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         FRESCAN_ACQUIRE_LOCK(&the_networks[net].lock);
  70         pos = freelist_alloc(&the_servers_pool_freelist[net]);
  71         FRESCAN_RELEASE_LOCK(&the_networks[net].lock);
  72
  73         if (pos == -1) {
  74                 ERROR("could not allocate servers\n");
  75                 return -1;
  76         }
  77
  78         *id = (frescan_ss_t)pos;
  79
  80         the_servers_pool[net][*id].net = net;
  81         the_servers_pool[net][*id].id  = *id;
  82         the_servers_pool[net][*id].params = *params;
  83         the_servers_pool[net][*id].current_budget = params->values.budget;
  84         the_servers_pool[net][*id].current_priority = params->prio;
  85         the_servers_pool[net][*id].pending_packets = 0;
  86
  87         INIT_LIST_HEAD(&the_servers_pool[net][*id].replenishments.repl_list);
  88         INIT_LIST_HEAD(&the_servers_pool[net][*id].packet_list.fifo_list);
  89
  90         // the repl timer sends a signal when it expires with the server id
  91         evp.sigev_notify = SIGEV_SIGNAL;
  92         evp.sigev_signo  = FRESCAN_REPL_SIGNAL_NUM;
  93         evp.sigev_value.sival_int  = (int)*id;
  94
  95         ret = timer_create (CLOCK_MONOTONIC,
  96                             &evp, &the_servers_pool[net][*id].repl_timer);
  97         if (ret != 0) {
  98                 ERROR("could not create timer\n");
  99                 return ret;
 100         }
 101
 102         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG,
 103               "server created, id:%u budget:%u prio:%u\n",
 104               *id,
 105               the_servers_pool[net][*id].params.values.budget,
 106               the_servers_pool[net][*id].params.prio);
 107
 108         return 0;
 109 }
 110
 111 /**
 112  * frescan_servers_update() - update a sporadic server data
 113  *
 114  * @net: the network instance
 115  * @params: the parameters for the server
 116  * @id: the identificator for the server
 117  *
 118  */
 119
 120 int frescan_servers_update(frescan_network_t net,
 121                            const frescan_server_params_t *params,
 122                            frescan_ss_t id)
 123 {
 124         the_servers_pool[net][id].params = *params;
 125         return 0;
 126 }
 127
 128 /**
 129  * frescan_servers_destroy() - delete a sporadic server
 130  *
 131  * @net: the network instance
 132  * @id: the identificator for the server
 133  *
 134  */
 135
 136 int frescan_servers_destroy(frescan_network_t net, frescan_ss_t id)
 137 {
 138         int ret;
 139
 140         // TODO: free the replenishment operations and the packets for the
 141         // server.
 142
 143         ret = timer_delete (the_servers_pool[net][id].repl_timer);
 144         if (ret != 0) {
 145                 ERROR("could not delete timer\n");
 146                 return ret;
 147         }
 148
 149         FRESCAN_ACQUIRE_LOCK(&the_networks[net].lock);
 150         list_del(&the_servers_pool[net][id].servers_list);
 151
 152         ret = freelist_free(&the_servers_pool_freelist[net], id);
 153         FRESCAN_RELEASE_LOCK(&the_networks[net].lock);
 154         if (ret != 0) {
 155                 ERROR("could not free server data from pool\n");
 156                 return ret;
 157         }
 158
 159         return 0;
 160 }
 161
 162 /**
 163  * frescan_servers_get_data() - get a sporadic server data
 164  *
 165  * @net: the network instance
 166  * @params: the parameters of the server
 167  * @id: the identificator for the server
 168  *
 169  */
 170
 171 int frescan_servers_get_data(frescan_network_t net,
 172                              frescan_server_params_t *params,
 173                              frescan_ss_t id)
 174 {
 175         *params = the_servers_pool[net][id].params;
 176         return 0;
 177 }
 178
 179 /**
 180  * frescan_servers_get_current_budget() - get the current sporadic server budget
 181  *
 182  * @net: the network instance
 183  * @id: the identificator for the server
 184  * @current_budget: the current budget of the server
 185  *
 186  */
 187
 188 int frescan_servers_get_current_budget(frescan_network_t net,
 189                                        frescan_ss_t id,
 190                                        frescan_budget_t *current_budget)
 191 {
 192         *current_budget = the_servers_pool[net][id].current_budget;
 193         return 0;
 194 }
 195
 196 /**
 197  * frescan_servers_get_highest_prio() - get the server with highest priority
 198  *
 199  * @net: the network instance
 200  * @id: the identificator for the server
 201  * @prio: the priority of that server
 202  *
 203  * For each active server, check the priority.
 204  * If "id" is returned with a value of FRESCAN_MX_IDS,
 205  * there are no active servers.
 206  * NOTE: id=FRESCAN_MX_IDS is the identifier for fixed priority messages
 207  * TODO: use a priority queue of active servers
 208  *
 209  */
 210
 211 int frescan_servers_get_highest_prio(frescan_network_t net,
 212                                      frescan_ss_t *id,
 213                                      frescan_prio_t *prio)
 214 {
 215         frescan_server_data_t *server;
 216
 217         if (list_empty(&the_active_servers->servers_list)) {
 218                 DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG, "server list is empty\n");
 219                 *id = FRESCAN_MX_IDS;
 220                 return 0;
 221         }
 222
 223         *prio = 0;
 224         list_for_each_entry(server, &the_active_servers[net].servers_list,
 225                             servers_list) {
 226                 if (server->current_priority >= *prio) {
 227                         *id = server->id;
 228                         *prio = server->current_priority;
 229                 }
 230         }
 231
 232         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG,
 233               "highest prio:%u id:%u\n", *prio, *id);
 234
 235         return 0;
 236 }
 237
 238 /**
 239  * frescan_servers_frame_sent() - hook to control the server budget and prio
 240  *
 241  * @net: the network instance
 242  * @id: the identificator for the server
 243  *
 244  * This function is called when a frame has been effectively sent through the
 245  * CAN bus and that frame is associated to a certain server. The function
 246  * decreases the capacity of the server and sets the priority to background
 247  * in case the budget is exhausted.
 248  *
 249  * NOTE: the replenishment operation is programmed using the corresponding
 250  * function at frescan_servers_replenishments module
 251  */
 252
 253 int frescan_servers_frame_sent(frescan_network_t net, frescan_ss_t id)
 254 {
 255         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG,
 256               "id:%u, current_budget:%u, current_priority:%u\n",
 257               id,
 258               the_servers_pool[net][id].current_budget,
 259               the_servers_pool[net][id].current_priority);
 260
 261         if (the_servers_pool[net][id].current_budget > 0) {
 262                 the_servers_pool[net][id].current_budget--;
 263                 if (the_servers_pool[net][id].current_budget == 0) {
 264                         the_servers_pool[net][id].current_priority =
 265                                         FRESCAN_BACKGROUND_PRIO;
 266                 }
 267         }
 268
 269         DEBUG(FRESCAN_SERVERS_ENABLE_DEBUG,
 270               "now... id:%u, current_budget:%u, current_priority:%u\n",
 271               id,
 272               the_servers_pool[net][id].current_budget,
 273               the_servers_pool[net][id].current_priority);
 274
 275         return 0;
 276 }