src_frescan/frescan_servers.c

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