On 15.01.16 15:21, Leif Lindholm wrote:
On Fri, Jan 15, 2016 at 03:14:54PM +0100, Alexander Graf wrote:
On 15.01.16 14:02, Leif Lindholm wrote:
U-Boot question: is gd->relocaddr always the offset from start of RAM? How does this work with gaps in memory map?
U-Boot always relocates itself at TOM (or at least what we consider TOM here). gd->relocaddr is the physical address of the start of U-Boot which is right below TOM.
Still ... would need additional handling if memory has holes (like, fitted with multiple DIMMs smaller than the individual memory window reserved for them). Or even on something like Juno, which has 2GB of RAM at 0x00_8000_0000, and a further 6GB at 0x08_8000_0000 (I think).
Yes. I think we'll have to just implement that when we hit the first board that does this (and has awareness in U-Boot for it).
Yeah, sure.
With the UEFI entry path, Linux will ignore memory nodes in dt, right?
Yep.
+#ifdef CONFIG_SYS_SDRAM_BASE
- efi_memory_map[0].physical_start = CONFIG_SYS_SDRAM_BASE;
- efi_memory_map[0].virtual_start = CONFIG_SYS_SDRAM_BASE;
- efi_memory_map[0].num_pages -= CONFIG_SYS_SDRAM_BASE >> 12;
#else #error "..." ?
If it's not defined, it's 0 :).
Make it #if CONFIG_SYS_SDRAM_BASE != 0 for clarity?
I really don't think we'll make it more readable with more #iffery here :).
It isn't really the kind of thing I'm here to review, but ... Current version requires knowledge of state of certain macros, the alternative is explicit without familiarity with the codebase.
Hrm. So how about a comment like this:
/* RAM starts at an offset above 0 */
right before the #ifdef?
Alex