Le sam. 18 sept. 2021 à 08:49, François Ozog <francois.o...@linaro.org> a écrit :
> Hi Paul > > Too posting because I think we also need to address this at a higher level. > > i think we discussed this topic quite a while back. I may be wrong but it > may be Bill Mills who proposed to have an eeprom on the extensions that the > carrier board can use to detect and fetch proper overlay. Another way would > be that the contract between the extension board and the carrier board > includes an i2c accessible storage to fetch an overlay that would identify > the board and give all details. > i just forgot to state that the mode is well known: SPD for DIMMs. > Bottom line, a software only solution seems not entirely satisfying. > In that suboptimal case, U-Boot shall be able to assemble a DT for itself > and another for OS (may be same in some cases) through scripting. And in > this case, come your questions below > > . > > Le sam. 18 sept. 2021 à 01:21, Ying-Chun Liu (PaulLiu) <paul...@debian.org> > a écrit : > >> Hi all, >> >> >> I have some questions about how to implement extension board usage. >> My case is on imx8mm-cl-iot-gate. It can add three different types of >> extension boards. >> One of the extension boards is SPI extension which have 3 empty slots. >> And you can add >> some small boards onto it. One of them is a "TPM2" module. >> >> >> My first question is if I want to use tpm2 in U-boot for measured boot. >> How to implement this right? Currently I just modify the dts used by >> U-boot to let it drive >> the extension board. And let it drive the TPM. But it is not good for >> upstreaming because >> when other types of extension boards installed then it is not working. >> Where to implement this? What is the best practice of this? > > >> The second question is about extension manager. >> I have read the extension.rst. I think I'll implement this anyway >> because then >> I can have a command to query what type of extension boards I have. >> And if the extension board is the 3 slots one. I can then detect which >> slot is the TPM. >> I'll implement this anyway because the "extension" command is convenient >> for users. >> But it seems to me that it only solves the problem for Linux kernel. >> It can apply a DTB Overlay to Linux DTB to let Linux knows we have that >> extension board. >> But it is too late for U-boot itself, right? >> >> >> The third question is I'm also dong SystemReady IR certificate. That means >> the dtb for Linux is directly provided by U-boot. We use U-boot dtb >> directly to Linux >> kernel. In this case, how to modify that dts dynamically to feed to the >> Linux kernel by >> the extension manager? >> What is the best practice if I want to use U-boot dts for Linux in >> implementation? >> >> >> Thanks a lot. >> >> >> Yours, >> Paul >> >> >> -- > François-Frédéric Ozog | *Director Business Development* > T: +33.67221.6485 > francois.o...@linaro.org | Skype: ffozog > > -- François-Frédéric Ozog | *Director Business Development* T: +33.67221.6485 francois.o...@linaro.org | Skype: ffozog _______________________________________________ boot-architecture mailing list boot-architecture@lists.linaro.org https://lists.linaro.org/mailman/listinfo/boot-architecture
