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