It extends the protocol to receive the adapter CAN communication errors
and forward them to the netdev upper levels.
Signed-off-by: Dario Binacchi <dario.binacchi@xxxxxxxxxxxxxxxxxxxx>
---
Changes in v4:
- Add description of slc_bump_err() function.
- Remove check for the 'e' character at the beggining of the function.
It was already checked by the caller function.
- Protect decoding against the case the len value is longer than the
received data.
- Some small changes to make the decoding more readable.
- Increment all the error counters at the end of the function.
Changes in v2:
- Protect decoding against the case the len value is longer than the
received data.
- Continue error handling even if no skb can be allocated.
drivers/net/can/slcan/slcan-core.c | 140 ++++++++++++++++++++++++++++-
1 file changed, 139 insertions(+), 1 deletion(-)
diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c
index b4f29ab2ab72..6c7c815eaf45 100644
--- a/drivers/net/can/slcan/slcan-core.c
+++ b/drivers/net/can/slcan/slcan-core.c
@@ -176,7 +176,7 @@ int slcan_enable_err_rst_on_open(struct net_device *ndev, bool on)
************************************************************************/
/* Send one completely decapsulated can_frame to the network layer */
-static void slc_bump(struct slcan *sl)
+static void slc_bump_frame(struct slcan *sl)
{
struct sk_buff *skb;
struct can_frame *cf;
@@ -255,6 +255,144 @@ static void slc_bump(struct slcan *sl)
dev_kfree_skb(skb);
}
+/* An error frame can contain more than one type of error.
+ *
+ * Examples:
+ *
+ * e1a : len 1, errors: ACK error
+ * e3bcO: len 3, errors: Bit0 error, CRC error, Tx overrun error
+ */
+static void slc_bump_err(struct slcan *sl)
+{
+ struct net_device *dev = sl->dev;
+ struct sk_buff *skb;
+ struct can_frame *cf;
+ char *cmd = sl->rbuff;
+ bool rx_errors = false, tx_errors = false, rx_over_errors = false;
+ int i, len;
+
+ /* get len from sanitized ASCII value */
+ len = cmd[1];
+ if (len >= '0' && len < '9')
+ len -= '0';
+ else
+ return;
+
+ if ((len + SLC_CMD_LEN + 1) > sl->rcount)
+ return;
+
+ skb = alloc_can_err_skb(dev, &cf);
+
+ if (skb)
+ cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+ cmd += SLC_CMD_LEN + 1;
+ for (i = 0; i < len; i++, cmd++) {
+ switch (*cmd) {
+ case 'a':
+ netdev_dbg(dev, "ACK error\n");
+ tx_errors = true;
+ if (skb) {
+ cf->can_id |= CAN_ERR_ACK;
+ cf->data[3] = CAN_ERR_PROT_LOC_ACK;
+ }
+
+ break;
+ case 'b':
+ netdev_dbg(dev, "Bit0 error\n");
+ tx_errors = true;
+ if (skb)
+ cf->data[2] |= CAN_ERR_PROT_BIT0;
+
+ break;
+ case 'B':
+ netdev_dbg(dev, "Bit1 error\n");
+ tx_errors = true;
+ if (skb)
+ cf->data[2] |= CAN_ERR_PROT_BIT1;
+
+ break;
+ case 'c':
+ netdev_dbg(dev, "CRC error\n");
+ rx_errors = true;
+ if (skb) {
+ cf->data[2] |= CAN_ERR_PROT_BIT;
+ cf->data[3] = CAN_ERR_PROT_LOC_CRC_SEQ;
+ }
+
+ break;
+ case 'f':
+ netdev_dbg(dev, "Form Error\n");
+ rx_errors = true;
+ if (skb)
+ cf->data[2] |= CAN_ERR_PROT_FORM;
+
+ break;
+ case 'o':
+ netdev_dbg(dev, "Rx overrun error\n");
+ rx_over_errors = true;
+ rx_errors = true;
+ if (skb) {
+ cf->can_id |= CAN_ERR_CRTL;
+ cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+ }
+
+ break;
+ case 'O':
+ netdev_dbg(dev, "Tx overrun error\n");
+ tx_errors = true;
+ if (skb) {
+ cf->can_id |= CAN_ERR_CRTL;
+ cf->data[1] = CAN_ERR_CRTL_TX_OVERFLOW;
+ }
+
+ break;
+ case 's':
+ netdev_dbg(dev, "Stuff error\n");
+ rx_errors = true;
+ if (skb)
+ cf->data[2] |= CAN_ERR_PROT_STUFF;
+
+ break;
+ default:
+ if (skb)
+ dev_kfree_skb(skb);
+
+ return;
+ }
+ }
+
+ if (rx_errors)
+ dev->stats.rx_errors++;
+
+ if (rx_over_errors)
+ dev->stats.rx_over_errors++;
+
+ if (tx_errors)
+ dev->stats.tx_errors++;
+
+ if (skb)
+ netif_rx(skb);
+}
+
+static void slc_bump(struct slcan *sl)
+{
+ switch (sl->rbuff[0]) {
+ case 'r':
+ fallthrough;
+ case 't':
+ fallthrough;
+ case 'R':
+ fallthrough;
+ case 'T':
+ return slc_bump_frame(sl);
+ case 'e':
+ return slc_bump_err(sl);
+ default:
+ return;
+ }
+}
+
/* parse tty input stream */
static void slcan_unesc(struct slcan *sl, unsigned char s)
{
--
2.32.0
