Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/kernel/irq/manage.c |
| 3 | * |
| 4 | * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar |
| 5 | * |
| 6 | * This file contains driver APIs to the irq subsystem. |
| 7 | */ |
| 8 | |
Paolo 'Blaisorblade' Giarrusso | b77d6ad | 2005-06-21 17:16:24 -0700 | [diff] [blame] | 9 | #include <linux/config.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | #include <linux/irq.h> |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/random.h> |
| 13 | #include <linux/interrupt.h> |
| 14 | |
| 15 | #include "internals.h" |
| 16 | |
| 17 | #ifdef CONFIG_SMP |
| 18 | |
| 19 | cpumask_t irq_affinity[NR_IRQS] = { [0 ... NR_IRQS-1] = CPU_MASK_ALL }; |
| 20 | |
Ashok Raj | 54d5d42 | 2005-09-06 15:16:15 -0700 | [diff] [blame] | 21 | #if defined (CONFIG_GENERIC_PENDING_IRQ) || defined (CONFIG_IRQBALANCE) |
| 22 | cpumask_t __cacheline_aligned pending_irq_cpumask[NR_IRQS]; |
| 23 | #endif |
| 24 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | /** |
| 26 | * synchronize_irq - wait for pending IRQ handlers (on other CPUs) |
Randy Dunlap | 1e5d533 | 2005-11-07 01:01:06 -0800 | [diff] [blame] | 27 | * @irq: interrupt number to wait for |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | * |
| 29 | * This function waits for any pending IRQ handlers for this interrupt |
| 30 | * to complete before returning. If you use this function while |
| 31 | * holding a resource the IRQ handler may need you will deadlock. |
| 32 | * |
| 33 | * This function may be called - with care - from IRQ context. |
| 34 | */ |
| 35 | void synchronize_irq(unsigned int irq) |
| 36 | { |
| 37 | struct irq_desc *desc = irq_desc + irq; |
| 38 | |
Matthew Wilcox | c2b5a25 | 2005-11-03 07:51:18 -0700 | [diff] [blame] | 39 | if (irq >= NR_IRQS) |
| 40 | return; |
| 41 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | while (desc->status & IRQ_INPROGRESS) |
| 43 | cpu_relax(); |
| 44 | } |
| 45 | |
| 46 | EXPORT_SYMBOL(synchronize_irq); |
| 47 | |
| 48 | #endif |
| 49 | |
| 50 | /** |
| 51 | * disable_irq_nosync - disable an irq without waiting |
| 52 | * @irq: Interrupt to disable |
| 53 | * |
| 54 | * Disable the selected interrupt line. Disables and Enables are |
| 55 | * nested. |
| 56 | * Unlike disable_irq(), this function does not ensure existing |
| 57 | * instances of the IRQ handler have completed before returning. |
| 58 | * |
| 59 | * This function may be called from IRQ context. |
| 60 | */ |
| 61 | void disable_irq_nosync(unsigned int irq) |
| 62 | { |
| 63 | irq_desc_t *desc = irq_desc + irq; |
| 64 | unsigned long flags; |
| 65 | |
Matthew Wilcox | c2b5a25 | 2005-11-03 07:51:18 -0700 | [diff] [blame] | 66 | if (irq >= NR_IRQS) |
| 67 | return; |
| 68 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 69 | spin_lock_irqsave(&desc->lock, flags); |
| 70 | if (!desc->depth++) { |
| 71 | desc->status |= IRQ_DISABLED; |
| 72 | desc->handler->disable(irq); |
| 73 | } |
| 74 | spin_unlock_irqrestore(&desc->lock, flags); |
| 75 | } |
| 76 | |
| 77 | EXPORT_SYMBOL(disable_irq_nosync); |
| 78 | |
| 79 | /** |
| 80 | * disable_irq - disable an irq and wait for completion |
| 81 | * @irq: Interrupt to disable |
| 82 | * |
| 83 | * Disable the selected interrupt line. Enables and Disables are |
| 84 | * nested. |
| 85 | * This function waits for any pending IRQ handlers for this interrupt |
| 86 | * to complete before returning. If you use this function while |
| 87 | * holding a resource the IRQ handler may need you will deadlock. |
| 88 | * |
| 89 | * This function may be called - with care - from IRQ context. |
| 90 | */ |
| 91 | void disable_irq(unsigned int irq) |
| 92 | { |
| 93 | irq_desc_t *desc = irq_desc + irq; |
| 94 | |
Matthew Wilcox | c2b5a25 | 2005-11-03 07:51:18 -0700 | [diff] [blame] | 95 | if (irq >= NR_IRQS) |
| 96 | return; |
| 97 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 98 | disable_irq_nosync(irq); |
| 99 | if (desc->action) |
| 100 | synchronize_irq(irq); |
| 101 | } |
| 102 | |
| 103 | EXPORT_SYMBOL(disable_irq); |
| 104 | |
| 105 | /** |
| 106 | * enable_irq - enable handling of an irq |
| 107 | * @irq: Interrupt to enable |
| 108 | * |
| 109 | * Undoes the effect of one call to disable_irq(). If this |
| 110 | * matches the last disable, processing of interrupts on this |
| 111 | * IRQ line is re-enabled. |
| 112 | * |
| 113 | * This function may be called from IRQ context. |
| 114 | */ |
| 115 | void enable_irq(unsigned int irq) |
| 116 | { |
| 117 | irq_desc_t *desc = irq_desc + irq; |
| 118 | unsigned long flags; |
| 119 | |
Matthew Wilcox | c2b5a25 | 2005-11-03 07:51:18 -0700 | [diff] [blame] | 120 | if (irq >= NR_IRQS) |
| 121 | return; |
| 122 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 123 | spin_lock_irqsave(&desc->lock, flags); |
| 124 | switch (desc->depth) { |
| 125 | case 0: |
| 126 | WARN_ON(1); |
| 127 | break; |
| 128 | case 1: { |
| 129 | unsigned int status = desc->status & ~IRQ_DISABLED; |
| 130 | |
| 131 | desc->status = status; |
| 132 | if ((status & (IRQ_PENDING | IRQ_REPLAY)) == IRQ_PENDING) { |
| 133 | desc->status = status | IRQ_REPLAY; |
| 134 | hw_resend_irq(desc->handler,irq); |
| 135 | } |
| 136 | desc->handler->enable(irq); |
| 137 | /* fall-through */ |
| 138 | } |
| 139 | default: |
| 140 | desc->depth--; |
| 141 | } |
| 142 | spin_unlock_irqrestore(&desc->lock, flags); |
| 143 | } |
| 144 | |
| 145 | EXPORT_SYMBOL(enable_irq); |
| 146 | |
| 147 | /* |
| 148 | * Internal function that tells the architecture code whether a |
| 149 | * particular irq has been exclusively allocated or is available |
| 150 | * for driver use. |
| 151 | */ |
| 152 | int can_request_irq(unsigned int irq, unsigned long irqflags) |
| 153 | { |
| 154 | struct irqaction *action; |
| 155 | |
| 156 | if (irq >= NR_IRQS) |
| 157 | return 0; |
| 158 | |
| 159 | action = irq_desc[irq].action; |
| 160 | if (action) |
| 161 | if (irqflags & action->flags & SA_SHIRQ) |
| 162 | action = NULL; |
| 163 | |
| 164 | return !action; |
| 165 | } |
| 166 | |
| 167 | /* |
| 168 | * Internal function to register an irqaction - typically used to |
| 169 | * allocate special interrupts that are part of the architecture. |
| 170 | */ |
| 171 | int setup_irq(unsigned int irq, struct irqaction * new) |
| 172 | { |
| 173 | struct irq_desc *desc = irq_desc + irq; |
| 174 | struct irqaction *old, **p; |
| 175 | unsigned long flags; |
| 176 | int shared = 0; |
| 177 | |
Matthew Wilcox | c2b5a25 | 2005-11-03 07:51:18 -0700 | [diff] [blame] | 178 | if (irq >= NR_IRQS) |
| 179 | return -EINVAL; |
| 180 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | if (desc->handler == &no_irq_type) |
| 182 | return -ENOSYS; |
| 183 | /* |
| 184 | * Some drivers like serial.c use request_irq() heavily, |
| 185 | * so we have to be careful not to interfere with a |
| 186 | * running system. |
| 187 | */ |
| 188 | if (new->flags & SA_SAMPLE_RANDOM) { |
| 189 | /* |
| 190 | * This function might sleep, we want to call it first, |
| 191 | * outside of the atomic block. |
| 192 | * Yes, this might clear the entropy pool if the wrong |
| 193 | * driver is attempted to be loaded, without actually |
| 194 | * installing a new handler, but is this really a problem, |
| 195 | * only the sysadmin is able to do this. |
| 196 | */ |
| 197 | rand_initialize_irq(irq); |
| 198 | } |
| 199 | |
| 200 | /* |
| 201 | * The following block of code has to be executed atomically |
| 202 | */ |
| 203 | spin_lock_irqsave(&desc->lock,flags); |
| 204 | p = &desc->action; |
| 205 | if ((old = *p) != NULL) { |
| 206 | /* Can't share interrupts unless both agree to */ |
| 207 | if (!(old->flags & new->flags & SA_SHIRQ)) { |
| 208 | spin_unlock_irqrestore(&desc->lock,flags); |
| 209 | return -EBUSY; |
| 210 | } |
| 211 | |
| 212 | /* add new interrupt at end of irq queue */ |
| 213 | do { |
| 214 | p = &old->next; |
| 215 | old = *p; |
| 216 | } while (old); |
| 217 | shared = 1; |
| 218 | } |
| 219 | |
| 220 | *p = new; |
| 221 | |
| 222 | if (!shared) { |
| 223 | desc->depth = 0; |
| 224 | desc->status &= ~(IRQ_DISABLED | IRQ_AUTODETECT | |
| 225 | IRQ_WAITING | IRQ_INPROGRESS); |
| 226 | if (desc->handler->startup) |
| 227 | desc->handler->startup(irq); |
| 228 | else |
| 229 | desc->handler->enable(irq); |
| 230 | } |
| 231 | spin_unlock_irqrestore(&desc->lock,flags); |
| 232 | |
| 233 | new->irq = irq; |
| 234 | register_irq_proc(irq); |
| 235 | new->dir = NULL; |
| 236 | register_handler_proc(irq, new); |
| 237 | |
| 238 | return 0; |
| 239 | } |
| 240 | |
| 241 | /** |
| 242 | * free_irq - free an interrupt |
| 243 | * @irq: Interrupt line to free |
| 244 | * @dev_id: Device identity to free |
| 245 | * |
| 246 | * Remove an interrupt handler. The handler is removed and if the |
| 247 | * interrupt line is no longer in use by any driver it is disabled. |
| 248 | * On a shared IRQ the caller must ensure the interrupt is disabled |
| 249 | * on the card it drives before calling this function. The function |
| 250 | * does not return until any executing interrupts for this IRQ |
| 251 | * have completed. |
| 252 | * |
| 253 | * This function must not be called from interrupt context. |
| 254 | */ |
| 255 | void free_irq(unsigned int irq, void *dev_id) |
| 256 | { |
| 257 | struct irq_desc *desc; |
| 258 | struct irqaction **p; |
| 259 | unsigned long flags; |
| 260 | |
| 261 | if (irq >= NR_IRQS) |
| 262 | return; |
| 263 | |
| 264 | desc = irq_desc + irq; |
| 265 | spin_lock_irqsave(&desc->lock,flags); |
| 266 | p = &desc->action; |
| 267 | for (;;) { |
| 268 | struct irqaction * action = *p; |
| 269 | |
| 270 | if (action) { |
| 271 | struct irqaction **pp = p; |
| 272 | |
| 273 | p = &action->next; |
| 274 | if (action->dev_id != dev_id) |
| 275 | continue; |
| 276 | |
| 277 | /* Found it - now remove it from the list of entries */ |
| 278 | *pp = action->next; |
Paolo 'Blaisorblade' Giarrusso | dbce706 | 2005-06-21 17:16:19 -0700 | [diff] [blame] | 279 | |
Paolo 'Blaisorblade' Giarrusso | b77d6ad | 2005-06-21 17:16:24 -0700 | [diff] [blame] | 280 | /* Currently used only by UML, might disappear one day.*/ |
| 281 | #ifdef CONFIG_IRQ_RELEASE_METHOD |
Paolo 'Blaisorblade' Giarrusso | dbce706 | 2005-06-21 17:16:19 -0700 | [diff] [blame] | 282 | if (desc->handler->release) |
| 283 | desc->handler->release(irq, dev_id); |
Paolo 'Blaisorblade' Giarrusso | b77d6ad | 2005-06-21 17:16:24 -0700 | [diff] [blame] | 284 | #endif |
Paolo 'Blaisorblade' Giarrusso | dbce706 | 2005-06-21 17:16:19 -0700 | [diff] [blame] | 285 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | if (!desc->action) { |
| 287 | desc->status |= IRQ_DISABLED; |
| 288 | if (desc->handler->shutdown) |
| 289 | desc->handler->shutdown(irq); |
| 290 | else |
| 291 | desc->handler->disable(irq); |
| 292 | } |
| 293 | spin_unlock_irqrestore(&desc->lock,flags); |
| 294 | unregister_handler_proc(irq, action); |
| 295 | |
| 296 | /* Make sure it's not being used on another CPU */ |
| 297 | synchronize_irq(irq); |
| 298 | kfree(action); |
| 299 | return; |
| 300 | } |
| 301 | printk(KERN_ERR "Trying to free free IRQ%d\n",irq); |
| 302 | spin_unlock_irqrestore(&desc->lock,flags); |
| 303 | return; |
| 304 | } |
| 305 | } |
| 306 | |
| 307 | EXPORT_SYMBOL(free_irq); |
| 308 | |
| 309 | /** |
| 310 | * request_irq - allocate an interrupt line |
| 311 | * @irq: Interrupt line to allocate |
| 312 | * @handler: Function to be called when the IRQ occurs |
| 313 | * @irqflags: Interrupt type flags |
| 314 | * @devname: An ascii name for the claiming device |
| 315 | * @dev_id: A cookie passed back to the handler function |
| 316 | * |
| 317 | * This call allocates interrupt resources and enables the |
| 318 | * interrupt line and IRQ handling. From the point this |
| 319 | * call is made your handler function may be invoked. Since |
| 320 | * your handler function must clear any interrupt the board |
| 321 | * raises, you must take care both to initialise your hardware |
| 322 | * and to set up the interrupt handler in the right order. |
| 323 | * |
| 324 | * Dev_id must be globally unique. Normally the address of the |
| 325 | * device data structure is used as the cookie. Since the handler |
| 326 | * receives this value it makes sense to use it. |
| 327 | * |
| 328 | * If your interrupt is shared you must pass a non NULL dev_id |
| 329 | * as this is required when freeing the interrupt. |
| 330 | * |
| 331 | * Flags: |
| 332 | * |
| 333 | * SA_SHIRQ Interrupt is shared |
| 334 | * SA_INTERRUPT Disable local interrupts while processing |
| 335 | * SA_SAMPLE_RANDOM The interrupt can be used for entropy |
| 336 | * |
| 337 | */ |
| 338 | int request_irq(unsigned int irq, |
| 339 | irqreturn_t (*handler)(int, void *, struct pt_regs *), |
| 340 | unsigned long irqflags, const char * devname, void *dev_id) |
| 341 | { |
| 342 | struct irqaction * action; |
| 343 | int retval; |
| 344 | |
| 345 | /* |
| 346 | * Sanity-check: shared interrupts must pass in a real dev-ID, |
| 347 | * otherwise we'll have trouble later trying to figure out |
| 348 | * which interrupt is which (messes up the interrupt freeing |
| 349 | * logic etc). |
| 350 | */ |
| 351 | if ((irqflags & SA_SHIRQ) && !dev_id) |
| 352 | return -EINVAL; |
| 353 | if (irq >= NR_IRQS) |
| 354 | return -EINVAL; |
| 355 | if (!handler) |
| 356 | return -EINVAL; |
| 357 | |
| 358 | action = kmalloc(sizeof(struct irqaction), GFP_ATOMIC); |
| 359 | if (!action) |
| 360 | return -ENOMEM; |
| 361 | |
| 362 | action->handler = handler; |
| 363 | action->flags = irqflags; |
| 364 | cpus_clear(action->mask); |
| 365 | action->name = devname; |
| 366 | action->next = NULL; |
| 367 | action->dev_id = dev_id; |
| 368 | |
| 369 | retval = setup_irq(irq, action); |
| 370 | if (retval) |
| 371 | kfree(action); |
| 372 | |
| 373 | return retval; |
| 374 | } |
| 375 | |
| 376 | EXPORT_SYMBOL(request_irq); |
| 377 | |