Re: [PATCH 00/10] Add support for Ethernet Boot on SK-AM62

[Siddharth Vadapalli <s-vadapalli@ti.com>]

On 12/01/24 18:12, Nishanth Menon wrote:
> On 18:06-20240112, Siddharth Vadapalli wrote:
>>
>>
>> On 12/01/24 18:02, Nishanth Menon wrote:
>>> On 12:17-20240112, Siddharth Vadapalli wrote:
>>>> Hello,
>>>>
>>>> This series enables Ethernet Boot on SK-AM62 device.
>>>> Product Link: https://www.ti.com/tool/SK-AM62
>>>> User Guide: https://www.ti.com/lit/pdf/spruj40
>>>>
>>>> Ethernet Boot flow is as follows:
>>>> 1. The BOOT MODE pins are configured for Ethernet Boot.
>>>> 2. On powering on the device, ROM uses the Ethernet Port corresponding
>>>> to CPSW3G's MAC Port 1 to transmit "TI K3 Bootp Boot".
>>>> 3. The TFTP server and DHCP server on the receiver device need to be
>>>> configured such that VCI string "TI K3 Bootp Boot" maps to the file
>>>> "tiboot3.bin" and the TFTP server should be capable of transferring
>>>> it to the device.
>>>> 4. ROM loads and executes "tiboot3.bin" provided by the TFTP server.
>>>> 5. The "tiboot3.bin" file is expected to be built using the config:
>>>> am62x_evm_r5_ethboot_defconfig
>>>> introduced in this series, which shall enable "tispl.bin" to be fetched
>>>> over TFTP using "tiboot3.bin".
>>>> 6. "tiboot3.bin" is configured to transmit "AM62X U-Boot R5 SPL" as its
>>>> NET_VCI_STRING, thereby implying that the DHCP server and TFTP server
>>>> need to be configured to transfer "tispl.bin" to the device.
>>>> 7. "tiboot3.bin" loads and executes "tispl.bin" provided by the TFTP
>>>> server.
>>>> 8. The "tispl.bin" file is expected to be built using the config:
>>>> am62x_evm_a53_defconfig
>>>> which has been updated in this series to enable Ethernet Boot specific
>>>> configs, allowing "u-boot.img" to be fetched over TFTP using
>>>> "tispl.bin".
>>>> 9. "tispl.bin" is configured to transmit "AM62X U-Boot A53 SPL" as its
>>>> NET_VCI_STRING. The DHCP server and TFTP server need to be configured to
>>>> transfer "u-boot.img" to the device for the aforementioned NET_VCI_STRING.
>>>> 10. "tispl.bin" then fetches "u-boot.img" using TFTP and loads and
>>>> executes it on the device, completing the process of Ethernet Boot on the
>>>> device.
>>>>
>>>> NOTE: ROM configures CPSW3G's MAC Port 1 for 100 Mbps full-duplex mode
>>>> of operation due to which it is expected that the Link Partner also
>>>> supports the same mode of operation.
>>>> Additionally, enabling "phy_gmii_sel" node at SPL stage will be
>>>> necessary and is not added as a part of this series with the aim of
>>>> adding the "bootph-all" property to its counterpart in Linux device-tree
>>>> first.
>>>
>>>
>>> NAK - instead of writing all this up in the commit message, why would
>>> you not spend that time updating the excellent documentation we have?
>>
>> I plan to document it after the feature is in. The reason for mentioning the
>> content above is for explaining the flow in case anyone wishes to test and
>> verify it. Wouldn't documenting it make it appear that the feature is present
>> when it isn't?
> 
> So you are saying this series does NOT work! why are you sending patches
> then? If you are introducing a feature and enabling it, ensure you send
> documentation along with it allowing people to be able to actually use
> the feature.

I have mentioned in the "NOTE" above that enabling "phy_gmii_sel" node at SPL
stage by adding the "bootph-all" property is necessary to verify this series.
I cannot post that with this series since Linux device-tree needs to have the
property added first and the merge window is closed now. Once it is in the Linux
device-tree, syncing U-Boot device-tree with Linux device-tree will enable
Ethernet Boot which is when the feature will work. That is when I was planning
to document it. However, based on your feedback, in the next version for this
series I will add the documentation as well along with the note that
"phy_gmii_sel" needs to be enabled at SPL stage for the feature to work.

Please let me know if that is acceptable.

> 

-- 
Regards,
Siddharth.