u-boot.git/lib/lmb.c, branch v2026.07

lmb: Rename LMB_LIMIT_DMA_BELOW_4G to LMB_LIMIT_DMA_BELOW_RAM_TOP

2026-06-08T19:28:49Z

Rename LMB_LIMIT_DMA_BELOW_4G to LMB_LIMIT_DMA_BELOW_RAM_TOP to make the Kconfig option more descriptive. No functional change. Suggested-by: Ilias Apalodimas Signed-off-by: Marek Vasut Reviewed-by: Ilias Apalodimas

lmb: Optionally limit available memory to 4 GiB on limited systems

2026-06-04T14:26:41Z

Some architectures can not DMA above 4 GiB boundary, limit available memory to memory below 4 GiB boundary. Signed-off-by: Marek Vasut Reviewed-by: Ilias Apalodimas Tested-by: Ilias Apalodimas #rpi4 8GiB

lmb: Reinstate access to memory above ram_top

2026-03-13T19:20:11Z

Revert commit eb052cbb896f ("lmb: add and reserve memory above ram_top") and commit 1a48b0be93d4 ("lmb: prohibit allocations above ram_top even from same bank"). These are based on incorrect premise of the first commit, that "U-Boot does not use memory above ram_top". While U-Boot itself indeed does not and should not use memory above ram_top, user can perfectly well use that memory from the U-Boot shell, for example to load content in there. Currently, attempt to use that memory to load large image using TFTP ends with "TFTP error: trying to overwrite reserved memory...". With this change in place, the memory can be used again. Fixes: eb052cbb896f ("lmb: add and reserve memory above ram_top") Fixes: 1a48b0be93d4 ("lmb: prohibit allocations above ram_top even from same bank") Reported-by: Yuya Hamamachi Signed-off-by: Marek Vasut

lmb: Remove unreachable code

2025-07-22T17:29:33Z

Code after a break is unreachable so remove it. Signed-off-by: Andrew Goodbody

arm: fix lmb region reservation when PRAM is defined

2025-07-22T17:29:31Z

PRAM usage is not taken into account when reserving lmb for ARM architecture, this means that predefined PRAM region is marked as reserved by the architecture and cannot be used by other users. Signed-off-by: Holger Brunck

lmb: add missing fallthrough in lmb_alloc_mem()

2025-07-09T16:39:37Z

Add fallthrough to clarify the intent. Addresses-Coverity-ID: CID 569481: Control flow issues (MISSING_BREAK) Signed-off-by: Heinrich Schuchardt Acked-by: Sughosh Ganu Reviewed-by: Ilias Apalodimas

lmb: use a single function to check for allocation and reservation requests

2025-06-25T15:50:37Z

The functions that handle allocation requests check if a region of memory overlaps with a used region. This is done through lmb_overlaps_region(). Similar checks are done for reservation requests made to the LMB module, where the caller asks specifically for a particular region of memory. These checks are being done through lmb_can_reserve_region(). There are subtle differences in the checking needed for allocation requests, as against reservation requests. In the former, it is only needed to be checked if a region is overlapping with an existing used region, and return as soon as an overlap is found. For reservation request checks, because U-Boot allows for re-use of in-use regions with a particular memory attribute, this check has to iterate through all the regions that might overlap with the requested region, and then check that the necessary conditions are met to allow for the overlap. Combine these two checks in a single function, lmb_overlap_checks() as both lmb_overlaps_region() and lmb_can_reserve_region() are pretty similar otherwise. Signed-off-by: Sughosh Ganu Reviewed-by: Ilias Apalodimas

lmb: use a single function to free up memory

2025-06-25T15:50:37Z

There is no need to have two separate API's for freeing up memory. Use a single API lmb_free() to achieve this. Signed-off-by: Sughosh Ganu Reviewed-by: Ilias Apalodimas

lmb: staticise lmb_add_memory()

2025-06-25T15:50:37Z

lmb_add_memory() is only called from the lmb module. Mark the function as static. Signed-off-by: Sughosh Ganu Reviewed-by: Ilias Apalodimas

lmb: replace the lmb_alloc() and lmb_alloc_base() API's

2025-06-25T15:50:37Z

There currently are two API's for requesting memory from the LMB module, lmb_alloc() and lmb_alloc_base(). The function which does the actual allocation is the same. Use the earlier introduced API lmb_alloc_mem() for both types of allocation requests. Signed-off-by: Sughosh Ganu Acked-by: Ilias Apalodimas