diff options
| -rw-r--r-- | module/elmcan.c | 205 |
1 files changed, 81 insertions, 124 deletions
diff --git a/module/elmcan.c b/module/elmcan.c index 33b0add..ec37af8 100644 --- a/module/elmcan.c +++ b/module/elmcan.c @@ -1,6 +1,5 @@ // 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 @@ -14,7 +13,6 @@ #define pr_fmt(fmt) "[elmcan] " fmt - #include <linux/init.h> #include <linux/module.h> #include <linux/moduleparam.h> @@ -39,7 +37,6 @@ #include <linux/can/error.h> #include <linux/can/led.h> - MODULE_ALIAS_LDISC(N_ELMCAN); MODULE_DESCRIPTION("ELM327 based CAN interface"); MODULE_LICENSE("GPL"); @@ -54,7 +51,6 @@ 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."); - /* Line discipline ID number */ #ifndef N_ELMCAN #define N_ELMCAN 29 @@ -72,21 +68,19 @@ MODULE_PARM_DESC(accept_flaky_uart, "Don't bail at the first invalid character. #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; @@ -146,7 +140,6 @@ struct elmcan { 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. @@ -154,11 +147,8 @@ struct elmcan { */ static DEFINE_SPINLOCK(elmcan_discdata_lock); - static inline void elm327_hw_failure(struct elmcan *elm); - - /*********************************************************************** * ELM327: Transmission * * * @@ -186,8 +176,8 @@ static void elm327_send(struct elmcan *elm, const void *buf, size_t len) 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; } @@ -196,7 +186,6 @@ static void elm327_send(struct elmcan *elm, const void *buf, size_t len) 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 @@ -211,7 +200,6 @@ static void elm327_kick_into_cmd_mode(struct elmcan *elm) } } - /* 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) { @@ -227,29 +215,27 @@ 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 * * * @@ -278,7 +264,6 @@ static char *elm327_init_script[] = { NULL }; - static void elm327_init(struct elmcan *elm) { elm->state = ELM_NOTINIT; @@ -298,16 +283,14 @@ static void elm327_init(struct elmcan *elm) /* 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 * * * @@ -337,8 +320,6 @@ static void elm327_feed_frame_to_netdev(struct elmcan *elm, can_led_event(elm->dev, CAN_LED_EVENT_RX); } - - /*********************************************************************** * ELM327: "Panic" handler * * * @@ -364,8 +345,6 @@ static inline void elm327_hw_failure(struct elmcan *elm) can_bus_off(elm->dev); } - - /*********************************************************************** * ELM327: Reception parser * * * @@ -384,7 +363,7 @@ static void elm327_parse_error(struct elmcan *elm, int 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"); + "The ELM327 reported UNABLE TO CONNECT. Please check your setup.\n"); } break; case 11: @@ -419,7 +398,7 @@ static void elm327_parse_error(struct elmcan *elm, int len) 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; @@ -431,7 +410,6 @@ static void elm327_parse_error(struct elmcan *elm, int len) elm327_feed_frame_to_netdev(elm, &frame); } - /* Parse CAN frames coming as ASCII from ELM327. * They can be of various formats: * @@ -459,8 +437,8 @@ static int elm327_parse_frame(struct elmcan *elm, int len) * - 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; } } @@ -469,12 +447,12 @@ static int elm327_parse_frame(struct elmcan *elm, int len) * 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. */ @@ -486,9 +464,9 @@ static int elm327_parse_frame(struct elmcan *elm, int len) * 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] == ' ') { @@ -532,16 +510,16 @@ static int elm327_parse_frame(struct elmcan *elm, int len) } /* 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. @@ -562,8 +540,8 @@ static int elm327_parse_frame(struct elmcan *elm, int len) /* 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. */ @@ -572,7 +550,6 @@ static int elm327_parse_frame(struct elmcan *elm, int len) return 0; } - static void elm327_parse_line(struct elmcan *elm, int len) { /* Skip empty lines */ @@ -617,44 +594,44 @@ static void elm327_handle_prompt(struct elmcan *elm) } /* 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. @@ -665,11 +642,11 @@ static void elm327_handle_prompt(struct elmcan *elm) 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; @@ -679,7 +656,6 @@ static void elm327_handle_prompt(struct elmcan *elm) 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. @@ -747,7 +723,7 @@ static void elm327_parse_rxbuf(struct elmcan *elm) * 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) { @@ -772,7 +748,7 @@ static void elm327_parse_rxbuf(struct elmcan *elm) 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) @@ -780,10 +756,6 @@ static void elm327_parse_rxbuf(struct elmcan *elm) } } - - - - /*********************************************************************** * netdev * * * @@ -802,7 +774,7 @@ static int elmcan_netdev_open(struct net_device *dev) return -EIO; } - if (elm->tty == NULL) { + if (!elm->tty) { spin_unlock_bh(&elm->lock); return -ENODEV; } @@ -858,7 +830,7 @@ 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; + struct can_frame *frame = (struct can_frame *)skb->data; if (skb->len != sizeof(struct can_frame)) goto out; @@ -878,9 +850,9 @@ static netdev_tx_t elmcan_netdev_start_xmit(struct sk_buff *skb, */ 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; } @@ -900,7 +872,6 @@ out: return NETDEV_TX_OK; } - static const struct net_device_ops elmcan_netdev_ops = { .ndo_open = elmcan_netdev_open, .ndo_stop = elmcan_netdev_close, @@ -908,10 +879,6 @@ static const struct net_device_ops elmcan_netdev_ops = { .ndo_change_mtu = can_change_mtu, }; - - - - /*********************************************************************** * Line discipline * * * @@ -930,7 +897,7 @@ static struct elmcan *get_elm(struct tty_struct *tty) 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); @@ -951,22 +918,21 @@ static void put_elm(struct elmcan *elm) 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. @@ -974,7 +940,7 @@ static bool elmcan_is_valid_rx_char(char c) * 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); @@ -983,9 +949,8 @@ static void elmcan_ldisc_rx(struct tty_struct *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++) { @@ -1035,7 +1000,6 @@ out: put_elm(elm); } - /* Write out remaining transmit buffer. * Scheduled when TTY is writable. */ @@ -1096,7 +1060,6 @@ static void elmcan_ldisc_tx_wakeup(struct tty_struct *tty) 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. @@ -1112,7 +1075,6 @@ static const u32 elmcan_bitrate_const[64] = { 62500, 71428, 83333, 100000, 125000, 166666, 250000, 500000 }; - /* Dummy needed to use bitrate_const */ static int elmcan_do_set_bittiming(struct net_device *netdev) { @@ -1121,7 +1083,6 @@ 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; @@ -1134,7 +1095,6 @@ static int elmcan_ldisc_open(struct tty_struct *tty) if (!tty->ops->write) return -EOPNOTSUPP; - dev = alloc_candev(sizeof(struct elmcan), 0); if (!dev) return -ENFILE; @@ -1180,8 +1140,7 @@ static int elmcan_ldisc_open(struct tty_struct *tty) return 0; out_err: - if (elm->txbuf) - kfree(elm->txbuf); + kfree(elm->txbuf); free_candev(elm->dev); return err; } @@ -1236,7 +1195,7 @@ static int elmcan_ldisc_hangup(struct tty_struct *tty) } 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; @@ -1277,8 +1236,6 @@ static struct tty_ldisc_ops elmcan_ldisc = { .ioctl = elmcan_ldisc_ioctl, }; - - static int __init elmcan_init(void) { int status; |