[U-Boot-Users] Ideas on U-Boot configuration with FDT
Wolfgang Denk
wd at denx.de
Sun May 20 11:33:35 CEST 2007
In message <46500875.6060706 at grandegger.com> you wrote:
>
> CFG_FDT_ADDR_FLASH:
> If defined, "fdt" is set to that address at compile time. The
> FDT can be used from the early beginning of the boot.
Just nitpicking: maybe we should call this CFG_FDT_ADDR_STATIC or
CFG_FDT_ADDR_DEFAULT or CFG_FDT_ADDR_INIT or something like that.
Rationale: flash is just one of the possible storage devies - it
could be ROM instead, or even RAM in certain configurations.
Also, while we are defining this, please keep in mind that sooner or
later someone will come up with the idea of storing the FDT in EEPROM,
so we might want to reserve such identifiers.
> CFG_FDT_ADDR_BY_ENV:
> If defined, the env variable "fdtaddr" is looked up early in the
> boot and "fdt" is set accordingly. This allows to hold more than
> one blob in FLASH and select one via env setting. This would
> allow for _one_ combination of images of U-Boot + Linux + Blobs
> for a _set_ of boards.
Traditionally, that should be named CFG_FDT_ADDR_IN_ENV
> CFG_FDT_ADDR_RAM:
> If defined, the blob is moved to RAM after relocation for
> further preparation or for performance reasons. "fdt" is re-set
> accordingly. The blob is then ready and in place for booting
> Linux. If CFG_FDT_ADDR_RAM is set to 0, the blob will be copied
> to a default location, e.g. before the initrd location.
I'm not sure I understand this - will CFG_FDT_ADDR_RAM hold the
*address* in RAM where the FDT gets copied to? That sounds pretty
static to me.
> A board-specific checkboad function is called as early as possible to
> verify the FDT.
"checkboard()" is a name that can mean anything. If the function is
to check or to verify the FDT, the function name should represent
this, i. e. please callit checkfdt() or verifyfdt() of probably
fdtcheck() / fdtverify() or fdt_check() / fdt_verify().
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The night sky over the planet Krikkit is the least interesting sight
in the entire Universe.
- Douglas Adams _Life, the Universe, and Everything_
More information about the U-Boot
mailing list