#include <linux/init.h>
#include <linux/module.h>
-#include <linux/moduleparam.h>
-#include <linux/atomic.h>
#include <linux/bitops.h>
#include <linux/ctype.h>
-#include <linux/delay.h>
#include <linux/errno.h>
-#include <linux/if_ether.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>
-#include <linux/can/led.h>
#include <linux/can/rx-offload.h>
/* Line discipline ID number.
#define ELM327_NAPI_WEIGHT 4
-#define ELM327_SIZE_RXBUF 224
#define ELM327_SIZE_TXBUF 32
+#define ELM327_SIZE_RXBUF 1024
#define ELM327_CAN_CONFIG_SEND_SFF 0x8000
#define ELM327_CAN_CONFIG_VARIABLE_DLC 0x4000
#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,
struct can_rx_offload offload;
/* TTY buffers */
+ u8 txbuf[ELM327_SIZE_TXBUF];
u8 rxbuf[ELM327_SIZE_RXBUF];
- u8 txbuf[ELM327_SIZE_TXBUF] ____cacheline_aligned;
/* Per-channel lock */
spinlock_t 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. */
- 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)
elm->drop_next_line = 0;
/* We can only set the bitrate as a fraction of 500000.
- * The bit timing constants in can327_bittiming_const will
+ * The bitrates listed in can327_bitrate_const will
* limit the user to the right values.
*/
elm->can_bitrate_divisor = 500000 / elm->can.bittiming.bitrate;
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 bool 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)) {
/* The line is likely garbled anyway, so bail.
* The main code will restart listening.
*/
+ kfree_skb(skb);
return -ENODATA;
}
/* This is not a well-formatted data line.
* Assume it's an error message.
*/
+ kfree_skb(skb);
return -ENODATA;
}
/* The line is too short to be a valid frame hex dump.
* Something interrupted the hex dump or it is invalid.
*/
+ kfree_skb(skb);
return -ENODATA;
}
* However, this will correctly drop the state machine back into
* command mode.
*/
+ kfree_skb(skb);
return -ENODATA;
}
} 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),
elm->rxfill -= i;
}
-static void elm327_parse_rxbuf(struct can327 *elm)
+static void elm327_parse_rxbuf(struct can327 *elm, size_t first_new_char_idx)
{
- size_t len;
- int i;
+ size_t len, pos;
lockdep_assert_held(&elm->lock);
break;
case ELM327_STATE_GETDUMMYCHAR:
- {
/* Wait for 'y' or '>' */
- for (i = 0; i < elm->rxfill; i++) {
- if (elm->rxbuf[i] == ELM327_DUMMY_CHAR) {
+ for (pos = 0; pos < elm->rxfill; pos++) {
+ if (elm->rxbuf[pos] == ELM327_DUMMY_CHAR) {
elm327_send(elm, "\r", 1);
elm->state = ELM327_STATE_GETPROMPT;
- i++;
+ pos++;
break;
- } else if (elm327_is_ready_char(elm->rxbuf[i])) {
+ } else if (elm327_is_ready_char(elm->rxbuf[pos])) {
elm327_send(elm, ELM327_DUMMY_STRING, 1);
- i++;
+ pos++;
break;
}
}
- elm327_drop_bytes(elm, i);
-
+ elm327_drop_bytes(elm, pos);
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 = first_new_char_idx;
+ 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, 0);
+ }
}
}
#if LINUX_VERSION_CODE < KERNEL_VERSION(5,10,0)
/* Dummy needed to use can_rx_offload */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5,5,0)
+static unsigned int *can327_mailbox_read(struct can_rx_offload *offload,
+ struct can_frame *cf,
+ u32 *timestamp, unsigned int n)
+{
+ WARN_ON_ONCE(1); /* This function is a dummy, so don't call it! */
+
+ return -ENOBUFS;
+}
+#else /* Since 4e9c9484b085 (included in v5.5) */
static struct sk_buff *can327_mailbox_read(struct can_rx_offload *offload,
unsigned int n, u32 *timestamp,
bool drop)
return ERR_PTR(-ENOBUFS);
}
#endif
+#endif
static int can327_netdev_open(struct net_device *dev)
{
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);
elm->can.state = CAN_STATE_STOPPED;
can_rx_offload_del(&elm->offload);
close_candev(dev);
- can_led_event(dev, CAN_LED_EVENT_STOP);
return 0;
}
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
+ /* This check will be part of can_dropped_invalid_skb()
+ * in future kernels.
*/
- spin_lock(&elm->lock);
+ if (elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+ goto out;
/* We shouldn't get here after a hardware fault:
* can_bus_off() calls netif_carrier_off()
*/
- WARN_ON_ONCE(elm->uart_side_failure);
-
- if (!elm->tty ||
- elm->uart_side_failure ||
- elm->can.ctrlmode & CAN_CTRLMODE_LISTENONLY) {
- spin_unlock(&elm->lock);
+ if (elm->uart_side_failure) {
+ WARN_ON_ONCE(elm->uart_side_failure);
goto out;
}
netif_stop_queue(dev);
+ /* BHs are already disabled, so no spin_lock_bh().
+ * See Documentation/networking/netdevices.txt
+ */
+ spin_lock(&elm->lock);
elm327_send_frame(elm, frame);
spin_unlock(&elm->lock);
dev->stats.tx_packets++;
dev->stats.tx_bytes += frame->len;
- can_led_event(dev, CAN_LED_EVENT_TX);
-
out:
kfree_skb(skb);
return NETDEV_TX_OK;
.ndo_change_mtu = can_change_mtu,
};
-static bool can327_is_valid_rx_char(char c)
+static bool can327_is_valid_rx_char(u8 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 == ' ');
+ static const bool lut_char_is_valid['z'] = {
+ ['\r'] = true,
+ [' '] = true,
+ ['.'] = true,
+ ['0'] = true, true, true, true, true,
+ ['5'] = true, true, true, true, true,
+ ['<'] = true,
+ [ELM327_READY_CHAR] = true,
+ ['?'] = true,
+ ['A'] = true, true, true, true, true, true, true,
+ ['H'] = true, true, true, true, true, true, true,
+ ['O'] = true, true, true, true, true, true, true,
+ ['V'] = true, true, true, true, true,
+ ['a'] = true,
+ ['b'] = true,
+ ['v'] = true,
+ [ELM327_DUMMY_CHAR] = true,
+ };
+ BUILD_BUG_ON(ELM327_DUMMY_CHAR >= 'z');
+
+ return (c < ARRAY_SIZE(lut_char_is_valid) &&
+ lut_char_is_valid[c]);
}
/* Handle incoming ELM327 ASCII data.
#endif
{
struct can327 *elm = (struct can327 *)tty->disc_data;
+ size_t first_new_char_idx;
+
+ if (elm->uart_side_failure)
+ return;
spin_lock_bh(&elm->lock);
- if (elm->uart_side_failure)
- goto out;
+ /* Store old rxfill, so elm327_parse_rxbuf() will have
+ * the option of skipping already checked characters.
+ */
+ first_new_char_idx = elm->rxfill;
while (count-- && elm->rxfill < ELM327_SIZE_RXBUF) {
if (fp && *fp++) {
elm327_uart_side_failure(elm);
- goto out;
+ spin_unlock_bh(&elm->lock);
+ return;
}
/* Ignore NUL characters, which the PIC microcontroller may
* 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.
*/
*cp);
elm327_uart_side_failure(elm);
- goto out;
+ spin_unlock_bh(&elm->lock);
+ return;
}
elm->rxbuf[elm->rxfill++] = *cp;
}
if (count >= 0) {
- netdev_err(elm->dev, "Receive buffer overflowed. Bad chip or wiring?");
+ netdev_err(elm->dev, "Receive buffer overflowed. Bad chip or wiring? count = %i", count);
elm327_uart_side_failure(elm);
- goto out;
+ spin_unlock_bh(&elm->lock);
+ return;
}
- elm327_parse_rxbuf(elm);
-
-out:
+ elm327_parse_rxbuf(elm, first_new_char_idx);
spin_unlock_bh(&elm->lock);
}
"Failed to write to tty %s.\n",
elm->tty->name);
elm327_uart_side_failure(elm);
+
spin_unlock_bh(&elm->lock);
return;
}
elm->txhead += written;
}
- if (!elm->txleft) {
+ if (!elm->txleft)
clear_bit(TTY_DO_WRITE_WAKEUP, &elm->tty->flags);
- spin_unlock_bh(&elm->lock);
- } else {
- spin_unlock_bh(&elm->lock);
- }
+
+ spin_unlock_bh(&elm->lock);
}
/* Called by the driver when there's room for more data. */
* or 7/8 of that. Divisors are 1 to 64.
* Currently we don't implement support for 7/8 rates.
*/
-static const u32 can327_bitrate_const[64] = {
+static const u32 can327_bitrate_const[] = {
7812, 7936, 8064, 8196, 8333, 8474, 8620, 8771,
8928, 9090, 9259, 9433, 9615, 9803, 10000, 10204,
10416, 10638, 10869, 11111, 11363, 11627, 11904, 12195,
elm->tty = tty;
tty->disc_data = elm;
- devm_can_led_init(elm->dev);
-
/* Let 'er rip */
err = register_candev(elm->dev);
- if (err)
- goto out_err;
+ if (err) {
+ free_candev(elm->dev);
+ return err;
+ }
netdev_info(elm->dev, "can327 on %s.\n", tty->name);
return 0;
-
-out_err:
- free_candev(elm->dev);
- return err;
}
/* Close down a can327 channel.
projects / elmcan.git / blobdiff