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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> | |
25 | ||
26 | #include <asm/setup.h> | |
27 | #include <asm/system_info.h> | |
28 | #include <asm/page.h> | |
29 | #include <asm/mach/arch.h> | |
30 | ||
31 | #include "atags.h" | |
32 | ||
6fa3eb70 | 33 | char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE; |
aa783b6f NP |
34 | |
35 | #ifndef MEM_SIZE | |
36 | #define MEM_SIZE (16*1024*1024) | |
37 | #endif | |
38 | ||
39 | static struct { | |
40 | struct tag_header hdr1; | |
41 | struct tag_core core; | |
42 | struct tag_header hdr2; | |
43 | struct tag_mem32 mem; | |
44 | struct tag_header hdr3; | |
45 | } default_tags __initdata = { | |
46 | { tag_size(tag_core), ATAG_CORE }, | |
47 | { 1, PAGE_SIZE, 0xff }, | |
48 | { tag_size(tag_mem32), ATAG_MEM }, | |
49 | { MEM_SIZE }, | |
50 | { 0, ATAG_NONE } | |
51 | }; | |
52 | ||
53 | static int __init parse_tag_core(const struct tag *tag) | |
54 | { | |
55 | if (tag->hdr.size > 2) { | |
56 | if ((tag->u.core.flags & 1) == 0) | |
57 | root_mountflags &= ~MS_RDONLY; | |
58 | ROOT_DEV = old_decode_dev(tag->u.core.rootdev); | |
59 | } | |
60 | return 0; | |
61 | } | |
62 | ||
63 | __tagtable(ATAG_CORE, parse_tag_core); | |
64 | ||
65 | static int __init parse_tag_mem32(const struct tag *tag) | |
66 | { | |
67 | return arm_add_memory(tag->u.mem.start, tag->u.mem.size); | |
68 | } | |
69 | ||
70 | __tagtable(ATAG_MEM, parse_tag_mem32); | |
71 | ||
72 | #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE) | |
73 | static int __init parse_tag_videotext(const struct tag *tag) | |
74 | { | |
75 | screen_info.orig_x = tag->u.videotext.x; | |
76 | screen_info.orig_y = tag->u.videotext.y; | |
77 | screen_info.orig_video_page = tag->u.videotext.video_page; | |
78 | screen_info.orig_video_mode = tag->u.videotext.video_mode; | |
79 | screen_info.orig_video_cols = tag->u.videotext.video_cols; | |
80 | screen_info.orig_video_ega_bx = tag->u.videotext.video_ega_bx; | |
81 | screen_info.orig_video_lines = tag->u.videotext.video_lines; | |
82 | screen_info.orig_video_isVGA = tag->u.videotext.video_isvga; | |
83 | screen_info.orig_video_points = tag->u.videotext.video_points; | |
84 | return 0; | |
85 | } | |
86 | ||
87 | __tagtable(ATAG_VIDEOTEXT, parse_tag_videotext); | |
88 | #endif | |
89 | ||
90 | #ifdef CONFIG_BLK_DEV_RAM | |
91 | static int __init parse_tag_ramdisk(const struct tag *tag) | |
92 | { | |
93 | extern int rd_size, rd_image_start, rd_prompt, rd_doload; | |
94 | ||
95 | rd_image_start = tag->u.ramdisk.start; | |
96 | rd_doload = (tag->u.ramdisk.flags & 1) == 0; | |
97 | rd_prompt = (tag->u.ramdisk.flags & 2) == 0; | |
98 | ||
99 | if (tag->u.ramdisk.size) | |
100 | rd_size = tag->u.ramdisk.size; | |
101 | ||
102 | return 0; | |
103 | } | |
104 | ||
105 | __tagtable(ATAG_RAMDISK, parse_tag_ramdisk); | |
106 | #endif | |
107 | ||
108 | static int __init parse_tag_serialnr(const struct tag *tag) | |
109 | { | |
110 | system_serial_low = tag->u.serialnr.low; | |
111 | system_serial_high = tag->u.serialnr.high; | |
112 | return 0; | |
113 | } | |
114 | ||
115 | __tagtable(ATAG_SERIAL, parse_tag_serialnr); | |
116 | ||
117 | static int __init parse_tag_revision(const struct tag *tag) | |
118 | { | |
119 | system_rev = tag->u.revision.rev; | |
120 | return 0; | |
121 | } | |
122 | ||
123 | __tagtable(ATAG_REVISION, parse_tag_revision); | |
124 | ||
125 | static int __init parse_tag_cmdline(const struct tag *tag) | |
126 | { | |
127 | #if defined(CONFIG_CMDLINE_EXTEND) | |
128 | strlcat(default_command_line, " ", COMMAND_LINE_SIZE); | |
129 | strlcat(default_command_line, tag->u.cmdline.cmdline, | |
130 | COMMAND_LINE_SIZE); | |
131 | #elif defined(CONFIG_CMDLINE_FORCE) | |
132 | pr_warning("Ignoring tag cmdline (using the default kernel command line)\n"); | |
133 | #else | |
134 | strlcpy(default_command_line, tag->u.cmdline.cmdline, | |
135 | COMMAND_LINE_SIZE); | |
136 | #endif | |
137 | return 0; | |
138 | } | |
139 | ||
140 | __tagtable(ATAG_CMDLINE, parse_tag_cmdline); | |
141 | ||
142 | /* | |
143 | * Scan the tag table for this tag, and call its parse function. | |
144 | * The tag table is built by the linker from all the __tagtable | |
145 | * declarations. | |
146 | */ | |
147 | static int __init parse_tag(const struct tag *tag) | |
148 | { | |
149 | extern struct tagtable __tagtable_begin, __tagtable_end; | |
150 | struct tagtable *t; | |
151 | ||
152 | for (t = &__tagtable_begin; t < &__tagtable_end; t++) | |
153 | if (tag->hdr.tag == t->tag) { | |
154 | t->parse(tag); | |
155 | break; | |
156 | } | |
157 | ||
158 | return t < &__tagtable_end; | |
159 | } | |
160 | ||
161 | /* | |
162 | * Parse all tags in the list, checking both the global and architecture | |
163 | * specific tag tables. | |
164 | */ | |
165 | static void __init parse_tags(const struct tag *t) | |
166 | { | |
167 | for (; t->hdr.size; t = tag_next(t)) | |
168 | if (!parse_tag(t)) | |
169 | printk(KERN_WARNING | |
170 | "Ignoring unrecognised tag 0x%08x\n", | |
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 | ||
181 | struct machine_desc * __init setup_machine_tags(phys_addr_t __atags_pointer, | |
182 | unsigned int machine_nr) | |
183 | { | |
184 | struct tag *tags = (struct tag *)&default_tags; | |
185 | struct machine_desc *mdesc = NULL, *p; | |
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) { | |
195 | printk("Machine: %s\n", p->name); | |
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) | |
225 | mdesc->fixup(tags, &from, &meminfo); | |
226 | ||
227 | if (tags->hdr.tag == ATAG_CORE) { | |
228 | if (meminfo.nr_banks != 0) | |
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 | } |