X-Git-Url: https://git.enpas.org/?a=blobdiff_plain;f=module%2Felmcan.c;h=4409642df1cbc1edcae56b3f92182ad1a93c56f4;hb=978a5f0b7752e110fd03936f3886e2afaf19eb27;hp=e07ecbc6b00879252c78b6e291bf6a05c4765215;hpb=08ace76b59ec1c409680165ea2286ab0fef63cc6;p=elmcan.git diff --git a/module/elmcan.c b/module/elmcan.c index e07ecbc..4409642 100644 --- a/module/elmcan.c +++ b/module/elmcan.c @@ -1,17 +1,16 @@ // SPDX-License-Identifier: GPL-2.0 -/* elmcan.c - ELM327 based CAN interface driver - * (tty line discipline) +/* ELM327 based CAN interface driver (tty line discipline) * - * This file is derived from linux/drivers/net/can/slcan.c + * This driver started as a derivative of linux/drivers/net/can/slcan.c + * and my thanks go to the original authors for their inspiration. * * elmcan.c Author : Max Staudt * slcan.c Author : Oliver Hartkopp * slip.c Authors : Laurence Culhane * Fred N. van Kempen - * */ -#define pr_fmt(fmt) "[elmcan] " fmt +#define pr_fmt(fmt) "elmcan: " fmt #include #include @@ -25,38 +24,40 @@ #include #include #include +#include #include #include #include #include #include +#include +#include #include +#include + #include #include #include #include +#include -MODULE_ALIAS_LDISC(N_ELMCAN); -MODULE_DESCRIPTION("ELM327 based CAN interface"); -MODULE_LICENSE("GPL"); -MODULE_AUTHOR("Max Staudt "); - -/* If this is enabled, we'll try to make the best of the situation - * even if we receive unexpected characters on the line. - * No guarantees. - * Handle with care, it's likely your hardware is unreliable! +/* Line discipline ID number. + * Starting with Linux v5.18-rc1, N_DEVELOPMENT is defined as 29: + * https://github.com/torvalds/linux/commit/c2faf737abfb10f88f2d2612d573e9edc3c42c37 */ -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."); +#ifndef N_DEVELOPMENT +#define N_DEVELOPMENT 29 +#endif -/* Line discipline ID number */ -#ifndef N_ELMCAN -#define N_ELMCAN 29 +/* Compatibility for Linux < 5.11 */ +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,11,0) +#define len can_dlc #endif -#define ELM327_SIZE_RXBUF 256 +#define ELM327_NAPI_WEIGHT 4 + +#define ELM327_SIZE_RXBUF 224 #define ELM327_SIZE_TXBUF 32 #define ELM327_CAN_CONFIG_SEND_SFF 0x8000 @@ -64,150 +65,132 @@ MODULE_PARM_DESC(accept_flaky_uart, "Don't bail at the first invalid character. #define ELM327_CAN_CONFIG_RECV_BOTH_SFF_EFF 0x2000 #define ELM327_CAN_CONFIG_BAUDRATE_MULT_8_7 0x1000 -#define ELM327_MAGIC_CHAR 'y' -#define ELM327_MAGIC_STRING "y" +#define ELM327_DUMMY_CHAR 'y' +#define ELM327_DUMMY_STRING "y" #define ELM327_READY_CHAR '>' /* Bits in elm->cmds_todo */ -enum ELM_TODO { - 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 +enum elm327_to_to_do_bits { + ELM327_TX_DO_CAN_DATA = 0, + ELM327_TX_DO_CANID_11BIT, + ELM327_TX_DO_CANID_29BIT_LOW, + ELM327_TX_DO_CANID_29BIT_HIGH, + ELM327_TX_DO_CAN_CONFIG_PART2, + ELM327_TX_DO_CAN_CONFIG, + ELM327_TX_DO_RESPONSES, + ELM327_TX_DO_SILENT_MONITOR, + ELM327_TX_DO_INIT }; struct elmcan { /* This must be the first member when using alloc_candev() */ struct can_priv can; - /* TTY and netdev devices that we're bridging */ - struct tty_struct *tty; - struct net_device *dev; + struct can_rx_offload offload; - /* Per-channel lock */ - spinlock_t lock; - - /* Keep track of how many things are using this struct. - * Once it reaches 0, we are in the process of cleaning up, - * and new operations will be cancelled immediately. - * Use atomic_t rather than refcount_t because we deliberately - * decrement to 0, and refcount_dec() spills a WARN_ONCE in - * that case. - */ - atomic_t refcount; + /* TTY buffers */ + u8 rxbuf[ELM327_SIZE_RXBUF]; + u8 txbuf[ELM327_SIZE_TXBUF] ____cacheline_aligned; - /* Stop the channel on hardware failure. - * Once this is true, nothing will be sent to the TTY. - */ - bool hw_failure; + /* TTY buffer accounting */ + struct work_struct tx_work; /* Flushes TTY TX buffer */ + u8 *txhead; /* Next TX byte */ + unsigned txleft; /* Bytes left to TX */ + int rxfill; /* Bytes already RX'd in buffer */ - /* TTY TX helpers */ - struct work_struct tx_work; /* Flushes TTY TX buffer */ - unsigned char *txbuf; - unsigned char *txhead; /* Pointer to next TX byte */ - int txleft; /* Bytes left to TX */ + /* TTY and netdev devices that we're bridging */ + struct tty_struct *tty; + struct net_device *dev; - /* TTY RX helpers */ - unsigned char rxbuf[ELM327_SIZE_RXBUF]; - int rxfill; + /* Per-channel lock */ + spinlock_t lock; /* State machine */ enum { - ELM_NOTINIT = 0, - ELM_GETMAGICCHAR, - ELM_GETPROMPT, - ELM_RECEIVING, + ELM327_STATE_NOTINIT = 0, + ELM327_STATE_GETDUMMYCHAR, + ELM327_STATE_GETPROMPT, + ELM327_STATE_RECEIVING, } state; - int drop_next_line; + /* Things we have yet to send */ + char **next_init_cmd; + unsigned long cmds_todo; /* The CAN frame and config the ELM327 is sending/using, * or will send/use after finishing all cmds_todo */ - struct can_frame can_frame; - unsigned short can_config; - unsigned long can_bitrate; - unsigned char can_bitrate_divisor; - int silent_monitoring; + struct can_frame can_frame_to_send; + u16 can_config; + u8 can_bitrate_divisor; - /* Things we have yet to send */ - char **next_init_cmd; - 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. - * Without this, we cannot do a clean shutdown. - */ -static DEFINE_SPINLOCK(elmcan_discdata_lock); + /* Parser state */ + bool drop_next_line; -static inline void elm327_hw_failure(struct elmcan *elm); + /* 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 uart_side_failure; +}; - /*********************************************************************** - * ELM327: Transmission * - * * - * (all functions assume elm->lock taken) * - ***********************************************************************/ +static inline void elm327_uart_side_failure(struct elmcan *elm); static void elm327_send(struct elmcan *elm, const void *buf, size_t len) { - int actual; + int written; + + lockdep_assert_held(elm->lock); - if (elm->hw_failure) + if (elm->uart_side_failure) return; memcpy(elm->txbuf, buf, len); - /* Order of next two lines is *very* important. - * When we are sending a little amount of data, - * the transfer may be completed inside the ops->write() - * routine, because it's running with interrupts enabled. - * In this case we *never* got WRITE_WAKEUP event, - * if we did not request it before write operation. - * 14 Oct 1994 Dmitry Gorodchanin. - */ - set_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags); - actual = elm->tty->ops->write(elm->tty, elm->txbuf, len); - if (actual < 0) { + written = elm->tty->ops->write(elm->tty, elm->txbuf, len); + if (written < 0) { netdev_err(elm->dev, "Failed to write to tty %s.\n", elm->tty->name); - elm327_hw_failure(elm); + elm327_uart_side_failure(elm); return; } - elm->txleft = len - actual; - elm->txhead = elm->txbuf + actual; + elm->txleft = len - written; + elm->txhead = elm->txbuf + written; + + if (elm->txleft) + set_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags); } /* Take the ELM327 out of almost any state and back into command mode. - * We send ELM327_MAGIC_CHAR which will either abort any running + * We send ELM327_DUMMY_CHAR which will either abort any running * operation, or be echoed back to us in case we're already in command * mode. */ static void elm327_kick_into_cmd_mode(struct elmcan *elm) { - if (elm->state != ELM_GETMAGICCHAR && elm->state != ELM_GETPROMPT) { - elm327_send(elm, ELM327_MAGIC_STRING, 1); + lockdep_assert_held(elm->lock); - elm->state = ELM_GETMAGICCHAR; + if (elm->state != ELM327_STATE_GETDUMMYCHAR && + elm->state != ELM327_STATE_GETPROMPT) { + elm327_send(elm, ELM327_DUMMY_STRING, 1); + + elm->state = ELM327_STATE_GETDUMMYCHAR; } } /* 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) { + lockdep_assert_held(elm->lock); + /* Schedule any necessary changes in ELM327's CAN configuration */ - if (elm->can_frame.can_id != frame->can_id) { + if (elm->can_frame_to_send.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)) { + if ((frame->can_id & CAN_EFF_FLAG) ^ + (elm->can_frame_to_send.can_id & CAN_EFF_FLAG)) { elm->can_config = (frame->can_id & CAN_EFF_FLAG ? 0 : ELM327_CAN_CONFIG_SEND_SFF) @@ -215,39 +198,36 @@ 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(TODO_CAN_CONFIG, &elm->cmds_todo); + set_bit(ELM327_TX_DO_CAN_CONFIG, &elm->cmds_todo); } if (frame->can_id & CAN_EFF_FLAG) { - 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); + clear_bit(ELM327_TX_DO_CANID_11BIT, &elm->cmds_todo); + set_bit(ELM327_TX_DO_CANID_29BIT_LOW, &elm->cmds_todo); + set_bit(ELM327_TX_DO_CANID_29BIT_HIGH, &elm->cmds_todo); } else { - 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); + set_bit(ELM327_TX_DO_CANID_11BIT, &elm->cmds_todo); + clear_bit(ELM327_TX_DO_CANID_29BIT_LOW, &elm->cmds_todo); + clear_bit(ELM327_TX_DO_CANID_29BIT_HIGH, &elm->cmds_todo); } } /* Schedule the CAN frame itself. */ - elm->can_frame = *frame; - set_bit(TODO_CAN_DATA, &elm->cmds_todo); + elm->can_frame_to_send = *frame; + set_bit(ELM327_TX_DO_CAN_DATA, &elm->cmds_todo); elm327_kick_into_cmd_mode(elm); } - /*********************************************************************** - * ELM327: Initialization sequence * - * * - * (assumes elm->lock taken) * - ***********************************************************************/ - +/* 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 */ "AT M0\r", /* v1.0: Memory Off */ "AT AL\r", /* v1.0: Allow Long messages */ - "AT BI\r", /* v1.0: Bypass Initialization */ + "AT BI\r", /* v1.0: Bypass Initialisation */ "AT CAF0\r", /* v1.0: CAN Auto Formatting Off */ "AT CFC0\r", /* v1.0: CAN Flow Control Off */ "AT CF 000\r", /* v1.0: Reset CAN ID Filter */ @@ -266,8 +246,10 @@ static char *elm327_init_script[] = { static void elm327_init(struct elmcan *elm) { - elm->state = ELM_NOTINIT; - elm->can_frame.can_id = 0x7df; + lockdep_assert_held(elm->lock); + + elm->state = ELM327_STATE_NOTINIT; + elm->can_frame_to_send.can_id = 0x7df; /* ELM327 HW default */ elm->rxfill = 0; elm->drop_next_line = 0; @@ -283,131 +265,126 @@ static void elm327_init(struct elmcan *elm) /* Configure ELM327 and then start monitoring */ elm->next_init_cmd = &elm327_init_script[0]; - 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); + set_bit(ELM327_TX_DO_INIT, &elm->cmds_todo); + set_bit(ELM327_TX_DO_SILENT_MONITOR, &elm->cmds_todo); + set_bit(ELM327_TX_DO_RESPONSES, &elm->cmds_todo); + set_bit(ELM327_TX_DO_CAN_CONFIG, &elm->cmds_todo); elm327_kick_into_cmd_mode(elm); } - /*********************************************************************** - * ELM327: Reception -> netdev glue * - * * - * (assumes elm->lock taken) * - ***********************************************************************/ - static void elm327_feed_frame_to_netdev(struct elmcan *elm, - const struct can_frame *frame) + struct sk_buff *skb) { - struct can_frame *cf; - struct sk_buff *skb; + lockdep_assert_held(elm->lock); if (!netif_running(elm->dev)) return; - skb = alloc_can_skb(elm->dev, &cf); - - if (!skb) - return; - - memcpy(cf, frame, sizeof(struct can_frame)); - - elm->dev->stats.rx_packets++; - elm->dev->stats.rx_bytes += frame->can_dlc; - netif_rx_ni(skb); + /* Queue for NAPI pickup. + * rx-offload will update stats and LEDs for us. + */ + if (can_rx_offload_queue_tail(&elm->offload, skb)) + elm->dev->stats.rx_fifo_errors++; - can_led_event(elm->dev, CAN_LED_EVENT_RX); +#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,15,0) + /* Wake NAPI */ + can_rx_offload_irq_finish(&elm->offload); +#endif } - /*********************************************************************** - * ELM327: "Panic" handler * - * * - * (assumes elm->lock taken) * - ***********************************************************************/ - /* 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 can_frame *frame; + struct sk_buff *skb; - memset(&frame, 0, sizeof(frame)); - frame.can_id = CAN_ERR_FLAG; - frame.can_dlc = CAN_ERR_DLC; - frame.data[5] = 'R'; - frame.data[6] = 'I'; - frame.data[7] = 'P'; - elm327_feed_frame_to_netdev(elm, &frame); + lockdep_assert_held(elm->lock); - netdev_err(elm->dev, "ELM327 misbehaved. Blocking further communication.\n"); + elm->uart_side_failure = true; - elm->hw_failure = true; + elm->can.can_stats.bus_off++; + netif_stop_queue(elm->dev); + elm->can.state = CAN_STATE_BUS_OFF; can_bus_off(elm->dev); + + netdev_err(elm->dev, "ELM327 misbehaved. Blocking further communication.\n"); + + skb = alloc_can_err_skb(elm->dev, &frame); + if (!skb) + return; + + frame->can_id |= CAN_ERR_BUSOFF; + elm327_feed_frame_to_netdev(elm, skb); } - /*********************************************************************** - * ELM327: Reception parser * - * * - * (assumes elm->lock taken) * - ***********************************************************************/ +/* Compare buffer to string length, then compare buffer to fixed string. + * This ensures two things: + * - It flags cases where the fixed string is only the start of the + * buffer, rather than exactly all of it. + * - It avoids byte comparisons in case the length doesn't match. + * + * strncmp() cannot be used here because it accepts the following wrong case: + * strncmp("CAN ER", "CAN ERROR", 6); + * This must fail, hence this helper function. + */ +static inline int check_len_then_cmp(const u8 *mem, size_t mem_len, const char *str) +{ + size_t str_len = strlen(str); -static void elm327_parse_error(struct elmcan *elm, int len) + return (mem_len == str_len) && !memcmp(mem, str, str_len); +} + +static void elm327_parse_error(struct elmcan *elm, size_t len) { - struct can_frame frame; + struct can_frame *frame; + struct sk_buff *skb; - memset(&frame, 0, sizeof(frame)); - frame.can_id = CAN_ERR_FLAG; - frame.can_dlc = CAN_ERR_DLC; + lockdep_assert_held(elm->lock); - switch (len) { - case 17: - if (!memcmp(elm->rxbuf, "UNABLE TO CONNECT", 17)) { - netdev_err(elm->dev, - "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 heuristically - * emit this 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, "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, "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 */ + skb = alloc_can_err_skb(elm->dev, &frame); + if (!skb) + /* It's okay to return here: + * The outer parsing loop will drop this UART buffer. + */ return; + + /* Filter possible error messages based on length of RX'd line */ + if (check_len_then_cmp(elm->rxbuf, len, "UNABLE TO CONNECT")) { + netdev_err(elm->dev, + "ELM327 reported UNABLE TO CONNECT. Please check your setup.\n"); + } else if (check_len_then_cmp(elm->rxbuf, len, "BUFFER FULL")) { + /* This will only happen if the last data line was complete. + * Otherwise, elm327_parse_frame() will heuristically + * emit this kind of error frame instead. + */ + frame->can_id |= CAN_ERR_CRTL; + frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW; + } else if (check_len_then_cmp(elm->rxbuf, len, "BUS ERROR")) { + frame->can_id |= CAN_ERR_BUSERROR; + } else if (check_len_then_cmp(elm->rxbuf, len, "CAN ERROR")) { + frame->can_id |= CAN_ERR_PROT; + } else if (check_len_then_cmp(elm->rxbuf, len, "can_id |= CAN_ERR_PROT; + } else if (check_len_then_cmp(elm->rxbuf, len, "BUS BUSY")) { + frame->can_id |= CAN_ERR_PROT; + frame->data[2] = CAN_ERR_PROT_OVERLOAD; + } else if (check_len_then_cmp(elm->rxbuf, len, "FB ERROR")) { + frame->can_id |= CAN_ERR_PROT; + frame->data[2] = CAN_ERR_PROT_TX; + } else if (len == 5 && !memcmp(elm->rxbuf, "ERR", 3)) { + /* ERR is followed by two digits, hence line length 5 */ + netdev_err(elm->dev, "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; + } else { + /* Something else has happened. + * Maybe garbage on the UART line. + * Emit a generic error frame. + */ } - elm327_feed_frame_to_netdev(elm, &frame); + elm327_feed_frame_to_netdev(elm, skb); } /* Parse CAN frames coming as ASCII from ELM327. @@ -422,14 +399,19 @@ static void elm327_parse_error(struct elmcan *elm, int len) * * We will use the spaces and line length to guess the format. */ -static int elm327_parse_frame(struct elmcan *elm, int len) +static int elm327_parse_frame(struct elmcan *elm, size_t len) { - struct can_frame frame; + struct can_frame *frame; + struct sk_buff *skb; int hexlen; int datastart; int i; - memset(&frame, 0, sizeof(frame)); + lockdep_assert_held(elm->lock); + + skb = alloc_can_skb(elm->dev, &frame); + if (!skb) + return -ENOMEM; /* Find first non-hex and non-space character: * - In the simplest case, there is none. @@ -443,12 +425,10 @@ static int elm327_parse_frame(struct elmcan *elm, int len) } } - /* If we accept stray characters coming in: - * Check for stray characters on a payload line. - * No idea what causes this. + /* Sanity check whether the line is really a clean hexdump, + * or terminated by an error message, or contains garbage. */ - if (accept_flaky_uart && - hexlen < len && + if (hexlen < len && !isdigit(elm->rxbuf[hexlen]) && !isupper(elm->rxbuf[hexlen]) && '<' != elm->rxbuf[hexlen] && @@ -456,7 +436,6 @@ static int elm327_parse_frame(struct elmcan *elm, int len) /* The line is likely garbled anyway, so bail. * The main code will restart listening. */ - elm327_kick_into_cmd_mode(elm); return -ENODATA; } @@ -467,10 +446,9 @@ static int elm327_parse_frame(struct elmcan *elm, int len) if (elm->rxbuf[2] == ' ' && elm->rxbuf[5] == ' ' && elm->rxbuf[8] == ' ' && elm->rxbuf[11] == ' ' && elm->rxbuf[13] == ' ') { - frame.can_id = CAN_EFF_FLAG; + frame->can_id = CAN_EFF_FLAG; datastart = 14; } else if (elm->rxbuf[3] == ' ' && elm->rxbuf[5] == ' ') { - frame.can_id = 0; datastart = 6; } else { /* This is not a well-formatted data line. @@ -491,44 +469,43 @@ static int elm327_parse_frame(struct elmcan *elm, int len) */ /* Read CAN data length */ - frame.can_dlc = (hex_to_bin(elm->rxbuf[datastart - 2]) << 0); + frame->len = (hex_to_bin(elm->rxbuf[datastart - 2]) << 0); /* Read CAN ID */ - if (frame.can_id & CAN_EFF_FLAG) { - frame.can_id |= (hex_to_bin(elm->rxbuf[0]) << 28) - | (hex_to_bin(elm->rxbuf[1]) << 24) - | (hex_to_bin(elm->rxbuf[3]) << 20) - | (hex_to_bin(elm->rxbuf[4]) << 16) - | (hex_to_bin(elm->rxbuf[6]) << 12) - | (hex_to_bin(elm->rxbuf[7]) << 8) - | (hex_to_bin(elm->rxbuf[9]) << 4) - | (hex_to_bin(elm->rxbuf[10]) << 0); + if (frame->can_id & CAN_EFF_FLAG) { + frame->can_id |= (hex_to_bin(elm->rxbuf[0]) << 28) + | (hex_to_bin(elm->rxbuf[1]) << 24) + | (hex_to_bin(elm->rxbuf[3]) << 20) + | (hex_to_bin(elm->rxbuf[4]) << 16) + | (hex_to_bin(elm->rxbuf[6]) << 12) + | (hex_to_bin(elm->rxbuf[7]) << 8) + | (hex_to_bin(elm->rxbuf[9]) << 4) + | (hex_to_bin(elm->rxbuf[10]) << 0); } else { - frame.can_id |= (hex_to_bin(elm->rxbuf[0]) << 8) - | (hex_to_bin(elm->rxbuf[1]) << 4) - | (hex_to_bin(elm->rxbuf[2]) << 0); + frame->can_id |= (hex_to_bin(elm->rxbuf[0]) << 8) + | (hex_to_bin(elm->rxbuf[1]) << 4) + | (hex_to_bin(elm->rxbuf[2]) << 0); } /* Check for RTR frame */ if (elm->rxfill >= hexlen + 3 && !memcmp(&elm->rxbuf[hexlen], "RTR", 3)) { - frame.can_id |= CAN_RTR_FLAG; + 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)) { - /* Incomplete frame. */ - - /* Probably the ELM327's RS232 TX buffer was full. + if (!(frame->can_id & CAN_RTR_FLAG) && + (hexlen < frame->len * 3 + datastart)) { + /* Incomplete frame. + * Probably the ELM327's RS232 TX buffer was full. * Emit an error frame and exit. */ - frame.can_id = CAN_ERR_FLAG | CAN_ERR_CRTL; - frame.can_dlc = CAN_ERR_DLC; - frame.data[1] = CAN_ERR_CRTL_RX_OVERFLOW; - elm327_feed_frame_to_netdev(elm, &frame); + frame->can_id = CAN_ERR_FLAG | CAN_ERR_CRTL; + frame->len = CAN_ERR_DLC; + frame->data[1] = CAN_ERR_CRTL_RX_OVERFLOW; + elm327_feed_frame_to_netdev(elm, skb); /* Signal failure to parse. * The line will be re-parsed as an error line, which will fail. @@ -539,19 +516,21 @@ 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])); + for (i = 0; i < frame->len; i++) { + 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. */ - elm327_feed_frame_to_netdev(elm, &frame); + elm327_feed_frame_to_netdev(elm, skb); return 0; } -static void elm327_parse_line(struct elmcan *elm, int len) +static void elm327_parse_line(struct elmcan *elm, size_t len) { + lockdep_assert_held(elm->lock); + /* Skip empty lines */ if (!len) return; @@ -560,97 +539,120 @@ static void elm327_parse_line(struct elmcan *elm, int len) if (elm->drop_next_line) { elm->drop_next_line = 0; return; - } else if (elm->rxbuf[0] == 'A' && elm->rxbuf[1] == 'T') { + } else if (!memcmp(elm->rxbuf, "AT", 2)) { return; } /* Regular parsing */ - switch (elm->state) { - case ELM_RECEIVING: - if (elm327_parse_frame(elm, len)) { - /* Parse an error line. */ - elm327_parse_error(elm, len); + if (elm->state == ELM327_STATE_RECEIVING + && 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; + /* Start afresh. */ + elm327_kick_into_cmd_mode(elm); } } static void elm327_handle_prompt(struct elmcan *elm) { - struct can_frame *frame = &elm->can_frame; - char local_txbuf[20]; + struct can_frame *frame = &elm->can_frame_to_send; + /* 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); if (!elm->cmds_todo) { /* Enter CAN monitor mode */ elm327_send(elm, "ATMA\r", 5); - elm->state = ELM_RECEIVING; + elm->state = ELM327_STATE_RECEIVING; + + /* We will be in the default state once this command is + * send, so enable the TX packet queue. + */ + netif_wake_queue(elm->dev); return; } /* Reconfigure ELM327 step by step as indicated by elm->cmds_todo */ - if (test_bit(TODO_INIT, &elm->cmds_todo)) { - strcpy(local_txbuf, *elm->next_init_cmd); + if (test_bit(ELM327_TX_DO_INIT, &elm->cmds_todo)) { + snprintf(local_txbuf, sizeof(local_txbuf), + "%s", + *elm->next_init_cmd); elm->next_init_cmd++; if (!(*elm->next_init_cmd)) { - clear_bit(TODO_INIT, &elm->cmds_todo); - netdev_info(elm->dev, "Initialization finished.\n"); + clear_bit(ELM327_TX_DO_INIT, &elm->cmds_todo); + /* Init finished. */ } - } else if (test_and_clear_bit(TODO_SILENT_MONITOR, &elm->cmds_todo)) { - sprintf(local_txbuf, "ATCSM%i\r", + } else if (test_and_clear_bit(ELM327_TX_DO_SILENT_MONITOR, &elm->cmds_todo)) { + snprintf(local_txbuf, sizeof(local_txbuf), + "ATCSM%i\r", !(!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))); - } else if (test_and_clear_bit(TODO_RESPONSES, &elm->cmds_todo)) { - sprintf(local_txbuf, "ATR%i\r", + } else if (test_and_clear_bit(ELM327_TX_DO_RESPONSES, &elm->cmds_todo)) { + snprintf(local_txbuf, sizeof(local_txbuf), + "ATR%i\r", !(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)); - } else if (test_and_clear_bit(TODO_CAN_CONFIG, &elm->cmds_todo)) { - sprintf(local_txbuf, "ATPC\r"); - set_bit(TODO_CAN_CONFIG_PART2, &elm->cmds_todo); + } else if (test_and_clear_bit(ELM327_TX_DO_CAN_CONFIG, &elm->cmds_todo)) { + 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(TODO_CAN_CONFIG_PART2, &elm->cmds_todo)) { - sprintf(local_txbuf, "ATPB%04X\r", + } else if (test_and_clear_bit(ELM327_TX_DO_CAN_CONFIG_PART2, &elm->cmds_todo)) { + snprintf(local_txbuf, sizeof(local_txbuf), + "ATPB%04X\r", elm->can_config); - } else if (test_and_clear_bit(TODO_CANID_29BIT_HIGH, &elm->cmds_todo)) { - sprintf(local_txbuf, "ATCP%02X\r", + } else if (test_and_clear_bit(ELM327_TX_DO_CANID_29BIT_HIGH, &elm->cmds_todo)) { + snprintf(local_txbuf, sizeof(local_txbuf), + "ATCP%02X\r", (frame->can_id & CAN_EFF_MASK) >> 24); - } else if (test_and_clear_bit(TODO_CANID_29BIT_LOW, &elm->cmds_todo)) { - sprintf(local_txbuf, "ATSH%06X\r", + } else if (test_and_clear_bit(ELM327_TX_DO_CANID_29BIT_LOW, &elm->cmds_todo)) { + snprintf(local_txbuf, sizeof(local_txbuf), + "ATSH%06X\r", frame->can_id & CAN_EFF_MASK & ((1 << 24) - 1)); - } else if (test_and_clear_bit(TODO_CANID_11BIT, &elm->cmds_todo)) { - sprintf(local_txbuf, "ATSH%03X\r", + } else if (test_and_clear_bit(ELM327_TX_DO_CANID_11BIT, &elm->cmds_todo)) { + snprintf(local_txbuf, sizeof(local_txbuf), + "ATSH%03X\r", frame->can_id & CAN_SFF_MASK); - } else if (test_and_clear_bit(TODO_CAN_DATA, &elm->cmds_todo)) { + } else if (test_and_clear_bit(ELM327_TX_DO_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"); + snprintf(local_txbuf, sizeof(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", + for (i = 0; i < frame->len; i++) { + 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; - elm->state = ELM_RECEIVING; + elm->state = ELM327_STATE_RECEIVING; + + /* We will be in the default state once this command is + * send, so enable the TX packet queue. + */ + netif_wake_queue(elm->dev); } elm327_send(elm, local_txbuf, strlen(local_txbuf)); @@ -664,34 +666,37 @@ static bool elm327_is_ready_char(char c) return (c & 0x3f) == ELM327_READY_CHAR; } -static void elm327_drop_bytes(struct elmcan *elm, int i) +static void elm327_drop_bytes(struct elmcan *elm, size_t i) { + lockdep_assert_held(elm->lock); + memmove(&elm->rxbuf[0], &elm->rxbuf[i], ELM327_SIZE_RXBUF - i); elm->rxfill -= i; } static void elm327_parse_rxbuf(struct elmcan *elm) { - int len; + size_t len; + int i; + + lockdep_assert_held(elm->lock); switch (elm->state) { - case ELM_NOTINIT: + case ELM327_STATE_NOTINIT: elm->rxfill = 0; break; - case ELM_GETMAGICCHAR: + case ELM327_STATE_GETDUMMYCHAR: { /* Wait for 'y' or '>' */ - int i; - for (i = 0; i < elm->rxfill; i++) { - if (elm->rxbuf[i] == ELM327_MAGIC_CHAR) { + if (elm->rxbuf[i] == ELM327_DUMMY_CHAR) { elm327_send(elm, "\r", 1); - elm->state = ELM_GETPROMPT; + elm->state = ELM327_STATE_GETPROMPT; i++; break; } else if (elm327_is_ready_char(elm->rxbuf[i])) { - elm327_send(elm, ELM327_MAGIC_STRING, 1); + elm327_send(elm, ELM327_DUMMY_STRING, 1); i++; break; } @@ -702,7 +707,7 @@ static void elm327_parse_rxbuf(struct elmcan *elm) break; } - case ELM_GETPROMPT: + case ELM327_STATE_GETPROMPT: /* Wait for '>' */ if (elm327_is_ready_char(elm->rxbuf[elm->rxfill - 1])) elm327_handle_prompt(elm); @@ -710,7 +715,7 @@ static void elm327_parse_rxbuf(struct elmcan *elm) elm->rxfill = 0; break; - case ELM_RECEIVING: + case ELM327_STATE_RECEIVING: /* Find delimiting feedback lines. */ for (len = 0; (len < elm->rxfill) && (elm->rxbuf[len] != '\r'); @@ -724,7 +729,7 @@ static void elm327_parse_rxbuf(struct elmcan *elm) */ 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])) { @@ -756,11 +761,17 @@ static void elm327_parse_rxbuf(struct elmcan *elm) } } - /*********************************************************************** - * netdev * - * * - * (takes elm->lock) * - ***********************************************************************/ +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,10,0) +/* Dummy needed to use can_rx_offload */ +static struct sk_buff *elmcan_mailbox_read(struct can_rx_offload *offload, + unsigned int n, u32 *timestamp, + bool drop) +{ + WARN_ON_ONCE(1); /* This function is a dummy, so don't call it! */ + + return ERR_PTR(-ENOBUFS); +} +#endif static int elmcan_netdev_open(struct net_device *dev) { @@ -768,17 +779,19 @@ static int elmcan_netdev_open(struct net_device *dev) int err; 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"); - spin_unlock_bh(&elm->lock); - return -EIO; - } if (!elm->tty) { spin_unlock_bh(&elm->lock); return -ENODEV; } + if (elm->uart_side_failure) + netdev_warn(elm->dev, "Reopening netdev after a UART side fault has been detected.\n"); + + /* Clear TTY buffers */ + elm->rxfill = 0; + elm->txleft = 0; + /* open_candev() checks for elm->can.bittiming.bitrate != 0 */ err = open_candev(dev); if (err) { @@ -789,6 +802,19 @@ static int elmcan_netdev_open(struct net_device *dev) elm327_init(elm); spin_unlock_bh(&elm->lock); +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,10,0) + elm->offload.mailbox_read = elmcan_mailbox_read; + err = can_rx_offload_add_fifo(dev, &elm->offload, ELM327_NAPI_WEIGHT); +#else + err = can_rx_offload_add_manual(dev, &elm->offload, ELM327_NAPI_WEIGHT); +#endif + if (err) { + close_candev(dev); + return err; + } + + can_rx_offload_enable(&elm->offload); + can_led_event(dev, CAN_LED_EVENT_OPEN); elm->can.state = CAN_STATE_ERROR_ACTIVE; netif_start_queue(dev); @@ -800,25 +826,20 @@ static int elmcan_netdev_close(struct net_device *dev) { struct elmcan *elm = netdev_priv(dev); + /* Interrupt whatever the ELM327 is doing right now */ spin_lock_bh(&elm->lock); - if (elm->tty) { - /* Interrupt whatever we're doing right now */ - elm327_send(elm, ELM327_MAGIC_STRING, 1); - - /* Clear the wakeup bit, as the netdev will be down and thus - * the wakeup handler won't clear it - */ - clear_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags); + elm327_send(elm, ELM327_DUMMY_STRING, 1); + spin_unlock_bh(&elm->lock); - spin_unlock_bh(&elm->lock); + netif_stop_queue(dev); - flush_work(&elm->tx_work); - } else { - spin_unlock_bh(&elm->lock); - } + /* Give UART one final chance to flush. */ + clear_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags); + flush_work(&elm->tx_work); + can_rx_offload_disable(&elm->offload); elm->can.state = CAN_STATE_STOPPED; - netif_stop_queue(dev); + can_rx_offload_del(&elm->offload); close_candev(dev); can_led_event(dev, CAN_LED_EVENT_STOP); @@ -832,13 +853,8 @@ static netdev_tx_t elmcan_netdev_start_xmit(struct sk_buff *skb, struct elmcan *elm = netdev_priv(dev); struct can_frame *frame = (struct can_frame *)skb->data; - if (skb->len != sizeof(struct can_frame)) - goto out; - - if (!netif_running(dev)) { - netdev_warn(elm->dev, "xmit: iface is down.\n"); - goto out; - } + if (can_dropped_invalid_skb(dev, skb)) + return NETDEV_TX_OK; /* BHs are already disabled, so no spin_lock_bh(). * See Documentation/networking/netdevices.txt @@ -848,10 +864,10 @@ static netdev_tx_t elmcan_netdev_start_xmit(struct sk_buff *skb, /* We shouldn't get here after a hardware fault: * can_bus_off() calls netif_carrier_off() */ - WARN_ON(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; @@ -863,7 +879,7 @@ static netdev_tx_t elmcan_netdev_start_xmit(struct sk_buff *skb, spin_unlock(&elm->lock); dev->stats.tx_packets++; - dev->stats.tx_bytes += frame->can_dlc; + dev->stats.tx_bytes += frame->len; can_led_event(dev, CAN_LED_EVENT_TX); @@ -879,51 +895,11 @@ static const struct net_device_ops elmcan_netdev_ops = { .ndo_change_mtu = can_change_mtu, }; - /*********************************************************************** - * Line discipline * - * * - * (takes elm->lock) * - ***********************************************************************/ - -/* Get a reference to our struct, taking into account locks/refcounts. - * This is to ensure ordering in case we are shutting down, and to ensure - * there is a refcount at all (otherwise tty->disc_data may be freed and - * before we increment the refcount). - * Use this for anything that can race against elmcan_ldisc_close(). - */ -static struct elmcan *get_elm(struct tty_struct *tty) -{ - struct elmcan *elm; - bool got_ref; - - spin_lock_bh(&elmcan_discdata_lock); - elm = (struct elmcan *)tty->disc_data; - - if (!elm) { - spin_unlock_bh(&elmcan_discdata_lock); - return NULL; - } - - got_ref = atomic_inc_not_zero(&elm->refcount); - spin_unlock_bh(&elmcan_discdata_lock); - - if (!got_ref) - return NULL; - - return elm; -} - -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) || + return (isdigit(c) || isupper(c) || - c == ELM327_MAGIC_CHAR || + c == ELM327_DUMMY_CHAR || c == ELM327_READY_CHAR || c == '<' || c == 'a' || @@ -939,24 +915,26 @@ static bool elmcan_is_valid_rx_char(char c) * This will not be re-entered while running, but other ldisc * functions may be called in parallel. */ +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,14,0) static void elmcan_ldisc_rx(struct tty_struct *tty, const unsigned char *cp, char *fp, int count) +#else +static void elmcan_ldisc_rx(struct tty_struct *tty, + const unsigned char *cp, const char *fp, int count) +#endif { - struct elmcan *elm = get_elm(tty); - - if (!elm) - return; + struct elmcan *elm = (struct elmcan *)tty->disc_data; 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; } @@ -974,7 +952,7 @@ static void elmcan_ldisc_rx(struct tty_struct *tty, netdev_err(elm->dev, "Received illegal character %02x.\n", *cp); - elm327_hw_failure(elm); + elm327_uart_side_failure(elm); goto out; } @@ -988,7 +966,7 @@ static void elmcan_ldisc_rx(struct tty_struct *tty, 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; } @@ -997,7 +975,6 @@ static void elmcan_ldisc_rx(struct tty_struct *tty, out: spin_unlock_bh(&elm->lock); - put_elm(elm); } /* Write out remaining transmit buffer. @@ -1005,59 +982,43 @@ out: */ static void elmcan_ldisc_tx_worker(struct work_struct *work) { - /* No need to use get_elm() here, as we'll always flush workers - * before destroying the elmcan object. - */ struct elmcan *elm = container_of(work, struct elmcan, tx_work); - ssize_t actual; + ssize_t written; - spin_lock_bh(&elm->lock); - if (elm->hw_failure) { - spin_unlock_bh(&elm->lock); + if (elm->uart_side_failure) return; - } - if (!elm->tty || !netif_running(elm->dev)) { - spin_unlock_bh(&elm->lock); - return; + spin_lock_bh(&elm->lock); + + if (elm->txleft) { + written = elm->tty->ops->write(elm->tty, elm->txhead, elm->txleft); + if (written < 0) { + netdev_err(elm->dev, + "Failed to write to tty %s.\n", + elm->tty->name); + elm327_uart_side_failure(elm); + spin_unlock_bh(&elm->lock); + return; + } else { + elm->txleft -= written; + elm->txhead += written; + } } - if (elm->txleft <= 0) { - /* Our TTY write buffer is empty: - * Allow netdev to hand us another packet - */ + if (!elm->txleft) { clear_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags); spin_unlock_bh(&elm->lock); - netif_wake_queue(elm->dev); - return; - } - - 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); - elm327_hw_failure(elm); + } else { spin_unlock_bh(&elm->lock); - return; } - - elm->txleft -= actual; - elm->txhead += actual; - spin_unlock_bh(&elm->lock); } /* Called by the driver when there's room for more data. */ static void elmcan_ldisc_tx_wakeup(struct tty_struct *tty) { - struct elmcan *elm = get_elm(tty); - - if (!elm) - return; + struct elmcan *elm = (struct elmcan *)tty->disc_data; schedule_work(&elm->tx_work); - - put_elm(elm); } /* ELM327 can only handle bitrates that are integer divisors of 500 kHz, @@ -1078,8 +1039,6 @@ static const u32 elmcan_bitrate_const[64] = { /* Dummy needed to use bitrate_const */ static int elmcan_do_set_bittiming(struct net_device *netdev) { - (void)netdev; - return 0; } @@ -1100,27 +1059,18 @@ static int elmcan_ldisc_open(struct tty_struct *tty) return -ENFILE; elm = netdev_priv(dev); - elm->txbuf = kmalloc(ELM327_SIZE_TXBUF, GFP_KERNEL); - if (!elm->txbuf) { - err = -ENOMEM; - goto out_err; - } - /* Configure TTY interface */ tty->receive_room = 65536; /* We don't flow control */ - elm->txleft = 0; /* Clear TTY TX buffer */ spin_lock_init(&elm->lock); - atomic_set(&elm->refcount, 1); INIT_WORK(&elm->tx_work, elmcan_ldisc_tx_worker); /* Configure CAN metadata */ - elm->can.state = CAN_STATE_STOPPED; elm->can.bitrate_const = elmcan_bitrate_const; elm->can.bitrate_const_cnt = ARRAY_SIZE(elmcan_bitrate_const); elm->can.do_set_bittiming = elmcan_do_set_bittiming; elm->can.ctrlmode_supported = CAN_CTRLMODE_LISTENONLY; - /* Configure netlink interface */ + /* Configure netdev interface */ elm->dev = dev; dev->netdev_ops = &elmcan_netdev_ops; @@ -1140,7 +1090,6 @@ static int elmcan_ldisc_open(struct tty_struct *tty) return 0; out_err: - kfree(elm->txbuf); free_candev(elm->dev); return err; } @@ -1154,27 +1103,13 @@ out_err: */ static void elmcan_ldisc_close(struct tty_struct *tty) { - struct elmcan *elm = get_elm(tty); + struct elmcan *elm = (struct elmcan *)tty->disc_data; - if (!elm) - return; - - /* unregister_netdev() calls .ndo_stop() so we don't have to. */ - unregister_candev(elm->dev); - - /* Decrease the refcount twice, once for our own get_elm(), - * and once to remove the count of 1 that we set in _open(). - * Once it reaches 0, we can safely destroy it. + /* unregister_netdev() calls .ndo_stop() so we don't have to. + * Our .ndo_stop() also flushes the TTY write wakeup handler, + * so we can safely set elm->tty = NULL after this. */ - put_elm(elm); - put_elm(elm); - - while (atomic_read(&elm->refcount) > 0) - msleep_interruptible(10); - - /* At this point, all ldisc calls to us have become no-ops. */ - - flush_work(&elm->tx_work); + unregister_candev(elm->dev); /* Mark channel as dead */ spin_lock_bh(&elm->lock); @@ -1184,54 +1119,45 @@ static void elmcan_ldisc_close(struct tty_struct *tty) netdev_info(elm->dev, "elmcan off %s.\n", tty->name); - kfree(elm->txbuf); free_candev(elm->dev); } -static int elmcan_ldisc_hangup(struct tty_struct *tty) -{ - elmcan_ldisc_close(tty); - return 0; -} - -static int elmcan_ldisc_ioctl(struct tty_struct *tty, struct file *file, +static int elmcan_ldisc_ioctl(struct tty_struct *tty, +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,17,0) + struct file *file, +#endif unsigned int cmd, unsigned long arg) { - struct elmcan *elm = get_elm(tty); + struct elmcan *elm = (struct elmcan *)tty->disc_data; unsigned int tmp; - if (!elm) - return -EINVAL; - switch (cmd) { case SIOCGIFNAME: tmp = strnlen(elm->dev->name, IFNAMSIZ - 1) + 1; - if (copy_to_user((void __user *)arg, elm->dev->name, tmp)) { - put_elm(elm); + if (copy_to_user((void __user *)arg, elm->dev->name, tmp)) return -EFAULT; - } - - put_elm(elm); return 0; case SIOCSIFHWADDR: - put_elm(elm); return -EINVAL; default: - put_elm(elm); +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,16,0) return tty_mode_ioctl(tty, file, cmd, arg); +#else + return tty_mode_ioctl(tty, cmd, arg); +#endif } } static struct tty_ldisc_ops elmcan_ldisc = { .owner = THIS_MODULE, .name = "elmcan", + .num = N_DEVELOPMENT, .receive_buf = elmcan_ldisc_rx, .write_wakeup = elmcan_ldisc_tx_wakeup, .open = elmcan_ldisc_open, .close = elmcan_ldisc_close, - .hangup = elmcan_ldisc_hangup, .ioctl = elmcan_ldisc_ioctl, }; @@ -1239,10 +1165,11 @@ static int __init elmcan_init(void) { int status; - pr_info("ELM327 based best-effort CAN interface driver\n"); - pr_info("This device is severely limited as a CAN interface, see documentation.\n"); - - status = tty_register_ldisc(N_ELMCAN, &elmcan_ldisc); +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,14,0) + status = tty_register_ldisc(N_DEVELOPMENT, &elmcan_ldisc); +#else + status = tty_register_ldisc(&elmcan_ldisc); +#endif if (status) pr_err("Can't register line discipline\n"); @@ -1254,13 +1181,22 @@ static void __exit elmcan_exit(void) /* This will only be called when all channels have been closed by * userspace - tty_ldisc.c takes care of the module's refcount. */ +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,14,0) int status; - status = tty_unregister_ldisc(N_ELMCAN); + status = tty_unregister_ldisc(N_DEVELOPMENT); if (status) pr_err("Can't unregister line discipline (error: %d)\n", status); +#else + tty_unregister_ldisc(&elmcan_ldisc); +#endif } module_init(elmcan_init); module_exit(elmcan_exit); + +MODULE_ALIAS_LDISC(N_DEVELOPMENT); +MODULE_DESCRIPTION("ELM327 based CAN interface"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Max Staudt ");