X-Git-Url: https://git.enpas.org/?a=blobdiff_plain;f=module%2Felmcan.c;h=106ae109585bb8a1997955d24a755dbb3676da4c;hb=af305c7448da594fed5d6fc26490d4b87774098b;hp=7ac1f5466a052a3c6e889e830fc6927313fc8b42;hpb=40ac32acdae89383ae44f32e612bf37fa0493631;p=elmcan.git diff --git a/module/elmcan.c b/module/elmcan.c index 7ac1f54..106ae10 100644 --- a/module/elmcan.c +++ b/module/elmcan.c @@ -1,19 +1,17 @@ // 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, even + * after almost none of their code is left. * * 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 @@ -32,34 +30,33 @@ #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. + * N_DEVELOPMENT will likely be defined from Linux 5.18 onwards: + * https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git/commit/?h=tty-next&id=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_NAPI_WEIGHT 4 + #define ELM327_SIZE_RXBUF 256 #define ELM327_SIZE_TXBUF 32 @@ -68,35 +65,35 @@ 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 { - 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 +enum ELM327_TX_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; + struct can_rx_offload offload; + /* TTY and netdev devices that we're bridging */ - struct tty_struct *tty; - struct net_device *dev; + struct tty_struct *tty; + struct net_device *dev; /* Per-channel lock */ - spinlock_t 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, @@ -105,27 +102,27 @@ struct elmcan { * decrement to 0, and refcount_dec() spills a WARN_ONCE in * that case. */ - atomic_t refcount; + atomic_t refcount; /* Stop the channel on hardware failure. * Once this is true, nothing will be sent to the TTY. */ - bool hw_failure; + bool hw_failure; /* 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 */ + 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 RX helpers */ - unsigned char *rxbuf; + unsigned char rxbuf[ELM327_SIZE_RXBUF]; int rxfill; /* State machine */ enum { ELM_NOTINIT = 0, - ELM_GETMAGICCHAR, + ELM_GETDUMMYCHAR, ELM_GETPROMPT, ELM_RECEIVING, } state; @@ -135,7 +132,7 @@ struct elmcan { /* The CAN frame and config the ELM327 is sending/using, * or will send/use after finishing all cmds_todo */ - struct can_frame can_frame; + struct can_frame can_frame_to_send; unsigned short can_config; unsigned long can_bitrate; unsigned char can_bitrate_divisor; @@ -146,7 +143,6 @@ 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. @@ -154,17 +150,9 @@ struct elmcan { */ static DEFINE_SPINLOCK(elmcan_discdata_lock); - static inline void elm327_hw_failure(struct elmcan *elm); - - - /*********************************************************************** - * ELM327: Transmission * - * * - * (all functions assume elm->lock taken) * - ***********************************************************************/ - +/* Assumes elm->lock taken. */ static void elm327_send(struct elmcan *elm, const void *buf, size_t len) { int actual; @@ -186,8 +174,8 @@ 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; } @@ -196,30 +184,33 @@ 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 + * 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. + * + * Assumes elm->lock taken. */ 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); + if (elm->state != ELM_GETDUMMYCHAR && elm->state != ELM_GETPROMPT) { + elm327_send(elm, ELM327_DUMMY_STRING, 1); - elm->state = ELM_GETMAGICCHAR; + elm->state = ELM_GETDUMMYCHAR; } } - -/* Schedule a CAN frame and necessary config changes to be sent to the TTY. */ +/* Schedule a CAN frame and necessary config changes to be sent to the TTY. + * + * Assumes elm->lock taken. + */ static void elm327_send_frame(struct elmcan *elm, struct can_frame *frame) { /* 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)) { + ^ (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) @@ -227,35 +218,31 @@ 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(ELM327_TX_DO_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(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(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(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(ELM_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 initialization sequence. + * + * Assumes elm->lock taken. + */ static char *elm327_init_script[] = { "AT WS\r", /* v1.0: Warm Start */ "AT PP FF OFF\r", /* v1.0: All Programmable Parameters Off */ @@ -278,11 +265,10 @@ static char *elm327_init_script[] = { NULL }; - static void elm327_init(struct elmcan *elm) { elm->state = ELM_NOTINIT; - elm->can_frame.can_id = 0x7df; + elm->can_frame_to_send.can_id = 0x7df; /* ELM327 HW default */ elm->rxfill = 0; elm->drop_next_line = 0; @@ -298,140 +284,128 @@ 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(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) * - ***********************************************************************/ - +/* 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; - 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. */ +/* Called when we're out of ideas and just want it all to end. + * Assumes elm->lock taken. + */ static inline void elm327_hw_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); + 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"); - elm->hw_failure = true; - can_bus_off(elm->dev); + skb = alloc_can_err_skb(elm->dev, &frame); + if (!skb) + return; + + frame->can_id |= CAN_ERR_BUSOFF; + elm327_feed_frame_to_netdev(elm, skb); } +/* Compare a buffer to a fixed string */ +static inline int _memstrcmp(const u8 *mem, const char *str) +{ + return memcmp(mem, str, strlen(str)); +} +/* 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. + */ +static inline int _len_memstrcmp(const u8 *mem, size_t mem_len, const char *str) +{ + size_t str_len = strlen(str); - /************************************************************************ - * ELM327: Reception parser * - * * - * (assumes elm->lock taken) * - ************************************************************************/ + return (mem_len != str_len) || memcmp(mem, str, str_len); +} -static void elm327_parse_error(struct elmcan *elm, int len) +/* Assumes elm->lock taken. */ +static void elm327_parse_error(struct elmcan *elm, size_t len) { - struct can_frame frame; - - memset(&frame, 0, sizeof(frame)); - frame.can_id = CAN_ERR_FLAG; - frame.can_dlc = CAN_ERR_DLC; + struct can_frame *frame; + struct sk_buff *skb; - 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 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, "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 */ + 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 (!_len_memstrcmp(elm->rxbuf, len, "UNABLE TO CONNECT")) { + netdev_err(elm->dev, + "ELM327 reported UNABLE TO CONNECT. Please check your setup.\n"); + } else if (!_len_memstrcmp(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 (!_len_memstrcmp(elm->rxbuf, len, "BUS ERROR")) { + frame->can_id |= CAN_ERR_BUSERROR; + } else if (!_len_memstrcmp(elm->rxbuf, len, "CAN ERROR")) { + frame->can_id |= CAN_ERR_PROT; + } else if (!_len_memstrcmp(elm->rxbuf, len, "can_id |= CAN_ERR_PROT; + } else if (!_len_memstrcmp(elm->rxbuf, len, "BUS BUSY")) { + frame->can_id |= CAN_ERR_PROT; + frame->data[2] = CAN_ERR_PROT_OVERLOAD; + } else if (!_len_memstrcmp(elm->rxbuf, len, "FB ERROR")) { + frame->can_id |= CAN_ERR_PROT; + frame->data[2] = CAN_ERR_PROT_TX; + } else if (len == 5 && !_memstrcmp(elm->rxbuf, "ERR")) { + /* 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. * They can be of various formats: * @@ -443,15 +417,20 @@ static void elm327_parse_error(struct elmcan *elm, int len) * Instead of a payload, RTR indicates a remote request. * * We will use the spaces and line length to guess the format. + * + * Assumes elm->lock taken. */ -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)); + 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. @@ -459,53 +438,50 @@ 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; } } - /* 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 - && !isdigit(elm->rxbuf[hexlen]) - && !isupper(elm->rxbuf[hexlen]) - && '<' != elm->rxbuf[hexlen] - && ' ' != elm->rxbuf[hexlen]) { + if (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. */ - elm327_kick_into_cmd_mode(elm); - return 3; + return -ENODATA; } /* Use spaces in CAN ID to distinguish 29 or 11 bit address length. * 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] == ' ') { - frame.can_id = CAN_EFF_FLAG; + 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] == ' ') { - frame.can_id = 0; + frame->can_id = 0; datastart = 6; } else { /* This is not a well-formatted data line. * Assume it's an error message. */ - return 1; + return -ENODATA; } if (hexlen < datastart) { /* The line is too short to be a valid frame hex dump. * Something interrupted the hex dump or it is invalid. */ - return 1; + return -ENODATA; } /* From here on all chars up to buf[hexlen] are hex or spaces, @@ -513,67 +489,66 @@ 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; + if (elm->rxfill >= hexlen + 3 && + !_memstrcmp(&elm->rxbuf[hexlen], "RTR")) { + 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. * However, this will correctly drop the state machine back into * command mode. */ - return 2; + return -ENODATA; } /* 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); + 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) +/* Assumes elm->lock taken. */ +static void elm327_parse_line(struct elmcan *elm, size_t len) { /* Skip empty lines */ if (!len) @@ -583,29 +558,25 @@ 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 (!_memstrcmp(elm->rxbuf, "AT")) { 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 == ELM_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); } } +/* Assumes elm->lock taken. */ static void elm327_handle_prompt(struct elmcan *elm) { - struct can_frame *frame = &elm->can_frame; + struct can_frame *frame = &elm->can_frame_to_send; char local_txbuf[20]; if (!elm->cmds_todo) { @@ -617,44 +588,44 @@ 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(ELM327_TX_DO_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); - netdev_info(elm->dev, "Initialization finished.\n"); + clear_bit(ELM327_TX_DO_INIT, &elm->cmds_todo); + /* Init finished. */ } - } else if (test_and_clear_bit(ELM_TODO_SILENT_MONITOR, &elm->cmds_todo)) { + } else if (test_and_clear_bit(ELM327_TX_DO_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(ELM327_TX_DO_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(ELM327_TX_DO_CAN_CONFIG, &elm->cmds_todo)) { sprintf(local_txbuf, "ATPC\r"); - set_bit(ELM_TODO_CAN_CONFIG_PART2, &elm->cmds_todo); + set_bit(ELM327_TX_DO_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(ELM327_TX_DO_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(ELM327_TX_DO_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(ELM327_TX_DO_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(ELM327_TX_DO_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(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. @@ -664,12 +635,12 @@ static void elm327_handle_prompt(struct elmcan *elm) /* 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++) { + 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 +650,6 @@ 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. @@ -688,34 +658,35 @@ static bool elm327_is_ready_char(char c) return (c & 0x3f) == ELM327_READY_CHAR; } -static void elm327_drop_bytes(struct elmcan *elm, int i) +/* Assumes elm->lock taken. */ +static void elm327_drop_bytes(struct elmcan *elm, size_t i) { memmove(&elm->rxbuf[0], &elm->rxbuf[i], ELM327_SIZE_RXBUF - i); elm->rxfill -= i; } +/* Assumes elm->lock taken. */ static void elm327_parse_rxbuf(struct elmcan *elm) { - int len; + size_t len; + int i; switch (elm->state) { case ELM_NOTINIT: elm->rxfill = 0; break; - case ELM_GETMAGICCHAR: + case ELM_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; 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; } @@ -747,7 +718,7 @@ 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 +743,7 @@ 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) @@ -780,15 +751,15 @@ static void elm327_parse_rxbuf(struct elmcan *elm) } } +/* 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! */ - - - - /*********************************************************************** - * netdev * - * * - * (takes elm->lock) * - ***********************************************************************/ + return ERR_PTR(-ENOBUFS); +} static int elmcan_netdev_open(struct net_device *dev) { @@ -802,7 +773,7 @@ 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; } @@ -817,6 +788,15 @@ static int elmcan_netdev_open(struct net_device *dev) elm327_init(elm); spin_unlock_bh(&elm->lock); + elm->offload.mailbox_read = elmcan_mailbox_read; + err = can_rx_offload_add_fifo(dev, &elm->offload, ELM327_NAPI_WEIGHT); + 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); @@ -828,10 +808,12 @@ static int elmcan_netdev_close(struct net_device *dev) { struct elmcan *elm = netdev_priv(dev); + netif_stop_queue(dev); + spin_lock_bh(&elm->lock); if (elm->tty) { /* Interrupt whatever we're doing right now */ - elm327_send(elm, ELM327_MAGIC_STRING, 1); + elm327_send(elm, ELM327_DUMMY_STRING, 1); /* Clear the wakeup bit, as the netdev will be down and thus * the wakeup handler won't clear it @@ -845,8 +827,9 @@ static int elmcan_netdev_close(struct net_device *dev) spin_unlock_bh(&elm->lock); } + 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); @@ -858,15 +841,7 @@ 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; - - if (skb->len != sizeof(struct can_frame)) - goto out; - - if (!netif_running(dev)) { - netdev_warn(elm->dev, "xmit: iface is down.\n"); - goto out; - } + struct can_frame *frame = (struct can_frame *)skb->data; /* BHs are already disabled, so no spin_lock_bh(). * See Documentation/networking/netdevices.txt @@ -876,11 +851,11 @@ 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->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; } @@ -891,7 +866,7 @@ 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); @@ -900,7 +875,6 @@ out: return NETDEV_TX_OK; } - static const struct net_device_ops elmcan_netdev_ops = { .ndo_open = elmcan_netdev_open, .ndo_stop = elmcan_netdev_close, @@ -908,16 +882,6 @@ 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 @@ -930,7 +894,7 @@ 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); @@ -951,30 +915,33 @@ 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 (isdigit(c) || + isupper(c) || + c == ELM327_DUMMY_CHAR || + c == ELM327_READY_CHAR || + c == '<' || + c == 'a' || + c == 'b' || + c == 'v' || + c == '.' || + c == '?' || + c == '\r' || + c == ' '); } /* Handle incoming ELM327 ASCII data. * 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) + 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); @@ -983,9 +950,8 @@ 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 +1001,6 @@ out: put_elm(elm); } - /* Write out remaining transmit buffer. * Scheduled when TTY is writable. */ @@ -1096,7 +1061,6 @@ 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. @@ -1112,16 +1076,12 @@ 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) { - (void)netdev; - return 0; } - static int elmcan_ldisc_open(struct tty_struct *tty) { struct net_device *dev; @@ -1134,15 +1094,13 @@ 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; elm = netdev_priv(dev); - elm->rxbuf = kmalloc(ELM327_SIZE_RXBUF, GFP_KERNEL); elm->txbuf = kmalloc(ELM327_SIZE_TXBUF, GFP_KERNEL); - if (!elm->rxbuf || !elm->txbuf) { + if (!elm->txbuf) { err = -ENOMEM; goto out_err; } @@ -1161,7 +1119,7 @@ static int elmcan_ldisc_open(struct tty_struct *tty) 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; @@ -1181,10 +1139,7 @@ static int elmcan_ldisc_open(struct tty_struct *tty) return 0; out_err: - if (elm->txbuf) - kfree(elm->txbuf); - if (elm->rxbuf) - kfree(elm->rxbuf); + kfree(elm->txbuf); free_candev(elm->dev); return err; } @@ -1218,29 +1173,37 @@ static void elmcan_ldisc_close(struct tty_struct *tty) /* At this point, all ldisc calls to us have become no-ops. */ + flush_work(&elm->tx_work); + /* Mark channel as dead */ spin_lock_bh(&elm->lock); tty->disc_data = NULL; elm->tty = NULL; spin_unlock_bh(&elm->lock); - flush_work(&elm->tx_work); - netdev_info(elm->dev, "elmcan off %s.\n", tty->name); kfree(elm->txbuf); - kfree(elm->rxbuf); free_candev(elm->dev); } +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,16,0) static int elmcan_ldisc_hangup(struct tty_struct *tty) +#else +static void elmcan_ldisc_hangup(struct tty_struct *tty) +#endif { elmcan_ldisc_close(tty); +#if LINUX_VERSION_CODE < KERNEL_VERSION(5,16,0) return 0; +#endif } -static int elmcan_ldisc_ioctl(struct tty_struct *tty, struct file *file, - unsigned int cmd, unsigned long arg) +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); unsigned int tmp; @@ -1265,14 +1228,18 @@ static int elmcan_ldisc_ioctl(struct tty_struct *tty, struct file *file, 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, - .magic = TTY_LDISC_MAGIC, .name = "elmcan", + .num = N_DEVELOPMENT, .receive_buf = elmcan_ldisc_rx, .write_wakeup = elmcan_ldisc_tx_wakeup, .open = elmcan_ldisc_open, @@ -1281,18 +1248,17 @@ static struct tty_ldisc_ops elmcan_ldisc = { .ioctl = elmcan_ldisc_ioctl, }; - - 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"); + pr_err("Can't register line discipline\n"); return status; } @@ -1302,13 +1268,22 @@ 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 ");