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-rw-r--r--arch/arm/kernel/atags_parse.c238
1 files changed, 238 insertions, 0 deletions
diff --git a/arch/arm/kernel/atags_parse.c b/arch/arm/kernel/atags_parse.c
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+++ b/arch/arm/kernel/atags_parse.c
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+/*
+ * 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;
+}