--- /dev/null
+/*
+ * (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 */
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