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. Can the DT perhaps go before U-Boot in the flash? We would need a way to find it though. With binman it is possible to put the DT anyway and have a symbol defined to its address. Would that help? Regards, Simon _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
