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linux/arch/ppc/kernel/l2cr.S
Kumar Gala 80ac2912f8 [PATCH] ppc: L2 cache prefetch fixes on 745x 
We run into problems if we blindly enable L2 prefetching without
checking that the L2 cache is actually enabled.  Additionaly, if we
disable the L2 cache we need to ensure that we disable L2 prefetching.

Signed-off-by: Kumar Gala <kumar.gala@freescale.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-01 10:52:29 -07:00

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/*
L2CR functions
Copyright © 1997-1998 by PowerLogix R & D, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
Thur, Dec. 12, 1998.
- First public release, contributed by PowerLogix.
***********
Sat, Aug. 7, 1999.
- Terry: Made sure code disabled interrupts before running. (Previously
it was assumed interrupts were already disabled).
- Terry: Updated for tentative G4 support. 4MB of memory is now flushed
instead of 2MB. (Prob. only 3 is necessary).
- Terry: Updated for workaround to HID0[DPM] processor bug
during global invalidates.
***********
Thu, July 13, 2000.
- Terry: Added isync to correct for an errata.
22 August 2001.
- DanM: Finally added the 7450 patch I've had for the past
several months. The L2CR is similar, but I'm going
to assume the user of this functions knows what they
are doing.
Author: Terry Greeniaus (tgree@phys.ualberta.ca)
Please e-mail updates to this file to me, thanks!
*/
#include <linux/config.h>
#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/ppc_asm.h>
#include <asm/cache.h>
#include <asm/page.h>
/* Usage:
When setting the L2CR register, you must do a few special
things. If you are enabling the cache, you must perform a
global invalidate. If you are disabling the cache, you must
flush the cache contents first. This routine takes care of
doing these things. When first enabling the cache, make sure
you pass in the L2CR you want, as well as passing in the
global invalidate bit set. A global invalidate will only be
performed if the L2I bit is set in applyThis. When enabling
the cache, you should also set the L2E bit in applyThis. If
you want to modify the L2CR contents after the cache has been
enabled, the recommended procedure is to first call
__setL2CR(0) to disable the cache and then call it again with
the new values for L2CR. Examples:
_setL2CR(0) - disables the cache
_setL2CR(0xB3A04000) - enables my G3 upgrade card:
- L2E set to turn on the cache
- L2SIZ set to 1MB
- L2CLK set to 1:1
- L2RAM set to pipelined synchronous late-write
- L2I set to perform a global invalidation
- L2OH set to 0.5 nS
- L2DF set because this upgrade card
requires it
A similar call should work for your card. You need to know
the correct setting for your card and then place them in the
fields I have outlined above. Other fields support optional
features, such as L2DO which caches only data, or L2TS which
causes cache pushes from the L1 cache to go to the L2 cache
instead of to main memory.
IMPORTANT:
Starting with the 7450, the bits in this register have moved
or behave differently. The Enable, Parity Enable, Size,
and L2 Invalidate are the only bits that have not moved.
The size is read-only for these processors with internal L2
cache, and the invalidate is a control as well as status.
-- Dan
*/
/*
* Summary: this procedure ignores the L2I bit in the value passed in,
* flushes the cache if it was already enabled, always invalidates the
* cache, then enables the cache if the L2E bit is set in the value
* passed in.
* -- paulus.
*/
_GLOBAL(_set_L2CR)
/* Make sure this is a 750 or 7400 chip */
BEGIN_FTR_SECTION
li r3,-1
blr
END_FTR_SECTION_IFCLR(CPU_FTR_L2CR)
mflr r9
/* Stop DST streams */
BEGIN_FTR_SECTION
DSSALL
sync
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
/* Turn off interrupts and data relocation. */
mfmsr r7 /* Save MSR in r7 */
rlwinm r4,r7,0,17,15
rlwinm r4,r4,0,28,26 /* Turn off DR bit */
sync
mtmsr r4
isync
/* Before we perform the global invalidation, we must disable dynamic
* power management via HID0[DPM] to work around a processor bug where
* DPM can possibly interfere with the state machine in the processor
* that invalidates the L2 cache tags.
*/
mfspr r8,SPRN_HID0 /* Save HID0 in r8 */
rlwinm r4,r8,0,12,10 /* Turn off HID0[DPM] */
sync
mtspr SPRN_HID0,r4 /* Disable DPM */
sync
/* Get the current enable bit of the L2CR into r4 */
mfspr r4,SPRN_L2CR
/* Tweak some bits */
rlwinm r5,r3,0,0,0 /* r5 contains the new enable bit */
rlwinm r3,r3,0,11,9 /* Turn off the invalidate bit */
rlwinm r3,r3,0,1,31 /* Turn off the enable bit */
/* Check to see if we need to flush */
rlwinm. r4,r4,0,0,0
beq 2f
/* Flush the cache. First, read the first 4MB of memory (physical) to
* put new data in the cache. (Actually we only need
* the size of the L2 cache plus the size of the L1 cache, but 4MB will
* cover everything just to be safe).
*/
/**** Might be a good idea to set L2DO here - to prevent instructions
from getting into the cache. But since we invalidate
the next time we enable the cache it doesn't really matter.
Don't do this unless you accomodate all processor variations.
The bit moved on the 7450.....
****/
BEGIN_FTR_SECTION
/* Disable L2 prefetch on some 745x and try to ensure
* L2 prefetch engines are idle. As explained by errata
* text, we can't be sure they are, we just hope very hard
* that well be enough (sic !). At least I noticed Apple
* doesn't even bother doing the dcbf's here...
*/
mfspr r4,SPRN_MSSCR0
rlwinm r4,r4,0,0,29
sync
mtspr SPRN_MSSCR0,r4
sync
isync
lis r4,KERNELBASE@h
dcbf 0,r4
dcbf 0,r4
dcbf 0,r4
dcbf 0,r4
END_FTR_SECTION_IFSET(CPU_FTR_SPEC7450)
/* TODO: use HW flush assist when available */
lis r4,0x0002
mtctr r4
li r4,0
1:
lwzx r0,r0,r4
addi r4,r4,32 /* Go to start of next cache line */
bdnz 1b
isync
/* Now, flush the first 4MB of memory */
lis r4,0x0002
mtctr r4
li r4,0
sync
1:
dcbf 0,r4
addi r4,r4,32 /* Go to start of next cache line */
bdnz 1b
2:
/* Set up the L2CR configuration bits (and switch L2 off) */
/* CPU errata: Make sure the mtspr below is already in the
* L1 icache
*/
b 20f
.balign L1_CACHE_LINE_SIZE
22:
sync
mtspr SPRN_L2CR,r3
sync
b 23f
20:
b 21f
21: sync
isync
b 22b
23:
/* Perform a global invalidation */
oris r3,r3,0x0020
sync
mtspr SPRN_L2CR,r3
sync
isync /* For errata */
BEGIN_FTR_SECTION
/* On the 7450, we wait for the L2I bit to clear......
*/
10: mfspr r3,SPRN_L2CR
andis. r4,r3,0x0020
bne 10b
b 11f
END_FTR_SECTION_IFSET(CPU_FTR_SPEC7450)
/* Wait for the invalidation to complete */
3: mfspr r3,SPRN_L2CR
rlwinm. r4,r3,0,31,31
bne 3b
11: rlwinm r3,r3,0,11,9 /* Turn off the L2I bit */
sync
mtspr SPRN_L2CR,r3
sync
/* See if we need to enable the cache */
cmplwi r5,0
beq 4f
/* Enable the cache */
oris r3,r3,0x8000
mtspr SPRN_L2CR,r3
sync
/* Enable L2 HW prefetch on 744x/745x */
BEGIN_FTR_SECTION
mfspr r3,SPRN_MSSCR0
ori r3,r3,3
sync
mtspr SPRN_MSSCR0,r3
sync
isync
END_FTR_SECTION_IFSET(CPU_FTR_SPEC7450)
4:
/* Restore HID0[DPM] to whatever it was before */
sync
mtspr 1008,r8
sync
/* Restore MSR (restores EE and DR bits to original state) */
SYNC
mtmsr r7
isync
mtlr r9
blr
_GLOBAL(_get_L2CR)
/* Return the L2CR contents */
li r3,0
BEGIN_FTR_SECTION
mfspr r3,SPRN_L2CR
END_FTR_SECTION_IFSET(CPU_FTR_L2CR)
blr
/*
* Here is a similar routine for dealing with the L3 cache
* on the 745x family of chips
*/
_GLOBAL(_set_L3CR)
/* Make sure this is a 745x chip */
BEGIN_FTR_SECTION
li r3,-1
blr
END_FTR_SECTION_IFCLR(CPU_FTR_L3CR)
/* Turn off interrupts and data relocation. */
mfmsr r7 /* Save MSR in r7 */
rlwinm r4,r7,0,17,15
rlwinm r4,r4,0,28,26 /* Turn off DR bit */
sync
mtmsr r4
isync
/* Stop DST streams */
DSSALL
sync
/* Get the current enable bit of the L3CR into r4 */
mfspr r4,SPRN_L3CR
/* Tweak some bits */
rlwinm r5,r3,0,0,0 /* r5 contains the new enable bit */
rlwinm r3,r3,0,22,20 /* Turn off the invalidate bit */
rlwinm r3,r3,0,2,31 /* Turn off the enable & PE bits */
rlwinm r3,r3,0,5,3 /* Turn off the clken bit */
/* Check to see if we need to flush */
rlwinm. r4,r4,0,0,0
beq 2f
/* Flush the cache.
*/
/* TODO: use HW flush assist */
lis r4,0x0008
mtctr r4
li r4,0
1:
lwzx r0,r0,r4
dcbf 0,r4
addi r4,r4,32 /* Go to start of next cache line */
bdnz 1b
2:
/* Set up the L3CR configuration bits (and switch L3 off) */
sync
mtspr SPRN_L3CR,r3
sync
oris r3,r3,L3CR_L3RES@h /* Set reserved bit 5 */
mtspr SPRN_L3CR,r3
sync
oris r3,r3,L3CR_L3CLKEN@h /* Set clken */
mtspr SPRN_L3CR,r3
sync
/* Wait for stabilize */
li r0,256
mtctr r0
1: bdnz 1b
/* Perform a global invalidation */
ori r3,r3,0x0400
sync
mtspr SPRN_L3CR,r3
sync
isync
/* We wait for the L3I bit to clear...... */
10: mfspr r3,SPRN_L3CR
andi. r4,r3,0x0400
bne 10b
/* Clear CLKEN */
rlwinm r3,r3,0,5,3 /* Turn off the clken bit */
mtspr SPRN_L3CR,r3
sync
/* Wait for stabilize */
li r0,256
mtctr r0
1: bdnz 1b
/* See if we need to enable the cache */
cmplwi r5,0
beq 4f
/* Enable the cache */
oris r3,r3,(L3CR_L3E | L3CR_L3CLKEN)@h
mtspr SPRN_L3CR,r3
sync
/* Wait for stabilize */
li r0,256
mtctr r0
1: bdnz 1b
/* Restore MSR (restores EE and DR bits to original state) */
4: SYNC
mtmsr r7
isync
blr
_GLOBAL(_get_L3CR)
/* Return the L3CR contents */
li r3,0
BEGIN_FTR_SECTION
mfspr r3,SPRN_L3CR
END_FTR_SECTION_IFSET(CPU_FTR_L3CR)
blr
/* --- End of PowerLogix code ---
*/
/* flush_disable_L1() - Flush and disable L1 cache
*
* clobbers r0, r3, ctr, cr0
* Must be called with interrupts disabled and MMU enabled.
*/
_GLOBAL(__flush_disable_L1)
/* Stop pending alitvec streams and memory accesses */
BEGIN_FTR_SECTION
DSSALL
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
sync
/* Load counter to 0x4000 cache lines (512k) and
* load cache with datas
*/
li r3,0x4000 /* 512kB / 32B */
mtctr r3
lis r3,KERNELBASE@h
1:
lwz r0,0(r3)
addi r3,r3,0x0020 /* Go to start of next cache line */
bdnz 1b
isync
sync
/* Now flush those cache lines */
li r3,0x4000 /* 512kB / 32B */
mtctr r3
lis r3,KERNELBASE@h
1:
dcbf 0,r3
addi r3,r3,0x0020 /* Go to start of next cache line */
bdnz 1b
sync
/* We can now disable the L1 cache (HID0:DCE, HID0:ICE) */
mfspr r3,SPRN_HID0
rlwinm r3,r3,0,18,15
mtspr SPRN_HID0,r3
sync
isync
blr
/* inval_enable_L1 - Invalidate and enable L1 cache
*
* Assumes L1 is already disabled and MSR:EE is off
*
* clobbers r3
*/
_GLOBAL(__inval_enable_L1)
/* Enable and then Flash inval the instruction & data cache */
mfspr r3,SPRN_HID0
ori r3,r3, HID0_ICE|HID0_ICFI|HID0_DCE|HID0_DCI
sync
isync
mtspr SPRN_HID0,r3
xori r3,r3, HID0_ICFI|HID0_DCI
mtspr SPRN_HID0,r3
sync
blr
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