Re: [U-Boot-Users] Ideas on U-Boot configuration with FDT

Wolfgang Grandegger wrote:

 CPU:  MPC5200 v1.0, Core v1.1 at 396 MHz
       Bus 132 MHz, IPB 66 MHz, PCI 33 MHz
 FDT:  FDT_ERR_BADMAGIC (or OK, or version number?)

At this level also the compatibility of the FDT tree could be checked
using fdt_boardcheck().

I think fdt_checkboard() (or boardcheck) should be run from inside the fdt_open_into() command. This takes advantage of the existing mechanism of fdt_open_into() to return an error. It also allows for a device tree to be opened after U-Boot has booted.

• After relocation, the blob is copied into memory via fdt_open_into() to a defined place and "fdt" is updated accordingly.

So we'll need to have CFG_FDT_ADDR_FLASH and CFG_FDT_ADDR_RAM.

Not sure, what location in RAM to use, but it should fit into the existing scheme. Any recommendations?

• When U-Boot is up, "fdt" points to a valid FDT, e.g. "fdt addr" is not necessary.

I think this feature needs to be optional. That is, if CFG_FDT_ADDR_xxx are defined, then we can enable this feature. Otherwise, fdt_addr will still be necessary. Remember, we'll still need to support architectures that don't have device trees.