It extends the protocol to receive the adapter CAN state changes
(warning, busoff, etc.) and forward them to the netdev upper levels.
Signed-off-by: Dario Binacchi <dario.binacchi@xxxxxxxxxxxxxxxxxxxx>
---
(no changes since v4)
Changes in v4:
- Add description of slc_bump_state() function.
- Remove check for the 's' character at the beggining of the function.
It was already checked by the caller function.
- Protect decoding against the case the frame len is longer than the
received data (add SLC_STATE_FRAME_LEN macro).
- Set cf to NULL in case of alloc_can_err_skb() failure.
- Some small changes to make the decoding more readable.
- Use the character 'b' instead of 'f' for bus-off state.
Changes in v3:
- Drop the patch "can: slcan: simplify the device de-allocation".
- Add the patch "can: netlink: dump bitrate 0 if can_priv::bittiming.bitrate is -1U".
Changes in v2:
- Continue error handling even if no skb can be allocated.
drivers/net/can/slcan/slcan-core.c | 74 +++++++++++++++++++++++++++++-
1 file changed, 73 insertions(+), 1 deletion(-)
diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c
index 4269b2267be2..54d29a410ad5 100644
--- a/drivers/net/can/slcan/slcan-core.c
+++ b/drivers/net/can/slcan/slcan-core.c
@@ -78,7 +78,11 @@ MODULE_PARM_DESC(maxdev, "Maximum number of slcan interfaces");
#define SLC_CMD_LEN 1
#define SLC_SFF_ID_LEN 3
#define SLC_EFF_ID_LEN 8
-
+#define SLC_STATE_LEN 1
+#define SLC_STATE_BE_RXCNT_LEN 3
+#define SLC_STATE_BE_TXCNT_LEN 3
+#define SLC_STATE_FRAME_LEN (1 + SLC_CMD_LEN + SLC_STATE_BE_RXCNT_LEN + \
+ SLC_STATE_BE_TXCNT_LEN)
struct slcan {
struct can_priv can;
int magic;
@@ -254,6 +258,72 @@ static void slc_bump_frame(struct slcan *sl)
dev_kfree_skb(skb);
}
+/* A change state frame must contain state info and receive and transmit
+ * error counters.
+ *
+ * Examples:
+ *
+ * sb256256 : state bus-off: rx counter 256, tx counter 256
+ * sa057033 : state active, rx counter 57, tx counter 33
+ */
+static void slc_bump_state(struct slcan *sl)
+{
+ struct net_device *dev = sl->dev;
+ struct sk_buff *skb;
+ struct can_frame *cf;
+ char *cmd = sl->rbuff;
+ u32 rxerr, txerr;
+ enum can_state state, rx_state, tx_state;
+
+ switch (cmd[1]) {
+ case 'a':
+ state = CAN_STATE_ERROR_ACTIVE;
+ break;
+ case 'w':
+ state = CAN_STATE_ERROR_WARNING;
+ break;
+ case 'p':
+ state = CAN_STATE_ERROR_PASSIVE;
+ break;
+ case 'b':
+ state = CAN_STATE_BUS_OFF;
+ break;
+ default:
+ return;
+ }
+
+ if (state == sl->can.state || sl->rcount < SLC_STATE_FRAME_LEN)
+ return;
+
+ cmd += SLC_STATE_BE_RXCNT_LEN + SLC_CMD_LEN + 1;
+ cmd[SLC_STATE_BE_TXCNT_LEN] = 0;
+ if (kstrtou32(cmd, 10, &txerr))
+ return;
+
+ *cmd = 0;
+ cmd -= SLC_STATE_BE_RXCNT_LEN;
+ if (kstrtou32(cmd, 10, &rxerr))
+ return;
+
+ skb = alloc_can_err_skb(dev, &cf);
+ if (skb) {
+ cf->data[6] = txerr;
+ cf->data[7] = rxerr;
+ } else {
+ cf = NULL;
+ }
+
+ tx_state = txerr >= rxerr ? state : 0;
+ rx_state = txerr <= rxerr ? state : 0;
+ can_change_state(dev, cf, tx_state, rx_state);
+
+ if (state == CAN_STATE_BUS_OFF)
+ can_bus_off(dev);
+
+ if (skb)
+ netif_rx(skb);
+}
+
/* An error frame can contain more than one type of error.
*
* Examples:
@@ -387,6 +457,8 @@ static void slc_bump(struct slcan *sl)
return slc_bump_frame(sl);
case 'e':
return slc_bump_err(sl);
+ case 's':
+ return slc_bump_state(sl);
default:
return;
}
--
2.32.0
