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  1. /*
  2.  * Copyright (c) 2006 Jakub Jermar
  3.  * All rights reserved.
  4.  *
  5.  * Redistribution and use in source and binary forms, with or without
  6.  * modification, are permitted provided that the following conditions
  7.  * are met:
  8.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - Redistributions in binary form must reproduce the above copyright
  12.  *   notice, this list of conditions and the following disclaimer in the
  13.  *   documentation and/or other materials provided with the distribution.
  14.  * - The name of the author may not be used to endorse or promote products
  15.  *   derived from this software without specific prior written permission.
  16.  *
  17.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27.  */
  28.  
  29. /** @addtogroup genericddi
  30.  * @{
  31.  */
  32. /**
  33.  * @file
  34.  * @brief   IRQ dispatcher.
  35.  *
  36.  * This file provides means of connecting IRQs with particular
  37.  * devices and logic for dispatching interrupts to IRQ handlers
  38.  * defined by those devices.
  39.  *
  40.  * This code is designed to support:
  41.  * - multiple devices sharing single IRQ
  42.  * - multiple IRQs per signle device
  43.  *
  44.  *
  45.  * Note about architectures.
  46.  *
  47.  * Some architectures has the term IRQ well defined. Examples
  48.  * of such architectures include amd64, ia32 and mips32. Some
  49.  * other architectures, such as sparc64, don't use the term
  50.  * at all. In those cases, we boldly step forward and define what
  51.  * an IRQ is.
  52.  *
  53.  * The implementation is generic enough and still allows the
  54.  * architectures to use the hardware layout effectively.
  55.  * For instance, on amd64 and ia32, where there is only 16
  56.  * IRQs, the irq_hash_table can be optimized to a one-dimensional
  57.  * array. Next, when it is known that the IRQ numbers (aka INR's)
  58.  * are unique, the claim functions can always return IRQ_ACCEPT.
  59.  *
  60.  *
  61.  * Note about the irq_hash_table.
  62.  *
  63.  * The hash table is configured to use two keys: inr and devno.
  64.  * However, the hash index is computed only from inr. Moreover,
  65.  * if devno is -1, the match is based on the return value of
  66.  * the claim() function instead of on devno.
  67.  */
  68.  
  69. #include <ddi/irq.h>
  70. #include <adt/hash_table.h>
  71. #include <arch/types.h>
  72. #include <synch/spinlock.h>
  73. #include <arch.h>
  74.  
  75. #define KEY_INR     0
  76. #define KEY_DEVNO   1
  77.  
  78. /**
  79.  * Spinlock protecting the hash table.
  80.  * This lock must be taken only when interrupts are disabled.
  81.  */
  82. SPINLOCK_INITIALIZE(irq_hash_table_lock);
  83. static hash_table_t irq_hash_table;
  84.  
  85. /**
  86.  * Hash table operations for cases when we know that
  87.  * there will be collisions between different keys.
  88.  */
  89. static index_t irq_ht_hash(unative_t *key);
  90. static bool irq_ht_compare(unative_t *key, count_t keys, link_t *item);
  91.  
  92. static hash_table_operations_t irq_ht_ops = {
  93.     .hash = irq_ht_hash,
  94.     .compare = irq_ht_compare,
  95.     .remove_callback = NULL     /* not used */
  96. };
  97.  
  98. /**
  99.  * Hash table operations for cases when we know that
  100.  * there will be no collisions between different keys.
  101.  * However, there might be still collisions among
  102.  * elements with single key (sharing of one IRQ).
  103.  */
  104. static index_t irq_lin_hash(unative_t *key);
  105. static bool irq_lin_compare(unative_t *key, count_t keys, link_t *item);
  106.  
  107. static hash_table_operations_t irq_lin_ops = {
  108.     .hash = irq_lin_hash,
  109.     .compare = irq_lin_compare,
  110.     .remove_callback = NULL     /* not used */
  111. };
  112.  
  113. /** Initialize IRQ subsystem.
  114.  *
  115.  * @param inrs Numbers of unique IRQ numbers or INRs.
  116.  * @param chains Number of chains in the hash table.
  117.  */
  118. void irq_init(count_t inrs, count_t chains)
  119. {
  120.     /*
  121.      * Be smart about the choice of the hash table operations.
  122.      * In cases in which inrs equals the requested number of
  123.      * chains (i.e. where there is no collision between
  124.      * different keys), we can use optimized set of operations.
  125.      */
  126.     if (inrs == chains)
  127.         hash_table_create(&irq_hash_table, chains, 2, &irq_lin_ops);
  128.     else
  129.         hash_table_create(&irq_hash_table, chains, 2, &irq_ht_ops);
  130. }
  131.  
  132. /** Initialize one IRQ structure.
  133.  *
  134.  * @param irq Pointer to the IRQ structure to be initialized.
  135.  *
  136.  */
  137. void irq_initialize(irq_t *irq)
  138. {
  139.     link_initialize(&irq->link);
  140.     spinlock_initialize(&irq->lock, "irq.lock");
  141.     irq->preack = false;
  142.     irq->inr = -1;
  143.     irq->devno = -1;
  144.     irq->trigger = (irq_trigger_t) 0;
  145.     irq->claim = NULL;
  146.     irq->handler = NULL;
  147.     irq->arg = NULL;
  148.     irq->notif_cfg.notify = false;
  149.     irq->notif_cfg.answerbox = NULL;
  150.     irq->notif_cfg.code = NULL;
  151.     irq->notif_cfg.method = 0;
  152.     irq->notif_cfg.counter = 0;
  153.     link_initialize(&irq->notif_cfg.link);
  154. }
  155.  
  156. /** Register IRQ for device.
  157.  *
  158.  * The irq structure must be filled with information
  159.  * about the interrupt source and with the claim()
  160.  * 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,
  169.         (unative_t) irq->devno
  170.     };
  171.    
  172.     ipl = interrupts_disable();
  173.     spinlock_lock(&irq_hash_table_lock);
  174.     hash_table_insert(&irq_hash_table, key, &irq->link);
  175.     spinlock_unlock(&irq_hash_table_lock);
  176.     interrupts_restore(ipl);
  177. }
  178.  
  179. /** Dispatch the IRQ.
  180.  *
  181.  * We assume this function is only called from interrupt
  182.  * context (i.e. that interrupts are disabled prior to
  183.  * this call).
  184.  *
  185.  * This function attempts to lookup a fitting IRQ
  186.  * 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,
  198.         (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.  */
  381.