WebSVN – HelenOS – Diff – //trunk/kernel/generic/src/ddi/irq.c

 /** @addtogroup genericddi
  * @{
  */
 /**
  * @file
- * @brief   IRQ redirector.
+ * @brief   IRQ dispatcher.
+ *
  * This file provides means of connecting IRQs with particular
  * devices and logic for dispatching interrupts to IRQ handlers
  * defined by those devices.
+ *
  * architectures to use the hardware layout effectively.
  * For instance, on amd64 and ia32, where there is only 16
  * IRQs, the irq_hash_table can be optimized to a one-dimensional
  * array. Next, when it is known that the IRQ numbers (aka INR's)
  * are unique, the claim functions can always return IRQ_ACCEPT.
+ *
+ *
+ * Note about the irq_hash_table.
+ *
+ * The hash table is configured to use two keys: inr and devno.
+ * However, the hash index is computed only from inr. Moreover,
+ * if devno is -1, the match is based on the return value of
+ * the claim() function instead of on devno.
  */
 #include <ddi/irq.h>
 #include <adt/hash_table.h>
 #include <arch/types.h>
 #include <typedefs.h>
 #include <synch/spinlock.h>
 #include <atomic.h>
 #include <arch.h>
+#define KEY_INR     0
+#define KEY_DEVNO   1
 /**
  * Spinlock protecting the hash table.
  * This lock must be taken only when interrupts are disabled.
  */
 SPINLOCK_INITIALIZE(irq_hash_table_lock);
      * In cases in which inrs equals the requested number of
      * chains (i.e. where there is no collision between
      * different keys), we can use optimized set of operations.
      */
     if (inrs == chains)
-        hash_table_create(&irq_hash_table, chains, 1, &irq_lin_ops);
+        hash_table_create(&irq_hash_table, chains, 2, &irq_lin_ops);
     else
-        hash_table_create(&irq_hash_table, chains, 1, &irq_ht_ops);
+        hash_table_create(&irq_hash_table, chains, 2, &irq_ht_ops);
+}
 /** Initialize one IRQ structure.
+ *
  * @param irq Pointer to the IRQ structure to be initialized.
     irq->claim = NULL;
     irq->handler = NULL;
     irq->arg = NULL;
     irq->notif_answerbox = NULL;
     irq->code = NULL;
+    irq->method = 0;
     atomic_set(&irq->counter, 0);
+}
 /** Register IRQ for device.
+ *
  * @param irq IRQ structure belonging to a device.
  */
 void irq_register(irq_t *irq)
+{
     ipl_t ipl;
+    unative_t key[] = {
+        (unative_t) irq->inr,
+        (unative_t) irq->devno
+    };
     ipl = interrupts_disable();
     spinlock_lock(&irq_hash_table_lock);
-    hash_table_insert(&irq_hash_table, (void *) &irq->inr, &irq->link);
+    hash_table_insert(&irq_hash_table, key, &irq->link);
     spinlock_unlock(&irq_hash_table_lock);
     interrupts_restore(ipl);
+}
 /** Dispatch the IRQ.
+ *
+ * We assume this function is only called from interrupt
+ * context (i.e. that interrupts are disabled prior to
+ * this call).
+ *
+ * This function attempts to lookup a fitting IRQ
+ * structure. In case of success, return with interrupts
+ * disabled and holding the respective structure.
+ *
  * @param inr Interrupt number (aka inr or irq).
+ *
  * @return IRQ structure of the respective device or NULL.
  */
-irq_t *irq_dispatch(inr_t inr)
+irq_t *irq_dispatch_and_lock(inr_t inr)
+{
-    ipl_t ipl;
     link_t *lnk;
+    unative_t key[] = {
+        (unative_t) inr,
+        (unative_t) -1      /* search will use claim() instead of devno */
+    };
-    ipl = interrupts_disable();
     spinlock_lock(&irq_hash_table_lock);
+    lnk = hash_table_find(&irq_hash_table, key);
+    if (lnk) {
+        irq_t *irq;
+        irq = hash_table_get_instance(lnk, irq_t, link);
+        spinlock_unlock(&irq_hash_table_lock);
+        return irq;
+    }
+    spinlock_unlock(&irq_hash_table_lock);
+    return NULL;
+}
+/** Find the IRQ structure corresponding to inr and devno.
+ *
+ * This functions attempts to lookup the IRQ structure
+ * corresponding to its arguments. On success, this
+ * function returns with interrups disabled, holding
+ * the lock of the respective IRQ structure.
+ *
+ * This function assumes interrupts are already disabled.
+ *
+ * @param inr INR being looked up.
+ * @param devno Devno being looked up.
+ *
+ * @return Locked IRQ structure on success or NULL on failure.
+ */
+irq_t *irq_find_and_lock(inr_t inr, devno_t devno)
+{
+    link_t *lnk;
+    unative_t keys[] = {
+        (unative_t) inr,
+        (unative_t) devno
+    };
+    spinlock_lock(&irq_hash_table_lock);
-    lnk = hash_table_find(&irq_hash_table, (void *) &inr);
+    lnk = hash_table_find(&irq_hash_table, keys);
     if (lnk) {
         irq_t *irq;
         irq = hash_table_get_instance(lnk, irq_t, link);
         spinlock_unlock(&irq_hash_table_lock);
-        interrupts_restore(ipl);
         return irq;
+    }
     spinlock_unlock(&irq_hash_table_lock);
-    interrupts_restore(ipl);
     return NULL;
+}
 /** Compute hash index for the key.
  * This function computes hash index into
  * the IRQ hash table for which there
  * can be collisions between different
  * INRs.
+ *
- * @param key Pointer to INR.
+ * The devno is not used to compute the hash.
+ *
+ * @param key The first of the keys is inr and the second is devno or -1.
+ *
  * @return Index into the hash table.
  */
-index_t irq_ht_hash(unative_t *key)
+index_t irq_ht_hash(unative_t key[])
+{
-    inr_t *inr = (inr_t *) key;
+    inr_t inr = (inr_t) key[KEY_INR];
-    return *inr % irq_hash_table.entries;
+    return inr % irq_hash_table.entries;
+}
 /** Compare hash table element with a key.
+ *
+ * There are two things to note about this function.
- * As usually, we do sort of a hack here.
+ * First, it is used for the more complex architecture setup
+ * in which there are way too many interrupt numbers (i.e. inr's)
- * Even when the key matches the inr member,
+ * to arrange the hash table so that collisions occur only
+ * among same inrs of different devnos. So the explicit check
- * we ask the device to either accept
+ * for inr match must be done.
+ * Second, if devno is -1, the second key (i.e. devno) is not
- * or decline to service the interrupt.
+ * used for the match and the result of the claim() function
+ * is used instead.
+ *
+ * This function assumes interrupts are already disabled.
+ *
- * @param key Pointer to key (i.e. inr).
+ * @param key Keys (i.e. inr and devno).
- * @param keys This is 1.
+ * @param keys This is 2.
  * @param item The item to compare the key with.
+ *
  * @return True on match or false otherwise.
  */
-bool irq_ht_compare(unative_t *key, count_t keys, link_t *item)
+bool irq_ht_compare(unative_t key[], count_t keys, link_t *item)
+{
     irq_t *irq = hash_table_get_instance(item, irq_t, link);
-    inr_t *inr = (inr_t *) key;
+    inr_t inr = (inr_t) key[KEY_INR];
+    devno_t devno = (devno_t) key[KEY_DEVNO];
     bool rv;
     spinlock_lock(&irq->lock);
+    if (devno == -1) {
+        /* Invoked by irq_dispatch(). */
-    rv = ((irq->inr == *inr) && (irq->claim() == IRQ_ACCEPT));
+        rv = ((irq->inr == inr) && (irq->claim() == IRQ_ACCEPT));
+    } else {
+        /* Invoked by irq_find(). */
+        rv = ((irq->inr == inr) && (irq->devno == devno));
+    }
+    /* unlock only on non-match */
+    if (!rv)
-    spinlock_unlock(&irq->lock);
+        spinlock_unlock(&irq->lock);
     return rv;
+}
 /** Compute hash index for the key.
  * This function computes hash index into
  * the IRQ hash table for which there
  * are no collisions between different
  * INRs.
+ *
- * @param key INR.
+ * @param key The first of the keys is inr and the second is devno or -1.
+ *
  * @return Index into the hash table.
  */
-index_t irq_lin_hash(unative_t *key)
+index_t irq_lin_hash(unative_t key[])
+{
-    inr_t *inr = (inr_t *) key;
+    inr_t inr = (inr_t) key[KEY_INR];
-    return *inr;
+    return inr;
+}
 /** Compare hash table element with a key.
+ *
+ * There are two things to note about this function.
- * As usually, we do sort of a hack here.
+ * First, it is used for the less complex architecture setup
- * We don't compare the inr member with
+ * in which there are not too many interrupt numbers (i.e. inr's)
- * the key because we know that there are
+ * to arrange the hash table so that collisions occur only
+ * among same inrs of different devnos. So the explicit check
- * no collision between different keys.
+ * for inr match is not done.
- * We only ask the device to either accept
+ * Second, if devno is -1, the second key (i.e. devno) is not
- * or decline to service the interrupt.
+ * used for the match and the result of the claim() function
+ * is used instead.
+ *
+ * This function assumes interrupts are already disabled.
+ *
- * @param key Pointer to key (i.e. inr).
+ * @param key Keys (i.e. inr and devno).
- * @param keys This is 1.
+ * @param keys This is 2.
  * @param item The item to compare the key with.
+ *
  * @return True on match or false otherwise.
  */
-bool irq_lin_compare(unative_t *key, count_t keys, link_t *item)
+bool irq_lin_compare(unative_t key[], count_t keys, link_t *item)
+{
     irq_t *irq = list_get_instance(item, irq_t, link);
+    devno_t devno = (devno_t) key[KEY_DEVNO];
     bool rv;
     spinlock_lock(&irq->lock);
+    if (devno == -1) {
+        /* Invoked by irq_dispatch() */
-    rv = (irq->claim() == IRQ_ACCEPT);
+        rv = (irq->claim() == IRQ_ACCEPT);
+    } else {
+        /* Invoked by irq_find() */
+        rv = (irq->devno == devno);
+    }
+    /* unlock only on non-match */
+    if (!rv)
-    spinlock_unlock(&irq->lock);
+        spinlock_unlock(&irq->lock);
     return rv;
+}
 /** @}

Subversion Repositories HelenOS

(root)//trunk/kernel/generic/src/ddi/irq.c – Rev 1921 → 1922