1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * arch/shmedia/boot/compressed/head.S
7 *
8 * Copied from
9 * arch/shmedia/kernel/head.S
10 * which carried the copyright:
11 * Copyright (C) 2000, 2001 Paolo Alberelli
12 *
13 * Modification for compressed loader:
14 * Copyright (C) 2002 Stuart Menefy (stuart.menefy@st.com)
15 */
16#include <asm/cache.h>
17#include <asm/tlb.h>
18#include <cpu/mmu_context.h>
19#include <cpu/registers.h>
20
21/*
22 * Fixed TLB entries to identity map the beginning of RAM
23 */
24#define MMUIR_TEXT_H 0x0000000000000003 | CONFIG_MEMORY_START
25 /* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */
26#define MMUIR_TEXT_L 0x000000000000009a | CONFIG_MEMORY_START
27 /* 512 Mb, Cacheable (Write-back), execute, Not User, Ph. Add. */
28
29#define MMUDR_CACHED_H 0x0000000000000003 | CONFIG_MEMORY_START
30 /* Enabled, Shared, ASID 0, Eff. Add. 0xA0000000 */
31#define MMUDR_CACHED_L 0x000000000000015a | CONFIG_MEMORY_START
32 /* 512 Mb, Cacheable (Write-back), read/write, Not User, Ph. Add. */
33
34#define ICCR0_INIT_VAL ICCR0_ON | ICCR0_ICI /* ICE + ICI */
35#define ICCR1_INIT_VAL ICCR1_NOLOCK /* No locking */
36
37#define OCCR0_INIT_VAL OCCR0_ON | OCCR0_OCI | OCCR0_WB /* OCE + OCI + WB */
38#define OCCR1_INIT_VAL OCCR1_NOLOCK /* No locking */
39
40 .text
41
42 .global startup
43startup:
44 /*
45 * Prevent speculative fetch on device memory due to
46 * uninitialized target registers.
47 * This must be executed before the first branch.
48 */
49 ptabs/u r63, tr0
50 ptabs/u r63, tr1
51 ptabs/u r63, tr2
52 ptabs/u r63, tr3
53 ptabs/u r63, tr4
54 ptabs/u r63, tr5
55 ptabs/u r63, tr6
56 ptabs/u r63, tr7
57 synci
58
59 /*
60 * Set initial TLB entries for cached and uncached regions.
61 * Note: PTA/BLINK is PIC code, PTABS/BLINK isn't !
62 */
63 /* Clear ITLBs */
64 pta 1f, tr1
65 movi ITLB_FIXED, r21
66 movi ITLB_LAST_VAR_UNRESTRICTED+TLB_STEP, r22
671: putcfg r21, 0, r63 /* Clear MMUIR[n].PTEH.V */
68 addi r21, TLB_STEP, r21
69 bne r21, r22, tr1
70
71 /* Clear DTLBs */
72 pta 1f, tr1
73 movi DTLB_FIXED, r21
74 movi DTLB_LAST_VAR_UNRESTRICTED+TLB_STEP, r22
751: putcfg r21, 0, r63 /* Clear MMUDR[n].PTEH.V */
76 addi r21, TLB_STEP, r21
77 bne r21, r22, tr1
78
79 /* Map one big (512Mb) page for ITLB */
80 movi ITLB_FIXED, r21
81 movi MMUIR_TEXT_L, r22 /* PTEL first */
82 putcfg r21, 1, r22 /* Set MMUIR[0].PTEL */
83 movi MMUIR_TEXT_H, r22 /* PTEH last */
84 putcfg r21, 0, r22 /* Set MMUIR[0].PTEH */
85
86 /* Map one big CACHED (512Mb) page for DTLB */
87 movi DTLB_FIXED, r21
88 movi MMUDR_CACHED_L, r22 /* PTEL first */
89 putcfg r21, 1, r22 /* Set MMUDR[0].PTEL */
90 movi MMUDR_CACHED_H, r22 /* PTEH last */
91 putcfg r21, 0, r22 /* Set MMUDR[0].PTEH */
92
93 /* ICache */
94 movi ICCR_BASE, r21
95 movi ICCR0_INIT_VAL, r22
96 movi ICCR1_INIT_VAL, r23
97 putcfg r21, ICCR_REG0, r22
98 putcfg r21, ICCR_REG1, r23
99 synci
100
101 /* OCache */
102 movi OCCR_BASE, r21
103 movi OCCR0_INIT_VAL, r22
104 movi OCCR1_INIT_VAL, r23
105 putcfg r21, OCCR_REG0, r22
106 putcfg r21, OCCR_REG1, r23
107 synco
108
109 /*
110 * Enable the MMU.
111 * From here-on code can be non-PIC.
112 */
113 movi SR_HARMLESS | SR_ENABLE_MMU, r22
114 putcon r22, SSR
115 movi 1f, r22
116 putcon r22, SPC
117 synco
118 rte /* And now go into the hyperspace ... */
1191: /* ... that's the next instruction ! */
120
121 /* Set initial stack pointer */
122 movi datalabel stack_start, r0
123 ld.l r0, 0, r15
124
125 /*
126 * Clear bss
127 */
128 pt 1f, tr1
129 movi datalabel __bss_start, r22
130 movi datalabel _end, r23
1311: st.l r22, 0, r63
132 addi r22, 4, r22
133 bne r22, r23, tr1
134
135 /*
136 * Decompress the kernel.
137 */
138 pt decompress_kernel, tr0
139 blink tr0, r18
140
141 /*
142 * Disable the MMU.
143 */
144 movi SR_HARMLESS, r22
145 putcon r22, SSR
146 movi 1f, r22
147 putcon r22, SPC
148 synco
149 rte /* And now go into the hyperspace ... */
1501: /* ... that's the next instruction ! */
151
152 /* Jump into the decompressed kernel */
153 movi datalabel (CONFIG_MEMORY_START + 0x2000)+1, r19
154 ptabs r19, tr0
155 blink tr0, r18
156
157 /* Shouldn't return here, but just in case, loop forever */
158 pt 1f, tr0
1591: blink tr0, r63
160

source code of linux/arch/sh/boot/compressed/head_64.S