> Am 31.07.2018 um 22:04 schrieb Stephen Warren <swar...@wwwdotorg.org>: > > On 07/31/2018 02:03 PM, Alexander Graf wrote: >>> Am 31.07.2018 um 21:44 schrieb Stephen Warren <swar...@wwwdotorg.org>: >>> >>> From: Stephen Warren <swar...@nvidia.com> >>> >>> Some boards define a maximum usable RAM top that's more restrictive than >>> the ranges defined by U-Boot's memory bank definitions[1]. In this case, >>> the unusable RAM isn't mapped in the page tables, and so the EFI code must >>> not attempt to allocate RAM from outside the usable regions. Fix >>> efi_find_free_memory() to detect when max_addr is unconstrained or out of >>> range, and substitue a valid value. >>> >>> [1] For example, when some peripherals can't access RAM above 4GiB, it's >>> simplest to force U-Boot's ram_top to a smaller value to avoid dealing >>> with this issue more explicitly. However, the RAM bank definitions still >>> describe the unusable RAM so that the booted OS has access to it, since >>> the OS can typically deal with such restrictions in a more complex >>> manner. >> That's what we have the efi bounce buffers for. Can't we just enable those >> for tegra? > > No, because that wouldn't help all the non-EFI code, or cause the RAM to be > mapped in the page tables due to the non-EFI code not needing it.
The non-efi code can still rely on ram_top just fine, no? I was more thinking of enabling the bounce buffer config option as alternative to your patch. Alex _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
