Commit 0a9cdcf0 authored by Dario Binacchi's avatar Dario Binacchi Committed by Marc Kleine-Budde
Browse files

can: slcan: extend the protocol with CAN state info 

It extends the protocol to receive the adapter CAN state changes
(warning, busoff, etc.) and forward them to the netdev upper levels.

Link: https://lore.kernel.org/all/20220628163137.413025-13-dario.binacchi@amarulasolutions.com


Signed-off-by: default avatarDario Binacchi <dario.binacchi@amarulasolutions.com>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent b32ff466

drivers/net/can/slcan/slcan-core.c

+73 −1
Original line number Diff line number Diff line
@@ -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;

	}