On Fri, 2009-07-10 at 22:37 +0200, Wolfgang Denk wrote:
Dear Kumar Gala,
In message 4B5A7126-FCDF-4EB0-9181-FB1BE571C715@kernel.crashing.org you wrote:
On May 22, 2009, at 10:26 AM, Peter Tyser wrote:
Previously, it was only unlocked when Linux was executed using the "bootm" command. Unlocking it unconditionally improves U-Boot performance and provides a common cache state when booting OSes.
Signed-off-by: Peter Tyser ptyser@xes-inc.com
lib_ppc/board.c | 8 +++++--- lib_ppc/bootm.c | 3 ++- 2 files changed, 7 insertions(+), 4 deletions(-)
Wolfgang, do you know any reason we can't do the unlock for ALL ppc's in board_init_r()?
Sorry, I don't remember if there was any speciofic reason, or what that might have been. Maybe the CHANGELOGs contain some hints?
The only platforms the define unlock_ram_in_cache() are 83xx, 85xx, 86xx, and 74xx_7xx.
It looks like the most of them had "issues" in their implementation that could explain why there weren't enabled: 83xx - ade50c7fa1b16ef98be17e9c3ae286aecf4f5605, 6eb2a44e27919fdc601e0c05404b298a7602c0e3
86xx - 392438406041415fe64ab8748ec5ab5ad01d1cf7
74xx - d685b74c64a38849f1a129b3ab846fbf67dd937e
85xx - this one works
My best guess was all the non-85xx implementations had bugs or other issues that caused U-Boot to become unstable after unlocking the cache. Perhaps those bugs are fixed now, but I only have 86xx hardware to test on. I've been running a few 86xx boards with the cache unlocked with no noticeable problems.
Peter