SPI driver for Raspberry Pi 4 (BMC2835)

[pierre fontaine]

Hi Johannes,

I'm also trying to make a secure boot using an SLB9670 TPM (SPI), Yocto
and a Raspberry 3, and as far as I'm documented
there are no hardware SPI driver due to the fact that `start.elf` and
`bootcode.bin` are being closed binaries
(https://pi3g.com/2019/02/04/qa-letstrust-tpm/).

However some people tried to deal with software SPI driver as a
workaround, but I don't know yet if it works (@see:
https://www.mail-archive.com/u-boot@lists.denx.de/msg330403.html).

Hope it brings some clues, if you manage to do something keep me updated !

Have a nice day,

Pierre Fontaine

Le 25/03/2020 à 09:08, J. Holland a écrit :
> Hi,
>
> does anyone know, if there is a SPI driver for Raspberry Pi 4 in U-Boot?
>
> I want to communicate with a TPM 2.0 via hardware SPI. So far I've
> compiled
> mainline U-Boot with TPM driver support. However, the SPI driver seems
> to be
> missing.
>
> The linux kernel ships the driver (drivers/spi/spi-bcm2835.c). Does
> anyone know
> if there is there a port for U-Boot or if anyone is currently working
> on it?
>
> In theory, I should be able to use the soft SPI driver (since there is a
> GPIO
> driver), but I'd very much prefer using the hardware SPI controller.
>
> Many thanks!
>
> Best,
> Johannes
>