Re: [PATCH] net: stmmac: add explicit check and error on invalid PTP clock rate

[Yanteng Si <si.yanteng@linux.dev>]

在 5/26/25 10:42 PM, Alexis Lothoré 写道:
> On Mon May 26, 2025 at 4:22 AM CEST, Yanteng Si wrote:
>> 在 5/23/25 7:46 PM, Alexis Lothoré 写道:
>>> While some platforms implementing dwmac open-code the clk_ptp_rate
>>> value, some others dynamically retrieve the value at runtime. If the
>>> retrieved value happens to be 0 for any reason, it will eventually
>>> propagate up to PTP initialization when bringing up the interface,
>>> leading to a divide by 0:
> [...]
>
>>   From your description, I cannot determine the scope
>> of "some platforms". My point is: if there are only
>> a few platforms, can we find a way to handle this in
>> the directory of the corresponding platform?
>  From what I can see, it can affect any platform using the stmmac driver as
> the platform driver (except maybe dwmac-qcom-ethqos.c, which enforces an
> open-coded clk_ptp_rate after the stmmac_probe_config_dt call that sets
> the clk_ptp_rate), if the platform declares a dedicated clk_ptp_ref clock.
> So I would rather say that it can affect most of the platforms.
>
> In my case, I have observed the issue with the dwmac-stm32.c driver, on an
> STM32MP157a-dk1 platform.
Okay!
>
>> And there need a Fixes tag.
> Ok, I'll add a relevant Fixes tag.

On this premise,


Reviewed-by: Yanteng Si <si.yanteng@linux.dev>


Thanks,

Yanteng

>
> Alexis
>
>>> Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
>>> ---
>>>    drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +++++
>>>    1 file changed, 5 insertions(+)
>>>
>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>>> index 918d7f2e8ba992208d7d6521a1e9dba01086058f..f68e3ece919cc88d0bf199a394bc7e44b5dee095 100644
>>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>>> @@ -835,6 +835,11 @@ int stmmac_init_tstamp_counter(struct stmmac_priv *priv, u32 systime_flags)
>>>    	if (!(priv->dma_cap.time_stamp || priv->dma_cap.atime_stamp))
>>>    		return -EOPNOTSUPP;
>>>    
>>> +	if (!priv->plat->clk_ptp_rate) {
>>> +		netdev_err(priv->dev, "Invalid PTP clock rate");
>>> +		return -EINVAL;
>>> +	}
>>> +
>>>    	stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags);
>>>    	priv->systime_flags = systime_flags;
>>>    
>>>
>>> ---
>>> base-commit: e0e2f78243385e7188a57fcfceb6a19f723f1dff
>>> change-id: 20250522-stmmac_tstamp_div-f55112f06029
>>>
>>> Best regards,
>
>
>