Initial revision
authorwdenk <wdenk>
Sun, 21 Oct 2001 10:56:49 +0000 (10:56 +0000)
committerwdenk <wdenk>
Sun, 21 Oct 2001 10:56:49 +0000 (10:56 +0000)
cpu/ppc4xx/dcr.S [new file with mode: 0644]

diff --git a/cpu/ppc4xx/dcr.S b/cpu/ppc4xx/dcr.S
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+/*
+ * (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 */