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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_unlock;
 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                 desc->status |= IRQ_PENDING;
 266                 goto out_unlock;
 267         }
 268
 269         desc->status |= IRQ_INPROGRESS;
 270         desc->status &= ~IRQ_PENDING;
 271         spin_unlock(&desc->lock);
 272
 273         action_ret = handle_IRQ_event(irq, regs, action);
 274         if (!noirqdebug)
 275                 note_interrupt(irq, desc, action_ret, regs);
 276
 277         spin_lock(&desc->lock);
 278         desc->status &= ~IRQ_INPROGRESS;
 279         if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
 280                 desc->chip->unmask(irq);
 281 out_unlock:
 282         spin_unlock(&desc->lock);
 283 }
 284
 285 /**
 286  *      handle_fasteoi_irq - irq handler for transparent controllers
 287  *      @irq:   the interrupt number
 288  *      @desc:  the interrupt description structure for this irq
 289  *      @regs:  pointer to a register structure
 290  *
 291  *      Only a single callback will be issued to the chip: an ->eoi()
 292  *      call when the interrupt has been serviced. This enables support
 293  *      for modern forms of interrupt handlers, which handle the flow
 294  *      details in hardware, transparently.
 295  */
 296 void fastcall
 297 handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc,
 298                    struct pt_regs *regs)
 299 {
 300         unsigned int cpu = smp_processor_id();
 301         struct irqaction *action;
 302         irqreturn_t action_ret;
 303
 304         spin_lock(&desc->lock);
 305
 306         if (unlikely(desc->status & IRQ_INPROGRESS))
 307                 goto out;
 308
 309         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 310         kstat_cpu(cpu).irqs[irq]++;
 311
 312         /*
 313          * If its disabled or no action available
 314          * keep it masked and get out of here
 315          */
 316         action = desc->action;
 317         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
 318                 desc->status |= IRQ_PENDING;
 319                 goto out;
 320         }
 321
 322         desc->status |= IRQ_INPROGRESS;
 323         desc->status &= ~IRQ_PENDING;
 324         spin_unlock(&desc->lock);
 325
 326         action_ret = handle_IRQ_event(irq, regs, action);
 327         if (!noirqdebug)
 328                 note_interrupt(irq, desc, action_ret, regs);
 329
 330         spin_lock(&desc->lock);
 331         desc->status &= ~IRQ_INPROGRESS;
 332 out:
 333         desc->chip->eoi(irq);
 334
 335         spin_unlock(&desc->lock);
 336 }
 337
 338 /**
 339  *      handle_edge_irq - edge type IRQ handler
 340  *      @irq:   the interrupt number
 341  *      @desc:  the interrupt description structure for this irq
 342  *      @regs:  pointer to a register structure
 343  *
 344  *      Interrupt occures on the falling and/or rising edge of a hardware
 345  *      signal. The occurence is latched into the irq controller hardware
 346  *      and must be acked in order to be reenabled. After the ack another
 347  *      interrupt can happen on the same source even before the first one
 348  *      is handled by the assosiacted event handler. If this happens it
 349  *      might be necessary to disable (mask) the interrupt depending on the
 350  *      controller hardware. This requires to reenable the interrupt inside
 351  *      of the loop which handles the interrupts which have arrived while
 352  *      the handler was running. If all pending interrupts are handled, the
 353  *      loop is left.
 354  */
 355 void fastcall
 356 handle_edge_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 357 {
 358         const unsigned int cpu = smp_processor_id();
 359
 360         spin_lock(&desc->lock);
 361
 362         desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);
 363
 364         /*
 365          * If we're currently running this IRQ, or its disabled,
 366          * we shouldn't process the IRQ. Mark it pending, handle
 367          * the necessary masking and go out
 368          */
 369         if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||
 370                     !desc->action)) {
 371                 desc->status |= (IRQ_PENDING | IRQ_MASKED);
 372                 mask_ack_irq(desc, irq);
 373                 goto out_unlock;
 374         }
 375
 376         kstat_cpu(cpu).irqs[irq]++;
 377
 378         /* Start handling the irq */
 379         desc->chip->ack(irq);
 380
 381         /* Mark the IRQ currently in progress.*/
 382         desc->status |= IRQ_INPROGRESS;
 383
 384         do {
 385                 struct irqaction *action = desc->action;
 386                 irqreturn_t action_ret;
 387
 388                 if (unlikely(!action)) {
 389                         desc->chip->mask(irq);
 390                         goto out_unlock;
 391                 }
 392
 393                 /*
 394                  * When another irq arrived while we were handling
 395                  * one, we could have masked the irq.
 396                  * Renable it, if it was not disabled in meantime.
 397                  */
 398                 if (unlikely((desc->status &
 399                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
 400                               (IRQ_PENDING | IRQ_MASKED))) {
 401                         desc->chip->unmask(irq);
 402                         desc->status &= ~IRQ_MASKED;
 403                 }
 404
 405                 desc->status &= ~IRQ_PENDING;
 406                 spin_unlock(&desc->lock);
 407                 action_ret = handle_IRQ_event(irq, regs, action);
 408                 if (!noirqdebug)
 409                         note_interrupt(irq, desc, action_ret, regs);
 410                 spin_lock(&desc->lock);
 411
 412         } while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);
 413
 414         desc->status &= ~IRQ_INPROGRESS;
 415 out_unlock:
 416         spin_unlock(&desc->lock);
 417 }
 418
 419 #ifdef CONFIG_SMP
 420 /**
 421  *      handle_percpu_IRQ - Per CPU local irq handler
 422  *      @irq:   the interrupt number
 423  *      @desc:  the interrupt description structure for this irq
 424  *      @regs:  pointer to a register structure
 425  *
 426  *      Per CPU interrupts on SMP machines without locking requirements
 427  */
 428 void fastcall
 429 handle_percpu_irq(unsigned int irq, struct irq_desc *desc, struct pt_regs *regs)
 430 {
 431         irqreturn_t action_ret;
 432
 433         kstat_this_cpu.irqs[irq]++;
 434
 435         if (desc->chip->ack)
 436                 desc->chip->ack(irq);
 437
 438         action_ret = handle_IRQ_event(irq, regs, desc->action);
 439         if (!noirqdebug)
 440                 note_interrupt(irq, desc, action_ret, regs);
 441
 442         if (desc->chip->eoi)
 443                 desc->chip->eoi(irq);
 444 }
 445
 446 #endif /* CONFIG_SMP */
 447
 448 void
 449 __set_irq_handler(unsigned int irq,
 450                   void fastcall (*handle)(unsigned int, irq_desc_t *,
 451                                           struct pt_regs *),
 452                   int is_chained)
 453 {
 454         struct irq_desc *desc;
 455         unsigned long flags;
 456
 457         if (irq >= NR_IRQS) {
 458                 printk(KERN_ERR
 459                        "Trying to install type control for IRQ%d\n", irq);
 460                 return;
 461         }
 462
 463         desc = irq_desc + irq;
 464
 465         if (!handle)
 466                 handle = handle_bad_irq;
 467
 468         if (desc->chip == &no_irq_chip) {
 469                 printk(KERN_WARNING "Trying to install %sinterrupt handler "
 470                        "for IRQ%d\n", is_chained ? "chained " : " ", irq);
 471                 /*
 472                  * Some ARM implementations install a handler for really dumb
 473                  * interrupt hardware without setting an irq_chip. This worked
 474                  * with the ARM no_irq_chip but the check in setup_irq would
 475                  * prevent us to setup the interrupt at all. Switch it to
 476                  * dummy_irq_chip for easy transition.
 477                  */
 478                 desc->chip = &dummy_irq_chip;
 479         }
 480
 481         spin_lock_irqsave(&desc->lock, flags);
 482
 483         /* Uninstall? */
 484         if (handle == handle_bad_irq) {
 485                 if (desc->chip != &no_irq_chip) {
 486                         desc->chip->mask(irq);
 487                         desc->chip->ack(irq);
 488                 }
 489                 desc->status |= IRQ_DISABLED;
 490                 desc->depth = 1;
 491         }
 492         desc->handle_irq = handle;
 493
 494         if (handle != handle_bad_irq && is_chained) {
 495                 desc->status &= ~IRQ_DISABLED;
 496                 desc->status |= IRQ_NOREQUEST | IRQ_NOPROBE;
 497                 desc->depth = 0;
 498                 desc->chip->unmask(irq);
 499         }
 500         spin_unlock_irqrestore(&desc->lock, flags);
 501 }
 502
 503 void
 504 set_irq_chip_and_handler(unsigned int irq, struct irq_chip *chip,
 505                          void fastcall (*handle)(unsigned int,
 506                                                  struct irq_desc *,
 507                                                  struct pt_regs *))
 508 {
 509         set_irq_chip(irq, chip);
 510         __set_irq_handler(irq, handle, 0);
 511 }
 512
 513 /*
 514  * Get a descriptive string for the highlevel handler, for
 515  * /proc/interrupts output:
 516  */
 517 const char *
 518 handle_irq_name(void fastcall (*handle)(unsigned int, struct irq_desc *,
 519                                         struct pt_regs *))
 520 {
 521         if (handle == handle_level_irq)
 522                 return "level  ";
 523         if (handle == handle_fasteoi_irq)
 524                 return "fasteoi";
 525         if (handle == handle_edge_irq)
 526                 return "edge   ";
 527         if (handle == handle_simple_irq)
 528                 return "simple ";
 529 #ifdef CONFIG_SMP
 530         if (handle == handle_percpu_irq)
 531                 return "percpu ";
 532 #endif
 533         if (handle == handle_bad_irq)
 534                 return "bad    ";
 535
 536         return NULL;
 537 }