#define ELM327_READY_CHAR '>'
/* Bits in elm->cmds_todo */
-enum ELM327_TX_DO_BITS {
+enum elm327_to_to_do_bits {
ELM327_TX_DO_CAN_DATA = 0,
ELM327_TX_DO_CANID_11BIT,
ELM327_TX_DO_CANID_29BIT_LOW,
/* Per-channel lock */
spinlock_t lock;
- /* Stop the channel on hardware failure.
+ /* Stop the channel on UART side hardware failure, e.g. stray
+ * characters or neverending lines. This may be caused by bad
+ * UART wiring, a bad ELM327, a bad UART bridge...
* Once this is true, nothing will be sent to the TTY.
*/
- bool hw_failure;
+ bool uart_side_failure;
/* TTY TX helpers */
struct work_struct tx_work; /* Flushes TTY TX buffer */
unsigned long cmds_todo;
};
-static inline void elm327_hw_failure(struct elmcan *elm);
+static inline void elm327_uart_side_failure(struct elmcan *elm);
static void elm327_send(struct elmcan *elm, const void *buf, size_t len)
{
lockdep_assert_held(elm->lock);
- if (elm->hw_failure)
+ if (elm->uart_side_failure)
return;
memcpy(elm->txbuf, buf, len);
netdev_err(elm->dev,
"Failed to write to tty %s.\n",
elm->tty->name);
- elm327_hw_failure(elm);
+ elm327_uart_side_failure(elm);
return;
}
elm327_kick_into_cmd_mode(elm);
}
-/* ELM327 initialisation sequence. */
+/* ELM327 initialisation sequence.
+ * The line length is limited by the buffer in elm327_handle_prompt().
+ */
static char *elm327_init_script[] = {
"AT WS\r", /* v1.0: Warm Start */
"AT PP FF OFF\r", /* v1.0: All Programmable Parameters Off */
}
/* Called when we're out of ideas and just want it all to end. */
-static inline void elm327_hw_failure(struct elmcan *elm)
+static inline void elm327_uart_side_failure(struct elmcan *elm)
{
struct can_frame *frame;
struct sk_buff *skb;
lockdep_assert_held(elm->lock);
- elm->hw_failure = true;
+ elm->uart_side_failure = true;
elm->can.can_stats.bus_off++;
netif_stop_queue(elm->dev);
static void elm327_handle_prompt(struct elmcan *elm)
{
struct can_frame *frame = &elm->can_frame_to_send;
- char local_txbuf[20];
+ /* Size this buffer for the largest ELM327 line we may generate,
+ * which is currently an 8 byte CAN frame's payload hexdump.
+ * Items in elm327_init_script must fit here, too!
+ */
+ char local_txbuf[sizeof("0102030405060708\r")];
lockdep_assert_held(elm->lock);
/* Reconfigure ELM327 step by step as indicated by elm->cmds_todo */
if (test_bit(ELM327_TX_DO_INIT, &elm->cmds_todo)) {
- strcpy(local_txbuf, *elm->next_init_cmd);
+ snprintf(local_txbuf, sizeof(local_txbuf),
+ "%s",
+ *elm->next_init_cmd);
elm->next_init_cmd++;
if (!(*elm->next_init_cmd)) {
}
} else if (test_and_clear_bit(ELM327_TX_DO_SILENT_MONITOR, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATCSM%i\r",
+ snprintf(local_txbuf, sizeof(local_txbuf),
+ "ATCSM%i\r",
!(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)));
} else if (test_and_clear_bit(ELM327_TX_DO_RESPONSES, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATR%i\r",
+ snprintf(local_txbuf, sizeof(local_txbuf),
+ "ATR%i\r",
!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
} else if (test_and_clear_bit(ELM327_TX_DO_CAN_CONFIG, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATPC\r");
+ snprintf(local_txbuf, sizeof(local_txbuf),
+ "ATPC\r");
set_bit(ELM327_TX_DO_CAN_CONFIG_PART2, &elm->cmds_todo);
} else if (test_and_clear_bit(ELM327_TX_DO_CAN_CONFIG_PART2, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATPB%04X\r",
+ snprintf(local_txbuf, sizeof(local_txbuf),
+ "ATPB%04X\r",
elm->can_config);
} else if (test_and_clear_bit(ELM327_TX_DO_CANID_29BIT_HIGH, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATCP%02X\r",
+ snprintf(local_txbuf, sizeof(local_txbuf),
+ "ATCP%02X\r",
(frame->can_id & CAN_EFF_MASK) >> 24);
} else if (test_and_clear_bit(ELM327_TX_DO_CANID_29BIT_LOW, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATSH%06X\r",
+ snprintf(local_txbuf, sizeof(local_txbuf),
+ "ATSH%06X\r",
frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1));
} else if (test_and_clear_bit(ELM327_TX_DO_CANID_11BIT, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATSH%03X\r",
+ snprintf(local_txbuf, sizeof(local_txbuf),
+ "ATSH%03X\r",
frame->can_id & CAN_SFF_MASK);
} else if (test_and_clear_bit(ELM327_TX_DO_CAN_DATA, &elm->cmds_todo)) {
/* Send an RTR frame. Their DLC is fixed.
* Some chips don't send them at all.
*/
- sprintf(local_txbuf, "ATRTR\r");
+ snprintf(local_txbuf, sizeof(local_txbuf),
+ "ATRTR\r");
} else {
/* Send a regular CAN data frame */
int i;
for (i = 0; i < frame->len; i++) {
- sprintf(&local_txbuf[2 * i], "%02X",
+ snprintf(&local_txbuf[2 * i], sizeof(local_txbuf),
+ "%02X",
frame->data[i]);
}
- sprintf(&local_txbuf[2 * i], "\r");
+ snprintf(&local_txbuf[2 * i], sizeof(local_txbuf),
+ "\r");
}
elm->drop_next_line = 1;
*/
netdev_err(elm->dev,
"RX buffer overflow. Faulty ELM327 or UART?\n");
- elm327_hw_failure(elm);
+ elm327_uart_side_failure(elm);
break;
} else if (len == elm->rxfill) {
if (elm327_is_ready_char(elm->rxbuf[elm->rxfill - 1])) {
int err;
spin_lock_bh(&elm->lock);
- if (elm->hw_failure) {
+ if (elm->uart_side_failure) {
netdev_err(elm->dev, "Refusing to open interface after a hardware fault has been detected.\n");
spin_unlock_bh(&elm->lock);
return -EIO;
/* We shouldn't get here after a hardware fault:
* can_bus_off() calls netif_carrier_off()
*/
- WARN_ON_ONCE(elm->hw_failure);
+ WARN_ON_ONCE(elm->uart_side_failure);
if (!elm->tty ||
- elm->hw_failure ||
+ elm->uart_side_failure ||
elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
spin_unlock(&elm->lock);
goto out;
spin_lock_bh(&elm->lock);
- if (elm->hw_failure)
+ if (elm->uart_side_failure)
goto out;
while (count-- && elm->rxfill < ELM327_SIZE_RXBUF) {
if (fp && *fp++) {
netdev_err(elm->dev, "Error in received character stream. Check your wiring.");
- elm327_hw_failure(elm);
+ elm327_uart_side_failure(elm);
goto out;
}
netdev_err(elm->dev,
"Received illegal character %02x.\n",
*cp);
- elm327_hw_failure(elm);
+ elm327_uart_side_failure(elm);
goto out;
}
if (count >= 0) {
netdev_err(elm->dev, "Receive buffer overflowed. Bad chip or wiring?");
- elm327_hw_failure(elm);
+ elm327_uart_side_failure(elm);
goto out;
}
struct elmcan *elm = container_of(work, struct elmcan, tx_work);
ssize_t written;
- if (elm->hw_failure)
+ if (elm->uart_side_failure)
return;
spin_lock_bh(&elm->lock);
netdev_err(elm->dev,
"Failed to write to tty %s.\n",
elm->tty->name);
- elm327_hw_failure(elm);
+ elm327_uart_side_failure(elm);
spin_unlock_bh(&elm->lock);
return;
} else {
projects / elmcan.git / blobdiff