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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 single device
  43.  * - multiple instances of the same device
  44.  *
  45.  *
  46.  * Note about architectures.
  47.  *
  48.  * Some architectures has the term IRQ well defined. Examples
  49.  * of such architectures include amd64, ia32 and mips32. Some
  50.  * other architectures, such as sparc64, don't use the term
  51.  * at all. In those cases, we boldly step forward and define what
  52.  * an IRQ is.
  53.  *
  54.  * The implementation is generic enough and still allows the
  55.  * architectures to use the hardware layout effectively.
  56.  * For instance, on amd64 and ia32, where there is only 16
  57.  * IRQs, the irq_hash_table can be optimized to a one-dimensional
  58.  * array. Next, when it is known that the IRQ numbers (aka INR's)
  59.  * are unique, the claim functions can always return IRQ_ACCEPT.
  60.  *
  61.  *
  62.  * Note about the irq_hash_table.
  63.  *
  64.  * The hash table is configured to use two keys: inr and devno.
  65.  * However, the hash index is computed only from inr. Moreover,
  66.  * if devno is -1, the match is based on the return value of
  67.  * the claim() function instead of on devno.
  68.  */
  69.  
  70. #include <ddi/irq.h>
  71. #include <adt/hash_table.h>
  72. #include <mm/slab.h>
  73. #include <arch/types.h>
  74. #include <synch/spinlock.h>
  75. #include <console/console.h>
  76. #include <memstr.h>
  77. #include <arch.h>
  78.  
  79. #define KEY_INR     0
  80. #define KEY_DEVNO   1
  81.  
  82. /**
  83.  * Spinlock protecting the kernel IRQ hash table.
  84.  * This lock must be taken only when interrupts are disabled.
  85.  */
  86. SPINLOCK_INITIALIZE(irq_kernel_hash_table_lock);
  87. /** The kernel IRQ hash table. */
  88. static hash_table_t irq_kernel_hash_table;
  89.  
  90. /**
  91.  * Spinlock protecting the uspace IRQ hash table.
  92.  * This lock must be taken only when interrupts are disabled.
  93.  */
  94. SPINLOCK_INITIALIZE(irq_uspace_hash_table_lock);
  95. /** The uspace IRQ hash table. */
  96. hash_table_t irq_uspace_hash_table;
  97.  
  98. /**
  99.  * Hash table operations for cases when we know that
  100.  * there will be collisions between different keys.
  101.  */
  102. static index_t irq_ht_hash(unative_t *key);
  103. static bool irq_ht_compare(unative_t *key, count_t keys, link_t *item);
  104. static void irq_ht_remove(link_t *item);
  105.  
  106. static hash_table_operations_t irq_ht_ops = {
  107.     .hash = irq_ht_hash,
  108.     .compare = irq_ht_compare,
  109.     .remove_callback = irq_ht_remove,
  110. };
  111.  
  112. /**
  113.  * Hash table operations for cases when we know that
  114.  * there will be no collisions between different keys.
  115.  * However, there might be still collisions among
  116.  * elements with single key (sharing of one IRQ).
  117.  */
  118. static index_t irq_lin_hash(unative_t *key);
  119. static bool irq_lin_compare(unative_t *key, count_t keys, link_t *item);
  120. static void irq_lin_remove(link_t *item);
  121.  
  122. static hash_table_operations_t irq_lin_ops = {
  123.     .hash = irq_lin_hash,
  124.     .compare = irq_lin_compare,
  125.     .remove_callback = irq_lin_remove,
  126. };
  127.  
  128. /** Number of buckets in either of the hash tables. */
  129. static count_t buckets;
  130.  
  131. /** Initialize IRQ subsystem.
  132.  *
  133.  * @param inrs Numbers of unique IRQ numbers or INRs.
  134.  * @param chains Number of chains in the hash table.
  135.  */
  136. void irq_init(count_t inrs, count_t chains)
  137. {
  138.     buckets = chains;
  139.     /*
  140.      * Be smart about the choice of the hash table operations.
  141.      * In cases in which inrs equals the requested number of
  142.      * chains (i.e. where there is no collision between
  143.      * different keys), we can use optimized set of operations.
  144.      */
  145.     if (inrs == chains) {
  146.         hash_table_create(&irq_uspace_hash_table, chains, 2,
  147.             &irq_lin_ops);
  148.         hash_table_create(&irq_kernel_hash_table, chains, 2,
  149.             &irq_lin_ops);
  150.     } else {
  151.         hash_table_create(&irq_uspace_hash_table, chains, 2,
  152.             &irq_ht_ops);
  153.         hash_table_create(&irq_kernel_hash_table, chains, 2,
  154.             &irq_ht_ops);
  155.     }
  156. }
  157.  
  158. /** Initialize one IRQ structure.
  159.  *
  160.  * @param irq Pointer to the IRQ structure to be initialized.
  161.  *
  162.  */
  163. void irq_initialize(irq_t *irq)
  164. {
  165.     memsetb(irq, sizeof(irq_t), 0);
  166.     link_initialize(&irq->link);
  167.     spinlock_initialize(&irq->lock, "irq.lock");
  168.     link_initialize(&irq->notif_cfg.link);
  169.     irq->inr = -1;
  170.     irq->devno = -1;
  171. }
  172.  
  173. /** Register IRQ for device.
  174.  *
  175.  * The irq structure must be filled with information
  176.  * about the interrupt source and with the claim()
  177.  * function pointer and handler() function pointer.
  178.  *
  179.  * @param irq       IRQ structure belonging to a device.
  180.  * @return      True on success, false on failure.
  181.  */
  182. void irq_register(irq_t *irq)
  183. {
  184.     ipl_t ipl;
  185.     unative_t key[] = {
  186.         (unative_t) irq->inr,
  187.         (unative_t) irq->devno
  188.     };
  189.    
  190.     ipl = interrupts_disable();
  191.     spinlock_lock(&irq_kernel_hash_table_lock);
  192.     spinlock_lock(&irq->lock);
  193.     hash_table_insert(&irq_kernel_hash_table, key, &irq->link);
  194.     spinlock_unlock(&irq->lock);   
  195.     spinlock_unlock(&irq_kernel_hash_table_lock);
  196.     interrupts_restore(ipl);
  197. }
  198.  
  199. /** Search and lock the uspace IRQ hash table.
  200.  *
  201.  */
  202. static irq_t *irq_dispatch_and_lock_uspace(inr_t inr)
  203. {
  204.     link_t *lnk;
  205.     unative_t key[] = {
  206.         (unative_t) inr,
  207.         (unative_t) -1    /* search will use claim() instead of devno */
  208.     };
  209.    
  210.     spinlock_lock(&irq_uspace_hash_table_lock);
  211.     lnk = hash_table_find(&irq_uspace_hash_table, key);
  212.     if (lnk) {
  213.         irq_t *irq;
  214.        
  215.         irq = hash_table_get_instance(lnk, irq_t, link);
  216.         spinlock_unlock(&irq_uspace_hash_table_lock);
  217.         return irq;
  218.     }
  219.     spinlock_unlock(&irq_uspace_hash_table_lock);
  220.    
  221.     return NULL;
  222. }
  223.  
  224. /** Search and lock the kernel IRQ hash table.
  225.  *
  226.  */
  227. static irq_t *irq_dispatch_and_lock_kernel(inr_t inr)
  228. {
  229.     link_t *lnk;
  230.     unative_t key[] = {
  231.         (unative_t) inr,
  232.         (unative_t) -1    /* search will use claim() instead of devno */
  233.     };
  234.    
  235.     spinlock_lock(&irq_kernel_hash_table_lock);
  236.     lnk = hash_table_find(&irq_kernel_hash_table, key);
  237.     if (lnk) {
  238.         irq_t *irq;
  239.        
  240.         irq = hash_table_get_instance(lnk, irq_t, link);
  241.         spinlock_unlock(&irq_kernel_hash_table_lock);
  242.         return irq;
  243.     }
  244.     spinlock_unlock(&irq_kernel_hash_table_lock);
  245.    
  246.     return NULL;
  247. }
  248.  
  249. /** Dispatch the IRQ.
  250.  *
  251.  * We assume this function is only called from interrupt
  252.  * context (i.e. that interrupts are disabled prior to
  253.  * this call).
  254.  *
  255.  * This function attempts to lookup a fitting IRQ
  256.  * structure. In case of success, return with interrupts
  257.  * disabled and holding the respective structure.
  258.  *
  259.  * @param inr Interrupt number (aka inr or irq).
  260.  *
  261.  * @return IRQ structure of the respective device or NULL.
  262.  */
  263. irq_t *irq_dispatch_and_lock(inr_t inr)
  264. {
  265.     irq_t *irq;
  266.    
  267.     /*
  268.      * If the kernel console is silenced,
  269.      * then try first the uspace handlers,
  270.      * eventually fall back to kernel handlers.
  271.      *
  272.      * If the kernel console is active,
  273.      * then do it the other way around.
  274.      */
  275.     if (silent) {
  276.         irq = irq_dispatch_and_lock_uspace(inr);
  277.         if (irq)
  278.             return irq;
  279.         return irq_dispatch_and_lock_kernel(inr);
  280.     }
  281.    
  282.     irq = irq_dispatch_and_lock_kernel(inr);
  283.     if (irq)
  284.         return irq;
  285.     return irq_dispatch_and_lock_uspace(inr);
  286. }
  287.  
  288. /** Compute hash index for the key.
  289.  *
  290.  * This function computes hash index into
  291.  * the IRQ hash table for which there
  292.  * can be collisions between different
  293.  * INRs.
  294.  *
  295.  * The devno is not used to compute the hash.
  296.  *
  297.  * @param key The first of the keys is inr and the second is devno or -1.
  298.  *
  299.  * @return Index into the hash table.
  300.  */
  301. index_t irq_ht_hash(unative_t key[])
  302. {
  303.     inr_t inr = (inr_t) key[KEY_INR];
  304.     return inr % buckets;
  305. }
  306.  
  307. /** Compare hash table element with a key.
  308.  *
  309.  * There are two things to note about this function.
  310.  * First, it is used for the more complex architecture setup
  311.  * in which there are way too many interrupt numbers (i.e. inr's)
  312.  * to arrange the hash table so that collisions occur only
  313.  * among same inrs of different devnos. So the explicit check
  314.  * for inr match must be done.
  315.  * Second, if devno is -1, the second key (i.e. devno) is not
  316.  * used for the match and the result of the claim() function
  317.  * is used instead.
  318.  *
  319.  * This function assumes interrupts are already disabled.
  320.  *
  321.  * @param key Keys (i.e. inr and devno).
  322.  * @param keys This is 2.
  323.  * @param item The item to compare the key with.
  324.  *
  325.  * @return True on match or false otherwise.
  326.  */
  327. bool irq_ht_compare(unative_t key[], count_t keys, link_t *item)
  328. {
  329.     irq_t *irq = hash_table_get_instance(item, irq_t, link);
  330.     inr_t inr = (inr_t) key[KEY_INR];
  331.     devno_t devno = (devno_t) key[KEY_DEVNO];
  332.  
  333.     bool rv;
  334.    
  335.     spinlock_lock(&irq->lock);
  336.     if (devno == -1) {
  337.         /* Invoked by irq_dispatch_and_lock(). */
  338.         rv = ((irq->inr == inr) &&
  339.             (irq->claim(irq) == IRQ_ACCEPT));
  340.     } else {
  341.         /* Invoked by irq_find_and_lock(). */
  342.         rv = ((irq->inr == inr) && (irq->devno == devno));
  343.     }
  344.    
  345.     /* unlock only on non-match */
  346.     if (!rv)
  347.         spinlock_unlock(&irq->lock);
  348.  
  349.     return rv;
  350. }
  351.  
  352. /** Unlock IRQ structure after hash_table_remove().
  353.  *
  354.  * @param lnk       Link in the removed and locked IRQ structure.
  355.  */
  356. void irq_ht_remove(link_t *lnk)
  357. {
  358.     irq_t *irq = hash_table_get_instance(lnk, irq_t, link);
  359.     spinlock_unlock(&irq->lock);
  360. }
  361.  
  362. /** Compute hash index for the key.
  363.  *
  364.  * This function computes hash index into
  365.  * the IRQ hash table for which there
  366.  * are no collisions between different
  367.  * INRs.
  368.  *
  369.  * @param key The first of the keys is inr and the second is devno or -1.
  370.  *
  371.  * @return Index into the hash table.
  372.  */
  373. index_t irq_lin_hash(unative_t key[])
  374. {
  375.     inr_t inr = (inr_t) key[KEY_INR];
  376.     return inr;
  377. }
  378.  
  379. /** Compare hash table element with a key.
  380.  *
  381.  * There are two things to note about this function.
  382.  * First, it is used for the less complex architecture setup
  383.  * in which there are not too many interrupt numbers (i.e. inr's)
  384.  * to arrange the hash table so that collisions occur only
  385.  * among same inrs of different devnos. So the explicit check
  386.  * for inr match is not done.
  387.  * Second, if devno is -1, the second key (i.e. devno) is not
  388.  * used for the match and the result of the claim() function
  389.  * is used instead.
  390.  *
  391.  * This function assumes interrupts are already disabled.
  392.  *
  393.  * @param key Keys (i.e. inr and devno).
  394.  * @param keys This is 2.
  395.  * @param item The item to compare the key with.
  396.  *
  397.  * @return True on match or false otherwise.
  398.  */
  399. bool irq_lin_compare(unative_t key[], count_t keys, link_t *item)
  400. {
  401.     irq_t *irq = list_get_instance(item, irq_t, link);
  402.     devno_t devno = (devno_t) key[KEY_DEVNO];
  403.     bool rv;
  404.    
  405.     spinlock_lock(&irq->lock);
  406.     if (devno == -1) {
  407.         /* Invoked by irq_dispatch_and_lock() */
  408.         rv = (irq->claim(irq) == IRQ_ACCEPT);
  409.     } else {
  410.         /* Invoked by irq_find_and_lock() */
  411.         rv = (irq->devno == devno);
  412.     }
  413.    
  414.     /* unlock only on non-match */
  415.     if (!rv)
  416.         spinlock_unlock(&irq->lock);
  417.    
  418.     return rv;
  419. }
  420.  
  421. /** Unlock IRQ structure after hash_table_remove().
  422.  *
  423.  * @param lnk       Link in the removed and locked IRQ structure.
  424.  */
  425. void irq_lin_remove(link_t *lnk)
  426. {
  427.     irq_t *irq = hash_table_get_instance(lnk, irq_t, link);
  428.     spinlock_unlock(&irq->lock);
  429. }
  430.  
  431. /** @}
  432.  */
  433.