diff options
| -rw-r--r-- | module/elmcan.c | 89 |
1 files changed, 26 insertions, 63 deletions
diff --git a/module/elmcan.c b/module/elmcan.c index acb6057..9b4ea45 100644 --- a/module/elmcan.c +++ b/module/elmcan.c @@ -1,24 +1,9 @@ // 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 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 <max-linux@enpas.org> - * slcan.c Author : Oliver Hartkopp <socketcan@hartkopp.net> - * slip.c Authors : Laurence Culhane <loz@holmes.demon.co.uk> - * Fred N. van Kempen <waltje@uwalt.nl.mugnet.org> - * - * This code barely bears any resemblance to slcan anymore, and whatever - * may be left is Linux specific boilerplate anyway, however I am leaving - * the GPL-2.0 identifier at the top just to be sure. - * - * Please feel free to use my own code, especially the ELM327 communication - * logic, in accordance with SPDX-License-Identifier BSD-3-Clause to port - * this driver to other systems. - * - Max - * + * and my thanks go to the original authors for their inspiration, even + * after almost none of their code is left. */ #define pr_fmt(fmt) "[elmcan] " fmt @@ -168,12 +153,7 @@ 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; @@ -209,6 +189,8 @@ static void elm327_send(struct elmcan *elm, const void *buf, size_t len) * 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 * mode. + * + * Assumes elm->lock taken. */ static void elm327_kick_into_cmd_mode(struct elmcan *elm) { @@ -219,7 +201,10 @@ static void elm327_kick_into_cmd_mode(struct elmcan *elm) } } -/* 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 */ @@ -255,12 +240,10 @@ static void elm327_send_frame(struct elmcan *elm, struct can_frame *frame) 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 */ @@ -310,12 +293,7 @@ static void elm327_init(struct elmcan *elm) 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) { @@ -344,13 +322,9 @@ static void elm327_feed_frame_to_netdev(struct elmcan *elm, #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; @@ -369,12 +343,7 @@ static inline void elm327_hw_failure(struct elmcan *elm) can_bus_off(elm->dev); } - /*********************************************************************** - * ELM327: Reception parser * - * * - * (assumes elm->lock taken) * - ***********************************************************************/ - +/* Assumes elm->lock taken. */ static void elm327_parse_error(struct elmcan *elm, int len) { struct can_frame frame; @@ -445,6 +414,8 @@ 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) { @@ -574,6 +545,7 @@ static int elm327_parse_frame(struct elmcan *elm, int len) return 0; } +/* Assumes elm->lock taken. */ static void elm327_parse_line(struct elmcan *elm, int len) { /* Skip empty lines */ @@ -604,6 +576,7 @@ static void elm327_parse_line(struct elmcan *elm, int len) } } +/* Assumes elm->lock taken. */ static void elm327_handle_prompt(struct elmcan *elm) { struct can_frame *frame = &elm->can_frame; @@ -688,12 +661,14 @@ static bool elm327_is_ready_char(char c) return (c & 0x3f) == ELM327_READY_CHAR; } +/* Assumes elm->lock taken. */ static void elm327_drop_bytes(struct elmcan *elm, int 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; @@ -780,12 +755,6 @@ static void elm327_parse_rxbuf(struct elmcan *elm) } } - /*********************************************************************** - * netdev * - * * - * (takes elm->lock) * - ***********************************************************************/ - /* Dummy needed to use can_rx_offload */ static struct sk_buff *elmcan_mailbox_read(struct can_rx_offload *offload, unsigned int n, u32 *timestamp, @@ -925,12 +894,6 @@ 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 @@ -1171,7 +1134,7 @@ 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; |