src_frescan/frescan_hw_buffer.c

   1 /*!
   2  * @file frescan_hw_buffer.c
   3  *
   4  * @brief functions to manage the hw transmission buffer
   5  *
   6  * @version 0.01
   7  *
   8  * @date 12-Mar-2008
   9  *
  10  * @author
  11  *      Daniel Sangorrin
  12  *
  13  * @comments
  14  *
  15  * This file contains the functions needed to manage the hw transmission buffer.
  16  * This is needed to update the transmission buffer of the CAN chip with the
  17  * message with highest priority. This could involve having to abort the
  18  * frame that is currently in the buffer.
  19  *
  20  * @license
  21  *
  22  * See MaRTE OS license
  23  *
  24  */
  25
  26 #include "frescan_hw_buffer.h"
  27
  28 #include <string.h> // memcpy
  29
  30 #include "frescan_data.h"    // the_networks
  31 #include "frescan_debug.h"   // DEBUG, ERROR
  32 #include "frescan_servers.h" // frescan_servers_get_highest_prio
  33 #include "frescan_queues.h"  // frescan_pqueue_xxx, frescan_servers_dequeue
  34 #include "frescan_id.h"      // frescan_id_set_field
  35
  36 /**
  37  * frescan_hw_buffer_abort - abort the packet in the hw tx buffer
  38  *
  39  * This function aborts the packet that is currently in the hw transmission
  40  * buffer of the chip. It is useful to prevent priority inversion when there
  41  * is another packet with highest priority waiting in the frescan queues.
  42  *
  43  * NOTE: if the frame is already being transmitted it won't abort it. In both
  44  * cases a IRQ will be raised and either 'frescan_hook_frame_sent' or
  45  * 'frescan_hook_frame_aborted' will be called.
  46  */
  47
  48 int frescan_hw_buffer_abort(frescan_network_t net)
  49 {
  50         int ret;
  51
  52         ret = ioctl(the_networks[net].fd, CAN_IOCTL_ABORT_FRAME, NULL);
  53         if (ret == -1) {
  54                 ERROR ("could not abort the frame\n");
  55                 return -1;
  56         }
  57
  58         return 0;
  59 }
  60
  61 /**
  62  * frescan_hw_buffer_update - update the hw tx buffer
  63  *
  64  * This function updates the hw tx buffer with the packet with highest
  65  * priority (including fp packets and server packets).
  66  *
  67  * TODO: use copy of pointer
  68  */
  69
  70 int frescan_hw_buffer_update(frescan_network_t net)
  71 {
  72         int ret;
  73         bool is_frame_in_chip, is_fp_highest_prio;
  74         uint32_t frag_flag;
  75         frescan_packet_t *packet;
  76         frescan_prio_queue_t *pqueue;
  77         frescan_prio_t fprio, sprio, prio;
  78         frescan_ss_t id;
  79
  80         ret = frescan_servers_get_highest_prio(net, &id, &sprio);
  81         if (ret != 0) return ret;
  82
  83         pqueue = the_networks[net].queues.tx_fp_queue;
  84
  85         ret = frescan_pqueue_get_highest_prio(pqueue, &packet, &fprio);
  86         if (ret != 0) return ret;
  87
  88         if ((id == FRESCAN_MX_IDS) && (packet == NULL)) {
  89                 DEBUG(FRESCAN_HW_BUFFER_ENABLE_DEBUG, "(ss:0 fp:0)\n");
  90                 return 0;
  91         }
  92
  93         if ((id != FRESCAN_MX_IDS) && (packet == NULL)) {
  94                 DEBUG(FRESCAN_HW_BUFFER_ENABLE_DEBUG, "(ss:1 fp:0)\n");
  95                 is_fp_highest_prio = false;
  96         }
  97
  98         if ((id == FRESCAN_MX_IDS) && (packet != NULL)) {
  99                 DEBUG(FRESCAN_HW_BUFFER_ENABLE_DEBUG, "(ss:0 fp:1)\n");
 100                 is_fp_highest_prio = true;
 101         }
 102
 103         if ((id != FRESCAN_MX_IDS) && (packet != NULL)) {
 104                 DEBUG(FRESCAN_HW_BUFFER_ENABLE_DEBUG, "(ss:1 fp:1)\n");
 105                 is_fp_highest_prio = (fprio > sprio);
 106         }
 107
 108         prio = (is_fp_highest_prio) ? fprio : sprio;
 109         is_frame_in_chip = (the_networks[net].last_packet != NULL);
 110
 111         if (is_frame_in_chip &&
 112            (prio > the_networks[net].last_packet_prio)) {
 113                 DEBUG(FRESCAN_HW_BUFFER_ENABLE_DEBUG,"abort frame\n");
 114                 ret = frescan_hw_buffer_abort(net);
 115                 if (ret != 0) {
 116                         ERROR ("could not abort frame\n");
 117                         return ret;
 118                 }
 119                 return 0;
 120         }
 121
 122         if (is_fp_highest_prio) {
 123                 ret = frescan_pqueue_dequeue(pqueue, &packet, &prio, 0);
 124                 if (ret != 0) return ret;
 125         } else {
 126                 ret = frescan_servers_dequeue(net, id, &packet, &prio);
 127                 if (ret != 0) return ret;
 128
 129                 frescan_id_set_field(&packet->frame->id,
 130                                       FRESCAN_FIELD_PRIO,
 131                                       (uint32_t)prio);
 132         }
 133
 134         if (packet->buffer_pending_bytes > 8) {
 135                 packet->frame->dlc = 8;
 136         } else {
 137                 packet->frame->dlc = packet->buffer_pending_bytes;
 138         }
 139
 140         memcpy(packet->frame->data,
 141                packet->buffer_read_pointer,
 142                packet->frame->dlc);
 143
 144         packet->buffer_pending_bytes -= packet->frame->dlc;
 145         packet->buffer_read_pointer  += packet->frame->dlc;
 146
 147         frag_flag = (packet->buffer_pending_bytes > 0) ? 1 : 0;
 148         frescan_id_set_field
 149                         (&packet->frame->id, FRESCAN_FIELD_FRAG_FLAG, frag_flag);
 150
 151         the_networks[net].last_packet = packet;
 152         the_networks[net].last_packet_prio = prio;
 153
 154         DEBUG(FRESCAN_HW_BUFFER_ENABLE_DEBUG,
 155               "frame->id:0x%X pend_bytes:%u dlc:%u fflag:%u\n",
 156               packet->frame->id,
 157               packet->buffer_pending_bytes,
 158               packet->frame->dlc,
 159               frag_flag);
 160
 161         ret = write(the_networks[net].fd,
 162                     (void *)packet->frame,
 163                     sizeof(struct can_frame_t));
 164
 165         if (ret != sizeof(struct can_frame_t)) {
 166                 ERROR ("could not send frame\n");
 167                 return ret;
 168         }
 169
 170         return 0;
 171 }