Re: [PATCH v2 1/2] efi: SPI NOR flash support

[Heinrich Schuchardt]

On 11.02.21 17:01, Michael Lawnick wrote:
> Am 11.02.2021 um 15:04 schrieb Heinrich Schuchardt:
>> On 11.02.21 13:50, Michael Lawnick wrote:
>>> Hi,
>>> Several boot parameters are stored in our SPI flash to configure the
>>> systems for different use cases.
>>
>> I still do not understand why you need access in GRUB. You can read and
>> write the SPI flash in U-Boot on your embedded system.
>
> In our latest system we get U-Boot from vendor. We try to change nothing
> in it. To execute our boot management we let start GRUB as an EFI app.
> The boot management needs configuration information which depends on
> customer deployment scenario saved in SPI flash. It is our boot
> management S/W which uses the EFI_SPI_NOR interface.

You should consider upstreaming your board to mainline U-Boot.

>
>> Maybe you could provide a short example script showing how the new
>> command would fit into the GRUB boot flow.
>
> The spi_nor command is more intended as an example application and for
> test, not intended for real use. I have no problem to deactivate it by
> default (put it to separate config module) or even completely remove it.
> My real point is the driver to abstract away the H/W and take EFI into
> use if available.

U-Boot does not provide the EFI_SPI_NOR_FLASH_PROTOCOL. How will you
ever use the spi_nor command?

How about creating a UEFI application that can run

* in the UEFI shell
* directly from the UEFI boot manager
* from GRUB EFI

and upstreaming that utility to Tianocore EDK II which already has the
protocol that you want to consume?

Best regards

Heinrich