/*
   * Copyright (C) Paul Mackerras 1997.
   *
   * Updates for PPC64 by Todd Inglett, Dave Engebretsen & Peter Bergner.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  #include <stdarg.h>
  #include <stddef.h>
  #include "elf.h"
  #include "page.h"
  #include "string.h"
  #include "stdio.h"
  #include "ops.h"
  #include "gunzip_util.h"
  #include "reg.h"
  
  static struct gunzip_state gzstate;
  
  struct addr_range {
  	void *addr;
  	unsigned long size;
  };
  
  #undef DEBUG
  
  static struct addr_range prep_kernel(void)
  {
  	char elfheader[256];
  	void *vmlinuz_addr = _vmlinux_start;
  	unsigned long vmlinuz_size = _vmlinux_end - _vmlinux_start;
  	void *addr = 0;
  	struct elf_info ei;
  	int len;
  
  	/* gunzip the ELF header of the kernel */
  	gunzip_start(&gzstate, vmlinuz_addr, vmlinuz_size);
  	gunzip_exactly(&gzstate, elfheader, sizeof(elfheader));
  
  	if (!parse_elf64(elfheader, &ei) && !parse_elf32(elfheader, &ei))
  		fatal("Error: not a valid PPC32 or PPC64 ELF file!
  \r");
  
  	if (platform_ops.image_hdr)
  		platform_ops.image_hdr(elfheader);
  
  	/* We need to alloc the memsize: gzip will expand the kernel
  	 * text/data, then possible rubbish we don't care about. But
  	 * the kernel bss must be claimed (it will be zero'd by the
  	 * kernel itself)
  	 */
  	printf("Allocating 0x%lx bytes for kernel ...
  \r", ei.memsize);
  
  	if (platform_ops.vmlinux_alloc) {
  		addr = platform_ops.vmlinux_alloc(ei.memsize);
  	} else {
  		/*
  		 * Check if the kernel image (without bss) would overwrite the
  		 * bootwrapper. The device tree has been moved in fdt_init()
  		 * to an area allocated with malloc() (somewhere past _end).
  		 */
  		if ((unsigned long)_start < ei.loadsize)
  			fatal("Insufficient memory for kernel at address 0!"
  			       " (_start=%p, uncompressed size=%08lx)
  \r",
  			       _start, ei.loadsize);
  
  		if ((unsigned long)_end < ei.memsize)
  			fatal("The final kernel image would overwrite the "
  					"device tree
  \r");
  	}
  
  	/* Finally, gunzip the kernel */
  	printf("gunzipping (0x%p <- 0x%p:0x%p)...", addr,
  	       vmlinuz_addr, vmlinuz_addr+vmlinuz_size);
  	/* discard up to the actual load data */
  	gunzip_discard(&gzstate, ei.elfoffset - sizeof(elfheader));
  	len = gunzip_finish(&gzstate, addr, ei.loadsize);
  	if (len != ei.loadsize)
  		fatal("ran out of data!  only got 0x%x of 0x%lx bytes.
  \r",
  				len, ei.loadsize);
  	printf("done 0x%x bytes
  \r", len);
  
  	flush_cache(addr, ei.loadsize);
  
  	return (struct addr_range){addr, ei.memsize};
  }
  
  static struct addr_range prep_initrd(struct addr_range vmlinux, void *chosen,
  				     unsigned long initrd_addr,
  				     unsigned long initrd_size)
  {
  	/* If we have an image attached to us, it overrides anything
  	 * supplied by the loader. */
  	if (_initrd_end > _initrd_start) {
  		printf("Attached initrd image at 0x%p-0x%p
  \r",
  		       _initrd_start, _initrd_end);
  		initrd_addr = (unsigned long)_initrd_start;
  		initrd_size = _initrd_end - _initrd_start;
  	} else if (initrd_size > 0) {
  		printf("Using loader supplied ramdisk at 0x%lx-0x%lx
  \r",
  		       initrd_addr, initrd_addr + initrd_size);
  	}
  
  	/* If there's no initrd at all, we're done */
  	if (! initrd_size)
  		return (struct addr_range){0, 0};
  
  	/*
  	 * If the initrd is too low it will be clobbered when the
  	 * kernel relocates to its final location.  In this case,
  	 * allocate a safer place and move it.
  	 */
  	if (initrd_addr < vmlinux.size) {
  		void *old_addr = (void *)initrd_addr;
  
  		printf("Allocating 0x%lx bytes for initrd ...
  \r",
  		       initrd_size);
  		initrd_addr = (unsigned long)malloc(initrd_size);
  		if (! initrd_addr)
  			fatal("Can't allocate memory for initial "
  			       "ramdisk !
  \r");
  		printf("Relocating initrd 0x%lx <- 0x%p (0x%lx bytes)
  \r",
  		       initrd_addr, old_addr, initrd_size);
  		memmove((void *)initrd_addr, old_addr, initrd_size);
  	}
  
  	printf("initrd head: 0x%lx
  \r", *((unsigned long *)initrd_addr));
  
  	/* Tell the kernel initrd address via device tree */
  	setprop_val(chosen, "linux,initrd-start", (u32)(initrd_addr));
  	setprop_val(chosen, "linux,initrd-end", (u32)(initrd_addr+initrd_size));
  
  	return (struct addr_range){(void *)initrd_addr, initrd_size};
  }
  
  /* A buffer that may be edited by tools operating on a zImage binary so as to
   * edit the command line passed to vmlinux (by setting /chosen/bootargs).
   * The buffer is put in it's own section so that tools may locate it easier.
   */
  static char cmdline[COMMAND_LINE_SIZE]
  	__attribute__((__section__("__builtin_cmdline")));
  
  static void prep_cmdline(void *chosen)
  {
  	if (cmdline[0] == '\0')
  		getprop(chosen, "bootargs", cmdline, COMMAND_LINE_SIZE-1);
  
  	printf("
  \rLinux/PowerPC load: %s", cmdline);
  	/* If possible, edit the command line */
  	if (console_ops.edit_cmdline)
  		console_ops.edit_cmdline(cmdline, COMMAND_LINE_SIZE);
  	printf("
  \r");
  
  	/* Put the command line back into the devtree for the kernel */
  	setprop_str(chosen, "bootargs", cmdline);
  }
  
  struct platform_ops platform_ops;
  struct dt_ops dt_ops;
  struct console_ops console_ops;
  struct loader_info loader_info;
  
  void start(void)
  {
  	struct addr_range vmlinux, initrd;
  	kernel_entry_t kentry;
  	unsigned long ft_addr = 0;
  	void *chosen;
  
  	/* Do this first, because malloc() could clobber the loader's
  	 * command line.  Only use the loader command line if a
  	 * built-in command line wasn't set by an external tool */
  	if ((loader_info.cmdline_len > 0) && (cmdline[0] == '\0'))
  		memmove(cmdline, loader_info.cmdline,
  			min(loader_info.cmdline_len, COMMAND_LINE_SIZE-1));
  
  	if (console_ops.open && (console_ops.open() < 0))
  		exit();
  	if (platform_ops.fixups)
  		platform_ops.fixups();
  
  	printf("
  \rzImage starting: loaded at 0x%p (sp: 0x%p)
  \r",
  	       _start, get_sp());
  
  	/* Ensure that the device tree has a /chosen node */
  	chosen = finddevice("/chosen");
  	if (!chosen)
  		chosen = create_node(NULL, "chosen");
  
  	vmlinux = prep_kernel();
  	initrd = prep_initrd(vmlinux, chosen,
  			     loader_info.initrd_addr, loader_info.initrd_size);
  	prep_cmdline(chosen);
  
  	printf("Finalizing device tree...");
  	if (dt_ops.finalize)
  		ft_addr = dt_ops.finalize();
  	if (ft_addr)
  		printf(" flat tree at 0x%lx
  \r", ft_addr);
  	else
  		printf(" using OF tree (promptr=%p)
  \r", loader_info.promptr);
  
  	if (console_ops.close)
  		console_ops.close();
  
  	kentry = (kernel_entry_t) vmlinux.addr;
  	if (ft_addr)
  		kentry(ft_addr, 0, NULL);
  	else
  		kentry((unsigned long)initrd.addr, initrd.size,
  		       loader_info.promptr);
  
  	/* console closed so printf in fatal below may not work */
  	fatal("Error: Linux kernel returned to zImage boot wrapper!
  \r");
  }