 #ifdef CONFIG_SMP
 417 /**
 418  *      handle_percpu_IRQ - Per CPU local irq handler
 419  *      @irq:   the interrupt number
 420  *      @desc:  the interrupt description structure for this irq
 421  *      @regs:  pointer to a register structure
 422  *
 423  *      Per CPU interrupts on SMP machines without locking requirements
 424  */
 425 void fastcall
 426 handle_percpu_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 427 {
 428         irqreturn_t action_ret;
 429
 430         kstat_this_cpu.irqs[irq]++;
 431
 432         if (desc->chip->ack)
 433                 desc->chip->ack(irq);
 434
 435         action_ret = handle_IRQ_event(irq, regs, desc->action);
 436         if (!noirqdebug)
 437                 note_interrupt(irq, desc, action_ret, regs);
 438
 439         if (desc->chip->eoi)
 440                 desc->chip->eoi(irq);
 441 }
 442
 443 #endif /* CONFIG_SMP */
 444
 445 void
 446 __set_irq_handler(unsigned int irq,
 447                   void fastcall (*handle)(unsigned int, irq_desc_t *,
 448                                           struct pt_regs *),
 449                   int is_chained)
 450 {
 451         struct irq_desc *desc;
 452         unsigned long flags;
 453
 454         if (irq >= NR_IRQS) {
 455                 printk(KERN_ERR
 456                        "Trying to install type control for IRQ%d\n", irq);
 457                 return;
 458         }
 459
 460         desc = irq_desc + irq;
 461
 462         if (!handle)
 463                 handle = handle_bad_irq;
 464
 465         if (desc->chip == &no_irq_chip) {
 466                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 467                        "for IRQ%d\n", is_chained ? "chained " : " ", irq);
 468                 /*
 469                  * Some ARM implementations install a handler for really dumb
 470                  * interrupt hardware without setting an irq_chip. This worked
 471                  * with the ARM no_irq_chip but the check in setup_irq would
 472                  * prevent us to setup the interrupt at all. Switch it to
 473                  * dummy_irq_chip for easy transition.
 474                  */
 475                 desc->chip = &dummy_irq_chip;
 476         }
 477
 478         spin_lock_irqsave(&desc->lock, flags);
 479
 480         /* Uninstall? */
 481         if (handle == handle_bad_irq) {
 482                 if (desc->chip != &no_irq_chip) {
 483                         desc->chip->mask(irq);
 484                         desc->chip->ack(irq);
 485                 }
 486                 desc->status |= IRQ_DISABLED;
 487                 desc->depth = 1;
 488         }
 489         desc->handle_irq = handle;
 490
 491         if (handle != handle_bad_irq && is_chained) {
 492                 desc->status &= ~IRQ_DISABLED;
 493                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 494                 desc->depth = 0;
 495                 desc->chip->unmask(irq);
 496         }
 497         spin_unlock_irqrestore(&desc->lock, flags);
 498 }
 499
 500 void
 501 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 502                          void fastcall (*handle)(unsigned int,
 503                                                  struct irq_desc *,
 504                                                  struct pt_regs *))
 505 {
 506         set_irq_chip(irq, chip);
 507         __set_irq_handler(irq, handle, 0);
 508 }
 509
 510 /*
 511  * Get a descriptive string for the highlevel handler, for
 512  * /proc/interrupts output:
 513  */
 514 const char *
 515 handle_irq_name(void fastcall (*handle)(unsigned int, struct irq_desc *,
 516                                         struct pt_regs *))
 517 {
 518         if (handle == handle_level_irq)
 519                 return "level  ";
 520         if (handle == handle_fasteoi_irq)
 521                 return "fasteoi";
 522         if (handle == handle_edge_irq)
 523                 return "edge   ";
 524         if (handle == handle_simple_irq)
 525                 return "simple ";
 526 #ifdef CONFIG_SMP
 527         if (handle == handle_percpu_irq)
 528                 return "percpu ";
 529 #endif
 530         if (handle == handle_bad_irq)
 531                 return "bad    ";
 532
 533         return NULL;
 534 }