On Tue, Apr 18, 2023 at 02:14:53PM +0300, Vladimir Oltean wrote:
> This was left as TODO in commit 01e23b2b3bad ("net: enetc: add support
> for preemptible traffic classes") since it's relatively complicated.
>
> Where this makes a difference is with a configuration as follows:
>
> ethtool --set-mm eno0 pmac-enabled on tx-enabled on verify-enabled on
>
> Preemptible packets should only be sent when the MAC Merge TX direction
> becomes active (i.o.w. when the verification process succeeds, aka when
> the link partner confirms it can process preemptible traffic). But the
> tc qdisc with the preemptible traffic classes is offloaded completely
> asynchronously w.r.t. the MM becoming active.
>
> The ENETC manual does suggest that this should be handled in the driver:
> "On startup, software should wait for the verification process to
> complete (MMCSR[VSTS]=011) before initiating traffic".
>
> Adding the necessary logic allows future selftests to uphold the claim
> that an inactive or disabled MAC Merge layer should never send data
> packets through the pMAC.
>
> This change moves enetc_set_ptcfpr() from enetc.c to enetc_ethtool.c,
> where its only caller is now - enetc_mm_commit_preemptible_tcs().
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
> int enetc_qos_query_caps(struct net_device *ndev, void *type_data);
> diff --git a/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c b/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c
> index deb674752851..838a92131963 100644
> --- a/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c
> +++ b/drivers/net/ethernet/freescale/enetc/enetc_ethtool.c
> @@ -991,6 +991,64 @@ static int enetc_get_mm(struct net_device *ndev, struct ethtool_mm_state *state)
> return 0;
> }
>
> +static int enetc_mm_wait_tx_active(struct enetc_hw *hw, int verify_time)
> +{
> + int timeout = verify_time * USEC_PER_MSEC * ENETC_MM_VERIFY_RETRIES;
> + u32 val;
> +
> + /* This will time out after the standard value of 3 verification
> + * attempts. To not sleep forever, it relies on a non-zero verify_time,
> + * guarantee which is provided by the ethtool nlattr policy.
> + */
> + return read_poll_timeout(enetc_port_rd, val,
> + ENETC_MMCSR_GET_VSTS(val) == 3,
nit: 3 is doing a lot of work here.
As a follow-up, perhaps it could become part of an enum?
> + ENETC_MM_VERIFY_SLEEP_US, timeout,
> + true, hw, ENETC_MMCSR);
> +}
...
