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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.  
  105. static hash_table_operations_t irq_ht_ops = {
  106.     .hash = irq_ht_hash,
  107.     .compare = irq_ht_compare,
  108.     .remove_callback = NULL     /* not used */
  109. };
  110.  
  111. /**
  112.  * Hash table operations for cases when we know that
  113.  * there will be no collisions between different keys.
  114.  * However, there might be still collisions among
  115.  * elements with single key (sharing of one IRQ).
  116.  */
  117. static index_t irq_lin_hash(unative_t *key);
  118. static bool irq_lin_compare(unative_t *key, count_t keys, link_t *item);
  119.  
  120. static hash_table_operations_t irq_lin_ops = {
  121.     .hash = irq_lin_hash,
  122.     .compare = irq_lin_compare,
  123.     .remove_callback = NULL     /* not used */
  124. };
  125.  
  126. /** Number of buckets in either of the hash tables. */
  127. static count_t buckets;
  128.  
  129. /** Initialize IRQ subsystem.
  130.  *
  131.  * @param inrs Numbers of unique IRQ numbers or INRs.
  132.  * @param chains Number of chains in the hash table.
  133.  */
  134. void irq_init(count_t inrs, count_t chains)
  135. {
  136.     buckets = chains;
  137.     /*
  138.      * Be smart about the choice of the hash table operations.
  139.      * In cases in which inrs equals the requested number of
  140.      * chains (i.e. where there is no collision between
  141.      * different keys), we can use optimized set of operations.
  142.      */
  143.     if (inrs == chains) {
  144.         hash_table_create(&irq_uspace_hash_table, chains, 2,
  145.             &irq_lin_ops);
  146.         hash_table_create(&irq_kernel_hash_table, chains, 2,
  147.             &irq_lin_ops);
  148.     } else {
  149.         hash_table_create(&irq_uspace_hash_table, chains, 2,
  150.             &irq_ht_ops);
  151.         hash_table_create(&irq_kernel_hash_table, chains, 2,
  152.             &irq_ht_ops);
  153.     }
  154. }
  155.  
  156. /** Initialize one IRQ structure.
  157.  *
  158.  * @param irq Pointer to the IRQ structure to be initialized.
  159.  *
  160.  */
  161. void irq_initialize(irq_t *irq)
  162. {
  163.     memsetb(irq, sizeof(irq_t), 0);
  164.     link_initialize(&irq->link);
  165.     spinlock_initialize(&irq->lock, "irq.lock");
  166.     link_initialize(&irq->notif_cfg.link);
  167.     irq->inr = -1;
  168.     irq->devno = -1;
  169. }
  170.  
  171. /** Register IRQ for device.
  172.  *
  173.  * The irq structure must be filled with information
  174.  * about the interrupt source and with the claim()
  175.  * function pointer and handler() function pointer.
  176.  *
  177.  * @param irq       IRQ structure belonging to a device.
  178.  * @return      True on success, false on failure.
  179.  */
  180. void irq_register(irq_t *irq)
  181. {
  182.     ipl_t ipl;
  183.     unative_t key[] = {
  184.         (unative_t) irq->inr,
  185.         (unative_t) irq->devno
  186.     };
  187.    
  188.     ipl = interrupts_disable();
  189.     spinlock_lock(&irq_kernel_hash_table_lock);
  190.     spinlock_lock(&irq->lock);
  191.     hash_table_insert(&irq_kernel_hash_table, key, &irq->link);
  192.     spinlock_unlock(&irq->lock);   
  193.     spinlock_unlock(&irq_kernel_hash_table_lock);
  194.     interrupts_restore(ipl);
  195. }
  196.  
  197. /** Search and lock the uspace IRQ hash table.
  198.  *
  199.  */
  200. static irq_t *irq_dispatch_and_lock_uspace(inr_t inr)
  201. {
  202.     link_t *lnk;
  203.     unative_t key[] = {
  204.         (unative_t) inr,
  205.         (unative_t) -1    /* search will use claim() instead of devno */
  206.     };
  207.    
  208.     spinlock_lock(&irq_uspace_hash_table_lock);
  209.     lnk = hash_table_find(&irq_uspace_hash_table, key);
  210.     if (lnk) {
  211.         irq_t *irq;
  212.        
  213.         irq = hash_table_get_instance(lnk, irq_t, link);
  214.         spinlock_unlock(&irq_uspace_hash_table_lock);
  215.         return irq;
  216.     }
  217.     spinlock_unlock(&irq_uspace_hash_table_lock);
  218.    
  219.     return NULL;
  220. }
  221.  
  222. /** Search and lock the kernel IRQ hash table.
  223.  *
  224.  */
  225. static irq_t *irq_dispatch_and_lock_kernel(inr_t inr)
  226. {
  227.     link_t *lnk;
  228.     unative_t key[] = {
  229.         (unative_t) inr,
  230.         (unative_t) -1    /* search will use claim() instead of devno */
  231.     };
  232.    
  233.     spinlock_lock(&irq_kernel_hash_table_lock);
  234.     lnk = hash_table_find(&irq_kernel_hash_table, key);
  235.     if (lnk) {
  236.         irq_t *irq;
  237.        
  238.         irq = hash_table_get_instance(lnk, irq_t, link);
  239.         spinlock_unlock(&irq_kernel_hash_table_lock);
  240.         return irq;
  241.     }
  242.     spinlock_unlock(&irq_kernel_hash_table_lock);
  243.    
  244.     return NULL;
  245. }
  246.  
  247. /** Dispatch the IRQ.
  248.  *
  249.  * We assume this function is only called from interrupt
  250.  * context (i.e. that interrupts are disabled prior to
  251.  * this call).
  252.  *
  253.  * This function attempts to lookup a fitting IRQ
  254.  * structure. In case of success, return with interrupts
  255.  * disabled and holding the respective structure.
  256.  *
  257.  * @param inr Interrupt number (aka inr or irq).
  258.  *
  259.  * @return IRQ structure of the respective device or NULL.
  260.  */
  261. irq_t *irq_dispatch_and_lock(inr_t inr)
  262. {
  263.     irq_t *irq;
  264.    
  265.     /*
  266.      * If the kernel console is silenced,
  267.      * then try first the uspace handlers,
  268.      * eventually fall back to kernel handlers.
  269.      *
  270.      * If the kernel console is active,
  271.      * then do it the other way around.
  272.      */
  273.     if (silent) {
  274.         irq = irq_dispatch_and_lock_uspace(inr);
  275.         if (irq)
  276.             return irq;
  277.         return irq_dispatch_and_lock_kernel(inr);
  278.     }
  279.    
  280.     irq = irq_dispatch_and_lock_kernel(inr);
  281.     if (irq)
  282.         return irq;
  283.     return irq_dispatch_and_lock_uspace(inr);
  284. }
  285.  
  286. /** Compute hash index for the key.
  287.  *
  288.  * This function computes hash index into
  289.  * the IRQ hash table for which there
  290.  * can be collisions between different
  291.  * INRs.
  292.  *
  293.  * The devno is not used to compute the hash.
  294.  *
  295.  * @param key The first of the keys is inr and the second is devno or -1.
  296.  *
  297.  * @return Index into the hash table.
  298.  */
  299. index_t irq_ht_hash(unative_t key[])
  300. {
  301.     inr_t inr = (inr_t) key[KEY_INR];
  302.     return inr % buckets;
  303. }
  304.  
  305. /** Compare hash table element with a key.
  306.  *
  307.  * There are two things to note about this function.
  308.  * First, it is used for the more complex architecture setup
  309.  * in which there are way too many interrupt numbers (i.e. inr's)
  310.  * to arrange the hash table so that collisions occur only
  311.  * among same inrs of different devnos. So the explicit check
  312.  * for inr match must be done.
  313.  * Second, if devno is -1, the second key (i.e. devno) is not
  314.  * used for the match and the result of the claim() function
  315.  * is used instead.
  316.  *
  317.  * This function assumes interrupts are already disabled.
  318.  *
  319.  * @param key Keys (i.e. inr and devno).
  320.  * @param keys This is 2.
  321.  * @param item The item to compare the key with.
  322.  *
  323.  * @return True on match or false otherwise.
  324.  */
  325. bool irq_ht_compare(unative_t key[], count_t keys, link_t *item)
  326. {
  327.     irq_t *irq = hash_table_get_instance(item, irq_t, link);
  328.     inr_t inr = (inr_t) key[KEY_INR];
  329.     devno_t devno = (devno_t) key[KEY_DEVNO];
  330.  
  331.     bool rv;
  332.    
  333.     spinlock_lock(&irq->lock);
  334.     if (devno == -1) {
  335.         /* Invoked by irq_dispatch_and_lock(). */
  336.         rv = ((irq->inr == inr) &&
  337.             (irq->claim(irq) == IRQ_ACCEPT));
  338.     } else {
  339.         /* Invoked by irq_find_and_lock(). */
  340.         rv = ((irq->inr == inr) && (irq->devno == devno));
  341.     }
  342.    
  343.     /* unlock only on non-match */
  344.     if (!rv)
  345.         spinlock_unlock(&irq->lock);
  346.  
  347.     return rv;
  348. }
  349.  
  350. /** Compute hash index for the key.
  351.  *
  352.  * This function computes hash index into
  353.  * the IRQ hash table for which there
  354.  * are no collisions between different
  355.  * INRs.
  356.  *
  357.  * @param key The first of the keys is inr and the second is devno or -1.
  358.  *
  359.  * @return Index into the hash table.
  360.  */
  361. index_t irq_lin_hash(unative_t key[])
  362. {
  363.     inr_t inr = (inr_t) key[KEY_INR];
  364.     return inr;
  365. }
  366.  
  367. /** Compare hash table element with a key.
  368.  *
  369.  * There are two things to note about this function.
  370.  * First, it is used for the less complex architecture setup
  371.  * in which there are not too many interrupt numbers (i.e. inr's)
  372.  * to arrange the hash table so that collisions occur only
  373.  * among same inrs of different devnos. So the explicit check
  374.  * for inr match is not done.
  375.  * Second, if devno is -1, the second key (i.e. devno) is not
  376.  * used for the match and the result of the claim() function
  377.  * is used instead.
  378.  *
  379.  * This function assumes interrupts are already disabled.
  380.  *
  381.  * @param key Keys (i.e. inr and devno).
  382.  * @param keys This is 2.
  383.  * @param item The item to compare the key with.
  384.  *
  385.  * @return True on match or false otherwise.
  386.  */
  387. bool irq_lin_compare(unative_t key[], count_t keys, link_t *item)
  388. {
  389.     irq_t *irq = list_get_instance(item, irq_t, link);
  390.     devno_t devno = (devno_t) key[KEY_DEVNO];
  391.     bool rv;
  392.    
  393.     spinlock_lock(&irq->lock);
  394.     if (devno == -1) {
  395.         /* Invoked by irq_dispatch_and_lock() */
  396.         rv = (irq->claim(irq) == IRQ_ACCEPT);
  397.     } else {
  398.         /* Invoked by irq_find_and_lock() */
  399.         rv = (irq->devno == devno);
  400.     }
  401.    
  402.     /* unlock only on non-match */
  403.     if (!rv)
  404.         spinlock_unlock(&irq->lock);
  405.    
  406.     return rv;
  407. }
  408.  
  409. /** @}
  410.  */
  411.