/*

   * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen IBM Corporation

   *

   * 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.

   *

   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.

   *

   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   */

  #include <linux/init.h>
  #include <linux/mm.h>
  #include <linux/proc_fs.h>
  #include <linux/slab.h>
  #include <linux/kernel.h>

  #include <asm/machdep.h>

  #include <asm/vdso_datapage.h>

  #include <asm/rtas.h>
  #include <asm/uaccess.h>
  #include <asm/prom.h>
  
  static loff_t  page_map_seek( struct file *file, loff_t off, int whence);
  static ssize_t page_map_read( struct file *file, char __user *buf, size_t nbytes,
  			      loff_t *ppos);
  static int     page_map_mmap( struct file *file, struct vm_area_struct *vma );

  static const struct file_operations page_map_fops = {

  	.llseek	= page_map_seek,
  	.read	= page_map_read,
  	.mmap	= page_map_mmap
  };
  
  /*
   * Create the ppc64 and ppc64/rtas directories early. This allows us to
   * assume that they have been previously created in drivers.
   */
  static int __init proc_ppc64_create(void)
  {
  	struct proc_dir_entry *root;
  
  	root = proc_mkdir("ppc64", NULL);
  	if (!root)
  		return 1;

  	if (!of_find_node_by_path("/rtas"))

  		return 0;
  
  	if (!proc_mkdir("rtas", root))
  		return 1;
  
  	if (!proc_symlink("rtas", NULL, "ppc64/rtas"))
  		return 1;
  
  	return 0;
  }
  core_initcall(proc_ppc64_create);
  
  static int __init proc_ppc64_init(void)
  {
  	struct proc_dir_entry *pde;
  
  	pde = create_proc_entry("ppc64/systemcfg", S_IFREG|S_IRUGO, NULL);
  	if (!pde)
  		return 1;

  	pde->data = vdso_data;

  	pde->size = PAGE_SIZE;
  	pde->proc_fops = &page_map_fops;
  
  	return 0;
  }
  __initcall(proc_ppc64_init);
  
  static loff_t page_map_seek( struct file *file, loff_t off, int whence)
  {
  	loff_t new;

  	struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);

  
  	switch(whence) {
  	case 0:
  		new = off;
  		break;
  	case 1:
  		new = file->f_pos + off;
  		break;
  	case 2:
  		new = dp->size + off;
  		break;
  	default:
  		return -EINVAL;
  	}
  	if ( new < 0 || new > dp->size )
  		return -EINVAL;
  	return (file->f_pos = new);
  }
  
  static ssize_t page_map_read( struct file *file, char __user *buf, size_t nbytes,
  			      loff_t *ppos)
  {

  	struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);

  	return simple_read_from_buffer(buf, nbytes, ppos, dp->data, dp->size);
  }
  
  static int page_map_mmap( struct file *file, struct vm_area_struct *vma )
  {

  	struct proc_dir_entry *dp = PDE(file->f_path.dentry->d_inode);

  	if ((vma->vm_end - vma->vm_start) > dp->size)
  		return -EINVAL;
  
  	remap_pfn_range(vma, vma->vm_start, __pa(dp->data) >> PAGE_SHIFT,
  						dp->size, vma->vm_page_prot);
  	return 0;
  }