src_frescan/frescan_servers.c_posix

   1 /*!
   2  * @file frescan_servers.c
   3  *
   4  * @brief FRESCAN sporadic servers
   5  *
   6  * @version 0.01
   7  *
   8  * @date 27-Feb-2008
   9  *
  10  * @author
  11  *      Daniel Sangorrin
  12  *
  13  * @comments
  14  *
  15  * This file contains the FRESCAN sporadic servers that allow to isolate
  16  * different streams of data by assigning them a budget and replenishment
  17  * period.
  18  *
  19  * @license
  20  *
  21  * See MaRTE OS license
  22  *
  23  */
  24
  25 #include "frescan_servers.h"
  26 #include "frescan_servers_replenishments.h" // frescan_replenishments_xxx
  27 #include "frescan_debug.h"
  28 #include "frescan_data.h"
  29 #include <misc/linux_list.h>
  30 #include <misc/timespec_operations.h>
  31 #include <signal.h>
  32 #include <time.h>
  33
  34 /**
  35  * frescan_servers_init() - initialize server structures
  36  *
  37  * @net: the network instance
  38  */
  39
  40 int frescan_servers_init(frescan_network_t net)
  41 {
  42         int ret, i;
  43
  44         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG, "initializing servers\n");
  45
  46         ret = freelist_init(&the_servers_pool_freelist[net], FRESCAN_MX_IDS);
  47         if (ret != 0) return ret;
  48
  49         for (i=0; i<FRESCAN_MX_NETWORKS; i++) {
  50                 INIT_LIST_HEAD(&the_active_servers[net].servers_list);
  51         }
  52
  53         ret = frescan_replenishments_init(net);
  54         if (ret != 0) {
  55                 ERROR("could not initialize the replenishments\n");
  56                 return -1;
  57         }
  58
  59         return 0;
  60 }
  61
  62 /**
  63  * frescan_servers_create() - create a sporadic server
  64  *
  65  * @net: the network instance
  66  * @params: the parameters for the server
  67  * @id: the identificator for the server as a return value
  68  *
  69  */
  70
  71 int frescan_servers_create(frescan_network_t net,
  72                            const frescan_server_params_t *params,
  73                            frescan_ss_t *id)
  74 {
  75         int ret, pos;
  76         struct sigevent evp;
  77
  78         FRESCAN_ACQUIRE_LOCK(&the_networks[net].lock);
  79         pos = freelist_alloc(&the_servers_pool_freelist[net]);
  80         FRESCAN_RELEASE_LOCK(&the_networks[net].lock);
  81
  82         if (pos == -1) {
  83                 ERROR("could not allocate servers\n");
  84                 return -1;
  85         }
  86
  87         *id = (frescan_ss_t)pos;
  88
  89         the_servers_pool[net][*id].net = net;
  90         the_servers_pool[net][*id].id  = *id;
  91         the_servers_pool[net][*id].params = *params;
  92         the_servers_pool[net][*id].current_budget = params->values.budget;
  93         the_servers_pool[net][*id].current_priority = params->prio;
  94         the_servers_pool[net][*id].pending_packets = 0;
  95
  96         // the first act_time is set to the server creation time
  97         clock_gettime (CLOCK_MONOTONIC, &the_servers_pool[net][*id].act_time);
  98
  99         INIT_LIST_HEAD(&the_servers_pool[net][*id].replenishments.repl_list);
 100         INIT_LIST_HEAD(&the_servers_pool[net][*id].packet_list.fifo_list);
 101
 102         // the repl timer sends a signal when it expires with the server id
 103         evp.sigev_notify = SIGEV_SIGNAL;
 104         evp.sigev_signo  = FRESCAN_REPL_SIGNAL_NUM;
 105         evp.sigev_value.sival_int  = (int)*id;
 106
 107         ret = timer_create (CLOCK_MONOTONIC,
 108                             &evp, &the_servers_pool[net][*id].repl_timer);
 109         if (ret != 0) {
 110                 ERROR("could not create timer\n");
 111                 return ret;
 112         }
 113
 114         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG,
 115               "server created, id:%u budget:%u prio:%u\n",
 116               *id,
 117               the_servers_pool[net][*id].params.values.budget,
 118               the_servers_pool[net][*id].params.prio);
 119
 120         return 0;
 121 }
 122
 123 /**
 124  * frescan_servers_update() - update a sporadic server data
 125  *
 126  * @net: the network instance
 127  * @params: the parameters for the server
 128  * @id: the identificator for the server
 129  *
 130  */
 131
 132 int frescan_servers_update(frescan_network_t net,
 133                            const frescan_server_params_t *params,
 134                            frescan_ss_t id)
 135 {
 136         the_servers_pool[net][id].params = *params;
 137         return 0;
 138 }
 139
 140 /**
 141  * frescan_servers_destroy() - delete a sporadic server
 142  *
 143  * @net: the network instance
 144  * @id: the identificator for the server
 145  *
 146  */
 147
 148 int frescan_servers_destroy(frescan_network_t net, frescan_ss_t id)
 149 {
 150         int ret;
 151
 152         // TODO: free the replenishment operations and the packets for the
 153         // server.
 154
 155         ret = timer_delete (the_servers_pool[net][id].repl_timer);
 156         if (ret != 0) {
 157                 ERROR("could not delete timer\n");
 158                 return ret;
 159         }
 160
 161         FRESCAN_ACQUIRE_LOCK(&the_networks[net].lock);
 162         list_del(&the_servers_pool[net][id].servers_list);
 163
 164         ret = freelist_free(&the_servers_pool_freelist[net], id);
 165         FRESCAN_RELEASE_LOCK(&the_networks[net].lock);
 166         if (ret != 0) {
 167                 ERROR("could not free server data from pool\n");
 168                 return ret;
 169         }
 170
 171         return 0;
 172 }
 173
 174 /**
 175  * frescan_servers_get_data() - get a sporadic server data
 176  *
 177  * @net: the network instance
 178  * @params: the parameters of the server
 179  * @id: the identificator for the server
 180  *
 181  */
 182
 183 int frescan_servers_get_data(frescan_network_t net,
 184                              frescan_server_params_t *params,
 185                              frescan_ss_t id)
 186 {
 187         *params = the_servers_pool[net][id].params;
 188         return 0;
 189 }
 190
 191 /**
 192  * frescan_servers_get_current_budget() - get the current sporadic server budget
 193  *
 194  * @net: the network instance
 195  * @id: the identificator for the server
 196  * @current_budget: the current budget of the server
 197  *
 198  */
 199
 200 int frescan_servers_get_current_budget(frescan_network_t net,
 201                                        frescan_ss_t id,
 202                                        frescan_budget_t *current_budget)
 203 {
 204         *current_budget = the_servers_pool[net][id].current_budget;
 205         return 0;
 206 }
 207
 208 /**
 209  * frescan_servers_get_highest_prio() - get the server with highest priority
 210  *
 211  * @net: the network instance
 212  * @id: the identificator for the server
 213  * @prio: the priority of that server
 214  *
 215  * For each active server, check the priority.
 216  * If "id" is returned with a value of FRESCAN_MX_IDS,
 217  * there are no active servers.
 218  * NOTE: id=FRESCAN_MX_IDS is the identifier for fixed priority messages
 219  * TODO: use a priority queue of active servers
 220  *
 221  */
 222
 223 int frescan_servers_get_highest_prio(frescan_network_t net,
 224                                      frescan_ss_t *id,
 225                                      frescan_prio_t *prio)
 226 {
 227         frescan_server_data_t *server;
 228
 229         if (list_empty(&the_active_servers->servers_list)) {
 230                 DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG, "server list is empty\n");
 231                 *id = FRESCAN_MX_IDS;
 232                 return 0;
 233         }
 234
 235         *prio = 0;
 236         list_for_each_entry(server, &the_active_servers[net].servers_list,
 237                             servers_list) {
 238                 if (server->current_priority >= *prio) {
 239                         *id = server->id;
 240                         *prio = server->current_priority;
 241                 }
 242         }
 243
 244         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG,
 245               "highest prio:%u id:%u\n", *prio, *id);
 246
 247         return 0;
 248 }
 249
 250 /**
 251  * frescan_servers_frame_sent() - hook to control the server budget and prio
 252  *
 253  * @net: the network instance
 254  * @id: the identificator for the server
 255  *
 256  * This function is called when a frame has been effectively sent through the
 257  * CAN bus and that frame is associated to a certain server. The function
 258  * decreases the capacity of the server and sets the priority to background
 259  * in case the budget is exhausted.
 260  *
 261  * NOTE: the replenishment operation is programmed using the corresponding
 262  * function at frescan_servers_replenishments module
 263  */
 264
 265 int frescan_servers_frame_sent(frescan_network_t net,
 266                                frescan_ss_t id,
 267                                frescan_packet_t *packet)
 268 {
 269         int ret;
 270         struct timespec *repl_time;
 271         frescan_server_data_t *server;
 272
 273         server = &the_servers_pool[net][id];
 274
 275         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG,
 276               "before.. id:%u, current_budget:%u, current_priority:%u\n",
 277               id, server->current_budget, server->current_priority);
 278
 279         if (server->current_budget > 0) {
 280                 server->current_budget--;
 281                 if (server->current_budget == 0) {
 282                         server->current_priority = FRESCAN_BACKGROUND_PRIO;
 283                 }
 284
 285                 if (smaller_timespec(&packet->timestamp, &server->act_time)) {
 286                         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG, "using act_time\n");
 287                         repl_time = &server->act_time;
 288                 } else {
 289                         repl_time = &packet->timestamp;
 290                 }
 291
 292                 ret = frescan_replenishment_program(net, id, repl_time);
 293                 if (ret != 0) return -1;
 294         }
 295
 296         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG,
 297               "after.. id:%u, current_budget:%u, current_priority:%u\n",
 298               id, server->current_budget, server->current_priority);
 299
 300         return 0;
 301 }