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