/*
* mmuAsm.S
*
* $Id$
*
* Copyright (C) 1999 Eric Valette (valette@crf.canon.fr)
*
* This file contains the low-level support for various MMU
* features.
*
* The license and distribution terms for this file may be
* found in found in the file LICENSE in this distribution or at
* http://www.OARcorp.com/rtems/license.html.
*
* T. Straumann - 11/2001: added support for 7400 (no AltiVec yet)
*/
#include <asm.h>
#include <rtems/score/cpu.h>
#include <libcpu/io.h>
/* Unfortunately, the CPU types defined in cpu.h are
* an 'enum' type and hence not available :-(
*/
#define PPC_601 0x1
#define PPC_603 0x3
#define PPC_604 0x4
#define PPC_603e 0x6
#define PPC_603ev 0x7
#define PPC_750 0x8
#define PPC_604e 0x9
#define PPC_604r 0xA
#define PPC_7400 0xC
#define PPC_620 0x16
#define PPC_860 0x50
#define PPC_821 PPC_860
#define PPC_8260 0x81
/* ALTIVEC instructions (not recognized by off-the shelf gcc yet) */
#define DSSALL .long 0x7e00066c /* DSSALL altivec instruction opcode */
/* A couple of defines to make the code more readable */
#define CACHE_LINE_SIZE 32
#ifndef MSSCR0
#define MSSCR0 1014
#else
#warning MSSCR0 seems to be known, update __FILE__
#endif
#define DL1HWF (1<<(31-8))
#define L2HWF (1<<(31-20))
/*
* Each setdbat routine start by invalidating the DBAT as some
* proc (604e) request the valid bit set to 0 before accepting
* to write in BAT
*/
.globl asm_setdbat0
.type asm_setdbat0,@function
asm_setdbat0:
li r0,0
sync
isync
mtspr DBAT0U,r0
mtspr DBAT0L,r0
sync
isync
mtspr DBAT0L, r4
mtspr DBAT0U, r3
sync
isync
blr
.globl asm_setdbat1
.type asm_setdbat1,@function
asm_setdbat1:
li r0,0
sync
isync
mtspr DBAT1U,r0
mtspr DBAT1L,r0
sync
isync
mtspr DBAT1L, r4
mtspr DBAT1U, r3
sync
isync
blr
.globl asm_setdbat2
.type asm_setdbat2,@function
asm_setdbat2:
li r0,0
sync
isync
mtspr DBAT2U,r0
mtspr DBAT2L,r0
sync
isync
mtspr DBAT2L, r4
mtspr DBAT2U, r3
sync
isync
blr
.globl asm_setdbat3
.type asm_setdbat3,@function
asm_setdbat3:
li r0,0
sync
isync
mtspr DBAT3U,r0
mtspr DBAT3L,r0
sync
isync
mtspr DBAT3L, r4
mtspr DBAT3U, r3
sync
isync
blr
.globl L1_caches_enables
.type L1_caches_enables, @function
L1_caches_enables:
/*
* Enable caches and 604-specific features if necessary.
*/
mfspr r9,PVR
rlwinm r9,r9,16,16,31
cmpi 0,r9,PPC_601
beq 4f /* not needed for 601 */
mfspr r11,HID0
andi. r0,r11,HID0_DCE
ori r11,r11,HID0_ICE|HID0_DCE
ori r8,r11,HID0_ICFI
bne 3f /* don't invalidate the D-cache */
ori r8,r8,HID0_DCI /* unless it wasn't enabled */
3:
sync
mtspr HID0,r8 /* enable and invalidate caches */
sync
mtspr HID0,r11 /* enable caches */
sync
isync
cmpi 0,r9,PPC_604 /* check for 604 */
cmpi 1,r9,PPC_604e /* or 604e */
cmpi 2,r9,PPC_604r /* or mach5 */
cror 2,2,6
cror 2,2,10
cmpi 1,r9,PPC_750 /* or 750 */
cror 2,2,6
cmpi 1,r9,PPC_7400 /* or 7400 */
bne 3f
ori r11,r11,HID0_BTIC /* enable branch tgt cache on 7400 */
3: cror 2,2,6
bne 4f
/* on 7400 SIED is actually SGE (store gathering enable) */
ori r11,r11,HID0_SIED|HID0_BHTE /* for 604[e], enable */
bne 2,5f
ori r11,r11,HID0_BTCD
5: mtspr HID0,r11 /* superscalar exec & br history tbl */
4:
blr
.globl get_L2CR
.type get_L2CR, @function
get_L2CR:
/* Make sure this is a > 750 chip */
mfspr r3,PVR
rlwinm r3,r3,16,16,31
cmplwi r3,PPC_750 /* it's a 750 */
beq 1f
cmplwi r3,PPC_7400 /* it's a 7400 */
beq 1f
li r3,0
blr
1:
/* Return the L2CR contents */
mfspr r3,L2CR
blr
.globl set_L2CR
.type set_L2CR, @function
set_L2CR:
/* 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(0xb9A14000) - enables my G3 MCP750 card:
* - L2E set to turn on the cache
* - L2SIZ set to 1MB
* - L2CLK set to %2
* - L2RAM set to pipelined syncronous late-write
* - L2I set to perform a global invalidation
* - L2OH set to 1 nS
*
* 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.
*/
/* Make sure this is a > 750 chip */
mfspr r0,PVR
rlwinm r0,r0,16,16,31
cmplwi r0,PPC_750
beq thisIs750
cmplwi r0,PPC_7400
beq thisIs750
li r3,-1
blr
thisIs750:
/* Get the current enable bit of the L2CR into r4 */
mfspr r4,L2CR
rlwinm r4,r4,0,0,0
/* See if we want to perform a global inval this time. */
rlwinm r6,r3,0,10,10 /* r6 contains the new invalidate bit */
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 */
or r3,r3,r4 /* Keep the enable bit the same as it was for now. */
mfmsr r7 /* shut off interrupts around critical flush/invalidate sections */
rlwinm r4,r7,0,17,15 /* Turn off EE bit - an external exception while we are flushing
the cache is fatal (comment this line and see!) */
mtmsr r4
bne dontDisableCache /* Only disable the cache if L2CRApply has the enable bit off */
cmplwi r0,PPC_7400 /* > 7400 ? */
bne disableCache /* use traditional method */
/* On the 7400, they recommend using the hardware flush feature */
DSSALL /* stop all data streams */
sync
/* we wouldn't have to flush L1, but for sake of consistency with the other code we do it anyway */
mfspr r4, MSSCR0
oris r4, r4, DL1HWF@h
mtspr MSSCR0, r4
sync
/* L1 flushed */
mfspr r4, L2CR
ori r4, r4, L2HWF
mtspr L2CR, r4
sync
/* L2 flushed */
b flushDone
disableCache:
/* Disable the cache. First, we turn off data relocation. */
rlwinm r4,r4,0,28,26 /* Turn off DR bit */
mtmsr r4
isync /* make sure memory accesses have completed */
/*
Now, read the first 2MB of memory 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 2MB will cover everything just to be safe).
*/
lis r4,0x0001
mtctr r4
li r4,0
loadLoop:
lwzx r0,r0,r4
addi r4,r4,CACHE_LINE_SIZE /* Go to start of next cache line */
bdnz loadLoop
/* Now, flush the first 2MB of memory */
lis r4,0x0001
mtctr r4
li r4,0
sync
flushLoop:
dcbf r0,r4
addi r4,r4,CACHE_LINE_SIZE /* Go to start of next cache line */
bdnz flushLoop
sync
rlwinm r4,r7,0,17,15 /* still mask EE but reenable data relocation */
mtmsr r4
isync
flushDone:
/* Turn off the L2CR enable bit. */
rlwinm r3,r3,0,1,31
dontDisableCache:
/* Set up the L2CR configuration bits */
sync
mtspr L2CR,r3
sync
cmplwi r6,0
beq noInval
/* Perform a global invalidation */
oris r3,r3,0x0020
sync
mtspr L2CR,r3
sync
invalCompleteLoop: /* Wait for the invalidation to complete */
mfspr r3,L2CR
rlwinm. r4,r3,0,31,31
bne invalCompleteLoop
rlwinm r3,r3,0,11,9; /* Turn off the L2I bit */
sync
mtspr L2CR,r3
sync
noInval:
/* re-enable interrupts, i.e. restore original MSR */
mtmsr r7 /* (no sync needed) */
/* See if we need to enable the cache */
cmplwi r5,0
beqlr
enableCache:
/* Enable the cache */
oris r3,r3,0x8000
mtspr L2CR,r3
sync
blr