Hi Prabhakar, On Thu, Jun 28, 2018 at 6:05 AM, Simon Glass <s...@chromium.org> wrote: > Hi, > > On 27 June 2018 at 08:06, York Sun <york....@nxp.com> wrote: >> >> +Simon >> >> On 06/27/2018 01:05 AM, Prabhakar Kushwaha wrote: >> > Hi All, >> > >> > We are trying to add support of device-tree for PowerPC platforms. As per >> > our analysis following 2 options can be used. >> > >> > a) CONFIG_OF_SEPARATE >> > b) CONFIG_OF_EMBED >> > >> > In PowerPC platforms, reset_vector is always expected at the **last** >> > address of flash. >> > U-boot binary has reset_vector at last followed by __bss sections(not >> > present in binary) and must be programmed in such a way that reset_vecrot >> > lie at **last** address of flash. >> > >> > Hence dtb cannot be appended at last of u-boot binary. >> > >> > So there looks to be following 2 possible solutions >> > a) Use CONFIG_OF_SEPARATE and append dtb at start of u-boot binary. This >> > require change in flash map because u-boot start address needs to shifted >> > (due to reset_vector requirements). >> > Exiting offset of env and fman ucode also needs shifting. This >> > approach requires modification in almost all existing PowerPC platform to >> > adhere to new **modified** flash map. >> > >> > b) Use CONFIG_OF_EMBED and embed dtb inside u-boot. This way no change in >> > exiting flash map. But its usage is being discouraged as per >> > doc/README.fdt-control. >> > >> >> Clearly putting dtb at the very end doesn't work, neither last 4KB. I >> think we either use CONFIG_OF_EMBED (many boards use this way), or try >> "fdtcontroladdr". > > > I discourage CONFIG_OF_EMBED - it is a debug feature. I'm not sure if > you have other options though. >
Agree. > Can the DT perhaps go before U-Boot in the flash? We would need a way > to find it though. > I don't see any issue that DT go after U-Boot in the flash. x86 does this way, and its reset vector is also the last address of flash. > With binman it is possible to put the DT anyway and have a symbol > defined to its address. Would that help? Regards, Bin _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot