On Tue, Jun 09, 2026 at 04:23:36PM +0200, Christophe Leroy (CS GROUP) wrote: > Le 05/06/2026 à 01:09, Tom Rini a écrit : > > On Fri, Jun 05, 2026 at 12:31:10AM +0200, Marek Vasut wrote: > > > On 6/4/26 9:37 AM, Ilias Apalodimas wrote: > > > > Currently, the bi_dram[] information is stored in the board info > > > > structure (bd). Because bd is only valid after reserve_board(), > > > > dram_init_banksize() must be called late in the initialization process. > > > > This limitation is problematic, as it forces us to rely on a variety of > > > > bespoke functions to determine board RAM, bank memory sizes, and other > > > > early setup requirements. > > > > > > > > By moving bi_dram[] into the global data (gd), we can run it earlier. > > > > This is particularly convenient since boards define their own > > > > dram_init_banksize() routines, which do not always rely on parsing > > > > Device Tree (DT) memory nodes. > > > > > > > > Additionally, U-Boot defaults to relocating to the top of the first > > > > memory > > > > bank. While boards currently use custom functions to override this > > > > behavior, having the DRAM bank information available earlier in gd makes > > > > relocating to a different bank trivial and standardizes the process. > > > Regarding the BD, this is likely really old, but it seems BD might be > > > passed > > > from U-Boot to Linux somehow ? See [1] and U-Boot > > > include/asm-generic/u-boot.h : > > > > > > 8 * NOTE: This header file defines an interface to U-Boot. Including > > > 9 * this (unmodified) header file in another file is considered normal > > > 10 * use of U-Boot, and does *not* fall under the heading of "derived > > > 11 * work". > > > > > > Are we certain we are not breaking ABI here ? > > > > > > [1] > > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/powerpc/boot/ppcboot.h > > > > I've added in Christophe as the maintainer of one of the active and in > > some ways oldest (since MPC8xx is very old) PowerPC platforms we still > > actively support. A tested-by on this series that also includes > > verifying Linux still comes up would be much appreciated. > > Traveling at the moment. I will try to give it a go in a couple weeks. > > > > > My suspicion is that anything DT-based shouldn't change here, and in > > turn if you're doing modern U-Boot you're probably doing > > not-extremely-ancient kernel and so DT based booting. > > > > Linux receives a pointer to the device tree from U-boot, nothing else as far > as I know.
Thanks. I strongly suspect everything in question applies to ancient U-Boot and/or Kernel. -- Tom
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