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aa783b6f NP |
1 | /* |
2 | * Tag parsing. | |
3 | * | |
4 | * Copyright (C) 1995-2001 Russell King | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | /* | |
12 | * This is the traditional way of passing data to the kernel at boot time. Rather | |
13 | * than passing a fixed inflexible structure to the kernel, we pass a list | |
14 | * of variable-sized tags to the kernel. The first tag must be a ATAG_CORE | |
15 | * tag for the list to be recognised (to distinguish the tagged list from | |
16 | * a param_struct). The list is terminated with a zero-length tag (this tag | |
17 | * is not parsed in any way). | |
18 | */ | |
19 | ||
20 | #include <linux/init.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/root_dev.h> | |
24 | #include <linux/screen_info.h> | |
1c2f87c2 | 25 | #include <linux/memblock.h> |
aa783b6f NP |
26 | |
27 | #include <asm/setup.h> | |
28 | #include <asm/system_info.h> | |
29 | #include <asm/page.h> | |
30 | #include <asm/mach/arch.h> | |
31 | ||
32 | #include "atags.h" | |
33 | ||
34 | static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE; | |
35 | ||
36 | #ifndef MEM_SIZE | |
37 | #define MEM_SIZE (16*1024*1024) | |
38 | #endif | |
39 | ||
40 | static struct { | |
41 | struct tag_header hdr1; | |
42 | struct tag_core core; | |
43 | struct tag_header hdr2; | |
44 | struct tag_mem32 mem; | |
45 | struct tag_header hdr3; | |
46 | } default_tags __initdata = { | |
47 | { tag_size(tag_core), ATAG_CORE }, | |
48 | { 1, PAGE_SIZE, 0xff }, | |
49 | { tag_size(tag_mem32), ATAG_MEM }, | |
50 | { MEM_SIZE }, | |
51 | { 0, ATAG_NONE } | |
52 | }; | |
53 | ||
54 | static int __init parse_tag_core(const struct tag *tag) | |
55 | { | |
56 | if (tag->hdr.size > 2) { | |
57 | if ((tag->u.core.flags & 1) == 0) | |
58 | root_mountflags &= ~MS_RDONLY; | |
59 | ROOT_DEV = old_decode_dev(tag->u.core.rootdev); | |
60 | } | |
61 | return 0; | |
62 | } | |
63 | ||
64 | __tagtable(ATAG_CORE, parse_tag_core); | |
65 | ||
66 | static int __init parse_tag_mem32(const struct tag *tag) | |
67 | { | |
68 | return arm_add_memory(tag->u.mem.start, tag->u.mem.size); | |
69 | } | |
70 | ||
71 | __tagtable(ATAG_MEM, parse_tag_mem32); | |
72 | ||
73 | #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE) | |
74 | static int __init parse_tag_videotext(const struct tag *tag) | |
75 | { | |
76 | screen_info.orig_x = tag->u.videotext.x; | |
77 | screen_info.orig_y = tag->u.videotext.y; | |
78 | screen_info.orig_video_page = tag->u.videotext.video_page; | |
79 | screen_info.orig_video_mode = tag->u.videotext.video_mode; | |
80 | screen_info.orig_video_cols = tag->u.videotext.video_cols; | |
81 | screen_info.orig_video_ega_bx = tag->u.videotext.video_ega_bx; | |
82 | screen_info.orig_video_lines = tag->u.videotext.video_lines; | |
83 | screen_info.orig_video_isVGA = tag->u.videotext.video_isvga; | |
84 | screen_info.orig_video_points = tag->u.videotext.video_points; | |
85 | return 0; | |
86 | } | |
87 | ||
88 | __tagtable(ATAG_VIDEOTEXT, parse_tag_videotext); | |
89 | #endif | |
90 | ||
91 | #ifdef CONFIG_BLK_DEV_RAM | |
92 | static int __init parse_tag_ramdisk(const struct tag *tag) | |
93 | { | |
94 | extern int rd_size, rd_image_start, rd_prompt, rd_doload; | |
95 | ||
96 | rd_image_start = tag->u.ramdisk.start; | |
97 | rd_doload = (tag->u.ramdisk.flags & 1) == 0; | |
98 | rd_prompt = (tag->u.ramdisk.flags & 2) == 0; | |
99 | ||
100 | if (tag->u.ramdisk.size) | |
101 | rd_size = tag->u.ramdisk.size; | |
102 | ||
103 | return 0; | |
104 | } | |
105 | ||
106 | __tagtable(ATAG_RAMDISK, parse_tag_ramdisk); | |
107 | #endif | |
108 | ||
109 | static int __init parse_tag_serialnr(const struct tag *tag) | |
110 | { | |
111 | system_serial_low = tag->u.serialnr.low; | |
112 | system_serial_high = tag->u.serialnr.high; | |
113 | return 0; | |
114 | } | |
115 | ||
116 | __tagtable(ATAG_SERIAL, parse_tag_serialnr); | |
117 | ||
118 | static int __init parse_tag_revision(const struct tag *tag) | |
119 | { | |
120 | system_rev = tag->u.revision.rev; | |
121 | return 0; | |
122 | } | |
123 | ||
124 | __tagtable(ATAG_REVISION, parse_tag_revision); | |
125 | ||
126 | static int __init parse_tag_cmdline(const struct tag *tag) | |
127 | { | |
128 | #if defined(CONFIG_CMDLINE_EXTEND) | |
129 | strlcat(default_command_line, " ", COMMAND_LINE_SIZE); | |
130 | strlcat(default_command_line, tag->u.cmdline.cmdline, | |
131 | COMMAND_LINE_SIZE); | |
132 | #elif defined(CONFIG_CMDLINE_FORCE) | |
8b521cb2 | 133 | pr_warn("Ignoring tag cmdline (using the default kernel command line)\n"); |
aa783b6f NP |
134 | #else |
135 | strlcpy(default_command_line, tag->u.cmdline.cmdline, | |
136 | COMMAND_LINE_SIZE); | |
137 | #endif | |
138 | return 0; | |
139 | } | |
140 | ||
141 | __tagtable(ATAG_CMDLINE, parse_tag_cmdline); | |
142 | ||
143 | /* | |
144 | * Scan the tag table for this tag, and call its parse function. | |
145 | * The tag table is built by the linker from all the __tagtable | |
146 | * declarations. | |
147 | */ | |
148 | static int __init parse_tag(const struct tag *tag) | |
149 | { | |
150 | extern struct tagtable __tagtable_begin, __tagtable_end; | |
151 | struct tagtable *t; | |
152 | ||
153 | for (t = &__tagtable_begin; t < &__tagtable_end; t++) | |
154 | if (tag->hdr.tag == t->tag) { | |
155 | t->parse(tag); | |
156 | break; | |
157 | } | |
158 | ||
159 | return t < &__tagtable_end; | |
160 | } | |
161 | ||
162 | /* | |
163 | * Parse all tags in the list, checking both the global and architecture | |
164 | * specific tag tables. | |
165 | */ | |
166 | static void __init parse_tags(const struct tag *t) | |
167 | { | |
168 | for (; t->hdr.size; t = tag_next(t)) | |
169 | if (!parse_tag(t)) | |
4ed89f22 | 170 | pr_warn("Ignoring unrecognised tag 0x%08x\n", |
aa783b6f NP |
171 | t->hdr.tag); |
172 | } | |
173 | ||
174 | static void __init squash_mem_tags(struct tag *tag) | |
175 | { | |
176 | for (; tag->hdr.size; tag = tag_next(tag)) | |
177 | if (tag->hdr.tag == ATAG_MEM) | |
178 | tag->hdr.tag = ATAG_NONE; | |
179 | } | |
180 | ||
ff69a4c8 RK |
181 | const struct machine_desc * __init |
182 | setup_machine_tags(phys_addr_t __atags_pointer, unsigned int machine_nr) | |
aa783b6f NP |
183 | { |
184 | struct tag *tags = (struct tag *)&default_tags; | |
ff69a4c8 | 185 | const struct machine_desc *mdesc = NULL, *p; |
aa783b6f NP |
186 | char *from = default_command_line; |
187 | ||
188 | default_tags.mem.start = PHYS_OFFSET; | |
189 | ||
190 | /* | |
191 | * locate machine in the list of supported machines. | |
192 | */ | |
193 | for_each_machine_desc(p) | |
194 | if (machine_nr == p->nr) { | |
4ed89f22 | 195 | pr_info("Machine: %s\n", p->name); |
aa783b6f NP |
196 | mdesc = p; |
197 | break; | |
198 | } | |
199 | ||
200 | if (!mdesc) { | |
201 | early_print("\nError: unrecognized/unsupported machine ID" | |
202 | " (r1 = 0x%08x).\n\n", machine_nr); | |
203 | dump_machine_table(); /* does not return */ | |
204 | } | |
205 | ||
206 | if (__atags_pointer) | |
207 | tags = phys_to_virt(__atags_pointer); | |
208 | else if (mdesc->atag_offset) | |
209 | tags = (void *)(PAGE_OFFSET + mdesc->atag_offset); | |
210 | ||
211 | #if defined(CONFIG_DEPRECATED_PARAM_STRUCT) | |
212 | /* | |
213 | * If we have the old style parameters, convert them to | |
214 | * a tag list. | |
215 | */ | |
216 | if (tags->hdr.tag != ATAG_CORE) | |
217 | convert_to_tag_list(tags); | |
218 | #endif | |
219 | if (tags->hdr.tag != ATAG_CORE) { | |
220 | early_print("Warning: Neither atags nor dtb found\n"); | |
221 | tags = (struct tag *)&default_tags; | |
222 | } | |
223 | ||
224 | if (mdesc->fixup) | |
1c2f87c2 | 225 | mdesc->fixup(tags, &from); |
aa783b6f NP |
226 | |
227 | if (tags->hdr.tag == ATAG_CORE) { | |
1c2f87c2 | 228 | if (memblock_phys_mem_size()) |
aa783b6f NP |
229 | squash_mem_tags(tags); |
230 | save_atags(tags); | |
231 | parse_tags(tags); | |
232 | } | |
233 | ||
234 | /* parse_early_param needs a boot_command_line */ | |
235 | strlcpy(boot_command_line, from, COMMAND_LINE_SIZE); | |
236 | ||
237 | return mdesc; | |
238 | } |