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  1. /*
  2.  * Copyright (c) 2007 Michal Konopa
  3.  * Copyright (c) 2007 Martin Jelen
  4.  * Copyright (c) 2007 Peter Majer
  5.  * Copyright (c) 2007 Jakub Jermar
  6.  * All rights reserved.
  7.  *
  8.  * Redistribution and use in source and binary forms, with or without
  9.  * modification, are permitted provided that the following conditions
  10.  * are met:
  11.  *
  12.  * - Redistributions of source code must retain the above copyright
  13.  *   notice, this list of conditions and the following disclaimer.
  14.  * - Redistributions in binary form must reproduce the above copyright
  15.  *   notice, this list of conditions and the following disclaimer in the
  16.  *   documentation and/or other materials provided with the distribution.
  17.  * - The name of the author may not be used to endorse or promote products
  18.  *   derived from this software without specific prior written permission.
  19.  *
  20.  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  21.  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  22.  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  23.  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  24.  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  25.  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26.  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27.  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28.  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  29.  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30.  */
  31.  
  32. /** @addtogroup rd
  33.  * @{
  34.  */
  35.  
  36. /**
  37.  * @file    rd.c
  38.  * @brief   Initial RAM disk for HelenOS.
  39.  */
  40.  
  41. #include <ipc/ipc.h>
  42. #include <ipc/services.h>
  43. #include <ipc/ns.h>
  44. #include <sysinfo.h>
  45. #include <as.h>
  46. #include <ddi.h>
  47. #include <align.h>
  48. #include <bool.h>
  49. #include <errno.h>
  50. #include <async.h>
  51. #include <align.h>
  52. #include <async.h>
  53. #include <futex.h>
  54. #include "rd.h"
  55.  
  56. /** Pointer to the ramdisk's image. */
  57. static void *rd_addr;
  58. /** Size of the ramdisk. */
  59. static size_t rd_size;
  60.  
  61. /**
  62.  * This futex protects the ramdisk's data.
  63.  * If we were to serve multiple requests (read + write or several writes)
  64.  * concurrently (i.e. from two or more threads), each read and write needs to be
  65.  * protected by this futex.
  66.  */
  67. atomic_t rd_futex = FUTEX_INITIALIZER;
  68.  
  69. /** Handle one connection to ramdisk.
  70.  *
  71.  * @param iid       Hash of the request that opened the connection.
  72.  * @param icall     Call data of the request that opened the connection.
  73.  */
  74. static void rd_connection(ipc_callid_t iid, ipc_call_t *icall)
  75. {
  76.     ipc_callid_t callid;
  77.     ipc_call_t call;
  78.     int retval;
  79.     void *fs_va = NULL;
  80.     ipcarg_t offset;
  81.  
  82.     /*
  83.      * We allocate VA for communication per connection.
  84.      * This allows us to potentionally have more clients and work
  85.      * concurrently.
  86.      */
  87.     fs_va = as_get_mappable_page(ALIGN_UP(BLOCK_SIZE, PAGE_SIZE));
  88.     if (!fs_va) {
  89.         /*
  90.          * Hang up the phone if we cannot proceed any further.
  91.          * This is the answer to the call that opened the connection.
  92.          */
  93.         ipc_answer_0(iid, EHANGUP);
  94.         return;
  95.     } else {
  96.         /*
  97.          * Answer the first IPC_M_CONNECT_ME_TO call.
  98.          * Return supported block size as ARG1.
  99.          */
  100.         ipc_answer_1(iid, EOK, BLOCK_SIZE);
  101.     }
  102.  
  103.     /*
  104.      * Now we wait for the client to send us its communication as_area.
  105.      */
  106.     size_t size;
  107.     if (ipc_share_out_receive(&callid, &size, NULL)) {
  108.         if (size >= BLOCK_SIZE) {
  109.             /*
  110.              * The client sends an as_area that can absorb the whole
  111.              * block.
  112.              */
  113.             (void) ipc_share_out_finalize(callid, fs_va);
  114.         } else {
  115.             /*
  116.              * The client offered as_area too small.
  117.              * Close the connection.
  118.              */
  119.             ipc_answer_0(callid, EHANGUP);
  120.             return;    
  121.         }
  122.     } else {
  123.         /*
  124.          * The client doesn't speak the same protocol.
  125.          * At this point we can't handle protocol variations.
  126.          * Close the connection.
  127.          */
  128.         ipc_answer_0(callid, EHANGUP);
  129.         return;
  130.     }
  131.    
  132.     while (1) {
  133.         callid = async_get_call(&call);
  134.         switch (IPC_GET_METHOD(call)) {
  135.         case IPC_M_PHONE_HUNGUP:
  136.             /*
  137.              * The other side has hung up.
  138.              * Answer the message and exit the fibril.
  139.              */
  140.             ipc_answer_0(callid, EOK);
  141.             return;
  142.         case RD_READ_BLOCK:
  143.             offset = IPC_GET_ARG1(call);
  144.             if (offset * BLOCK_SIZE > rd_size - BLOCK_SIZE) {
  145.                 /*
  146.                  * Reading past the end of the device.
  147.                  */
  148.                 retval = ELIMIT;
  149.                 break;
  150.             }
  151.             futex_down(&rd_futex);
  152.             memcpy(fs_va, rd_addr + offset, BLOCK_SIZE);
  153.             futex_up(&rd_futex);
  154.             retval = EOK;
  155.             break;
  156.         case RD_WRITE_BLOCK:
  157.             offset = IPC_GET_ARG1(call);
  158.             if (offset * BLOCK_SIZE > rd_size - BLOCK_SIZE) {
  159.                 /*
  160.                  * Writing past the end of the device.
  161.                  */
  162.                 retval = ELIMIT;
  163.                 break;
  164.             }
  165.             futex_up(&rd_futex);
  166.             memcpy(rd_addr + offset, fs_va, BLOCK_SIZE);
  167.             futex_down(&rd_futex);
  168.             retval = EOK;
  169.             break;
  170.         default:
  171.             /*
  172.              * The client doesn't speak the same protocol.
  173.              * Instead of closing the connection, we just ignore
  174.              * the call. This can be useful if the client uses a
  175.              * newer version of the protocol.
  176.              */
  177.             retval = EINVAL;
  178.             break;
  179.         }
  180.         ipc_answer_0(callid, retval);
  181.     }
  182. }
  183.  
  184. /** Prepare the ramdisk image for operation. */
  185. static bool rd_init(void)
  186. {
  187.     int retval, flags;
  188.  
  189.     rd_size = sysinfo_value("rd.size");
  190.     void *rd_ph_addr = (void *) sysinfo_value("rd.address.physical");
  191.    
  192.     if (rd_size == 0)
  193.         return false;
  194.    
  195.     rd_addr = as_get_mappable_page(rd_size);
  196.    
  197.     flags = AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE;
  198.     retval = physmem_map(rd_ph_addr, rd_addr,
  199.         ALIGN_UP(rd_size, PAGE_SIZE) >> PAGE_WIDTH, flags);
  200.  
  201.     if (retval < 0)
  202.         return false;
  203.     return true;
  204. }
  205.  
  206. int main(int argc, char **argv)
  207. {
  208.     if (rd_init()) {
  209.         ipcarg_t phonead;
  210.        
  211.         async_set_client_connection(rd_connection);
  212.        
  213.         /* Register service at nameserver */
  214.         if (ipc_connect_to_me(PHONE_NS, SERVICE_RD, 0, 0, &phonead) != 0)
  215.             return -1;
  216.        
  217.         async_manager();
  218.        
  219.         /* Never reached */
  220.         return 0;
  221.     }
  222.    
  223.     return -1;
  224. }
  225.  
  226. /**
  227.  * @}
  228.  */
  229.