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SubjectRe: [PATCH v3 13/13] can: slcan: extend the protocol with CAN state info
On 12.06.2022 23:39:27, Dario Binacchi wrote:
> 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@amarulasolutions.com>
>
> ---
>
> 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 | 66 ++++++++++++++++++++++++++++++
> 1 file changed, 66 insertions(+)
>
> diff --git a/drivers/net/can/slcan/slcan-core.c b/drivers/net/can/slcan/slcan-core.c
> index 48077edb9497..5ba1c141f942 100644
> --- a/drivers/net/can/slcan/slcan-core.c
> +++ b/drivers/net/can/slcan/slcan-core.c
> @@ -78,6 +78,9 @@ 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
>
> struct slcan {
> struct can_priv can;
> @@ -175,6 +178,67 @@ int slcan_enable_err_rst_on_open(struct net_device *ndev, bool on)
> * STANDARD SLCAN DECAPSULATION *
> ************************************************************************/
>
> +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;
> +
> + if (*cmd != 's')
> + return;

Checked by the caller?

> +
> + cmd += SLC_CMD_LEN;
> + switch (*cmd) {
> + 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 'f':
> + state = CAN_STATE_BUS_OFF;
> + break;
> + default:
> + return;
> + }
> +
> + if (state == sl->can.state)
> + return;
> +
> + cmd += SLC_STATE_BE_RXCNT_LEN + 1;

Have you checked that you have received that much data?

> + 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;

Why do you parse TX first and then RX?

> +
> + skb = alloc_can_err_skb(dev, &cf);
> +
> + if (skb) {
> + cf->data[6] = txerr;
> + cf->data[7] = rxerr;
> + }
> +
> + tx_state = txerr >= rxerr ? state : 0;
> + rx_state = txerr <= rxerr ? state : 0;
> + can_change_state(dev, skb ? cf : NULL, tx_state, rx_state);

alloc_can_err_skb() set cf to NULL if no skb can be allocated.

> +
> + if (state == CAN_STATE_BUS_OFF)
> + can_bus_off(dev);
> +
> + if (skb)
> + netif_rx(skb);
> +}
> +
> static void slc_bump_err(struct slcan *sl)
> {
> struct net_device *dev = sl->dev;
> @@ -378,6 +442,8 @@ 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
>
>

Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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