On Monday 17 November 2014 11:39:02 Kevin Cernekee wrote: > On Mon, Nov 17, 2014 at 10:46 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > On Monday 17 November 2014 09:01:02 Kevin Cernekee wrote: > >> > If you wanted to do that however, starting with BMIPS you'd have > >> > to make it possible to define a new platform without the > >> > arch/mips/include/asm/mach-bmips/ directory (this should be possible > >> > already, so the hardest part is done), replace all global function > >> > calls (arch_init_irq, prom_init, get_system_type, ...) with generic > >> > platform-independent implementations or wrappers around per-platform > >> > callbacks, and move the Kconfig section for CONFIG_BMIPS_MULTIPLATFORM > >> > outside of the "System type" choice statement. > >> > >> Right. The other question is how much support for legacy non-DT > >> bootloaders really belongs in a true multiplatform kernel, as this > >> stuff gets hairy fast. > > > > Yes, that's why I suggested following PowerPC rather than ARM in this > > regard. If you move the boot loader abstraction into the decompressor > > instead of the platform code, you can avoid a lot of the problems. > > One possible complication: for BCM63xx/BCM7xxx (MIPS) there is no > decompressor in the kernel. The firmware loads an ELF image into > memory and jumps directly to kernel_entry. > Right, that complicates it a bit, but is there a reason why a decompressor would be hard to do, or would be considered a bad thing? There is already generic decompressor code in arch/mips/boot/compressed/ that I would assume you could use without firmware changes. Are you worried about boot time overhead? Arnd
