LwIP and multiple network interfaces

[Jerome Forissier]

On 1/3/25 02:52, E Shattow wrote:
> 
> 
> On 1/2/25 17:40, Tom Rini wrote:
>> On Thu, Jan 02, 2025 at 05:34:57PM -0800, E Shattow wrote:
>>
>>> Tom sorry about sending this reply twice, struggle here is with Thunderbird
>>> mail UI sometimes hiding "Reply All" and it missed the mail list first time
>>> around.
>>
>> No problem.
>>
>>> On 1/2/25 14:47, Tom Rini wrote:
>>>> On Thu, Jan 02, 2025 at 02:26:06PM -0800, E Shattow wrote:
>>>>> Problem: 'dhcp' must be ran twice when the network cable is plugged into a
>>>>> port other than the first network port.
>>>>>
>>>>> Network cable plugged into bottom (first) Ethernet port:
>>>>> 1. Power on
>>>>> 2. StarFive # dhcp
>>>>>
>>>>> ethernet at 16030000 Waiting for PHY auto negotiation to complete....... done
>>>>> DHCP client bound to address 192.168.2.51 (3678 ms)
>>>>>
>>>>>
>>>>> Network cable plugged into top (second) Ethernet port:
>>>>> 1. Power on
>>>>> 2. StarFive # dhcp
>>>>> ethernet at 16030000 Waiting for PHY auto negotiation to complete.........
>>>>> TIMEOUT !
>>>>> phy_startup() failed: -110
>>>>> FAILED: -110
>>>>> ethernet at 16040000 Waiting for PHY auto negotiation to complete...... done
>>>>> ethernet at 16030000 Waiting for PHY auto negotiation to complete.........
>>>>> TIMEOUT !
>>>>> phy_startup() failed: -110
>>>>> FAILED: -110
>>>>> Could not start ethernet at 16030000
>>>>> 3. StarFive # dhcp
>>>>> DHCP client bound to address 192.168.2.77 (31 ms)
>>>>
>>>> What happens when you set ethact to 1 first?
>>>>
>>>
>>>
>>> '1' literal does not seem to do something so I guess it is meant the id of
>>> the first ethernet interface:
>>
>> Yes, I misspoke sorry.
>>
>>>  From power-on:
>>>
>>> ...
>>> starfive_7110_pcie pcie at 2b000000: Starfive PCIe bus probed.
>>> starfive_7110_pcie pcie at 2c000000: Starfive PCIe bus probed.
>>> In:    serial at 10000000
>>> Out:   serial at 10000000
>>> Err:   serial at 10000000
>>> Net:   eth0: ethernet at 16030000, eth1: ethernet at 16040000
>>> starting USB...
>>> No USB controllers found
>>> Working FDT set to ff700a10
>>> StarFive # env print ethact
>>> ## Error: "ethact" not defined
>>> StarFive # env set ethact 1
>>> StarFive # dhcp
>>> ethernet at 16030000 Waiting for PHY auto negotiation to complete.........
>>> TIMEOUT !
>>> phy_startup() failed: -110
>>> FAILED: -110
>>> ethernet at 16040000 Waiting for PHY auto negotiation to complete...... done
>>> EQOS_DMA_MODE_SWR stuck
>>> FAILED: -110
>>> Could not start ethernet at 16030000
>>>
>>> Again, from power-on:
>>>
>>> starfive_7110_pcie pcie at 2b000000: Starfive PCIe bus probed.
>>> starfive_7110_pcie pcie at 2c000000: Starfive PCIe bus probed.
>>> In:    serial at 10000000
>>> Out:   serial at 10000000
>>> Err:   serial at 10000000
>>> Net:   eth0: ethernet at 16030000, eth1: ethernet at 16040000
>>> starting USB...
>>> No USB controllers found
>>> Working FDT set to ff700a10
>>> StarFive # env print ethact
>>> ## Error: "ethact" not defined
>>> StarFive # env set ethact ethernet at 16040000
>>> StarFive # dhcp
>>> ethernet at 16040000 Waiting for PHY auto negotiation to complete...... done
>>> DHCP client bound to address 192.168.2.77 (149 ms)
>>
>> So then yes, the second interface works when ethact is set to use that
>> directly. This is the same behavior as the legacy stack I believe.
>>
> 
> Legacy stack does actually rotate and complete successfully when ethact environment variable does not exist and (eventually) configure the second interface though. Here with LwIP the procedure fails.
> 
> Notice that here it starts with ethernet at 16030000, then rotates to ethernet at 16040000 unsuccessfully, and back again to ethernet at 16030000 before (again) failing and giving up. There is a network cable plugged into 'ethernet at 16040000' port and if we try the command again the environment variable ethact retained 'ethact=ethernet at 16040000' from the failed procedure so you're right it works as it should... except that it totally failed to do what was expected the first time.

That's unexpected indeed.

> Is this exposing a problem with this board network driver and behavior or is it something with LwIP ?
Hard to tell at this point. One thing I know for sure is that lwIP expects
eth_set_current() (called from do_dhcp()) to actually pick a valid
interface if there is one. So it should definitely select ethernet at 16040000
in your scenario. Adding debug prints to eth_set_current(),
eth_current_changed() etc. should help.

Thanks,
-- 
Jerome