// SPDX-License-Identifier: GPL-2.0
-/*
- * elmcan.c - ELM327 based CAN interface driver
+/* elmcan.c - ELM327 based CAN interface driver
* (tty line discipline)
*
* This file is derived from linux/drivers/net/can/slcan.c
#define pr_fmt(fmt) "[elmcan] " fmt
-
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/can/error.h>
#include <linux/can/led.h>
-
MODULE_ALIAS_LDISC(N_ELMCAN);
MODULE_DESCRIPTION("ELM327 based CAN interface");
MODULE_LICENSE("GPL");
module_param_named(accept_flaky_uart, accept_flaky_uart, bool, 0444);
MODULE_PARM_DESC(accept_flaky_uart, "Don't bail at the first invalid character. Behavior undefined.");
-
/* Line discipline ID number */
#ifndef N_ELMCAN
#define N_ELMCAN 29
#define ELM327_MAGIC_STRING "y"
#define ELM327_READY_CHAR '>'
-
/* Bits in elm->cmds_todo */
enum ELM_TODO {
- ELM_TODO_CAN_DATA = 0,
- ELM_TODO_CANID_11BIT,
- ELM_TODO_CANID_29BIT_LOW,
- ELM_TODO_CANID_29BIT_HIGH,
- ELM_TODO_CAN_CONFIG_PART2,
- ELM_TODO_CAN_CONFIG,
- ELM_TODO_RESPONSES,
- ELM_TODO_SILENT_MONITOR,
- ELM_TODO_INIT
+ TODO_CAN_DATA = 0,
+ TODO_CANID_11BIT,
+ TODO_CANID_29BIT_LOW,
+ TODO_CANID_29BIT_HIGH,
+ TODO_CAN_CONFIG_PART2,
+ TODO_CAN_CONFIG,
+ TODO_RESPONSES,
+ TODO_SILENT_MONITOR,
+ TODO_INIT
};
-
struct elmcan {
/* This must be the first member when using alloc_candev() */
struct can_priv can;
unsigned long cmds_todo;
};
-
/* A lock for all tty->disc_data handled by this ldisc.
* This is to prevent a case where tty->disc_data is set to NULL,
* yet someone is still trying to dereference it.
*/
static DEFINE_SPINLOCK(elmcan_discdata_lock);
-
static inline void elm327_hw_failure(struct elmcan *elm);
-
-
/***********************************************************************
* ELM327: Transmission *
* *
actual = elm->tty->ops->write(elm->tty, elm->txbuf, len);
if (actual < 0) {
netdev_err(elm->dev,
- "Failed to write to tty %s.\n",
- elm->tty->name);
+ "Failed to write to tty %s.\n",
+ elm->tty->name);
elm327_hw_failure(elm);
return;
}
elm->txhead = elm->txbuf + actual;
}
-
/* Take the ELM327 out of almost any state and back into command mode.
* We send ELM327_MAGIC_CHAR which will either abort any running
* operation, or be echoed back to us in case we're already in command
}
}
-
/* Schedule a CAN frame and necessary config changes to be sent to the TTY. */
static void elm327_send_frame(struct elmcan *elm, struct can_frame *frame)
{
| ELM327_CAN_CONFIG_RECV_BOTH_SFF_EFF
| elm->can_bitrate_divisor;
- set_bit(ELM_TODO_CAN_CONFIG, &elm->cmds_todo);
+ set_bit(TODO_CAN_CONFIG, &elm->cmds_todo);
}
if (frame->can_id & CAN_EFF_FLAG) {
- clear_bit(ELM_TODO_CANID_11BIT, &elm->cmds_todo);
- set_bit(ELM_TODO_CANID_29BIT_LOW, &elm->cmds_todo);
- set_bit(ELM_TODO_CANID_29BIT_HIGH, &elm->cmds_todo);
+ clear_bit(TODO_CANID_11BIT, &elm->cmds_todo);
+ set_bit(TODO_CANID_29BIT_LOW, &elm->cmds_todo);
+ set_bit(TODO_CANID_29BIT_HIGH, &elm->cmds_todo);
} else {
- set_bit(ELM_TODO_CANID_11BIT, &elm->cmds_todo);
- clear_bit(ELM_TODO_CANID_29BIT_LOW, &elm->cmds_todo);
- clear_bit(ELM_TODO_CANID_29BIT_HIGH, &elm->cmds_todo);
+ set_bit(TODO_CANID_11BIT, &elm->cmds_todo);
+ clear_bit(TODO_CANID_29BIT_LOW, &elm->cmds_todo);
+ clear_bit(TODO_CANID_29BIT_HIGH, &elm->cmds_todo);
}
}
/* Schedule the CAN frame itself. */
elm->can_frame = *frame;
- set_bit(ELM_TODO_CAN_DATA, &elm->cmds_todo);
+ set_bit(TODO_CAN_DATA, &elm->cmds_todo);
elm327_kick_into_cmd_mode(elm);
}
-
-
/***********************************************************************
* ELM327: Initialization sequence *
* *
NULL
};
-
static void elm327_init(struct elmcan *elm)
{
elm->state = ELM_NOTINIT;
/* Configure ELM327 and then start monitoring */
elm->next_init_cmd = &elm327_init_script[0];
- set_bit(ELM_TODO_INIT, &elm->cmds_todo);
- set_bit(ELM_TODO_SILENT_MONITOR, &elm->cmds_todo);
- set_bit(ELM_TODO_RESPONSES, &elm->cmds_todo);
- set_bit(ELM_TODO_CAN_CONFIG, &elm->cmds_todo);
+ set_bit(TODO_INIT, &elm->cmds_todo);
+ set_bit(TODO_SILENT_MONITOR, &elm->cmds_todo);
+ set_bit(TODO_RESPONSES, &elm->cmds_todo);
+ set_bit(TODO_CAN_CONFIG, &elm->cmds_todo);
elm327_kick_into_cmd_mode(elm);
}
-
-
/***********************************************************************
* ELM327: Reception -> netdev glue *
* *
can_led_event(elm->dev, CAN_LED_EVENT_RX);
}
-
-
/***********************************************************************
* ELM327: "Panic" handler *
* *
can_bus_off(elm->dev);
}
-
-
/***********************************************************************
* ELM327: Reception parser *
* *
case 17:
if (!memcmp(elm->rxbuf, "UNABLE TO CONNECT", 17)) {
netdev_err(elm->dev,
- "The ELM327 reported UNABLE TO CONNECT. Please check your setup.\n");
+ "The ELM327 reported UNABLE TO CONNECT. Please check your setup.\n");
}
break;
case 11:
case 5:
if (!memcmp(elm->rxbuf, "ERR", 3)) {
netdev_err(elm->dev, "The ELM327 reported an ERR%c%c. Please power it off and on again.\n",
- elm->rxbuf[3], elm->rxbuf[4]);
+ elm->rxbuf[3], elm->rxbuf[4]);
frame.can_id |= CAN_ERR_CRTL;
}
break;
elm327_feed_frame_to_netdev(elm, &frame);
}
-
/* Parse CAN frames coming as ASCII from ELM327.
* They can be of various formats:
*
* - An error message may replace the end of the data line.
*/
for (hexlen = 0; hexlen <= len; hexlen++) {
- if (hex_to_bin(elm->rxbuf[hexlen]) < 0
- && elm->rxbuf[hexlen] != ' ') {
+ if (hex_to_bin(elm->rxbuf[hexlen]) < 0 &&
+ elm->rxbuf[hexlen] != ' ') {
break;
}
}
* Check for stray characters on a payload line.
* No idea what causes this.
*/
- if (accept_flaky_uart
- && hexlen < len
- && !isdigit(elm->rxbuf[hexlen])
- && !isupper(elm->rxbuf[hexlen])
- && '<' != elm->rxbuf[hexlen]
- && ' ' != elm->rxbuf[hexlen]) {
+ if (accept_flaky_uart &&
+ hexlen < len &&
+ !isdigit(elm->rxbuf[hexlen]) &&
+ !isupper(elm->rxbuf[hexlen]) &&
+ '<' != elm->rxbuf[hexlen] &&
+ ' ' != elm->rxbuf[hexlen]) {
/* The line is likely garbled anyway, so bail.
* The main code will restart listening.
*/
* No out-of-bounds access:
* We use the fact that we can always read from elm->rxbuf.
*/
- if (elm->rxbuf[2] == ' ' && elm->rxbuf[5] == ' '
- && elm->rxbuf[8] == ' ' && elm->rxbuf[11] == ' '
- && elm->rxbuf[13] == ' ') {
+ if (elm->rxbuf[2] == ' ' && elm->rxbuf[5] == ' ' &&
+ elm->rxbuf[8] == ' ' && elm->rxbuf[11] == ' ' &&
+ elm->rxbuf[13] == ' ') {
frame.can_id = CAN_EFF_FLAG;
datastart = 14;
} else if (elm->rxbuf[3] == ' ' && elm->rxbuf[5] == ' ') {
}
/* Check for RTR frame */
- if (elm->rxfill >= hexlen + 3
- && !memcmp(&elm->rxbuf[hexlen], "RTR", 3)) {
+ if (elm->rxfill >= hexlen + 3 &&
+ !memcmp(&elm->rxbuf[hexlen], "RTR", 3)) {
frame.can_id |= CAN_RTR_FLAG;
}
/* Is the line long enough to hold the advertised payload?
* Note: RTR frames have a DLC, but no actual payload.
*/
- if (!(frame.can_id & CAN_RTR_FLAG)
- && (hexlen < frame.can_dlc * 3 + datastart)) {
+ if (!(frame.can_id & CAN_RTR_FLAG) &&
+ (hexlen < frame.can_dlc * 3 + datastart)) {
/* Incomplete frame. */
/* Probably the ELM327's RS232 TX buffer was full.
/* Parse the data nibbles. */
for (i = 0; i < frame.can_dlc; i++) {
- frame.data[i] = (hex_to_bin(elm->rxbuf[datastart+3*i]) << 4)
- | (hex_to_bin(elm->rxbuf[datastart+3*i+1]) << 0);
+ frame.data[i] = (hex_to_bin(elm->rxbuf[datastart + 3*i]) << 4)
+ | (hex_to_bin(elm->rxbuf[datastart + 3*i + 1]));
}
/* Feed the frame to the network layer. */
return 0;
}
-
static void elm327_parse_line(struct elmcan *elm, int len)
{
/* Skip empty lines */
}
/* Reconfigure ELM327 step by step as indicated by elm->cmds_todo */
- if (test_bit(ELM_TODO_INIT, &elm->cmds_todo)) {
+ if (test_bit(TODO_INIT, &elm->cmds_todo)) {
strcpy(local_txbuf, *elm->next_init_cmd);
elm->next_init_cmd++;
if (!(*elm->next_init_cmd)) {
- clear_bit(ELM_TODO_INIT, &elm->cmds_todo);
+ clear_bit(TODO_INIT, &elm->cmds_todo);
netdev_info(elm->dev, "Initialization finished.\n");
}
- } else if (test_and_clear_bit(ELM_TODO_SILENT_MONITOR, &elm->cmds_todo)) {
+ } else if (test_and_clear_bit(TODO_SILENT_MONITOR, &elm->cmds_todo)) {
sprintf(local_txbuf, "ATCSM%i\r",
!(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)));
- } else if (test_and_clear_bit(ELM_TODO_RESPONSES, &elm->cmds_todo)) {
+ } else if (test_and_clear_bit(TODO_RESPONSES, &elm->cmds_todo)) {
sprintf(local_txbuf, "ATR%i\r",
!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
- } else if (test_and_clear_bit(ELM_TODO_CAN_CONFIG, &elm->cmds_todo)) {
+ } else if (test_and_clear_bit(TODO_CAN_CONFIG, &elm->cmds_todo)) {
sprintf(local_txbuf, "ATPC\r");
- set_bit(ELM_TODO_CAN_CONFIG_PART2, &elm->cmds_todo);
+ set_bit(TODO_CAN_CONFIG_PART2, &elm->cmds_todo);
- } else if (test_and_clear_bit(ELM_TODO_CAN_CONFIG_PART2, &elm->cmds_todo)) {
+ } else if (test_and_clear_bit(TODO_CAN_CONFIG_PART2, &elm->cmds_todo)) {
sprintf(local_txbuf, "ATPB%04X\r",
elm->can_config);
- } else if (test_and_clear_bit(ELM_TODO_CANID_29BIT_HIGH, &elm->cmds_todo)) {
+ } else if (test_and_clear_bit(TODO_CANID_29BIT_HIGH, &elm->cmds_todo)) {
sprintf(local_txbuf, "ATCP%02X\r",
(frame->can_id & CAN_EFF_MASK) >> 24);
- } else if (test_and_clear_bit(ELM_TODO_CANID_29BIT_LOW, &elm->cmds_todo)) {
+ } else if (test_and_clear_bit(TODO_CANID_29BIT_LOW, &elm->cmds_todo)) {
sprintf(local_txbuf, "ATSH%06X\r",
frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1));
- } else if (test_and_clear_bit(ELM_TODO_CANID_11BIT, &elm->cmds_todo)) {
+ } else if (test_and_clear_bit(TODO_CANID_11BIT, &elm->cmds_todo)) {
sprintf(local_txbuf, "ATSH%03X\r",
frame->can_id & CAN_SFF_MASK);
- } else if (test_and_clear_bit(ELM_TODO_CAN_DATA, &elm->cmds_todo)) {
+ } else if (test_and_clear_bit(TODO_CAN_DATA, &elm->cmds_todo)) {
if (frame->can_id & CAN_RTR_FLAG) {
/* Send an RTR frame. Their DLC is fixed.
* Some chips don't send them at all.
int i;
for (i = 0; i < frame->can_dlc; i++) {
- sprintf(&local_txbuf[2*i], "%02X",
+ sprintf(&local_txbuf[2 * i], "%02X",
frame->data[i]);
}
- sprintf(&local_txbuf[2*i], "\r");
+ sprintf(&local_txbuf[2 * i], "\r");
}
elm->drop_next_line = 1;
elm327_send(elm, local_txbuf, strlen(local_txbuf));
}
-
static bool elm327_is_ready_char(char c)
{
/* Bits 0xc0 are sometimes set (randomly), hence the mask.
* Did we even connect at the right baud rate?
*/
netdev_err(elm->dev,
- "RX buffer overflow. Faulty ELM327 or UART?\n");
+ "RX buffer overflow. Faulty ELM327 or UART?\n");
elm327_hw_failure(elm);
break;
} else if (len == elm->rxfill) {
elm327_parse_line(elm, len);
/* Remove parsed data from RX buffer. */
- elm327_drop_bytes(elm, len+1);
+ elm327_drop_bytes(elm, len + 1);
/* More data to parse? */
if (elm->rxfill)
}
}
-
-
-
-
/***********************************************************************
* netdev *
* *
return -EIO;
}
- if (elm->tty == NULL) {
+ if (!elm->tty) {
spin_unlock_bh(&elm->lock);
return -ENODEV;
}
struct net_device *dev)
{
struct elmcan *elm = netdev_priv(dev);
- struct can_frame *frame = (struct can_frame *) skb->data;
+ struct can_frame *frame = (struct can_frame *)skb->data;
if (skb->len != sizeof(struct can_frame))
goto out;
*/
WARN_ON(elm->hw_failure);
- if (elm->tty == NULL
- || elm->hw_failure
- || elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
+ if (!elm->tty ||
+ elm->hw_failure ||
+ elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
spin_unlock(&elm->lock);
goto out;
}
return NETDEV_TX_OK;
}
-
static const struct net_device_ops elmcan_netdev_ops = {
.ndo_open = elmcan_netdev_open,
.ndo_stop = elmcan_netdev_close,
.ndo_change_mtu = can_change_mtu,
};
-
-
-
-
/***********************************************************************
* Line discipline *
* *
bool got_ref;
spin_lock_bh(&elmcan_discdata_lock);
- elm = (struct elmcan *) tty->disc_data;
+ elm = (struct elmcan *)tty->disc_data;
if (!elm) {
spin_unlock_bh(&elmcan_discdata_lock);
atomic_dec(&elm->refcount);
}
-
static bool elmcan_is_valid_rx_char(char c)
{
- return (accept_flaky_uart
- || isdigit(c)
- || isupper(c)
- || ELM327_MAGIC_CHAR == c
- || ELM327_READY_CHAR == c
- || '<' == c
- || 'a' == c
- || 'b' == c
- || 'v' == c
- || '.' == c
- || '?' == c
- || '\r' == c
- || ' ' == c);
+ return (accept_flaky_uart ||
+ isdigit(c) ||
+ isupper(c) ||
+ c == ELM327_MAGIC_CHAR ||
+ c == ELM327_READY_CHAR ||
+ c == '<' ||
+ c == 'a' ||
+ c == 'b' ||
+ c == 'v' ||
+ c == '.' ||
+ c == '?' ||
+ c == '\r' ||
+ c == ' ');
}
/* Handle incoming ELM327 ASCII data.
* functions may be called in parallel.
*/
static void elmcan_ldisc_rx(struct tty_struct *tty,
- const unsigned char *cp, char *fp, int count)
+ const unsigned char *cp, char *fp, int count)
{
struct elmcan *elm = get_elm(tty);
spin_lock_bh(&elm->lock);
- if (elm->hw_failure) {
+ if (elm->hw_failure)
goto out;
- }
while (count-- && elm->rxfill < ELM327_SIZE_RXBUF) {
if (fp && *fp++) {
put_elm(elm);
}
-
/* Write out remaining transmit buffer.
* Scheduled when TTY is writable.
*/
put_elm(elm);
}
-
/* ELM327 can only handle bitrates that are integer divisors of 500 kHz,
* or 7/8 of that. Divisors are 1 to 64.
* Currently we don't implement support for 7/8 rates.
62500, 71428, 83333, 100000, 125000, 166666, 250000, 500000
};
-
/* Dummy needed to use bitrate_const */
static int elmcan_do_set_bittiming(struct net_device *netdev)
{
return 0;
}
-
static int elmcan_ldisc_open(struct tty_struct *tty)
{
struct net_device *dev;
if (!tty->ops->write)
return -EOPNOTSUPP;
-
dev = alloc_candev(sizeof(struct elmcan), 0);
if (!dev)
return -ENFILE;
return 0;
out_err:
- if (elm->txbuf)
- kfree(elm->txbuf);
+ kfree(elm->txbuf);
free_candev(elm->dev);
return err;
}
}
static int elmcan_ldisc_ioctl(struct tty_struct *tty, struct file *file,
- unsigned int cmd, unsigned long arg)
+ unsigned int cmd, unsigned long arg)
{
struct elmcan *elm = get_elm(tty);
unsigned int tmp;
.ioctl = elmcan_ldisc_ioctl,
};
-
-
static int __init elmcan_init(void)
{
int status;
projects / elmcan.git / commitdiff