lincan/src/ioctl_remote.c

   1 /* ioctl_remote.c
   2  * Linux CAN-bus device driver.
   3  * Written by Arnaud Westenberg email:arnaud@wanadoo.nl
   4  * Rewritten for new CAN queues by Pavel Pisa - OCERA team member
   5  * email:pisa@cmp.felk.cvut.cz
   6  * This software is released under the GPL-License.
   7  * Version lincan-0.3  17 Nov 2004
   8  */
   9
  10 #include "../include/can.h"
  11 #include "../include/can_sysdep.h"
  12 #include "../include/main.h"
  13 #include "../include/read.h"
  14 #include "../include/ioctl.h"
  15
  16 /* This is the 'RTR' read handler for remote transmission request messages */
  17 int can_ioctl_remote_read(struct canuser_t *canuser, struct canmsg_t *rtr_msg,
  18                           unsigned long rtr_id, int options)
  19 {
  20         can_spin_irqflags_t flags;
  21         struct rtr_id *rtr_current, *new_rtr_entry;
  22         struct msgobj_t *obj;
  23         struct canchip_t *chip;
  24         /*struct canque_ends_t *qends;*/
  25
  26         DEBUGMSG("Remote transmission request\n");
  27
  28         /*qends = canuser->qends;*/
  29
  30         /* Initialize hardware pointers */
  31         obj = canuser->msgobj;
  32         if (obj == NULL) {
  33                 CANMSG("Could not assign buffer structure\n");
  34                 return -ENODEV;
  35         }
  36
  37         if ( (chip = obj->hostchip) == NULL) {
  38                 CANMSG("Device is not correctly configured,\n");
  39                 CANMSG("please reload the driver.\n");
  40                 return -ENODEV;
  41         }
  42
  43         can_spin_lock_irqsave(&hardware_p->rtr_lock, flags);
  44         if (hardware_p->rtr_queue == NULL) { //No remote messages pending
  45                 new_rtr_entry=(struct rtr_id *)kmalloc(sizeof(struct rtr_id),GFP_ATOMIC);
  46                 if (new_rtr_entry == NULL) {
  47                         can_spin_unlock_irqrestore(&hardware_p->rtr_lock,
  48                                                                 flags);
  49                         return -ENOMEM;
  50                 }
  51                 hardware_p->rtr_queue=new_rtr_entry;
  52         }
  53         else {
  54                 rtr_current=hardware_p->rtr_queue;
  55                 while (rtr_current->next != NULL)
  56                         rtr_current=rtr_current->next;
  57                 new_rtr_entry=(struct rtr_id *)kmalloc(sizeof(struct rtr_id),GFP_ATOMIC);
  58                 rtr_current->next=new_rtr_entry;
  59         }
  60         init_waitqueue_head(&new_rtr_entry->rtr_wq);
  61         new_rtr_entry->id = rtr_id;
  62         new_rtr_entry->rtr_message = rtr_msg;
  63         new_rtr_entry->next=NULL;
  64
  65         can_spin_unlock_irqrestore(&hardware_p->rtr_lock, flags);
  66
  67         /* Send remote transmission request */
  68         chip->chipspecops->remote_request(chip,obj);
  69         obj->ret = 0;
  70         interruptible_sleep_on(&new_rtr_entry->rtr_wq);
  71
  72         can_spin_lock_irqsave(&hardware_p->rtr_lock, flags);
  73         if (hardware_p->rtr_queue == new_rtr_entry) {
  74                 if (new_rtr_entry->next != NULL)
  75                         hardware_p->rtr_queue=new_rtr_entry->next;
  76                 else
  77                         hardware_p->rtr_queue=NULL;
  78         }
  79         else {
  80                 rtr_current=hardware_p->rtr_queue;
  81                 while (rtr_current->next != new_rtr_entry)
  82                         rtr_current=rtr_current->next;
  83                 if (new_rtr_entry->next != NULL)
  84                         rtr_current->next=new_rtr_entry->next;
  85                 else
  86                         rtr_current->next=NULL;
  87         }
  88         can_spin_unlock_irqrestore(&hardware_p->rtr_lock, flags);
  89         kfree(new_rtr_entry);
  90
  91         return obj->ret;
  92 }
  93