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| -rw-r--r-- | cpu/ppc4xx/dcr.S | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/cpu/ppc4xx/dcr.S b/cpu/ppc4xx/dcr.S new file mode 100644 index 000000000..7102364eb --- /dev/null +++ b/cpu/ppc4xx/dcr.S @@ -0,0 +1,198 @@ +/* + * (C) Copyright 2001 + * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com + * + * See file CREDITS for list of people who contributed to this + * project. + * + * 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., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + */ +#include <config.h> + +#if defined(CONFIG_4xx) && defined(CFG_CMD_SETGETDCR) + +#include <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 /* CONFIG_4xx & CFG_CMD_SETGETDCR */ |