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2292 hudecek 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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/** @addtogroup genericddi
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 * @{
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 */
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/**
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 * @file
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 * @brief   IRQ dispatcher.
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 *
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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
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 * 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.
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 *
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 *
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 * 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.
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 */
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69
#include <ddi/irq.h>
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#include <adt/hash_table.h>
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#include <arch/types.h>
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#include <synch/spinlock.h>
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#include <arch.h>
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75
#define KEY_INR     0
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#define KEY_DEVNO   1
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78
/**
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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;
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85
/**
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 * Hash table operations for cases when we know that
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 * there will be collisions between different keys.
88
 */
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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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92
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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98
/**
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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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 */
104
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);
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107
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 */
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};
112
 
113
/** 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.
117
 */
118
void irq_init(count_t inrs, count_t chains)
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{
120
    /*
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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
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     * different keys), we can use optimized set of operations.
125
     */
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    if (inrs == chains)
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        hash_table_create(&irq_hash_table, chains, 2, &irq_lin_ops);
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    else
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        hash_table_create(&irq_hash_table, chains, 2, &irq_ht_ops);
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}
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/** Initialize one IRQ structure.
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 *
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 * @param irq Pointer to the IRQ structure to be initialized.
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 *
136
 */
137
void irq_initialize(irq_t *irq)
138
{
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    link_initialize(&irq->link);
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    spinlock_initialize(&irq->lock, "irq.lock");
2307 hudecek 141
    irq->preack = false;
2292 hudecek 142
    irq->inr = -1;
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    irq->devno = -1;
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    irq->trigger = (irq_trigger_t) 0;
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    irq->claim = NULL;
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    irq->handler = NULL;
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    irq->arg = NULL;
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    irq->notif_cfg.notify = false;
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    irq->notif_cfg.answerbox = NULL;
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    irq->notif_cfg.code = NULL;
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    irq->notif_cfg.method = 0;
152
    irq->notif_cfg.counter = 0;
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    link_initialize(&irq->notif_cfg.link);
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}
155
 
156
/** Register IRQ for device.
157
 *
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 * The irq structure must be filled with information
159
 * about the interrupt source and with the claim()
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 * function pointer and irq_handler() function pointer.
161
 *
162
 * @param irq IRQ structure belonging to a device.
163
 */
164
void irq_register(irq_t *irq)
165
{
166
    ipl_t ipl;
167
    unative_t key[] = {
168
        (unative_t) irq->inr,
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        (unative_t) irq->devno
170
    };
171
 
172
    ipl = interrupts_disable();
173
    spinlock_lock(&irq_hash_table_lock);
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    hash_table_insert(&irq_hash_table, key, &irq->link);
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    spinlock_unlock(&irq_hash_table_lock);
176
    interrupts_restore(ipl);
177
}
178
 
179
/** Dispatch the IRQ.
180
 *
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 * We assume this function is only called from interrupt
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 * context (i.e. that interrupts are disabled prior to
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 * this call).
184
 *
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 * This function attempts to lookup a fitting IRQ
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 * structure. In case of success, return with interrupts
187
 * disabled and holding the respective structure.
188
 *
189
 * @param inr Interrupt number (aka inr or irq).
190
 *
191
 * @return IRQ structure of the respective device or NULL.
192
 */
193
irq_t *irq_dispatch_and_lock(inr_t inr)
194
{
195
    link_t *lnk;
196
    unative_t key[] = {
197
        (unative_t) inr,
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        (unative_t) -1      /* search will use claim() instead of devno */
199
    };
200
 
201
    spinlock_lock(&irq_hash_table_lock);
202
 
203
    lnk = hash_table_find(&irq_hash_table, key);
204
    if (lnk) {
205
        irq_t *irq;
206
 
207
        irq = hash_table_get_instance(lnk, irq_t, link);
208
 
209
        spinlock_unlock(&irq_hash_table_lock);
210
        return irq;
211
    }
212
 
213
    spinlock_unlock(&irq_hash_table_lock);
214
 
215
    return NULL;   
216
}
217
 
218
/** Find the IRQ structure corresponding to inr and devno.
219
 *
220
 * This functions attempts to lookup the IRQ structure
221
 * corresponding to its arguments. On success, this
222
 * function returns with interrups disabled, holding
223
 * the lock of the respective IRQ structure.
224
 *
225
 * This function assumes interrupts are already disabled.
226
 *
227
 * @param inr INR being looked up.
228
 * @param devno Devno being looked up.
229
 *
230
 * @return Locked IRQ structure on success or NULL on failure.
231
 */
232
irq_t *irq_find_and_lock(inr_t inr, devno_t devno)
233
{
234
    link_t *lnk;
235
    unative_t keys[] = {
236
        (unative_t) inr,
237
        (unative_t) devno
238
    };
239
 
240
    spinlock_lock(&irq_hash_table_lock);
241
 
242
    lnk = hash_table_find(&irq_hash_table, keys);
243
    if (lnk) {
244
        irq_t *irq;
245
 
246
        irq = hash_table_get_instance(lnk, irq_t, link);
247
 
248
        spinlock_unlock(&irq_hash_table_lock);
249
        return irq;
250
    }
251
 
252
    spinlock_unlock(&irq_hash_table_lock);
253
 
254
    return NULL;   
255
}
256
 
257
/** Compute hash index for the key.
258
 *
259
 * This function computes hash index into
260
 * the IRQ hash table for which there
261
 * can be collisions between different
262
 * INRs.
263
 *
264
 * The devno is not used to compute the hash.
265
 *
266
 * @param key The first of the keys is inr and the second is devno or -1.
267
 *
268
 * @return Index into the hash table.
269
 */
270
index_t irq_ht_hash(unative_t key[])
271
{
272
    inr_t inr = (inr_t) key[KEY_INR];
273
    return inr % irq_hash_table.entries;
274
}
275
 
276
/** Compare hash table element with a key.
277
 *
278
 * There are two things to note about this function.
279
 * First, it is used for the more complex architecture setup
280
 * in which there are way too many interrupt numbers (i.e. inr's)
281
 * to arrange the hash table so that collisions occur only
282
 * among same inrs of different devnos. So the explicit check
283
 * for inr match must be done.
284
 * Second, if devno is -1, the second key (i.e. devno) is not
285
 * used for the match and the result of the claim() function
286
 * is used instead.
287
 *
288
 * This function assumes interrupts are already disabled.
289
 *
290
 * @param key Keys (i.e. inr and devno).
291
 * @param keys This is 2.
292
 * @param item The item to compare the key with.
293
 *
294
 * @return True on match or false otherwise.
295
 */
296
bool irq_ht_compare(unative_t key[], count_t keys, link_t *item)
297
{
298
    irq_t *irq = hash_table_get_instance(item, irq_t, link);
299
    inr_t inr = (inr_t) key[KEY_INR];
300
    devno_t devno = (devno_t) key[KEY_DEVNO];
301
 
302
    bool rv;
303
 
304
    spinlock_lock(&irq->lock);
305
    if (devno == -1) {
306
        /* Invoked by irq_dispatch_and_lock(). */
307
        rv = ((irq->inr == inr) && (irq->claim() == IRQ_ACCEPT));
308
    } else {
309
        /* Invoked by irq_find_and_lock(). */
310
        rv = ((irq->inr == inr) && (irq->devno == devno));
311
    }
312
 
313
    /* unlock only on non-match */
314
    if (!rv)
315
        spinlock_unlock(&irq->lock);
316
 
317
    return rv;
318
}
319
 
320
/** Compute hash index for the key.
321
 *
322
 * This function computes hash index into
323
 * the IRQ hash table for which there
324
 * are no collisions between different
325
 * INRs.
326
 *
327
 * @param key The first of the keys is inr and the second is devno or -1.
328
 *
329
 * @return Index into the hash table.
330
 */
331
index_t irq_lin_hash(unative_t key[])
332
{
333
    inr_t inr = (inr_t) key[KEY_INR];
334
    return inr;
335
}
336
 
337
/** Compare hash table element with a key.
338
 *
339
 * There are two things to note about this function.
340
 * First, it is used for the less complex architecture setup
341
 * in which there are not too many interrupt numbers (i.e. inr's)
342
 * to arrange the hash table so that collisions occur only
343
 * among same inrs of different devnos. So the explicit check
344
 * for inr match is not done.
345
 * Second, if devno is -1, the second key (i.e. devno) is not
346
 * used for the match and the result of the claim() function
347
 * is used instead.
348
 *
349
 * This function assumes interrupts are already disabled.
350
 *
351
 * @param key Keys (i.e. inr and devno).
352
 * @param keys This is 2.
353
 * @param item The item to compare the key with.
354
 *
355
 * @return True on match or false otherwise.
356
 */
357
bool irq_lin_compare(unative_t key[], count_t keys, link_t *item)
358
{
359
    irq_t *irq = list_get_instance(item, irq_t, link);
360
    devno_t devno = (devno_t) key[KEY_DEVNO];
361
    bool rv;
362
 
363
    spinlock_lock(&irq->lock);
364
    if (devno == -1) {
365
        /* Invoked by irq_dispatch_and_lock() */
366
        rv = (irq->claim() == IRQ_ACCEPT);
367
    } else {
368
        /* Invoked by irq_find_and_lock() */
369
        rv = (irq->devno == devno);
370
    }
371
 
372
    /* unlock only on non-match */
373
    if (!rv)
374
        spinlock_unlock(&irq->lock);
375
 
376
    return rv;
377
}
378
 
379
/** @}
380
 */