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