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1919 jermar 1
/*
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 * Copyright (C) 2006 Jakub Jermar
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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1920 jermar 29
/** @addtogroup genericddi
1919 jermar 30
 * @{
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 */
32
/**
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 * @file
1922 jermar 34
 * @brief   IRQ dispatcher.
1919 jermar 35
 *
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 * This file provides means of connecting IRQs with particular
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 * devices and logic for dispatching interrupts to IRQ handlers
38
 * defined by those devices.
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 *
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 * This code is designed to support:
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 * - multiple devices sharing single IRQ
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 * - multiple IRQs per signle device
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 *
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 *
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 * Note about architectures.
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 *
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 * Some architectures has the term IRQ well defined. Examples
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 * of such architectures include amd64, ia32 and mips32. Some
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 * other architectures, such as sparc64, don't use the term
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 * at all. In those cases, we boldly step forward and define what
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 * an IRQ is.
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 *
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 * The implementation is generic enough and still allows the
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 * architectures to use the hardware layout effectively.
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 * For instance, on amd64 and ia32, where there is only 16
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 * IRQs, the irq_hash_table can be optimized to a one-dimensional
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 * array. Next, when it is known that the IRQ numbers (aka INR's)
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 * are unique, the claim functions can always return IRQ_ACCEPT.
1922 jermar 59
 *
60
 *
61
 * Note about the irq_hash_table.
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 *
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 * The hash table is configured to use two keys: inr and devno.
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 * However, the hash index is computed only from inr. Moreover,
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 * if devno is -1, the match is based on the return value of
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 * the claim() function instead of on devno.
1919 jermar 67
 */
68
 
1920 jermar 69
#include <ddi/irq.h>
1919 jermar 70
#include <adt/hash_table.h>
71
#include <arch/types.h>
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#include <typedefs.h>
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#include <synch/spinlock.h>
1921 jermar 74
#include <atomic.h>
1919 jermar 75
#include <arch.h>
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1922 jermar 77
#define KEY_INR     0
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#define KEY_DEVNO   1
79
 
1919 jermar 80
/**
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 * Spinlock protecting the hash table.
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 * This lock must be taken only when interrupts are disabled.
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 */
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SPINLOCK_INITIALIZE(irq_hash_table_lock);
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static hash_table_t irq_hash_table;
86
 
87
/**
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 * Hash table operations for cases when we know that
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 * there will be collisions between different keys.
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 */
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static index_t irq_ht_hash(unative_t *key);
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static bool irq_ht_compare(unative_t *key, count_t keys, link_t *item);
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94
static hash_table_operations_t irq_ht_ops = {
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    .hash = irq_ht_hash,
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    .compare = irq_ht_compare,
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    .remove_callback = NULL     /* not used */
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};
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100
/**
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 * Hash table operations for cases when we know that
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 * there will be no collisions between different keys.
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 * However, there might be still collisions among
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 * elements with single key (sharing of one IRQ).
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 */
106
static index_t irq_lin_hash(unative_t *key);
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static bool irq_lin_compare(unative_t *key, count_t keys, link_t *item);
108
 
109
static hash_table_operations_t irq_lin_ops = {
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    .hash = irq_lin_hash,
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    .compare = irq_lin_compare,
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    .remove_callback = NULL     /* not used */
113
};
114
 
115
/** Initialize IRQ subsystem.
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 *
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 * @param inrs Numbers of unique IRQ numbers or INRs.
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 * @param chains Number of chains in the hash table.
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 */
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void irq_init(count_t inrs, count_t chains)
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{
122
    /*
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     * Be smart about the choice of the hash table operations.
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     * In cases in which inrs equals the requested number of
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     * chains (i.e. where there is no collision between
126
     * different keys), we can use optimized set of operations.
127
     */
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    if (inrs == chains)
1922 jermar 129
        hash_table_create(&irq_hash_table, chains, 2, &irq_lin_ops);
1919 jermar 130
    else
1922 jermar 131
        hash_table_create(&irq_hash_table, chains, 2, &irq_ht_ops);
1919 jermar 132
}
133
 
134
/** Initialize one IRQ structure.
135
 *
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 * @param irq Pointer to the IRQ structure to be initialized.
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 *
138
 */
139
void irq_initialize(irq_t *irq)
140
{
141
    link_initialize(&irq->link);
1921 jermar 142
    spinlock_initialize(&irq->lock, "irq.lock");
1919 jermar 143
    irq->inr = -1;
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    irq->devno = -1;
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    irq->trigger = 0;
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    irq->claim = NULL;
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    irq->handler = NULL;
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    irq->arg = NULL;
1921 jermar 149
    irq->notif_answerbox = NULL;
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    irq->code = NULL;
1922 jermar 151
    irq->method = 0;
1921 jermar 152
    atomic_set(&irq->counter, 0);
1919 jermar 153
}
154
 
155
/** Register IRQ for device.
156
 *
157
 * The irq structure must be filled with information
158
 * about the interrupt source and with the claim()
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 * function pointer and irq_handler() function pointer.
160
 *
161
 * @param irq IRQ structure belonging to a device.
162
 */
163
void irq_register(irq_t *irq)
164
{
165
    ipl_t ipl;
1922 jermar 166
    unative_t key[] = {
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        (unative_t) irq->inr,
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        (unative_t) irq->devno
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    };
1919 jermar 170
 
171
    ipl = interrupts_disable();
172
    spinlock_lock(&irq_hash_table_lock);
1922 jermar 173
    hash_table_insert(&irq_hash_table, key, &irq->link);
1919 jermar 174
    spinlock_unlock(&irq_hash_table_lock);
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    interrupts_restore(ipl);
176
}
177
 
178
/** Dispatch the IRQ.
179
 *
1922 jermar 180
 * We assume this function is only called from interrupt
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 * context (i.e. that interrupts are disabled prior to
182
 * this call).
183
 *
184
 * This function attempts to lookup a fitting IRQ
185
 * structure. In case of success, return with interrupts
186
 * disabled and holding the respective structure.
187
 *
1919 jermar 188
 * @param inr Interrupt number (aka inr or irq).
189
 *
190
 * @return IRQ structure of the respective device or NULL.
191
 */
1922 jermar 192
irq_t *irq_dispatch_and_lock(inr_t inr)
1919 jermar 193
{
194
    link_t *lnk;
1922 jermar 195
    unative_t key[] = {
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        (unative_t) inr,
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        (unative_t) -1      /* search will use claim() instead of devno */
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    };
1919 jermar 199
 
200
    spinlock_lock(&irq_hash_table_lock);
201
 
1922 jermar 202
    lnk = hash_table_find(&irq_hash_table, key);
1919 jermar 203
    if (lnk) {
204
        irq_t *irq;
205
 
206
        irq = hash_table_get_instance(lnk, irq_t, link);
207
 
208
        spinlock_unlock(&irq_hash_table_lock);
209
        return irq;
210
    }
211
 
212
    spinlock_unlock(&irq_hash_table_lock);
213
 
214
    return NULL;   
215
}
216
 
1922 jermar 217
/** Find the IRQ structure corresponding to inr and devno.
218
 *
219
 * This functions attempts to lookup the IRQ structure
220
 * corresponding to its arguments. On success, this
221
 * function returns with interrups disabled, holding
222
 * the lock of the respective IRQ structure.
223
 *
224
 * This function assumes interrupts are already disabled.
225
 *
226
 * @param inr INR being looked up.
227
 * @param devno Devno being looked up.
228
 *
229
 * @return Locked IRQ structure on success or NULL on failure.
230
 */
231
irq_t *irq_find_and_lock(inr_t inr, devno_t devno)
232
{
233
    link_t *lnk;
234
    unative_t keys[] = {
235
        (unative_t) inr,
236
        (unative_t) devno
237
    };
238
 
239
    spinlock_lock(&irq_hash_table_lock);
240
 
241
    lnk = hash_table_find(&irq_hash_table, keys);
242
    if (lnk) {
243
        irq_t *irq;
244
 
245
        irq = hash_table_get_instance(lnk, irq_t, link);
246
 
247
        spinlock_unlock(&irq_hash_table_lock);
248
        return irq;
249
    }
250
 
251
    spinlock_unlock(&irq_hash_table_lock);
252
 
253
    return NULL;   
254
}
255
 
1919 jermar 256
/** Compute hash index for the key.
257
 *
258
 * This function computes hash index into
259
 * the IRQ hash table for which there
260
 * can be collisions between different
261
 * INRs.
262
 *
1922 jermar 263
 * The devno is not used to compute the hash.
1919 jermar 264
 *
1922 jermar 265
 * @param key The first of the keys is inr and the second is devno or -1.
266
 *
1919 jermar 267
 * @return Index into the hash table.
268
 */
1922 jermar 269
index_t irq_ht_hash(unative_t key[])
1919 jermar 270
{
1922 jermar 271
    inr_t inr = (inr_t) key[KEY_INR];
272
    return inr % irq_hash_table.entries;
1919 jermar 273
}
274
 
275
/** Compare hash table element with a key.
276
 *
1922 jermar 277
 * There are two things to note about this function.
278
 * First, it is used for the more complex architecture setup
279
 * in which there are way too many interrupt numbers (i.e. inr's)
280
 * to arrange the hash table so that collisions occur only
281
 * among same inrs of different devnos. So the explicit check
282
 * for inr match must be done.
283
 * Second, if devno is -1, the second key (i.e. devno) is not
284
 * used for the match and the result of the claim() function
285
 * is used instead.
1919 jermar 286
 *
1922 jermar 287
 * This function assumes interrupts are already disabled.
288
 *
289
 * @param key Keys (i.e. inr and devno).
290
 * @param keys This is 2.
1919 jermar 291
 * @param item The item to compare the key with.
292
 *
293
 * @return True on match or false otherwise.
294
 */
1922 jermar 295
bool irq_ht_compare(unative_t key[], count_t keys, link_t *item)
1919 jermar 296
{
297
    irq_t *irq = hash_table_get_instance(item, irq_t, link);
1922 jermar 298
    inr_t inr = (inr_t) key[KEY_INR];
299
    devno_t devno = (devno_t) key[KEY_DEVNO];
300
 
1921 jermar 301
    bool rv;
1919 jermar 302
 
1921 jermar 303
    spinlock_lock(&irq->lock);
1922 jermar 304
    if (devno == -1) {
305
        /* Invoked by irq_dispatch(). */
306
        rv = ((irq->inr == inr) && (irq->claim() == IRQ_ACCEPT));
307
    } else {
308
        /* Invoked by irq_find(). */
309
        rv = ((irq->inr == inr) && (irq->devno == devno));
310
    }
311
 
312
    /* unlock only on non-match */
313
    if (!rv)
314
        spinlock_unlock(&irq->lock);
1921 jermar 315
 
316
    return rv;
1919 jermar 317
}
318
 
319
/** Compute hash index for the key.
320
 *
321
 * This function computes hash index into
322
 * the IRQ hash table for which there
323
 * are no collisions between different
324
 * INRs.
325
 *
1922 jermar 326
 * @param key The first of the keys is inr and the second is devno or -1.
1919 jermar 327
 *
328
 * @return Index into the hash table.
329
 */
1922 jermar 330
index_t irq_lin_hash(unative_t key[])
1919 jermar 331
{
1922 jermar 332
    inr_t inr = (inr_t) key[KEY_INR];
333
    return inr;
1919 jermar 334
}
335
 
336
/** Compare hash table element with a key.
337
 *
1922 jermar 338
 * There are two things to note about this function.
339
 * First, it is used for the less complex architecture setup
340
 * in which there are not too many interrupt numbers (i.e. inr's)
341
 * to arrange the hash table so that collisions occur only
342
 * among same inrs of different devnos. So the explicit check
343
 * for inr match is not done.
344
 * Second, if devno is -1, the second key (i.e. devno) is not
345
 * used for the match and the result of the claim() function
346
 * is used instead.
1919 jermar 347
 *
1922 jermar 348
 * This function assumes interrupts are already disabled.
349
 *
350
 * @param key Keys (i.e. inr and devno).
351
 * @param keys This is 2.
1919 jermar 352
 * @param item The item to compare the key with.
353
 *
354
 * @return True on match or false otherwise.
355
 */
1922 jermar 356
bool irq_lin_compare(unative_t key[], count_t keys, link_t *item)
1919 jermar 357
{
358
    irq_t *irq = list_get_instance(item, irq_t, link);
1922 jermar 359
    devno_t devno = (devno_t) key[KEY_DEVNO];
1921 jermar 360
    bool rv;
1919 jermar 361
 
1921 jermar 362
    spinlock_lock(&irq->lock);
1922 jermar 363
    if (devno == -1) {
364
        /* Invoked by irq_dispatch() */
365
        rv = (irq->claim() == IRQ_ACCEPT);
366
    } else {
367
        /* Invoked by irq_find() */
368
        rv = (irq->devno == devno);
369
    }
1921 jermar 370
 
1922 jermar 371
    /* unlock only on non-match */
372
    if (!rv)
373
        spinlock_unlock(&irq->lock);
374
 
1921 jermar 375
    return rv;
1919 jermar 376
}
377
 
378
/** @}
379
 */