ARM: 7505/1: split out ATAGS parsing

Make ATAGS parsing into a source file of its own, namely atags_parse.c.
Also rename compat.c to atags_compat.c to make it clearer what it is
about.  Same for atags.c which is now atags_proc.c. Gather all the atags
function declarations into a common atags.h.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/Makefile

@@ -15,11 +15,11 @@ CFLAGS_REMOVE_return_address.o = -pg
 
 # Object file lists.
 
-obj-y		:= elf.o entry-armv.o entry-common.o irq.o opcodes.o \
+obj-y		:= atags_parse.o elf.o entry-armv.o entry-common.o irq.o opcodes.o \
 		   process.o ptrace.o return_address.o sched_clock.o \
 		   setup.o signal.o stacktrace.o sys_arm.o time.o traps.o
 
-obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += compat.o
+obj-$(CONFIG_DEPRECATED_PARAM_STRUCT) += atags_compat.o
 
 obj-$(CONFIG_LEDS)		+= leds.o
 obj-$(CONFIG_OC_ETM)		+= etm.o
@@ -52,7 +52,7 @@ test-kprobes-objs		+= kprobes-test-thumb.o
 else
 test-kprobes-objs		+= kprobes-test-arm.o
 endif
-obj-$(CONFIG_ATAGS_PROC)	+= atags.o
+obj-$(CONFIG_ATAGS_PROC)	+= atags_proc.o
 obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
 obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
 obj-$(CONFIG_KGDB)		+= kgdb.o

arch/arm/kernel/atags.h

@@ -3,3 +3,6 @@ extern void save_atags(struct tag *tags);
 #else
 static inline void save_atags(struct tag *tags) { }
 #endif
+
+void convert_to_tag_list(struct tag *tags);
+struct machine_desc *setup_machine_tags(phys_addr_t __atags_pointer, unsigned int machine_nr);

arch/arm/kernel/compat.c → arch/arm/kernel/atags_compat.c

@@ -1,5 +1,5 @@
 /*
- *  linux/arch/arm/kernel/compat.c
+ *  linux/arch/arm/kernel/atags_compat.c
  *
  *  Copyright (C) 2001 Russell King
  *
@@ -26,7 +26,7 @@
 
 #include <asm/mach/arch.h>
 
-#include "compat.h"
+#include "atags.h"
 
 /*
  * Usage:

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;
+}