* 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 <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>
*/
-#define pr_fmt(fmt) "[elmcan] " fmt
+#define pr_fmt(fmt) "elmcan: " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/if_ether.h>
#include <linux/kernel.h>
#include <linux/list.h>
+#include <linux/lockdep.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/can/led.h>
#include <linux/can/rx-offload.h>
-MODULE_ALIAS_LDISC(N_DEVELOPMENT);
-MODULE_DESCRIPTION("ELM327 based CAN interface");
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Max Staudt <max-linux@enpas.org>");
-
/* 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
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,
* 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[ELM327_SIZE_RXBUF];
/* State machine */
enum {
- ELM_NOTINIT = 0,
- ELM_GETDUMMYCHAR,
- ELM_GETPROMPT,
- ELM_RECEIVING,
+ ELM327_STATE_NOTINIT = 0,
+ ELM327_STATE_GETDUMMYCHAR,
+ ELM327_STATE_GETPROMPT,
+ ELM327_STATE_RECEIVING,
} state;
- int drop_next_line;
+ bool drop_next_line;
/* The CAN frame and config the ELM327 is sending/using,
* or will send/use after finishing all cmds_todo
*/
struct can_frame can_frame_to_send;
- unsigned short can_config;
- unsigned long can_bitrate;
- unsigned char can_bitrate_divisor;
- int silent_monitoring;
+ u16 can_config;
+ u8 can_bitrate_divisor;
/* Things we have yet to send */
char **next_init_cmd;
static inline void elm327_hw_failure(struct elmcan *elm);
-/* Assumes elm->lock taken. */
static void elm327_send(struct elmcan *elm, const void *buf, size_t len)
{
int actual;
+ lockdep_assert_held(elm->lock);
+
if (elm->hw_failure)
return;
* 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_GETDUMMYCHAR && elm->state != ELM_GETPROMPT) {
+ lockdep_assert_held(elm->lock);
+
+ if (elm->state != ELM327_STATE_GETDUMMYCHAR &&
+ elm->state != ELM327_STATE_GETPROMPT) {
elm327_send(elm, ELM327_DUMMY_STRING, 1);
- elm->state = ELM_GETDUMMYCHAR;
+ elm->state = ELM327_STATE_GETDUMMYCHAR;
}
}
-/* Schedule a CAN frame and necessary config changes to be sent to the TTY.
- *
- * Assumes elm->lock taken.
- */
+/* 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_to_send.can_id != frame->can_id) {
/* Set the new CAN ID for transmission. */
elm327_kick_into_cmd_mode(elm);
}
-/* ELM327 initialization sequence.
- *
- * Assumes elm->lock taken.
- */
+/* ELM327 initialisation sequence. */
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 */
static void elm327_init(struct elmcan *elm)
{
- elm->state = ELM_NOTINIT;
+ 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;
elm327_kick_into_cmd_mode(elm);
}
-/* Assumes elm->lock taken. */
static void elm327_feed_frame_to_netdev(struct elmcan *elm,
struct sk_buff *skb)
{
+ lockdep_assert_held(elm->lock);
+
if (!netif_running(elm->dev))
return;
#endif
}
-/* Called when we're out of ideas and just want it all to end.
- * 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)
{
struct can_frame *frame;
struct sk_buff *skb;
- skb = alloc_can_err_skb(elm->dev, &frame);
- if (!skb)
- return;
+ lockdep_assert_held(elm->lock);
- frame->data[5] = 'R';
- frame->data[6] = 'I';
- frame->data[7] = 'P';
+ elm->hw_failure = true;
- elm327_feed_frame_to_netdev(elm, skb);
+ 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 */
return (mem_len != str_len) || memcmp(mem, str, str_len);
}
-/* Assumes elm->lock taken. */
static void elm327_parse_error(struct elmcan *elm, size_t len)
{
struct can_frame *frame;
struct sk_buff *skb;
+ lockdep_assert_held(elm->lock);
+
skb = alloc_can_err_skb(elm->dev, &frame);
if (!skb)
/* It's okay to return here:
* 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, size_t len)
{
int datastart;
int i;
+ lockdep_assert_held(elm->lock);
+
skb = alloc_can_skb(elm->dev, &frame);
if (!skb)
return -ENOMEM;
return 0;
}
-/* Assumes elm->lock taken. */
static void elm327_parse_line(struct elmcan *elm, size_t len)
{
+ lockdep_assert_held(elm->lock);
+
/* Skip empty lines */
if (!len)
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);
}
}
-/* Assumes elm->lock taken. */
static void elm327_handle_prompt(struct elmcan *elm)
{
struct can_frame *frame = &elm->can_frame_to_send;
char local_txbuf[20];
+ 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;
return;
}
}
elm->drop_next_line = 1;
- elm->state = ELM_RECEIVING;
+ elm->state = ELM327_STATE_RECEIVING;
}
elm327_send(elm, local_txbuf, strlen(local_txbuf));
return (c & 0x3f) == ELM327_READY_CHAR;
}
-/* Assumes elm->lock taken. */
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;
}
-/* Assumes elm->lock taken. */
static void elm327_parse_rxbuf(struct elmcan *elm)
{
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_GETDUMMYCHAR:
+ case ELM327_STATE_GETDUMMYCHAR:
{
/* Wait for 'y' or '>' */
- int i;
-
for (i = 0; i < elm->rxfill; i++) {
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])) {
break;
}
- case ELM_GETPROMPT:
+ case ELM327_STATE_GETPROMPT:
/* Wait for '>' */
if (elm327_is_ready_char(elm->rxbuf[elm->rxfill - 1]))
elm327_handle_prompt(elm);
elm->rxfill = 0;
break;
- case ELM_RECEIVING:
+ case ELM327_STATE_RECEIVING:
/* Find <CR> delimiting feedback lines. */
for (len = 0;
(len < elm->rxfill) && (elm->rxbuf[len] != '\r');
struct elmcan *elm = netdev_priv(dev);
struct can_frame *frame = (struct can_frame *)skb->data;
- if (!netif_running(dev)) {
- netdev_warn(elm->dev, "xmit: iface is down.\n");
- goto out;
- }
-
/* BHs are already disabled, so no spin_lock_bh().
* See Documentation/networking/netdevices.txt
*/
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 <max-linux@enpas.org>");
projects / elmcan.git / blobdiff