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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 <memstr.h>
  76. #include <arch.h>
  77.  
  78. #define KEY_INR     0
  79. #define KEY_DEVNO   1
  80.  
  81. /**
  82.  * Spinlock protecting the kernel IRQ hash table.
  83.  * This lock must be taken only when interrupts are disabled.
  84.  */
  85. SPINLOCK_INITIALIZE(irq_kernel_hash_table_lock);
  86. /** The kernel IRQ hash table. */
  87. static hash_table_t irq_kernel_hash_table;
  88.  
  89. /**
  90.  * Spinlock protecting the uspace IRQ hash table.
  91.  * This lock must be taken only when interrupts are disabled.
  92.  */
  93. SPINLOCK_INITIALIZE(irq_uspace_hash_table_lock);
  94. /** The uspace IRQ hash table. */
  95. hash_table_t irq_uspace_hash_table;
  96.  
  97. /**
  98.  * Hash table operations for cases when we know that
  99.  * there will be collisions between different keys.
  100.  */
  101. static index_t irq_ht_hash(unative_t *key);
  102. static bool irq_ht_compare(unative_t *key, count_t keys, link_t *item);
  103.  
  104. static hash_table_operations_t irq_ht_ops = {
  105.     .hash = irq_ht_hash,
  106.     .compare = irq_ht_compare,
  107.     .remove_callback = NULL     /* not used */
  108. };
  109.  
  110. /**
  111.  * Hash table operations for cases when we know that
  112.  * there will be no collisions between different keys.
  113.  * However, there might be still collisions among
  114.  * elements with single key (sharing of one IRQ).
  115.  */
  116. static index_t irq_lin_hash(unative_t *key);
  117. static bool irq_lin_compare(unative_t *key, count_t keys, link_t *item);
  118.  
  119. static hash_table_operations_t irq_lin_ops = {
  120.     .hash = irq_lin_hash,
  121.     .compare = irq_lin_compare,
  122.     .remove_callback = NULL     /* not used */
  123. };
  124.  
  125. /** Number of buckets in either of the hash tables. */
  126. static count_t buckets;
  127.  
  128. /** Initialize IRQ subsystem.
  129.  *
  130.  * @param inrs Numbers of unique IRQ numbers or INRs.
  131.  * @param chains Number of chains in the hash table.
  132.  */
  133. void irq_init(count_t inrs, count_t chains)
  134. {
  135.     buckets = chains;
  136.     /*
  137.      * Be smart about the choice of the hash table operations.
  138.      * In cases in which inrs equals the requested number of
  139.      * chains (i.e. where there is no collision between
  140.      * different keys), we can use optimized set of operations.
  141.      */
  142.     if (inrs == chains) {
  143.         hash_table_create(&irq_uspace_hash_table, chains, 2,
  144.             &irq_lin_ops);
  145.         hash_table_create(&irq_kernel_hash_table, chains, 2,
  146.             &irq_lin_ops);
  147.     } else {
  148.         hash_table_create(&irq_uspace_hash_table, chains, 2,
  149.             &irq_ht_ops);
  150.         hash_table_create(&irq_kernel_hash_table, chains, 2,
  151.             &irq_ht_ops);
  152.     }
  153. }
  154.  
  155. /** Initialize one IRQ structure.
  156.  *
  157.  * @param irq Pointer to the IRQ structure to be initialized.
  158.  *
  159.  */
  160. void irq_initialize(irq_t *irq)
  161. {
  162.     memsetb(irq, 0, sizeof(irq_t));
  163.     link_initialize(&irq->link);
  164.     spinlock_initialize(&irq->lock, "irq.lock");
  165.     link_initialize(&irq->notif_cfg.link);
  166.     irq->inr = -1;
  167.     irq->devno = -1;
  168. }
  169.  
  170. /** Register IRQ for device.
  171.  *
  172.  * The irq structure must be filled with information
  173.  * about the interrupt source and with the claim()
  174.  * function pointer and handler() function pointer.
  175.  *
  176.  * @param irq       IRQ structure belonging to a device.
  177.  * @return      True on success, false on failure.
  178.  */
  179. void irq_register(irq_t *irq)
  180. {
  181.     ipl_t ipl;
  182.     unative_t key[] = {
  183.         (unative_t) irq->inr,
  184.         (unative_t) irq->devno
  185.     };
  186.    
  187.     ipl = interrupts_disable();
  188.     spinlock_lock(&irq_kernel_hash_table_lock);
  189.     spinlock_lock(&irq->lock);
  190.     hash_table_insert(&irq_kernel_hash_table, key, &irq->link);
  191.     spinlock_unlock(&irq->lock);   
  192.     spinlock_unlock(&irq_kernel_hash_table_lock);
  193.     interrupts_restore(ipl);
  194. }
  195.  
  196. /** Dispatch the IRQ.
  197.  *
  198.  * We assume this function is only called from interrupt
  199.  * context (i.e. that interrupts are disabled prior to
  200.  * this call).
  201.  *
  202.  * This function attempts to lookup a fitting IRQ
  203.  * structure. In case of success, return with interrupts
  204.  * disabled and holding the respective structure.
  205.  *
  206.  * @param inr Interrupt number (aka inr or irq).
  207.  *
  208.  * @return IRQ structure of the respective device or NULL.
  209.  */
  210. irq_t *irq_dispatch_and_lock(inr_t inr)
  211. {
  212.     link_t *lnk;
  213.     unative_t key[] = {
  214.         (unative_t) inr,
  215.         (unative_t) -1      /* search will use claim() instead of devno */
  216.     };
  217.    
  218.     /*
  219.      * Try uspace handlers first.
  220.      */
  221.     spinlock_lock(&irq_uspace_hash_table_lock);
  222.     lnk = hash_table_find(&irq_uspace_hash_table, key);
  223.     if (lnk) {
  224.         irq_t *irq;
  225.        
  226.         irq = hash_table_get_instance(lnk, irq_t, link);
  227.         spinlock_unlock(&irq_uspace_hash_table_lock);
  228.         return irq;
  229.     }
  230.     spinlock_unlock(&irq_uspace_hash_table_lock);
  231.  
  232.     /*
  233.      * Fallback to kernel handlers.
  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. /** Compute hash index for the key.
  250.  *
  251.  * This function computes hash index into
  252.  * the IRQ hash table for which there
  253.  * can be collisions between different
  254.  * INRs.
  255.  *
  256.  * The devno is not used to compute the hash.
  257.  *
  258.  * @param key The first of the keys is inr and the second is devno or -1.
  259.  *
  260.  * @return Index into the hash table.
  261.  */
  262. index_t irq_ht_hash(unative_t key[])
  263. {
  264.     inr_t inr = (inr_t) key[KEY_INR];
  265.     return inr % buckets;
  266. }
  267.  
  268. /** Compare hash table element with a key.
  269.  *
  270.  * There are two things to note about this function.
  271.  * First, it is used for the more complex architecture setup
  272.  * in which there are way too many interrupt numbers (i.e. inr's)
  273.  * to arrange the hash table so that collisions occur only
  274.  * among same inrs of different devnos. So the explicit check
  275.  * for inr match must be done.
  276.  * Second, if devno is -1, the second key (i.e. devno) is not
  277.  * used for the match and the result of the claim() function
  278.  * is used instead.
  279.  *
  280.  * This function assumes interrupts are already disabled.
  281.  *
  282.  * @param key Keys (i.e. inr and devno).
  283.  * @param keys This is 2.
  284.  * @param item The item to compare the key with.
  285.  *
  286.  * @return True on match or false otherwise.
  287.  */
  288. bool irq_ht_compare(unative_t key[], count_t keys, link_t *item)
  289. {
  290.     irq_t *irq = hash_table_get_instance(item, irq_t, link);
  291.     inr_t inr = (inr_t) key[KEY_INR];
  292.     devno_t devno = (devno_t) key[KEY_DEVNO];
  293.  
  294.     bool rv;
  295.    
  296.     spinlock_lock(&irq->lock);
  297.     if (devno == -1) {
  298.         /* Invoked by irq_dispatch_and_lock(). */
  299.         rv = ((irq->inr == inr) &&
  300.             (irq->claim(irq) == IRQ_ACCEPT));
  301.     } else {
  302.         /* Invoked by irq_find_and_lock(). */
  303.         rv = ((irq->inr == inr) && (irq->devno == devno));
  304.     }
  305.    
  306.     /* unlock only on non-match */
  307.     if (!rv)
  308.         spinlock_unlock(&irq->lock);
  309.  
  310.     return rv;
  311. }
  312.  
  313. /** Compute hash index for the key.
  314.  *
  315.  * This function computes hash index into
  316.  * the IRQ hash table for which there
  317.  * are no collisions between different
  318.  * INRs.
  319.  *
  320.  * @param key The first of the keys is inr and the second is devno or -1.
  321.  *
  322.  * @return Index into the hash table.
  323.  */
  324. index_t irq_lin_hash(unative_t key[])
  325. {
  326.     inr_t inr = (inr_t) key[KEY_INR];
  327.     return inr;
  328. }
  329.  
  330. /** Compare hash table element with a key.
  331.  *
  332.  * There are two things to note about this function.
  333.  * First, it is used for the less complex architecture setup
  334.  * in which there are not too many interrupt numbers (i.e. inr's)
  335.  * to arrange the hash table so that collisions occur only
  336.  * among same inrs of different devnos. So the explicit check
  337.  * for inr match is not done.
  338.  * Second, if devno is -1, the second key (i.e. devno) is not
  339.  * used for the match and the result of the claim() function
  340.  * is used instead.
  341.  *
  342.  * This function assumes interrupts are already disabled.
  343.  *
  344.  * @param key Keys (i.e. inr and devno).
  345.  * @param keys This is 2.
  346.  * @param item The item to compare the key with.
  347.  *
  348.  * @return True on match or false otherwise.
  349.  */
  350. bool irq_lin_compare(unative_t key[], count_t keys, link_t *item)
  351. {
  352.     irq_t *irq = list_get_instance(item, irq_t, link);
  353.     devno_t devno = (devno_t) key[KEY_DEVNO];
  354.     bool rv;
  355.    
  356.     spinlock_lock(&irq->lock);
  357.     if (devno == -1) {
  358.         /* Invoked by irq_dispatch_and_lock() */
  359.         rv = (irq->claim(irq) == IRQ_ACCEPT);
  360.     } else {
  361.         /* Invoked by irq_find_and_lock() */
  362.         rv = (irq->devno == devno);
  363.     }
  364.    
  365.     /* unlock only on non-match */
  366.     if (!rv)
  367.         spinlock_unlock(&irq->lock);
  368.    
  369.     return rv;
  370. }
  371.  
  372. /** @}
  373.  */
  374.