#define ELM327_READY_CHAR '>'
/* Bits in elm->cmds_todo */
-enum elm327_to_to_do_bits {
+enum elm327_tx_do {
ELM327_TX_DO_CAN_DATA = 0,
ELM327_TX_DO_CANID_11BIT,
ELM327_TX_DO_CANID_29BIT_LOW,
/* 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. */
- if ((frame->can_id & CAN_EFF_FLAG) ^
- (elm->can_frame_to_send.can_id & CAN_EFF_FLAG)) {
+ if ((frame->can_id ^ 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)
elm327_feed_frame_to_netdev(elm, skb);
}
-/* 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.
+/* Compares a byte buffer (non-NUL terminated) to the payload part of a string,
+ * and returns true iff the buffer (content *and* length) is exactly that
+ * string, without the terminating NUL byte.
*
- * 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.
+ * Example: If reference is "BUS ERROR", then this returns true iff nbytes == 9
+ * and !memcmp(buf, "BUS ERROR", 9).
+ *
+ * The reason to use strings is so we can easily include them in the C code,
+ * and to avoid hardcoding lengths.
*/
-static inline int check_len_then_cmp(const u8 *mem, size_t mem_len, const char *str)
+static inline int elm327_rxbuf_cmp(const u8 *buf, size_t nbytes, const char *reference)
{
- size_t str_len = strlen(str);
+ size_t ref_len = strlen(reference);
- return (mem_len == str_len) && !memcmp(mem, str, str_len);
+ return (nbytes == ref_len) && !memcmp(buf, reference, ref_len);
}
static void elm327_parse_error(struct can327 *elm, size_t len)
return;
/* Filter possible error messages based on length of RX'd line */
- if (check_len_then_cmp(elm->rxbuf, len, "UNABLE TO CONNECT")) {
+ if (elm327_rxbuf_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")) {
+ } else if (elm327_rxbuf_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")) {
+ } else if (elm327_rxbuf_cmp(elm->rxbuf, len, "BUS ERROR")) {
frame->can_id |= CAN_ERR_BUSERROR;
- } else if (check_len_then_cmp(elm->rxbuf, len, "CAN ERROR")) {
+ } else if (elm327_rxbuf_cmp(elm->rxbuf, len, "CAN ERROR")) {
frame->can_id |= CAN_ERR_PROT;
- } else if (check_len_then_cmp(elm->rxbuf, len, "<RX ERROR")) {
+ } else if (elm327_rxbuf_cmp(elm->rxbuf, len, "<RX ERROR")) {
frame->can_id |= CAN_ERR_PROT;
- } else if (check_len_then_cmp(elm->rxbuf, len, "BUS BUSY")) {
+ } else if (elm327_rxbuf_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")) {
+ } else if (elm327_rxbuf_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)) {
} 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)));
+ !!(elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY));
} else if (test_and_clear_bit(ELM327_TX_DO_RESPONSES, &elm->cmds_todo)) {
snprintf(local_txbuf, sizeof(local_txbuf),
break;
case ELM327_STATE_GETDUMMYCHAR:
- {
/* Wait for 'y' or '>' */
for (i = 0; i < elm->rxfill; i++) {
if (elm->rxbuf[i] == ELM327_DUMMY_CHAR) {
}
elm327_drop_bytes(elm, i);
-
break;
- }
case ELM327_STATE_GETPROMPT:
/* Wait for '>' */
case ELM327_STATE_RECEIVING:
/* Find <CR> delimiting feedback lines. */
- for (len = 0;
- (len < elm->rxfill) && (elm->rxbuf[len] != '\r');
- len++) {
- /* empty loop */
- }
+ len = 0;
+ while (len < elm->rxfill && elm->rxbuf[len] != '\r')
+ len++;
if (len == ELM327_SIZE_RXBUF) {
- /* Line exceeds buffer. It's probably all garbage.
+ /* Assume the buffer ran full with garbage.
* Did we even connect at the right baud rate?
*/
netdev_err(elm->dev,
"RX buffer overflow. Faulty ELM327 or UART?\n");
elm327_uart_side_failure(elm);
- break;
} else if (len == elm->rxfill) {
if (elm327_is_ready_char(elm->rxbuf[elm->rxfill - 1])) {
/* The ELM327's AT ST response timeout ran out,
elm->rxfill = 0;
elm327_handle_prompt(elm);
- break;
}
/* No <CR> found - we haven't received a full line yet.
* Wait for more data.
*/
- break;
- }
-
- /* We have a full line to parse. */
- elm327_parse_line(elm, len);
+ } else {
+ /* We have a full line to parse. */
+ elm327_parse_line(elm, len);
- /* Remove parsed data from RX buffer. */
- elm327_drop_bytes(elm, len + 1);
+ /* Remove parsed data from RX buffer. */
+ elm327_drop_bytes(elm, len + 1);
- /* More data to parse? */
- if (elm->rxfill)
- elm327_parse_rxbuf(elm);
+ /* More data to parse? */
+ if (elm->rxfill)
+ elm327_parse_rxbuf(elm);
+ }
}
}
* See ELM327 documentation, which refers to a Microchip PIC
* bug description.
*/
- if (*cp != 0) {
+ if (*cp) {
/* Check for stray characters on the UART line.
* Likely caused by bad hardware.
*/
projects / elmcan.git / commitdiff