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/*
* (C) Copyright 2001
* Erik Theisen, Wave 7 Optics, etheisen@mindspring.com
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <config.h>
#if defined(CONFIG_4xx) && defined(CONFIG_CMD_SETGETDCR)
#include <asm/ppc4xx.h>
#define _LINUX_CONFIG_H 1 /* avoid reading Linux autoconf.h file */
#include <ppc_asm.tmpl>
#include <ppc_defs.h>
#include <asm/cache.h>
#include <asm/mmu.h>
#define _ASMLANGUAGE
/*****************************************************************************
*
* XXX - DANGER
* These routines make use of self modifying code. DO NOT CALL THEM
* UNTIL THEY ARE RELOCATED TO RAM. Additionally, I do not
* recommend them for use in anything other than an interactive
* debugging environment. This is mainly due to performance reasons.
*
****************************************************************************/
/*
* static void _create_MFDCR(unsigned short dcrn)
*
* Builds a 'mfdcr' instruction for get_dcr
* function.
*/
.section ".text"
.align 2
.type _create_MFDCR,@function
_create_MFDCR:
/*
* Build up a 'mfdcr' instruction formatted as follows:
*
* OPCD | RT | DCRF | XO | CR |
* ---------------|--------------|--------------|----|
* 0 5 | 6 10 | 11 20 | 21 30 | 31 |
* | | DCRN | | |
* 31 | %r3 | (5..9|0..4) | 323 | 0 |
*
* Where:
* OPCD = opcode - 31
* RT = destination register - %r3 return register
* DCRF = DCRN # with upper and lower halves swapped
* XO = extended opcode - 323
* CR = CR[CR0] NOT undefined - 0
*/
rlwinm r0, r3, 27, 27, 31 /* OPCD = 31 */
rlwinm r3, r3, 5, 22, 26
or r3, r3, r0
slwi r3, r3, 10
oris r3, r3, 0x3e30 /* RT = %r3 */
ori r3, r3, 323 /* XO = 323 */
slwi r3, r3, 1 /* CR = 0 */
mflr r4
stw r3, 0(r4) /* Store instr in get_dcr() */
dcbst r0, r4 /* Make sure val is written out */
sync /* Wait for write to complete */
icbi r0, r4 /* Make sure old instr is dumped */
isync /* Wait for icbi to complete */
blr
.Lfe1: .size _create_MFDCR,.Lfe1-_create_MFDCR
/* end _create_MFDCR() */
/*
* static void _create_MTDCR(unsigned short dcrn, unsigned long value)
*
* Builds a 'mtdcr' instruction for set_dcr
* function.
*/
.section ".text"
.align 2
.type _create_MTDCR,@function
_create_MTDCR:
/*
* Build up a 'mtdcr' instruction formatted as follows:
*
* OPCD | RS | DCRF | XO | CR |
* ---------------|--------------|--------------|----|
* 0 5 | 6 10 | 11 20 | 21 30 | 31 |
* | | DCRN | | |
* 31 | %r3 | (5..9|0..4) | 451 | 0 |
*
* Where:
* OPCD = opcode - 31
* RS = source register - %r4
* DCRF = dest. DCRN # with upper and lower halves swapped
* XO = extended opcode - 451
* CR = CR[CR0] NOT undefined - 0
*/
rlwinm r0, r3, 27, 27, 31 /* OPCD = 31 */
rlwinm r3, r3, 5, 22, 26
or r3, r3, r0
slwi r3, r3, 10
oris r3, r3, 0x3e40 /* RS = %r4 */
ori r3, r3, 451 /* XO = 451 */
slwi r3, r3, 1 /* CR = 0 */
mflr r5
stw r3, 0(r5) /* Store instr in set_dcr() */
dcbst r0, r5 /* Make sure val is written out */
sync /* Wait for write to complete */
icbi r0, r5 /* Make sure old instr is dumped */
isync /* Wait for icbi to complete */
blr
.Lfe2: .size _create_MTDCR,.Lfe2-_create_MTDCR
/* end _create_MTDCR() */
/*
* unsigned long get_dcr(unsigned short dcrn)
*
* Return a given DCR's value.
*/
/* */
/* XXX - This is self modifying code, hence */
/* it is in the data section. */
/* */
.section ".data"
.align 2
.globl get_dcr
.type get_dcr,@function
get_dcr:
mflr r0 /* Get link register */
stwu r1, -32(r1) /* Save back chain and move SP */
stw r0, +36(r1) /* Save link register */
bl _create_MFDCR /* Build following instruction */
/* XXX - we build this instuction up on the fly. */
.long 0 /* Get DCR's value */
lwz r0, +36(r1) /* Get saved link register */
mtlr r0 /* Restore link register */
addi r1, r1, +32 /* Remove frame from stack */
blr /* Return to calling function */
.Lfe3: .size get_dcr,.Lfe3-get_dcr
/* end get_dcr() */
/*
* unsigned void set_dcr(unsigned short dcrn, unsigned long value)
*
* Return a given DCR's value.
*/
/*
* XXX - This is self modifying code, hence
* it is in the data section.
*/
.section ".data"
.align 2
.globl set_dcr
.type set_dcr,@function
set_dcr:
mflr r0 /* Get link register */
stwu r1, -32(r1) /* Save back chain and move SP */
stw r0, +36(r1) /* Save link register */
bl _create_MTDCR /* Build following instruction */
/* XXX - we build this instuction up on the fly. */
.long 0 /* Set DCR's value */
lwz r0, +36(r1) /* Get saved link register */
mtlr r0 /* Restore link register */
addi r1, r1, +32 /* Remove frame from stack */
blr /* Return to calling function */
.Lfe4: .size set_dcr,.Lfe4-set_dcr
/* end set_dcr() */
#endif
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