diff options
Diffstat (limited to 'arch/arm/kernel/atags_parse.c')
| -rw-r--r-- | arch/arm/kernel/atags_parse.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c new file mode 100644 index 000000000000..14512e6931d8 --- /dev/null +++ b/arch/arm/kernel/atags_parse.c @@ -0,0 +1,238 @@ +/* + * Tag parsing. + * + * Copyright (C) 1995-2001 Russell King + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +/* + * This is the traditional way of passing data to the kernel at boot time. Rather + * than passing a fixed inflexible structure to the kernel, we pass a list + * of variable-sized tags to the kernel. The first tag must be a ATAG_CORE + * tag for the list to be recognised (to distinguish the tagged list from + * a param_struct). The list is terminated with a zero-length tag (this tag + * is not parsed in any way). + */ + +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/root_dev.h> +#include <linux/screen_info.h> + +#include <asm/setup.h> +#include <asm/system_info.h> +#include <asm/page.h> +#include <asm/mach/arch.h> + +#include "atags.h" + +static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE; + +#ifndef MEM_SIZE +#define MEM_SIZE (16*1024*1024) +#endif + +static struct { + struct tag_header hdr1; + struct tag_core core; + struct tag_header hdr2; + struct tag_mem32 mem; + struct tag_header hdr3; +} default_tags __initdata = { + { tag_size(tag_core), ATAG_CORE }, + { 1, PAGE_SIZE, 0xff }, + { tag_size(tag_mem32), ATAG_MEM }, + { MEM_SIZE }, + { 0, ATAG_NONE } +}; + +static int __init parse_tag_core(const struct tag *tag) +{ + if (tag->hdr.size > 2) { + if ((tag->u.core.flags & 1) == 0) + root_mountflags &= ~MS_RDONLY; + ROOT_DEV = old_decode_dev(tag->u.core.rootdev); + } + return 0; +} + +__tagtable(ATAG_CORE, parse_tag_core); + +static int __init parse_tag_mem32(const struct tag *tag) +{ + return arm_add_memory(tag->u.mem.start, tag->u.mem.size); +} + +__tagtable(ATAG_MEM, parse_tag_mem32); + +#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE) +static int __init parse_tag_videotext(const struct tag *tag) +{ + screen_info.orig_x = tag->u.videotext.x; + screen_info.orig_y = tag->u.videotext.y; + screen_info.orig_video_page = tag->u.videotext.video_page; + screen_info.orig_video_mode = tag->u.videotext.video_mode; + screen_info.orig_video_cols = tag->u.videotext.video_cols; + screen_info.orig_video_ega_bx = tag->u.videotext.video_ega_bx; + screen_info.orig_video_lines = tag->u.videotext.video_lines; + screen_info.orig_video_isVGA = tag->u.videotext.video_isvga; + screen_info.orig_video_points = tag->u.videotext.video_points; + return 0; +} + +__tagtable(ATAG_VIDEOTEXT, parse_tag_videotext); +#endif + +#ifdef CONFIG_BLK_DEV_RAM +static int __init parse_tag_ramdisk(const struct tag *tag) +{ + extern int rd_size, rd_image_start, rd_prompt, rd_doload; + + rd_image_start = tag->u.ramdisk.start; + rd_doload = (tag->u.ramdisk.flags & 1) == 0; + rd_prompt = (tag->u.ramdisk.flags & 2) == 0; + + if (tag->u.ramdisk.size) + rd_size = tag->u.ramdisk.size; + + return 0; +} + +__tagtable(ATAG_RAMDISK, parse_tag_ramdisk); +#endif + +static int __init parse_tag_serialnr(const struct tag *tag) +{ + system_serial_low = tag->u.serialnr.low; + system_serial_high = tag->u.serialnr.high; + return 0; +} + +__tagtable(ATAG_SERIAL, parse_tag_serialnr); + +static int __init parse_tag_revision(const struct tag *tag) +{ + system_rev = tag->u.revision.rev; + return 0; +} + +__tagtable(ATAG_REVISION, parse_tag_revision); + +static int __init parse_tag_cmdline(const struct tag *tag) +{ +#if defined(CONFIG_CMDLINE_EXTEND) + strlcat(default_command_line, " ", COMMAND_LINE_SIZE); + strlcat(default_command_line, tag->u.cmdline.cmdline, + COMMAND_LINE_SIZE); +#elif defined(CONFIG_CMDLINE_FORCE) + pr_warning("Ignoring tag cmdline (using the default kernel command line)\n"); +#else + strlcpy(default_command_line, tag->u.cmdline.cmdline, + COMMAND_LINE_SIZE); +#endif + return 0; +} + +__tagtable(ATAG_CMDLINE, parse_tag_cmdline); + +/* + * Scan the tag table for this tag, and call its parse function. + * The tag table is built by the linker from all the __tagtable + * declarations. + */ +static int __init parse_tag(const struct tag *tag) +{ + extern struct tagtable __tagtable_begin, __tagtable_end; + struct tagtable *t; + + for (t = &__tagtable_begin; t < &__tagtable_end; t++) + if (tag->hdr.tag == t->tag) { + t->parse(tag); + break; + } + + return t < &__tagtable_end; +} + +/* + * Parse all tags in the list, checking both the global and architecture + * specific tag tables. + */ +static void __init parse_tags(const struct tag *t) +{ + for (; t->hdr.size; t = tag_next(t)) + if (!parse_tag(t)) + printk(KERN_WARNING + "Ignoring unrecognised tag 0x%08x\n", + t->hdr.tag); +} + +static void __init squash_mem_tags(struct tag *tag) +{ + for (; tag->hdr.size; tag = tag_next(tag)) + if (tag->hdr.tag == ATAG_MEM) + tag->hdr.tag = ATAG_NONE; +} + +struct machine_desc * __init setup_machine_tags(phys_addr_t __atags_pointer, + unsigned int machine_nr) +{ + struct tag *tags = (struct tag *)&default_tags; + struct machine_desc *mdesc = NULL, *p; + char *from = default_command_line; + + default_tags.mem.start = PHYS_OFFSET; + + /* + * locate machine in the list of supported machines. + */ + for_each_machine_desc(p) + if (machine_nr == p->nr) { + printk("Machine: %s\n", p->name); + mdesc = p; + break; + } + + if (!mdesc) { + early_print("\nError: unrecognized/unsupported machine ID" + " (r1 = 0x%08x).\n\n", machine_nr); + dump_machine_table(); /* does not return */ + } + + if (__atags_pointer) + tags = phys_to_virt(__atags_pointer); + else if (mdesc->atag_offset) + tags = (void *)(PAGE_OFFSET + mdesc->atag_offset); + +#if defined(CONFIG_DEPRECATED_PARAM_STRUCT) + /* + * If we have the old style parameters, convert them to + * a tag list. + */ + if (tags->hdr.tag != ATAG_CORE) + convert_to_tag_list(tags); +#endif + if (tags->hdr.tag != ATAG_CORE) { + early_print("Warning: Neither atags nor dtb found\n"); + tags = (struct tag *)&default_tags; + } + + if (mdesc->fixup) + mdesc->fixup(tags, &from, &meminfo); + + if (tags->hdr.tag == ATAG_CORE) { + if (meminfo.nr_banks != 0) + squash_mem_tags(tags); + save_atags(tags); + parse_tags(tags); + } + + /* parse_early_param needs a boot_command_line */ + strlcpy(boot_command_line, from, COMMAND_LINE_SIZE); + + return mdesc; +} |