Re: [PATCH net-next 4/7] net: lan966x: Implement SIOCSHWTSTAMP and SIOCGHWTSTAMP

[Richard Cochran <richardcochran@gmail.com>]

On Thu, Jan 27, 2022 at 11:23:30AM +0100, Horatiu Vultur wrote:

> diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c b/drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c
> index 69d8f43e2b1b..9ff4d3fca5a1 100644
> --- a/drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c
> +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c
> @@ -35,6 +35,90 @@ static u64 lan966x_ptp_get_nominal_value(void)
>  	return res;
>  }
>  
> +int lan966x_ptp_hwtstamp_set(struct lan966x_port *port, struct ifreq *ifr)
> +{
> +	struct lan966x *lan966x = port->lan966x;
> +	bool l2 = false, l4 = false;
> +	struct hwtstamp_config cfg;
> +	struct lan966x_phc *phc;
> +
> +	/* For now don't allow to run ptp on ports that are part of a bridge,
> +	 * because in case of transparent clock the HW will still forward the
> +	 * frames, so there would be duplicate frames
> +	 */
> +	if (lan966x->bridge_mask & BIT(port->chip_port))
> +		return -EINVAL;
> +
> +	if (copy_from_user(&cfg, ifr->ifr_data, sizeof(cfg)))
> +		return -EFAULT;
> +
> +	switch (cfg.tx_type) {
> +	case HWTSTAMP_TX_ON:
> +		port->ptp_cmd = IFH_REW_OP_TWO_STEP_PTP;
> +		break;
> +	case HWTSTAMP_TX_ONESTEP_SYNC:
> +		port->ptp_cmd = IFH_REW_OP_ONE_STEP_PTP;
> +		break;
> +	case HWTSTAMP_TX_OFF:
> +		port->ptp_cmd = IFH_REW_OP_NOOP;
> +		break;
> +	default:
> +		return -ERANGE;
> +	}
> +
> +	mutex_lock(&lan966x->ptp_lock);

No need to lock stack variables.  Move locking down to ...

> +	switch (cfg.rx_filter) {
> +	case HWTSTAMP_FILTER_NONE:
> +		break;
> +	case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
> +	case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
> +	case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
> +		l4 = true;
> +		break;
> +	case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
> +	case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
> +	case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
> +		l2 = true;
> +		break;
> +	case HWTSTAMP_FILTER_PTP_V2_EVENT:
> +	case HWTSTAMP_FILTER_PTP_V2_SYNC:
> +	case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
> +		l2 = true;
> +		l4 = true;
> +		break;
> +	default:
> +		mutex_unlock(&lan966x->ptp_lock);
> +		return -ERANGE;
> +	}
> +
> +	if (l2 && l4)
> +		cfg.rx_filter = HWTSTAMP_FILTER_PTP_V2_EVENT;
> +	else if (l2)
> +		cfg.rx_filter = HWTSTAMP_FILTER_PTP_V2_L2_EVENT;
> +	else if (l4)
> +		cfg.rx_filter = HWTSTAMP_FILTER_PTP_V2_L4_EVENT;
> +	else
> +		cfg.rx_filter = HWTSTAMP_FILTER_NONE;
> +
> +	/* Commit back the result & save it */

... here

> +	phc = &lan966x->phc[LAN966X_PHC_PORT];
> +	memcpy(&phc->hwtstamp_config, &cfg, sizeof(cfg));
> +	mutex_unlock(&lan966x->ptp_lock);
> +
> +	return copy_to_user(ifr->ifr_data, &cfg, sizeof(cfg)) ? -EFAULT : 0;
> +}

Thanks,
Richard