u-boot-brain/cpu/mips
Shinya Kuribayashi e1390801a3 [MIPS] Request for the 'mips_cache_lock()' removal
The initial intension of having mips_cache_lock() was to use the cache
as memory for temporary stack use so that a C environment can be set up
as early as possible.

But now mips_cache_lock() follow lowlevel_init(). We've already have the
real memory initilaized at this point, therefore we could/should use it.
No reason to lock at all.

Other problems:

Cache locking is not consistent across MIPS implementaions. Some imple-
mentations don't support locking at all. The style of locking varies -
some support per line locking, others per way, etc. Some parts use bits
in status registers instead of cache ops. Current mips_cache_lock() is
not necessarily general-purpose.

And this is worthy of special mention; once U-Boot/MIPS locks the lines,
they are never get unlocked, so the code relies on whatever gets loaded
after U-Boot to re-initialize the cache and clear the locks. We're sup-
posed to have CFG_INIT_RAM_LOCK and unlock_ram_in_cache() implemented,
but leave the situation as it is for a long time.

For these reasons, I proposed the removal of mips_cache_lock() from the
global start-up code.

This patch adds CFG_INIT_RAM_LOCK_MIPS to make existing users aware that
*things have changed*. If he wants the same behavior as before, he needs
to have CFG_INIT_RAM_LOCK_MIPS in his config file.

If we don't have any regression report through several releases, then
we'll remove codes entirely.

Signed-off-by: Shinya Kuribayashi <skuribay@ruby.dti.ne.jp>
Acked-by: Andrew Dyer <amdyer@gmail.com>
2008-03-25 11:39:29 +09:00
..
asc_serial.c * Patch by Steven Scholz, 10 Oct 2003 2003-10-09 20:09:04 +00:00
asc_serial.h * Patch by Steven Scholz, 10 Oct 2003 2003-10-09 20:09:04 +00:00
au1x00_eth.c [MIPS] au1x00_eth.c: Fixed a warning on pb1000 build. 2007-11-17 18:54:16 +09:00
au1x00_serial.c Fix au1x00_serial baud rate calculation: 2005-09-25 16:50:33 +02:00
au1x00_usb_ohci.c Add support for AMD's Pb1x00 eval board; 2005-09-25 00:53:22 +02:00
au1x00_usb_ohci.h Add support for AMD's Pb1x00 eval board; 2005-09-25 00:53:22 +02:00
cache.S [MIPS] Request for the 'mips_cache_lock()' removal 2008-03-25 11:39:29 +09:00
config.mk cpu/mips/cofigl.mk: Make a needlessly deffered expansion immediate. 2008-02-23 09:44:19 +01:00
cpu.c [MIPS] MIPS 4K core: Coding style cleanups 2007-11-17 20:05:26 +09:00
incaip_clock.c Code cleanup, especially MIPS for GCC 4.x 2005-12-04 00:40:34 +01:00
incaip_wdt.S * Code cleanup: 2003-06-27 21:31:46 +00:00
interrupts.c * Code cleanup: 2003-06-27 21:31:46 +00:00
Makefile Move "ar" flags to config.mk to allow for silent "make -s" 2006-10-09 01:02:05 +02:00
start.S [MIPS] Request for the 'mips_cache_lock()' removal 2008-03-25 11:39:29 +09:00