-/* This is the 'RTR' read handler for remote transmission request messages */
-inline ssize_t can_rtr_read(struct chip_t *chip, struct msgobj_t *obj,
- char *buffer)
-{
- can_spin_irqflags_t flags;
- struct rtr_id *rtr_current, *new_rtr_entry;
- struct canmsg_t read_msg;
-
- DEBUGMSG("Remote transmission request\n");
- can_spin_lock_irqsave(&hardware_p->rtr_lock, flags);
- if (hardware_p->rtr_queue == NULL) { //No remote messages pending
- new_rtr_entry=(struct rtr_id *)kmalloc(sizeof(struct rtr_id),GFP_ATOMIC);
- if (new_rtr_entry == NULL) {
- can_spin_unlock_irqrestore(&hardware_p->rtr_lock,
- flags);
- return -ENOMEM;
- }
- hardware_p->rtr_queue=new_rtr_entry;
- }
- else {
- rtr_current=hardware_p->rtr_queue;
- while (rtr_current->next != NULL)
- rtr_current=rtr_current->next;
- new_rtr_entry=(struct rtr_id *)kmalloc(sizeof(struct rtr_id),GFP_ATOMIC);
- rtr_current->next=new_rtr_entry;
- }
- init_waitqueue_head(&new_rtr_entry->rtr_wq);
- new_rtr_entry->id = read_msg.id;
- new_rtr_entry->rtr_message = &read_msg;
- new_rtr_entry->next=NULL;
-
- can_spin_unlock_irqrestore(&hardware_p->rtr_lock, flags);
-
- /* Send remote transmission request */
- chip->chipspecops->remote_request(chip,obj);
- obj->ret = 0;
- interruptible_sleep_on(&new_rtr_entry->rtr_wq);
-
- can_spin_lock_irqsave(&hardware_p->rtr_lock, flags);
- copy_to_user(buffer, &read_msg, sizeof(struct canmsg_t));
- if (hardware_p->rtr_queue == new_rtr_entry) {
- if (new_rtr_entry->next != NULL)
- hardware_p->rtr_queue=new_rtr_entry->next;
- else
- hardware_p->rtr_queue=NULL;
- }
- else {
- rtr_current=hardware_p->rtr_queue;
- while (rtr_current->next != new_rtr_entry)
- rtr_current=rtr_current->next;
- if (new_rtr_entry->next != NULL)
- rtr_current->next=new_rtr_entry->next;
- else
- rtr_current->next=NULL;
- }
- can_spin_unlock_irqrestore(&hardware_p->rtr_lock, flags);
- kfree(new_rtr_entry);
-
- return obj->ret;
-}
-
-ssize_t can_read(struct file *file, char *buffer, size_t length, loff_t *offset)
-{
- struct canuser_t *canuser = (struct canuser_t*)(file->private_data);
- struct msgobj_t *obj;
- struct chip_t *chip;
- struct canmsg_t read_msg;
- struct canque_ends_t *qends;
- int ret=0;
-
- if(!canuser || (canuser->magic != CAN_USER_MAGIC)){
- CANMSG("can_read: bad canuser magic\n");
- return -ENODEV;
- }
-
- if (length < sizeof(struct canmsg_t)) {
- DEBUGMSG("Trying to read less bytes than a CAN message, \n");
- DEBUGMSG("this will always return zero.\n");
- return 0;
- }
- /* Initialize hardware pointers */
- obj = canuser->msgobj;
- if (obj == NULL) {
- CANMSG("Could not assign buffer structure\n");
- return -1;
- }
- qends = canuser->qends;
- if ( (chip = obj->hostchip) == NULL) {
- CANMSG("Device is not correctly configured,\n");
- CANMSG("please reload the driver.\n");
- return -1;
- }
-
- copy_from_user(&read_msg, buffer, sizeof(struct canmsg_t));
- if (read_msg.flags & MSG_RTR)
- ret = can_rtr_read(chip, obj, buffer);
- else
- ret = can_std_read(file, qends, obj, buffer, length);
-
- return ret;
-}
-
-