-/* read.c
- * Linux CAN-bus device driver.
- * Written by Arnaud Westenberg email:arnaud@wanadoo.nl
- * Rewritten for new CAN queues by Pavel Pisa - OCERA team member
- * email:pisa@cmp.felk.cvut.cz
- * This software is released under the GPL-License.
- * Version lincan-0.2 9 Jul 2003
- */
+/**************************************************************************/
+/* File: read.c - read system call support for receiving CAN messages */
+/* */
+/* LinCAN - (Not only) Linux CAN bus driver */
+/* Copyright (C) 2002-2009 DCE FEE CTU Prague <http://dce.felk.cvut.cz> */
+/* Copyright (C) 2002-2009 Pavel Pisa <pisa@cmp.felk.cvut.cz> */
+/* Funded by OCERA and FRESCOR IST projects */
+/* Based on CAN driver code by Arnaud Westenberg <arnaud@wanadoo.nl> */
+/* */
+/* LinCAN is free software; you can redistribute it and/or modify it */
+/* under terms of the GNU General Public License as published by the */
+/* Free Software Foundation; either version 2, or (at your option) any */
+/* later version. LinCAN is distributed in the hope that it will be */
+/* useful, but WITHOUT ANY WARRANTY; without even the implied warranty */
+/* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU */
+/* General Public License for more details. You should have received a */
+/* copy of the GNU General Public License along with LinCAN; see file */
+/* COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, */
+/* Cambridge, MA 02139, USA. */
+/* */
+/* To allow use of LinCAN in the compact embedded systems firmware */
+/* and RT-executives (RTEMS for example), main authors agree with next */
+/* special exception: */
+/* */
+/* Including LinCAN header files in a file, instantiating LinCAN generics */
+/* or templates, or linking other files with LinCAN objects to produce */
+/* an application image/executable, does not by itself cause the */
+/* resulting application image/executable to be covered by */
+/* the GNU General Public License. */
+/* This exception does not however invalidate any other reasons */
+/* why the executable file might be covered by the GNU Public License. */
+/* Publication of enhanced or derived LinCAN files is required although. */
+/**************************************************************************/
#include "../include/can.h"
#include "../include/can_sysdep.h"
#include "../include/main.h"
#include "../include/read.h"
-#include "../include/ioctl.h"
/* This is the 'Normal' read handler for normal transmission messages */
-inline ssize_t can_std_read(struct file *file, struct canque_ends_t *qends,
- struct msgobj_t *obj, char *buffer, size_t length)
+ssize_t can_read(struct file *file, char *buffer, size_t length, loff_t *offset)
{
- int ret;
+ struct canuser_t *canuser = (struct canuser_t*)(file->private_data);
+ struct canque_ends_t *qends;
int bytes_to_copy;
struct canque_edge_t *qedge;
struct canque_slot_t *slot;
-
+ int ret;
+
+ 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;
+ }
+
+ qends = canuser->qends;
+
ret=canque_test_outslot(qends, &qedge, &slot);
if(ret<0){
if (file->f_flags & O_NONBLOCK) {
return -EIO;
}
}
-
- copy_to_user(buffer, &slot->msg, sizeof(struct canmsg_t));
+
+ ret = copy_to_user(buffer, &slot->msg, sizeof(struct canmsg_t));
canque_free_outslot(qends, qedge, slot);
buffer += sizeof(struct canmsg_t);
bytes_to_copy = length-sizeof(struct canmsg_t);
-
+ if(ret) return -EFAULT;
+
while (bytes_to_copy > 0) {
ret=canque_test_outslot(qends, &qedge, &slot);
if(ret<0)
break;
- copy_to_user(buffer, &slot->msg, sizeof(struct canmsg_t));
+ ret = copy_to_user(buffer, &slot->msg, sizeof(struct canmsg_t));
canque_free_outslot(qends, qedge, slot);
buffer += sizeof(struct canmsg_t);
bytes_to_copy -= sizeof(struct canmsg_t);
+ if(ret) return -EFAULT;
}
return length-bytes_to_copy;
}
-/* 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)
-{
- unsigned long flags;
- struct rtr_id *rtr_current, *new_rtr_entry;
- struct canmsg_t read_msg;
-
- DEBUGMSG("Remote transmission request\n");
- 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) {
- 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;
-
- 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);
-
- 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;
- }
- 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_close: 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;
-}
-
-
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