+// SPDX-License-Identifier: GPL-2.0
/*
* elmcan.c - ELM327 based CAN interface driver
* (tty line discipline)
* slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk>
* Fred N. van Kempen <waltje@uwalt.nl.mugnet.org>
*
- * SPDX-License-Identifier: GPL-2.0
- *
*/
#define pr_fmt(fmt) "[elmcan] " fmt
* No guarantees.
* Handle with care, it's likely your hardware is unreliable!
*/
-static bool accept_flaky_uart = false;
+static bool accept_flaky_uart;
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.");
int drop_next_line;
/* The CAN frame and config the ELM327 is sending/using,
- * or will send/use after finishing all cmds_todo */
+ * or will send/use after finishing all cmds_todo
+ */
struct can_frame can_frame;
unsigned short can_config;
unsigned long can_bitrate;
{
int actual;
- if (elm->hw_failure) {
+ if (elm->hw_failure)
return;
- }
memcpy(elm->txbuf, buf, len);
set_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags);
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);
+ netdev_err(elm->dev,
+ "Failed to write to tty %s.\n",
+ elm->tty->name);
elm327_hw_failure(elm);
return;
}
/* Schedule any necessary changes in ELM327's CAN configuration */
if (elm->can_frame.can_id != frame->can_id) {
/* Set the new CAN ID for transmission. */
- if ((frame->can_id & CAN_EFF_FLAG) ^ (elm->can_frame.can_id & CAN_EFF_FLAG)) {
- elm->can_config = (frame->can_id & CAN_EFF_FLAG ? 0 : ELM327_CAN_CONFIG_SEND_SFF)
+ if ((frame->can_id & CAN_EFF_FLAG)
+ ^ (elm->can_frame.can_id & CAN_EFF_FLAG)) {
+ elm->can_config = (frame->can_id & CAN_EFF_FLAG
+ ? 0
+ : ELM327_CAN_CONFIG_SEND_SFF)
| ELM327_CAN_CONFIG_VARIABLE_DLC
| ELM327_CAN_CONFIG_RECV_BOTH_SFF_EFF
| elm->can_bitrate_divisor;
* (assumes elm->lock taken) *
************************************************************************/
-static void elm327_feed_frame_to_netdev(struct elmcan *elm, const struct can_frame *frame)
+static void elm327_feed_frame_to_netdev(struct elmcan *elm,
+ const struct can_frame *frame)
{
struct can_frame *cf;
struct sk_buff *skb;
- if (!netif_running(elm->dev)) {
+ if (!netif_running(elm->dev))
return;
- }
skb = alloc_can_skb(elm->dev, &cf);
frame.data[7] = 'P';
elm327_feed_frame_to_netdev(elm, &frame);
- netdev_err(elm->dev, "ELM327 misbehaved. "
- "Blocking further communication.\n");
+ netdev_err(elm->dev, "ELM327 misbehaved. Blocking further communication.\n");
elm->hw_failure = true;
can_bus_off(elm->dev);
frame.can_id = CAN_ERR_FLAG;
frame.can_dlc = CAN_ERR_DLC;
- switch(len) {
- 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");
- }
- break;
- case 11:
- if (!memcmp(elm->rxbuf, "BUFFER FULL", 11)) {
- /* This case will only happen if the last data
- * line was complete.
- * Otherwise, elm327_parse_frame() will emit the
- * error frame instead.
- */
- frame.can_id |= CAN_ERR_CRTL;
- frame.data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
- }
- break;
- case 9:
- if (!memcmp(elm->rxbuf, "BUS ERROR", 9)) {
- frame.can_id |= CAN_ERR_BUSERROR;
- }
- if (!memcmp(elm->rxbuf, "CAN ERROR", 9)
- || !memcmp(elm->rxbuf, "<RX ERROR", 9)) {
- frame.can_id |= CAN_ERR_PROT;
- }
- break;
- case 8:
- if (!memcmp(elm->rxbuf, "BUS BUSY", 8)) {
- frame.can_id |= CAN_ERR_PROT;
- frame.data[2] = CAN_ERR_PROT_OVERLOAD;
- }
- if (!memcmp(elm->rxbuf, "FB ERROR", 8)) {
- frame.can_id |= CAN_ERR_PROT;
- frame.data[2] = CAN_ERR_PROT_TX;
- }
- break;
- 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]);
- frame.can_id |= CAN_ERR_CRTL;
- }
- break;
- default:
- /* Don't emit an error frame if we're unsure */
- return;
+ switch (len) {
+ 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");
+ }
+ break;
+ case 11:
+ if (!memcmp(elm->rxbuf, "BUFFER FULL", 11)) {
+ /* This case will only happen if the last data
+ * line was complete.
+ * Otherwise, elm327_parse_frame() will emit the
+ * error frame instead.
+ */
+ frame.can_id |= CAN_ERR_CRTL;
+ frame.data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+ }
+ break;
+ case 9:
+ if (!memcmp(elm->rxbuf, "BUS ERROR", 9))
+ frame.can_id |= CAN_ERR_BUSERROR;
+ if (!memcmp(elm->rxbuf, "CAN ERROR", 9))
+ frame.can_id |= CAN_ERR_PROT;
+ if (!memcmp(elm->rxbuf, "<RX ERROR", 9))
+ frame.can_id |= CAN_ERR_PROT;
+ break;
+ case 8:
+ if (!memcmp(elm->rxbuf, "BUS BUSY", 8)) {
+ frame.can_id |= CAN_ERR_PROT;
+ frame.data[2] = CAN_ERR_PROT_OVERLOAD;
+ }
+ if (!memcmp(elm->rxbuf, "FB ERROR", 8)) {
+ frame.can_id |= CAN_ERR_PROT;
+ frame.data[2] = CAN_ERR_PROT_TX;
+ }
+ break;
+ 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]);
+ frame.can_id |= CAN_ERR_CRTL;
+ }
+ break;
+ default:
+ /* Don't emit an error frame if we're unsure */
+ return;
}
elm327_feed_frame_to_netdev(elm, &frame);
}
/* Is the line long enough to hold the advertised 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);
+ | (hex_to_bin(elm->rxbuf[datastart+3*i+1]) << 0);
}
/* Feed the frame to the network layer. */
static void elm327_parse_line(struct elmcan *elm, int len)
{
/* Skip empty lines */
- if (!len) {
+ if (!len)
return;
- }
/* Skip echo lines */
if (elm->drop_next_line) {
}
/* Regular parsing */
- switch(elm->state) {
- case ELM_RECEIVING:
- if (elm327_parse_frame(elm, len)) {
- /* Parse an error line. */
- elm327_parse_error(elm, len);
-
- /* Start afresh. */
- elm327_kick_into_cmd_mode(elm);
- }
- break;
- default:
- break;
+ switch (elm->state) {
+ case ELM_RECEIVING:
+ if (elm327_parse_frame(elm, len)) {
+ /* Parse an error line. */
+ elm327_parse_error(elm, len);
+
+ /* Start afresh. */
+ elm327_kick_into_cmd_mode(elm);
+ }
+ break;
+ default:
+ break;
}
}
static void elm327_handle_prompt(struct elmcan *elm)
{
- if (elm->cmds_todo) {
- struct can_frame *frame = &elm->can_frame;
- char local_txbuf[20];
-
- if (test_bit(ELM_TODO_INIT, &elm->cmds_todo)) {
- elm327_send(elm, *elm->next_init_cmd, strlen(*elm->next_init_cmd));
- elm->next_init_cmd++;
- if (!(*elm->next_init_cmd)) {
- clear_bit(ELM_TODO_INIT, &elm->cmds_todo);
- netdev_info(elm->dev, "Initialization finished.\n");
- }
+ struct can_frame *frame = &elm->can_frame;
+ char local_txbuf[20];
- /* Some chips are unreliable and need extra time after
- * init commands, as seen with a clone.
- * So let's do a dummy get-cmd-prompt dance.
- */
- elm->state = ELM_NOTINIT;
- elm327_kick_into_cmd_mode(elm);
+ if (!elm->cmds_todo) {
+ /* Enter CAN monitor mode */
+ elm327_send(elm, "ATMA\r", 5);
+ elm->state = ELM_RECEIVING;
- return;
+ return;
+ }
- } else if (test_and_clear_bit(ELM_TODO_SILENT_MONITOR, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATCSM%i\r",
- !(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)));
+ /* Reconfigure ELM327 step by step as indicated by elm->cmds_todo */
+ if (test_bit(ELM_TODO_INIT, &elm->cmds_todo)) {
+ elm327_send(elm, *elm->next_init_cmd, strlen(*elm->next_init_cmd));
+ elm->next_init_cmd++;
+ if (!(*elm->next_init_cmd)) {
+ clear_bit(ELM_TODO_INIT, &elm->cmds_todo);
+ netdev_info(elm->dev, "Initialization finished.\n");
+ }
- } else if (test_and_clear_bit(ELM_TODO_RESPONSES, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATR%i\r",
- !(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
+ /* Some chips are unreliable and need extra time after
+ * init commands, as seen with a clone.
+ * So let's do a dummy get-cmd-prompt dance.
+ */
+ elm->state = ELM_NOTINIT;
+ elm327_kick_into_cmd_mode(elm);
- } else if (test_and_clear_bit(ELM_TODO_CAN_CONFIG, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATPC\r");
- set_bit(ELM_TODO_CAN_CONFIG_PART2, &elm->cmds_todo);
+ return;
- } else if (test_and_clear_bit(ELM_TODO_CAN_CONFIG_PART2, &elm->cmds_todo)) {
- sprintf(local_txbuf, "ATPB%04X\r",
- elm->can_config);
+ } else if (test_and_clear_bit(ELM_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_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_RESPONSES, &elm->cmds_todo)) {
+ sprintf(local_txbuf, "ATR%i\r",
+ !(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
- } else if (test_and_clear_bit(ELM_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_CAN_CONFIG, &elm->cmds_todo)) {
+ sprintf(local_txbuf, "ATPC\r");
+ set_bit(ELM_TODO_CAN_CONFIG_PART2, &elm->cmds_todo);
- } else if (test_and_clear_bit(ELM_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_CONFIG_PART2, &elm->cmds_todo)) {
+ sprintf(local_txbuf, "ATPB%04X\r",
+ elm->can_config);
- } else if (test_and_clear_bit(ELM_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.
- */
- sprintf(local_txbuf, "ATRTR\r");
- } else {
- /* Send a regular CAN data frame */
- int i;
+ } else if (test_and_clear_bit(ELM_TODO_CANID_29BIT_HIGH, &elm->cmds_todo)) {
+ sprintf(local_txbuf, "ATCP%02X\r",
+ (frame->can_id & CAN_EFF_MASK) >> 24);
- for (i = 0; i < frame->can_dlc; i++) {
- sprintf(&local_txbuf[2*i], "%02X",
- frame->data[i]);
- }
+ } else if (test_and_clear_bit(ELM_TODO_CANID_29BIT_LOW, &elm->cmds_todo)) {
+ sprintf(local_txbuf, "ATSH%06X\r",
+ frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1));
- sprintf(&local_txbuf[2*i], "\r");
+ } else if (test_and_clear_bit(ELM_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)) {
+ if (frame->can_id & CAN_RTR_FLAG) {
+ /* Send an RTR frame. Their DLC is fixed.
+ * Some chips don't send them at all.
+ */
+ sprintf(local_txbuf, "ATRTR\r");
+ } else {
+ /* Send a regular CAN data frame */
+ int i;
+
+ for (i = 0; i < frame->can_dlc; i++) {
+ sprintf(&local_txbuf[2*i], "%02X",
+ frame->data[i]);
}
- elm->drop_next_line = 1;
- elm->state = ELM_RECEIVING;
+ sprintf(&local_txbuf[2*i], "\r");
}
- elm327_send(elm, local_txbuf, strlen(local_txbuf));
- } else {
- /* Enter CAN monitor mode */
- elm327_send(elm, "ATMA\r", 5);
+ elm->drop_next_line = 1;
elm->state = ELM_RECEIVING;
}
+
+ elm327_send(elm, local_txbuf, strlen(local_txbuf));
}
case ELM_GETPROMPT:
/* Wait for '>' */
- if (elm327_is_ready_char(elm->rxbuf[elm->rxfill - 1])) {
+ if (elm327_is_ready_char(elm->rxbuf[elm->rxfill - 1]))
elm327_handle_prompt(elm);
- }
elm->rxfill = 0;
return;
/* Line exceeds buffer. It's probably all garbage.
* Did we even connect at the right baud rate?
*/
- netdev_err(elm->dev, "RX buffer overflow. Faulty ELM327 connected?\n");
+ netdev_err(elm->dev,
+ "RX buffer overflow. Faulty ELM327 or UART?\n");
elm327_hw_failure(elm);
return;
} else if (len == elm->rxfill) {
- if (elm->state == ELM_RECEIVING
- && elm327_is_ready_char(elm->rxbuf[elm->rxfill - 1])) {
+ if (elm327_is_ready_char(elm->rxbuf[elm->rxfill - 1])) {
/* The ELM327's AT ST response timeout ran out,
* so we got a prompt.
* Clear RX buffer and restart listening.
elm327_handle_prompt(elm);
return;
- } else {
- /* We haven't received a full line yet.
- * Wait for more data.
- */
- return;
}
+
+ /* No <CR> found - we haven't received a full line yet.
+ * Wait for more data.
+ */
+ return;
}
/* We have a full line to parse. */
elm327_drop_bytes(elm, len+1);
/* More data to parse? */
- if (elm->rxfill) {
+ if (elm->rxfill)
elm327_parse_rxbuf(elm);
- }
}
}
spin_lock_bh(&elm->lock);
if (elm->hw_failure) {
- netdev_err(elm->dev, "Refusing to open interface after "
- "a hardware fault has been detected.\n");
+ netdev_err(elm->dev, "Refusing to open interface after a hardware fault has been detected.\n");
spin_unlock_bh(&elm->lock);
return -EIO;
}
}
/* Send a can_frame to a TTY queue. */
-static netdev_tx_t elmcan_netdev_start_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t elmcan_netdev_start_xmit(struct sk_buff *skb,
+ struct net_device *dev)
{
struct elmcan *elm = netdev_priv(dev);
struct can_frame *frame = (struct can_frame *) skb->data;
* This is to ensure ordering in case we are shutting down, and to ensure
* there is a refcount at all (because tty->disc_data may be NULL).
*/
-static struct elmcan* get_elm(struct tty_struct *tty)
+static struct elmcan *get_elm(struct tty_struct *tty)
{
struct elmcan *elm;
bool got_ref;
got_ref = atomic_inc_not_zero(&elm->refcount);
spin_unlock_bh(&elmcan_discdata_lock);
- if (!got_ref) {
+ if (!got_ref)
return NULL;
- }
return elm;
}
* with the UART line.
*/
netdev_err(elm->dev,
- "Received illegal character %02x.\n",
- *cp);
+ "Received illegal character %02x.\n",
+ *cp);
elm327_hw_failure(elm);
spin_unlock_bh(&elm->lock);
actual = elm->tty->ops->write(elm->tty, elm->txhead, elm->txleft);
if (actual < 0) {
- netdev_err(elm->dev, "Failed to write to tty %s.\n", elm->tty->name);
+ netdev_err(elm->dev,
+ "Failed to write to tty %s.\n",
+ elm->tty->name);
elm327_hw_failure(elm);
spin_unlock_bh(&elm->lock);
return;
* Currently we don't implement support for 7/8 rates.
*/
static const u32 elmcan_bitrate_const[64] = {
- 7812, 7936, 8064, 8196, 8333, 8474, 8620, 8771,
- 8928, 9090, 9259, 9433, 9615, 9803, 10000, 10204,
+ 7812, 7936, 8064, 8196, 8333, 8474, 8620, 8771,
+ 8928, 9090, 9259, 9433, 9615, 9803, 10000, 10204,
10416, 10638, 10869, 11111, 11363, 11627, 11904, 12195,
12500, 12820, 13157, 13513, 13888, 14285, 14705, 15151,
15625, 16129, 16666, 17241, 17857, 18518, 19230, 20000,
put_elm(elm);
/* Spin until refcount reaches 0 */
- while(atomic_read(&elm->refcount) > 0)
- msleep(1);
+ while (atomic_read(&elm->refcount) > 0)
+ msleep_interruptible(10);
/* At this point, all ldisc calls to us will be no-ops.
* Since the refcount is 0, they are bailing immediately.
/* Fill in our line protocol discipline, and register it */
status = tty_register_ldisc(N_ELMCAN, &elmcan_ldisc);
- if (status) {
+ if (status)
pr_err("can't register line discipline\n");
- }
+
return status;
}
int status;
status = tty_unregister_ldisc(N_ELMCAN);
- if (status) {
- pr_err("Can't unregister line discipline (error: %d)\n", status);
- }
+ if (status)
+ pr_err("Can't unregister line discipline (error: %d)\n",
+ status);
}
module_init(elmcan_init);
projects / elmcan.git / commitdiff