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c74078f8
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1/*
2 * (C) Copyright 2001
3 * Erik Theisen, Wave 7 Optics, etheisen@mindspring.com
4 *
1a459660 5 * SPDX-License-Identifier: GPL-2.0+
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6 */
7#include <config.h>
8
3a1ed1e1 9#if defined(CONFIG_4xx) && defined(CONFIG_CMD_SETGETDCR)
c74078f8 10
b36df561 11#include <asm/ppc4xx.h>
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12
13#define _LINUX_CONFIG_H 1 /* avoid reading Linux autoconf.h file */
14
15#include <ppc_asm.tmpl>
16#include <ppc_defs.h>
17
18#include <asm/cache.h>
19#include <asm/mmu.h>
20
21#define _ASMLANGUAGE
22
23/*****************************************************************************
24 *
25 * XXX - DANGER
26 * These routines make use of self modifying code. DO NOT CALL THEM
27 * UNTIL THEY ARE RELOCATED TO RAM. Additionally, I do not
28 * recommend them for use in anything other than an interactive
29 * debugging environment. This is mainly due to performance reasons.
30 *
31 ****************************************************************************/
32
33/*
34 * static void _create_MFDCR(unsigned short dcrn)
35 *
36 * Builds a 'mfdcr' instruction for get_dcr
37 * function.
38 */
39 .section ".text"
40 .align 2
41 .type _create_MFDCR,@function
42_create_MFDCR:
43 /*
44 * Build up a 'mfdcr' instruction formatted as follows:
45 *
46 * OPCD | RT | DCRF | XO | CR |
47 * ---------------|--------------|--------------|----|
48 * 0 5 | 6 10 | 11 20 | 21 30 | 31 |
49 * | | DCRN | | |
50 * 31 | %r3 | (5..9|0..4) | 323 | 0 |
51 *
52 * Where:
53 * OPCD = opcode - 31
54 * RT = destination register - %r3 return register
55 * DCRF = DCRN # with upper and lower halves swapped
56 * XO = extended opcode - 323
57 * CR = CR[CR0] NOT undefined - 0
58 */
59 rlwinm r0, r3, 27, 27, 31 /* OPCD = 31 */
60 rlwinm r3, r3, 5, 22, 26
61 or r3, r3, r0
62 slwi r3, r3, 10
63 oris r3, r3, 0x3e30 /* RT = %r3 */
64 ori r3, r3, 323 /* XO = 323 */
65 slwi r3, r3, 1 /* CR = 0 */
66
67 mflr r4
68 stw r3, 0(r4) /* Store instr in get_dcr() */
69 dcbst r0, r4 /* Make sure val is written out */
70 sync /* Wait for write to complete */
71 icbi r0, r4 /* Make sure old instr is dumped */
72 isync /* Wait for icbi to complete */
73
74 blr
75.Lfe1: .size _create_MFDCR,.Lfe1-_create_MFDCR
76/* end _create_MFDCR() */
77
78/*
79 * static void _create_MTDCR(unsigned short dcrn, unsigned long value)
80 *
81 * Builds a 'mtdcr' instruction for set_dcr
82 * function.
83 */
84 .section ".text"
85 .align 2
86 .type _create_MTDCR,@function
87_create_MTDCR:
88 /*
89 * Build up a 'mtdcr' instruction formatted as follows:
90 *
91 * OPCD | RS | DCRF | XO | CR |
92 * ---------------|--------------|--------------|----|
93 * 0 5 | 6 10 | 11 20 | 21 30 | 31 |
94 * | | DCRN | | |
95 * 31 | %r3 | (5..9|0..4) | 451 | 0 |
96 *
97 * Where:
98 * OPCD = opcode - 31
99 * RS = source register - %r4
100 * DCRF = dest. DCRN # with upper and lower halves swapped
101 * XO = extended opcode - 451
102 * CR = CR[CR0] NOT undefined - 0
103 */
104 rlwinm r0, r3, 27, 27, 31 /* OPCD = 31 */
105 rlwinm r3, r3, 5, 22, 26
106 or r3, r3, r0
107 slwi r3, r3, 10
108 oris r3, r3, 0x3e40 /* RS = %r4 */
109 ori r3, r3, 451 /* XO = 451 */
110 slwi r3, r3, 1 /* CR = 0 */
111
112 mflr r5
113 stw r3, 0(r5) /* Store instr in set_dcr() */
114 dcbst r0, r5 /* Make sure val is written out */
115 sync /* Wait for write to complete */
116 icbi r0, r5 /* Make sure old instr is dumped */
117 isync /* Wait for icbi to complete */
118
119 blr
120.Lfe2: .size _create_MTDCR,.Lfe2-_create_MTDCR
121/* end _create_MTDCR() */
122
123
124/*
125 * unsigned long get_dcr(unsigned short dcrn)
126 *
127 * Return a given DCR's value.
128 */
129 /* */
130 /* XXX - This is self modifying code, hence */
131 /* it is in the data section. */
132 /* */
133 .section ".data"
134 .align 2
135 .globl get_dcr
136 .type get_dcr,@function
137get_dcr:
138 mflr r0 /* Get link register */
139 stwu r1, -32(r1) /* Save back chain and move SP */
140 stw r0, +36(r1) /* Save link register */
141
142 bl _create_MFDCR /* Build following instruction */
143 /* XXX - we build this instuction up on the fly. */
144 .long 0 /* Get DCR's value */
145
146 lwz r0, +36(r1) /* Get saved link register */
147 mtlr r0 /* Restore link register */
148 addi r1, r1, +32 /* Remove frame from stack */
149 blr /* Return to calling function */
150.Lfe3: .size get_dcr,.Lfe3-get_dcr
151/* end get_dcr() */
152
153
154/*
155 * unsigned void set_dcr(unsigned short dcrn, unsigned long value)
156 *
157 * Return a given DCR's value.
158 */
159 /*
160 * XXX - This is self modifying code, hence
161 * it is in the data section.
162 */
163 .section ".data"
164 .align 2
165 .globl set_dcr
166 .type set_dcr,@function
167set_dcr:
168 mflr r0 /* Get link register */
169 stwu r1, -32(r1) /* Save back chain and move SP */
170 stw r0, +36(r1) /* Save link register */
171
172 bl _create_MTDCR /* Build following instruction */
173 /* XXX - we build this instuction up on the fly. */
174 .long 0 /* Set DCR's value */
175
176 lwz r0, +36(r1) /* Get saved link register */
177 mtlr r0 /* Restore link register */
178 addi r1, r1, +32 /* Remove frame from stack */
179 blr /* Return to calling function */
180.Lfe4: .size set_dcr,.Lfe4-set_dcr
181/* end set_dcr() */
068b60a0 182#endif