imx8mp EQOS regression in dwc_eth_qos,c

[Marek Vasut]

On 2/14/23 18:31, Elmar Psilog wrote:
> Am 13.02.23 um 22:20 schrieb Marek Vasut:
> 
>> On 2/13/23 22:04, Fabio Estevam wrote:
>>> Adding Marek, who has sent some EQOS patches recently.
>>>
>>> On Mon, Feb 13, 2023 at 6:02 PM Elmar Psilog <epsi at gmx.de> wrote:
>>>>
>>>> Hello,
>>>> Think I found a regression in EQOS driver with fixed-phy. Maybe someone
>>>> with a imx8mp board might check that use case to confirm? That would be
>>>> great.
>>>> While ethernet was working in v2022.04 a "ping" in v2023.01 returns
>>>>
>>>> ERROR: no/invalid <fixed-link> property!
>>>> invalid speed 0 eqos_adjust_link() failed: -22 FAILED
>>>>
>>>> although devicetree/hardware kept unchanged.
>>>> This happens because in file fixed.c in in function fixedphy_config()
>>>> the call
>>>>
>>>>           val = ofnode_read_u32_default(node, "speed", 0);
>>>>
>>>> returns 0 instead of 1000 and also the duplex is not set. Found 
>>>> that  in
>>>> file/function dwc_eth_qos.c / eqos_start() the line
>>>>
>>>> eqos->phy->node = eqos->phy_of_node;
>>>>
>>>> is responsible for losing the information. Don't know what magic 
>>>> happens
>>>> here - so I can't fix it - I just followed the data. So all works well
>>>> and even the parsing of old and new fixed-link devicetree works til 
>>>> that
>>>> line. After that I don't get speed anymore. Maybe you can have a 
>>>> look at
>>>> this?
>>
>> Try this patch (needs CONFIG_FIXED_PHY=y) :
>>
>> diff --git a/drivers/net/dwc_eth_qos.c b/drivers/net/dwc_eth_qos.c
>> index d488bd0c288..592af53b352 100644
>> --- a/drivers/net/dwc_eth_qos.c
>> +++ b/drivers/net/dwc_eth_qos.c
>> @@ -791,9 +791,21 @@ static int eqos_start(struct udevice *dev)
>>          */
>>         if (!eqos->phy) {
>>                 int addr = -1;
>> -               addr = eqos_get_phy_addr(eqos, dev);
>> -               eqos->phy = phy_connect(eqos->mii, addr, dev,
>> - eqos->config->interface(dev));
>> +               ofnode fixed_node;
>> +
>> +               if (IS_ENABLED(CONFIG_PHY_FIXED)) {
>> +                       fixed_node = ofnode_find_subnode(dev_ofnode(dev),
>> + "fixed-link");
>> +                       if (ofnode_valid(fixed_node)) {
>> +                               eqos->phy = 
>> fixed_phy_create(dev_ofnode(dev));
>> +               }
>> +
>> +               if (!eqos->phy) {
>> +                       addr = eqos_get_phy_addr(eqos, dev);
>> +                       eqos->phy = phy_connect(eqos->mii, addr, dev,
>> + eqos->config->interface(dev));
>> +               }
>> +
>>                 if (!eqos->phy) {
>>                         pr_err("phy_connect() failed");
>>                         goto err_stop_resets;
> 
> Thanks Fabio for forwarding and Marek for the quick patch! Don't get 
> this exactly.
> Bit confused about the closing "}"  in if(IS_ENABLED) seems to be missed 
> (or an else path)?
> Where exactly should this be? From the insertion it looks like you mean:

Yes, the { shouldn't be at the end of 'if (ofnode_valid(fixed_node)) {' .

> +               if (IS_ENABLED(CONFIG_PHY_FIXED)) {
> +                       fixed_node = ofnode_find_subnode(dev_ofnode(dev),
> +                               "fixed-link");
> +                       if (ofnode_valid(fixed_node)) {
> +                               eqos->phy = 
> fixed_phy_create(dev_ofnode(dev));

Add this here (*) too (see below):

eqos->phy_of_node = fixed_node;

> +                       }

This works too.

> +               }
> +               if (!eqos->phy) {
> +                       addr = eqos_get_phy_addr(eqos, dev);
> +                       eqos->phy = phy_connect(eqos->mii, addr, dev, 
> eqos->config->interface(dev));
> +               }
> ....
> 
> But that doesn't solve the issue. The magic line
> 
> eqos->phy->node = eqos->phy_of_node;
> 
> will still executed.

See (*) above , does that help ?

> Likely a different issue but connected to EQOS: I am wondering why the 
> clocks for ethernet look so much different if FEC is not configured. 
> Shouldn't be the case, right? At least imx8mp.dtsi doesn't tell about 
> any 24MHz clock. Also counter is "0"? Well, EQOS works with uncommenting 
> the line above and this clock, but why?

Each device is probed on first use, so the clock are left unconfigured 
until the device is actually used (e.g. for ethernet transfer). Note 
that there is a huge series which overhauls the EQoS and FEC clock on 
the ML, see:

[PATCH v3 01/14] clk: imx8mp: Add EQoS MAC clock