Re: [PATCH net] net: sparx5: start the domain 0 TOD counter on non-PTP lan969x variants

[Daniel Machon <daniel.machon@microchip.com>]

Hi Quentin,

> Currently the base non-PTP capable lan969x variants don't forward any
> ethernet frames. Testing showed that starting the domain 0 TOD counter
> gets them working again.

Ack. Not initializing the TOD domains on certain variants is a problem.

However, TOD domains shouldn't affect basic forwarding. I tried it on my board
with PTP forced off - no forwarding issues.

Certain TSN features do require TOD domains to be configured, though. How did
you test this, and what exactly did you see fail?

> 
> Fix by moving the TOD counter start code into a helper and calling it in
> sparx5_ptp_init(). Non-PTP capable lan969x parts now start the domain 0
> counter, and PTP-capable parts start all three, as they used to. A similar
> workaround that starts all three and registers the PHC clocks is
> implemented in the vendor BSP 6.18 kernel [1].

What we do downstream, is to ensure that all domains and PHC's are configured
and registered on all variants, with a very simple is_sparx5() check. 

> 
> [1] https://github.com/microchip-ung/linux/tree/bsp-6.18-2026
> 
> Fixes: 207966787b71 ("net: sparx5: add feature support")
> Signed-off-by: Quentin Freimanis <quentin@q-lab.dev>
> ---
> If anyone with access to documentation more detailed than the
> register map knows WHY this clock needs to be running, I'd like to add
> that to the commit message.


> 
>  .../ethernet/microchip/sparx5/sparx5_ptp.c    | 72 +++++++++++++------
>  1 file changed, 49 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_ptp.c b/drivers/net/ethernet/microchip/sparx5/sparx5_ptp.c
> index 5953e04ef14e..b436684ddae6 100644
> --- a/drivers/net/ethernet/microchip/sparx5/sparx5_ptp.c
> +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_ptp.c
> @@ -573,6 +573,42 @@ static int sparx5_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
>         return 0;
>  }
> 
> +static int sparx5_ptp_tod_start(struct sparx5 *sparx5, u8 phc_mask)
> +{
> +       u64 tod_adj = sparx5_ptp_get_nominal_value(sparx5);
> +       int i;
> +
> +       if (phc_mask > GENMASK(SPARX5_PHC_COUNT - 1, 0))
> +               return -EINVAL;
> +
> +       /* Disable master counters */
> +       spx5_wr(PTP_PTP_DOM_CFG_PTP_ENA_SET(0), sparx5, PTP_PTP_DOM_CFG);
> +
> +       /* Configure the nominal TOD increment per clock cycle */
> +       spx5_rmw(PTP_PTP_DOM_CFG_PTP_CLKCFG_DIS_SET(phc_mask),
> +                PTP_PTP_DOM_CFG_PTP_CLKCFG_DIS,
> +                sparx5, PTP_PTP_DOM_CFG);
> +
> +       for (i = 0; i < SPARX5_PHC_COUNT; ++i) {
> +               if (!(phc_mask & BIT(i)))
> +                       continue;
> +
> +               spx5_wr((u32)tod_adj & 0xFFFFFFFF, sparx5,
> +                       PTP_CLK_PER_CFG(i, 0));
> +               spx5_wr((u32)(tod_adj >> 32), sparx5,
> +                       PTP_CLK_PER_CFG(i, 1));
> +       }
> +
> +       spx5_rmw(PTP_PTP_DOM_CFG_PTP_CLKCFG_DIS_SET(0),
> +                PTP_PTP_DOM_CFG_PTP_CLKCFG_DIS,
> +                sparx5, PTP_PTP_DOM_CFG);
> +
> +       /* Enable master counters */
> +       spx5_wr(PTP_PTP_DOM_CFG_PTP_ENA_SET(phc_mask), sparx5, PTP_PTP_DOM_CFG);
> +
> +       return 0;
> +}
> +
>  static struct ptp_clock_info sparx5_ptp_clock_info = {
>         .owner          = THIS_MODULE,
>         .name           = "sparx5 ptp",
> @@ -605,7 +641,6 @@ static int sparx5_ptp_phc_init(struct sparx5 *sparx5,
> 
>  int sparx5_ptp_init(struct sparx5 *sparx5)
>  {
> -       u64 tod_adj = sparx5_ptp_get_nominal_value(sparx5);
>         const struct sparx5_ops *ops = sparx5->data->ops;
>         struct sparx5_port *port;
>         int err, i;
> @@ -622,8 +657,17 @@ int sparx5_ptp_init(struct sparx5 *sparx5)
>                 sparx5->ptp = 1;
>         }
> 
> -       if (!sparx5->ptp)
> +       if (!sparx5->ptp) {
> +               if (!is_sparx5(sparx5)) {
> +                       /* the base, non-ptp-capable lan969x variants need the first tod counter

Nit: s/the/The

> +                        * running to forward frames.
> +                        */
> +                       err = sparx5_ptp_tod_start(sparx5, BIT(0));
> +                       if (err)
> +                               return err;
> +               }
>                 return 0;
> +       }
> 
>         for (i = 0; i < SPARX5_PHC_COUNT; ++i) {
>                 err = sparx5_ptp_phc_init(sparx5, i, &sparx5_ptp_clock_info);
> @@ -635,27 +679,9 @@ int sparx5_ptp_init(struct sparx5 *sparx5)
>         spin_lock_init(&sparx5->ptp_ts_id_lock);
>         mutex_init(&sparx5->ptp_lock);
> 
> -       /* Disable master counters */
> -       spx5_wr(PTP_PTP_DOM_CFG_PTP_ENA_SET(0), sparx5, PTP_PTP_DOM_CFG);
> -
> -       /* Configure the nominal TOD increment per clock cycle */
> -       spx5_rmw(PTP_PTP_DOM_CFG_PTP_CLKCFG_DIS_SET(0x7),
> -                PTP_PTP_DOM_CFG_PTP_CLKCFG_DIS,
> -                sparx5, PTP_PTP_DOM_CFG);
> -
> -       for (i = 0; i < SPARX5_PHC_COUNT; ++i) {
> -               spx5_wr((u32)tod_adj & 0xFFFFFFFF, sparx5,
> -                       PTP_CLK_PER_CFG(i, 0));
> -               spx5_wr((u32)(tod_adj >> 32), sparx5,
> -                       PTP_CLK_PER_CFG(i, 1));
> -       }
> -
> -       spx5_rmw(PTP_PTP_DOM_CFG_PTP_CLKCFG_DIS_SET(0),
> -                PTP_PTP_DOM_CFG_PTP_CLKCFG_DIS,
> -                sparx5, PTP_PTP_DOM_CFG);
> -
> -       /* Enable master counters */
> -       spx5_wr(PTP_PTP_DOM_CFG_PTP_ENA_SET(0x7), sparx5, PTP_PTP_DOM_CFG);
> +       err = sparx5_ptp_tod_start(sparx5, GENMASK(SPARX5_PHC_COUNT - 1, 0));
> +       if (err)
> +               return err;
> 
>         for (i = 0; i < sparx5->data->consts->n_ports; i++) {
>                 port = sparx5->ports[i];
> --
> 2.55.0
> 
>

/Daniel