Bug in p1_p2_rdb_pc? Caching-inhibited bit for initial L2 SRAM entry in TLB
Pali Rohár
pali at kernel.org
Tue Apr 5 10:57:37 CEST 2022
Hello!
I suspect that there is a bug in board/freescale/p1_p2_rdb_pc/tlb.c code
which configures TLB entry for initial L2 SRAM.
When L2 is 512 kB long (e.g. on P2020) then U-Boot *unsets* MAS2_I bit
for first half of L2 and for second half of L2 U-Boot *sets* this bit.
See code:
https://source.denx.de/u-boot/u-boot/-/blob/v2022.04/board/freescale/p1_p2_rdb_pc/tlb.c#L99-104
I do not think that one part of L2 SRAM should be configured differently
as second part. Therefore I think that this is a bug in U-Boot code.
Do you know is correct configuration of TLB entries for initial L2 SRAM?
MAS2_I is Caching-inhibited bit which is described as:
Caching-inhibited:
* 0 - Accesses to this page are considered cacheable.
* 1 - The page is considered caching-inhibited. All loads and stores to
the page bypass the caches and are performed directly to main
memory. A read or write to a caching-inhibited page affects only
the memory element specified by the operation.
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