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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->state = IPC_PHONE_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->state = IPC_PHONE_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.     IPC_SET_RETVAL(call->data, err);
  188.     _ipc_answer_free_call(call);
  189. }
  190.  
  191. /* Unsafe unchecking ipc_call */
  192. static void _ipc_call(phone_t *phone, answerbox_t *box, call_t *call)
  193. {
  194.     if (! (call->flags & IPC_CALL_FORWARDED)) {
  195.         atomic_inc(&phone->active_calls);
  196.         call->data.phone = phone;
  197.     }
  198.  
  199.     spinlock_lock(&box->lock);
  200.     list_append(&call->list, &box->calls);
  201.     spinlock_unlock(&box->lock);
  202.     waitq_wakeup(&box->wq, 0);
  203. }
  204.  
  205. /** Send a asynchronous request using phone to answerbox
  206.  *
  207.  * @param phone Phone connected to answerbox
  208.  * @param request Request to be sent
  209.  */
  210. int ipc_call(phone_t *phone, call_t *call)
  211. {
  212.     answerbox_t *box;
  213.  
  214.     spinlock_lock(&phone->lock);
  215.     if (phone->state != IPC_PHONE_CONNECTED) {
  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 {
  221.             if (phone->state == IPC_PHONE_HUNGUP)
  222.                 ipc_backsend_err(phone, call, EHANGUP);
  223.             else
  224.                 ipc_backsend_err(phone, call, ENOENT);
  225.         }
  226.         return ENOENT;
  227.     }
  228.     box = phone->callee;
  229.     _ipc_call(phone, box, call);
  230.    
  231.     spinlock_unlock(&phone->lock);
  232.     return 0;
  233. }
  234.  
  235. /** Disconnect phone from answerbox
  236.  *
  237.  * This call leaves the phone in HUNGUP state. The change to 'free' is done
  238.  * lazily later.
  239.  *
  240.  * @param phone Phone to be hung up
  241.  * @param aggressive If false, the phone is only marked hungup, and all
  242.  *              messages are allowed to complete.
  243.  *              If true, all messages in all queues are discarded. There
  244.  *              may still be some messages that will be 'in-transit' on
  245.  *              other CPU.
  246.  *              
  247.  * @return 0 - phone disconnected, -1 - the phone was already disconnected
  248.  */
  249. int ipc_phone_hangup(phone_t *phone, int aggressive)
  250. {
  251.     answerbox_t *box;
  252.     call_t *call;
  253.    
  254.     spinlock_lock(&phone->lock);
  255.     if (phone->state == IPC_PHONE_FREE || phone->state ==IPC_PHONE_HUNGUP \
  256.         || phone->state == IPC_PHONE_CONNECTING) {
  257.         spinlock_unlock(&phone->lock);
  258.         return -1;
  259.     }
  260.     box = phone->callee;
  261.     if (phone->state != IPC_PHONE_SLAMMED) {
  262.         /* Remove myself from answerbox */
  263.         spinlock_lock(&box->lock);
  264.         list_remove(&phone->list);
  265.         spinlock_unlock(&box->lock);
  266.  
  267.         if (phone->state != IPC_PHONE_SLAMMED) {
  268.             call = ipc_call_alloc(0);
  269.             IPC_SET_METHOD(call->data, IPC_M_PHONE_HUNGUP);
  270.             call->flags |= IPC_CALL_DISCARD_ANSWER;
  271.             _ipc_call(phone, box, call);
  272.         }
  273.     }
  274.  
  275.     if (aggressive && atomic_get(&phone->active_calls) > 0) {
  276.         /* TODO: Do some stuff be VERY aggressive */
  277.     }
  278.  
  279.     phone->callee = 0;
  280.    
  281.     phone->state = IPC_PHONE_HUNGUP;
  282.     spinlock_unlock(&phone->lock);
  283.  
  284.     return 0;
  285. }
  286.  
  287. /** Forwards call from one answerbox to a new one
  288.  *
  289.  * @param call Call to be redirected.
  290.  * @param newphone Phone to target answerbox.
  291.  * @param oldbox Old answerbox
  292.  * @return 0 on forward ok, error code, if there was error
  293.  *
  294.  * - the return value serves only as an information for the forwarder,
  295.  *   the original caller is notified automatically with EFORWARD
  296.  */
  297. int ipc_forward(call_t *call, phone_t *newphone, answerbox_t *oldbox)
  298. {
  299.     spinlock_lock(&oldbox->lock);
  300.     list_remove(&call->list);
  301.     spinlock_unlock(&oldbox->lock);
  302.  
  303.     return ipc_call(newphone, call);
  304. }
  305.  
  306.  
  307. /** Wait for phone call
  308.  *
  309.  * @param box Answerbox expecting the call.
  310.  * @param usec Timeout in microseconds. See documentation for waitq_sleep_timeout() for
  311.  *         decription of its special meaning.
  312.  * @param flags Select mode of sleep operation. See documentation for waitq_sleep_timeout()i
  313.  *      for description of its special meaning.
  314.  * @return Recived message address
  315.  * - to distinguish between call and answer, look at call->flags
  316.  */
  317. call_t * ipc_wait_for_call(answerbox_t *box, __u32 usec, int flags)
  318. {
  319.     call_t *request;
  320.     ipl_t ipl;
  321.     int rc;
  322.  
  323. restart:
  324.     rc = waitq_sleep_timeout(&box->wq, usec, flags);
  325.     if (SYNCH_FAILED(rc))
  326.         return NULL;
  327.    
  328.     spinlock_lock(&box->lock);
  329.     if (!list_empty(&box->irq_notifs)) {
  330.         ipl = interrupts_disable();
  331.         spinlock_lock(&box->irq_lock);
  332.  
  333.         request = list_get_instance(box->irq_notifs.next, call_t, list);
  334.         list_remove(&request->list);
  335.  
  336.         spinlock_unlock(&box->irq_lock);
  337.         interrupts_restore(ipl);
  338.     } else if (!list_empty(&box->answers)) {
  339.         /* Handle asynchronous answers */
  340.         request = list_get_instance(box->answers.next, call_t, list);
  341.         list_remove(&request->list);
  342.         atomic_dec(&request->data.phone->active_calls);
  343.     } else if (!list_empty(&box->calls)) {
  344.         /* Handle requests */
  345.         request = list_get_instance(box->calls.next, call_t, list);
  346.         list_remove(&request->list);
  347.         /* Append request to dispatch queue */
  348.         list_append(&request->list, &box->dispatched_calls);
  349.     } else {
  350.         /* This can happen regularly after ipc_cleanup, remove
  351.          * the warning in the future when the IPC is
  352.          * more debugged */
  353.         printf("WARNING: Spurious IPC wakeup.\n");
  354.         spinlock_unlock(&box->lock);
  355.         goto restart;
  356.     }
  357.     spinlock_unlock(&box->lock);
  358.     return request;
  359. }
  360.  
  361. /** Answer all calls from list with EHANGUP msg */
  362. static void ipc_cleanup_call_list(link_t *lst)
  363. {
  364.     call_t *call;
  365.  
  366.     while (!list_empty(lst)) {
  367.         call = list_get_instance(lst->next, call_t, list);
  368.         list_remove(&call->list);
  369.  
  370.         IPC_SET_RETVAL(call->data, EHANGUP);
  371.         _ipc_answer_free_call(call);
  372.     }
  373. }
  374.  
  375. /** Cleans up all IPC communication of the given task
  376.  *
  377.  *
  378.  */
  379. void ipc_cleanup(task_t *task)
  380. {
  381.     int i;
  382.     call_t *call;
  383.     phone_t *phone;
  384.    
  385.     /* Disconnect all our phones ('ipc_phone_hangup') */
  386.     for (i=0;i < IPC_MAX_PHONES; i++)
  387.         ipc_phone_hangup(&task->phones[i], 1);
  388.  
  389.     /* Disconnect all connected irqs */
  390.     ipc_irq_cleanup(&task->answerbox);
  391.  
  392.     /* Disconnect all phones connected to our answerbox */
  393. restart_phones:
  394.     spinlock_lock(&task->answerbox.lock);
  395.     while (!list_empty(&task->answerbox.connected_phones)) {
  396.         phone = list_get_instance(task->answerbox.connected_phones.next,
  397.                       phone_t,
  398.                       list);
  399.         if (! spinlock_trylock(&phone->lock)) {
  400.             spinlock_unlock(&task->answerbox.lock);
  401.             goto restart_phones;
  402.         }
  403.        
  404.         /* Disconnect phone */
  405.         ASSERT(phone->state == IPC_PHONE_CONNECTED);
  406.         phone->state = IPC_PHONE_SLAMMED;
  407.         list_remove(&phone->list);
  408.  
  409.         spinlock_unlock(&phone->lock);
  410.     }
  411.  
  412.     /* Answer all messages in 'calls' and 'dispatched_calls' queues */
  413.     spinlock_lock(&task->answerbox.lock);
  414.     ipc_cleanup_call_list(&task->answerbox.dispatched_calls);
  415.     ipc_cleanup_call_list(&task->answerbox.calls);
  416.     spinlock_unlock(&task->answerbox.lock);
  417.    
  418.     /* Wait for all async answers to arrive */
  419.     while (1) {
  420.         /* Go through all phones, until all are FREE... */
  421.         /* Locking not needed, no one else should modify
  422.          * it, when we are in cleanup */
  423.         for (i=0;i < IPC_MAX_PHONES; i++) {
  424.             if (task->phones[i].state == IPC_PHONE_HUNGUP && \
  425.                 atomic_get(&task->phones[i].active_calls) == 0)
  426.                 task->phones[i].state = IPC_PHONE_FREE;
  427.             if (task->phones[i].state != IPC_PHONE_FREE)
  428.                 break;
  429.         }
  430.         /* Voila, got into cleanup */
  431.         if (i == IPC_MAX_PHONES)
  432.             break;
  433.        
  434.         call = ipc_wait_for_call(&task->answerbox, SYNCH_NO_TIMEOUT, SYNCH_FLAGS_NONE);
  435.         ASSERT((call->flags & IPC_CALL_ANSWERED) || (call->flags & IPC_CALL_NOTIF));
  436.         ASSERT(! (call->flags & IPC_CALL_STATIC_ALLOC));
  437.        
  438.         atomic_dec(&task->active_calls);
  439.         ipc_call_free(call);
  440.     }
  441. }
  442.  
  443.  
  444. /** Initilize ipc subsystem */
  445. void ipc_init(void)
  446. {
  447.     ipc_call_slab = slab_cache_create("ipc_call",
  448.                       sizeof(call_t),
  449.                       0,
  450.                       NULL, NULL, 0);
  451.     ipc_irq_make_table(IRQ_COUNT);
  452. }
  453.  
  454.