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  1. /*
  2.  * Copyright (C) 2006 Ondrej Palkovsky
  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. /* Lock ordering
  30.  *
  31.  * First the answerbox, then the phone
  32.  */
  33.  
  34. #include <synch/spinlock.h>
  35. #include <synch/waitq.h>
  36. #include <synch/synch.h>
  37. #include <ipc/ipc.h>
  38. #include <errno.h>
  39. #include <mm/slab.h>
  40. #include <arch.h>
  41. #include <proc/task.h>
  42. #include <memstr.h>
  43. #include <debug.h>
  44.  
  45. #include <print.h>
  46. #include <proc/thread.h>
  47. #include <arch/interrupt.h>
  48. #include <ipc/irq.h>
  49.  
  50. /* Open channel that is assigned automatically to new tasks */
  51. answerbox_t *ipc_phone_0 = NULL;
  52.  
  53. static slab_cache_t *ipc_call_slab;
  54.  
  55. /* Initialize new call */
  56. static void _ipc_call_init(call_t *call)
  57. {
  58.     memsetb((__address)call, sizeof(*call), 0);
  59.     call->callerbox = &TASK->answerbox;
  60.     call->sender = TASK;
  61. }
  62.  
  63. /** Allocate & initialize call structure
  64.  *
  65.  * The call is initialized, so that the reply will be directed
  66.  * to TASK->answerbox
  67.  *
  68.  * @param flags Parameters for slab_alloc (ATOMIC, etc.)
  69.  */
  70. call_t * ipc_call_alloc(int flags)
  71. {
  72.     call_t *call;
  73.  
  74.     call = slab_alloc(ipc_call_slab, flags);
  75.     _ipc_call_init(call);
  76.  
  77.     return call;
  78. }
  79.  
  80. /** Initialize allocated call */
  81. void ipc_call_static_init(call_t *call)
  82. {
  83.     _ipc_call_init(call);
  84.     call->flags |= IPC_CALL_STATIC_ALLOC;
  85. }
  86.  
  87. /** Deallocate call stracuture */
  88. void ipc_call_free(call_t *call)
  89. {
  90.     slab_free(ipc_call_slab, call);
  91. }
  92.  
  93. /** Initialize answerbox structure
  94.  */
  95. void ipc_answerbox_init(answerbox_t *box)
  96. {
  97.     spinlock_initialize(&box->lock, "ipc_box_lock");
  98.     spinlock_initialize(&box->irq_lock, "ipc_box_irqlock");
  99.     waitq_initialize(&box->wq);
  100.     list_initialize(&box->connected_phones);
  101.     list_initialize(&box->calls);
  102.     list_initialize(&box->dispatched_calls);
  103.     list_initialize(&box->answers);
  104.     list_initialize(&box->irq_notifs);
  105.     box->task = TASK;
  106. }
  107.  
  108. /** Connect phone to answerbox */
  109. void ipc_phone_connect(phone_t *phone, answerbox_t *box)
  110. {
  111.     spinlock_lock(&phone->lock);
  112.  
  113.     ASSERT(!phone->callee);
  114.     phone->busy = IPC_BUSY_CONNECTED;
  115.     phone->callee = box;
  116.  
  117.     spinlock_lock(&box->lock);
  118.     list_append(&phone->list, &box->connected_phones);
  119.     spinlock_unlock(&box->lock);
  120.  
  121.     spinlock_unlock(&phone->lock);
  122. }
  123.  
  124. /** Initialize phone structure and connect phone to answerbox
  125.  */
  126. void ipc_phone_init(phone_t *phone)
  127. {
  128.     spinlock_initialize(&phone->lock, "phone_lock");
  129.     phone->callee = NULL;
  130.     phone->busy = IPC_BUSY_FREE;
  131.     atomic_set(&phone->active_calls, 0);
  132. }
  133.  
  134. /** Helper function to facilitate synchronous calls */
  135. void ipc_call_sync(phone_t *phone, call_t *request)
  136. {
  137.     answerbox_t sync_box;
  138.  
  139.     ipc_answerbox_init(&sync_box);
  140.  
  141.     /* We will receive data on special box */
  142.     request->callerbox = &sync_box;
  143.  
  144.     ipc_call(phone, request);
  145.     ipc_wait_for_call(&sync_box, SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE);
  146. }
  147.  
  148. /** Answer message that was not dispatched and is not entered in
  149.  * any queue
  150.  */
  151. static void _ipc_answer_free_call(call_t *call)
  152. {
  153.     answerbox_t *callerbox = call->callerbox;
  154.  
  155.     call->flags |= IPC_CALL_ANSWERED;
  156.  
  157.     spinlock_lock(&callerbox->lock);
  158.     list_append(&call->list, &callerbox->answers);
  159.     spinlock_unlock(&callerbox->lock);
  160.     waitq_wakeup(&callerbox->wq, 0);
  161. }
  162.  
  163. /** Answer message, that is in callee queue
  164.  *
  165.  * @param box Answerbox that is answering the message
  166.  * @param call Modified request that is being sent back
  167.  */
  168. void ipc_answer(answerbox_t *box, call_t *call)
  169. {
  170.     /* Remove from active box */
  171.     spinlock_lock(&box->lock);
  172.     list_remove(&call->list);
  173.     spinlock_unlock(&box->lock);
  174.     /* Send back answer */
  175.     _ipc_answer_free_call(call);
  176. }
  177.  
  178. /** Simulate sending back a message
  179.  *
  180.  * Most errors are better handled by forming a normal backward
  181.  * message and sending it as a normal answer.
  182.  */
  183. void ipc_backsend_err(phone_t *phone, call_t *call, __native err)
  184. {
  185.     call->data.phone = phone;
  186.     atomic_inc(&phone->active_calls);
  187.     if (phone->busy == IPC_BUSY_CONNECTED)
  188.         IPC_SET_RETVAL(call->data, EHANGUP);
  189.     else
  190.         IPC_SET_RETVAL(call->data, ENOENT);
  191.  
  192.     _ipc_answer_free_call(call);
  193. }
  194.  
  195. /* Unsafe unchecking ipc_call */
  196. static void _ipc_call(phone_t *phone, answerbox_t *box, call_t *call)
  197. {
  198.     if (! (call->flags & IPC_CALL_FORWARDED)) {
  199.         atomic_inc(&phone->active_calls);
  200.         call->data.phone = phone;
  201.     }
  202.  
  203.     spinlock_lock(&box->lock);
  204.     list_append(&call->list, &box->calls);
  205.     spinlock_unlock(&box->lock);
  206.     waitq_wakeup(&box->wq, 0);
  207. }
  208.  
  209. /** Send a asynchronous request using phone to answerbox
  210.  *
  211.  * @param phone Phone connected to answerbox
  212.  * @param request Request to be sent
  213.  */
  214. int ipc_call(phone_t *phone, call_t *call)
  215. {
  216.     answerbox_t *box;
  217.  
  218.     spinlock_lock(&phone->lock);
  219.  
  220.     box = phone->callee;
  221.     if (!box) {
  222.         /* Trying to send over disconnected phone */
  223.         spinlock_unlock(&phone->lock);
  224.         if (call->flags & IPC_CALL_FORWARDED) {
  225.             IPC_SET_RETVAL(call->data, EFORWARD);
  226.             _ipc_answer_free_call(call);
  227.         } else { /* Simulate sending back a message */
  228.             if (phone->busy == IPC_BUSY_CONNECTED)
  229.                 ipc_backsend_err(phone, call, EHANGUP);
  230.             else
  231.                 ipc_backsend_err(phone, call, ENOENT);
  232.         }
  233.  
  234.         return ENOENT;
  235.     }
  236.     _ipc_call(phone, box, call);
  237.    
  238.     spinlock_unlock(&phone->lock);
  239.     return 0;
  240. }
  241.  
  242. /** Disconnect phone from answerbox
  243.  *
  244.  * It is allowed to call disconnect on already disconnected phone
  245.  *
  246.  * @return 0 - phone disconnected, -1 - the phone was already disconnected
  247.  */
  248. int ipc_phone_hangup(phone_t *phone)
  249. {
  250.     answerbox_t *box;
  251.     call_t *call;
  252.    
  253.     spinlock_lock(&phone->lock);
  254.     box = phone->callee;
  255.     if (!box) {
  256.         if (phone->busy == IPC_BUSY_CONNECTING) {
  257.             spinlock_unlock(&phone->lock);
  258.             return -1;
  259.         }
  260.         /* Already disconnected phone */
  261.         phone->busy = IPC_BUSY_FREE;
  262.         spinlock_unlock(&phone->lock);
  263.         return 0;
  264.     }
  265.  
  266.     spinlock_lock(&box->lock);
  267.     list_remove(&phone->list);
  268.     phone->callee = NULL;
  269.     spinlock_unlock(&box->lock);
  270.  
  271.     call = ipc_call_alloc(0);
  272.     IPC_SET_METHOD(call->data, IPC_M_PHONE_HUNGUP);
  273.     call->flags |= IPC_CALL_DISCARD_ANSWER;
  274.     _ipc_call(phone, box, call);
  275.  
  276.     phone->busy = IPC_BUSY_FREE;
  277.  
  278.     spinlock_unlock(&phone->lock);
  279.  
  280.     return 0;
  281. }
  282.  
  283. /** Forwards call from one answerbox to a new one
  284.  *
  285.  * @param call Call to be redirected.
  286.  * @param newphone Phone to target answerbox.
  287.  * @param oldbox Old answerbox
  288.  * @return 0 on forward ok, error code, if there was error
  289.  *
  290.  * - the return value serves only as an information for the forwarder,
  291.  *   the original caller is notified automatically with EFORWARD
  292.  */
  293. int ipc_forward(call_t *call, phone_t *newphone, answerbox_t *oldbox)
  294. {
  295.     spinlock_lock(&oldbox->lock);
  296.     list_remove(&call->list);
  297.     spinlock_unlock(&oldbox->lock);
  298.  
  299.     return ipc_call(newphone, call);
  300. }
  301.  
  302.  
  303. /** Wait for phone call
  304.  *
  305.  * @param box Answerbox expecting the call.
  306.  * @param usec Timeout in microseconds. See documentation for waitq_sleep_timeout() for
  307.  *         decription of its special meaning.
  308.  * @param flags Select mode of sleep operation. See documentation for waitq_sleep_timeout()i
  309.  *      for description of its special meaning.
  310.  * @return Recived message address
  311.  * - to distinguish between call and answer, look at call->flags
  312.  */
  313. call_t * ipc_wait_for_call(answerbox_t *box, __u32 usec, int flags)
  314. {
  315.     call_t *request;
  316.     ipl_t ipl;
  317.     int rc;
  318.  
  319. restart:
  320.     rc = waitq_sleep_timeout(&box->wq, usec, flags);
  321.     if (SYNCH_FAILED(rc))
  322.         return NULL;
  323.    
  324.     spinlock_lock(&box->lock);
  325.     if (!list_empty(&box->irq_notifs)) {
  326.         ipl = interrupts_disable();
  327.         spinlock_lock(&box->irq_lock);
  328.  
  329.         request = list_get_instance(box->irq_notifs.next, call_t, list);
  330.         list_remove(&request->list);
  331.  
  332.         spinlock_unlock(&box->irq_lock);
  333.         interrupts_restore(ipl);
  334.     } else if (!list_empty(&box->answers)) {
  335.         /* Handle asynchronous answers */
  336.         request = list_get_instance(box->answers.next, call_t, list);
  337.         list_remove(&request->list);
  338.         atomic_dec(&request->data.phone->active_calls);
  339.     } else if (!list_empty(&box->calls)) {
  340.         /* Handle requests */
  341.         request = list_get_instance(box->calls.next, call_t, list);
  342.         list_remove(&request->list);
  343.         /* Append request to dispatch queue */
  344.         list_append(&request->list, &box->dispatched_calls);
  345.     } else {
  346.         /* This can happen regularly after ipc_cleanup, remove
  347.          * the warning in the future when the IPC is
  348.          * more debugged */
  349.         printf("WARNING: Spurious IPC wakeup.\n");
  350.         spinlock_unlock(&box->lock);
  351.         goto restart;
  352.     }
  353.     spinlock_unlock(&box->lock);
  354.     return request;
  355. }
  356.  
  357. /** Answer all calls from list with EHANGUP msg */
  358. static void ipc_cleanup_call_list(link_t *lst)
  359. {
  360.     call_t *call;
  361.  
  362.     while (!list_empty(lst)) {
  363.         call = list_get_instance(lst->next, call_t, list);
  364.         list_remove(&call->list);
  365.  
  366.         IPC_SET_RETVAL(call->data, EHANGUP);
  367.         _ipc_answer_free_call(call);
  368.     }
  369. }
  370.  
  371. /** Cleans up all IPC communication of the given task
  372.  *
  373.  *
  374.  */
  375. void ipc_cleanup(task_t *task)
  376. {
  377.     int i;
  378.     call_t *call;
  379.     phone_t *phone;
  380.    
  381.     /* Disconnect all our phones ('ipc_phone_hangup') */
  382.     for (i=0;i < IPC_MAX_PHONES; i++)
  383.         ipc_phone_hangup(&task->phones[i]);
  384.  
  385.     /* Disconnect all connected irqs */
  386.     ipc_irq_cleanup(&task->answerbox);
  387.  
  388.     /* Disconnect all phones connected to our answerbox */
  389. restart_phones:
  390.     spinlock_lock(&task->answerbox.lock);
  391.     while (!list_empty(&task->answerbox.connected_phones)) {
  392.         phone = list_get_instance(task->answerbox.connected_phones.next,
  393.                       phone_t,
  394.                       list);
  395.         if (! spinlock_trylock(&phone->lock)) {
  396.             spinlock_unlock(&task->answerbox.lock);
  397.             goto restart_phones;
  398.         }
  399.        
  400.         /* Disconnect phone */
  401.         phone->callee = NULL;
  402.         list_remove(&phone->list);
  403.  
  404.         spinlock_unlock(&phone->lock);
  405.     }
  406.  
  407.     /* Answer all messages in 'calls' and 'dispatched_calls' queues */
  408.     spinlock_lock(&task->answerbox.lock);
  409.     ipc_cleanup_call_list(&task->answerbox.dispatched_calls);
  410.     ipc_cleanup_call_list(&task->answerbox.calls);
  411.     spinlock_unlock(&task->answerbox.lock);
  412.    
  413.     /* Wait for all async answers to arrive */
  414.     while (atomic_get(&task->active_calls)) {
  415.         call = ipc_wait_for_call(&task->answerbox, SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE);
  416.         ASSERT((call->flags & IPC_CALL_ANSWERED) || (call->flags & IPC_CALL_NOTIF));
  417.         ASSERT(! (call->flags & IPC_CALL_STATIC_ALLOC));
  418.        
  419.         atomic_dec(&task->active_calls);
  420.         ipc_call_free(call);
  421.     }
  422. }
  423.  
  424.  
  425. /** Initilize ipc subsystem */
  426. void ipc_init(void)
  427. {
  428.     ipc_call_slab = slab_cache_create("ipc_call",
  429.                       sizeof(call_t),
  430.                       0,
  431.                       NULL, NULL, 0);
  432.     ipc_irq_make_table(IRQ_COUNT);
  433. }
  434.  
  435.