/*
   * Copyright 2010 Benjamin Herrenschmidt, IBM Corp
   *                <benh@kernel.crashing.org>
   *     and        David Gibson, 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/kernel.h>
  #include <linux/debugfs.h>
  #include <linux/slab.h>
  #include <linux/export.h>
  #include <asm/debug.h>
  #include <asm/prom.h>
  #include <asm/scom.h>
  #include <asm/uaccess.h>
  
  const struct scom_controller *scom_controller;
  EXPORT_SYMBOL_GPL(scom_controller);
  
  struct device_node *scom_find_parent(struct device_node *node)
  {
  	struct device_node *par, *tmp;
  	const u32 *p;
  
  	for (par = of_node_get(node); par;) {
  		if (of_get_property(par, "scom-controller", NULL))
  			break;
  		p = of_get_property(par, "scom-parent", NULL);
  		tmp = par;
  		if (p == NULL)
  			par = of_get_parent(par);
  		else
  			par = of_find_node_by_phandle(*p);
  		of_node_put(tmp);
  	}
  	return par;
  }
  EXPORT_SYMBOL_GPL(scom_find_parent);
  
  scom_map_t scom_map_device(struct device_node *dev, int index)
  {
  	struct device_node *parent;
  	unsigned int cells, size;
  	const __be32 *prop, *sprop;
  	u64 reg, cnt;
  	scom_map_t ret;
  
  	parent = scom_find_parent(dev);
  
  	if (parent == NULL)
  		return 0;
  
  	/*
  	 * We support "scom-reg" properties for adding scom registers
  	 * to a random device-tree node with an explicit scom-parent
  	 *
  	 * We also support the simple "reg" property if the device is
  	 * a direct child of a scom controller.
  	 *
  	 * In case both exist, "scom-reg" takes precedence.
  	 */
  	prop = of_get_property(dev, "scom-reg", &size);
  	sprop = of_get_property(parent, "#scom-cells", NULL);
  	if (!prop && parent == dev->parent) {
  		prop = of_get_property(dev, "reg", &size);
  		sprop = of_get_property(parent, "#address-cells", NULL);
  	}
  	if (!prop)
  		return NULL;
  	cells = sprop ? be32_to_cpup(sprop) : 1;
  	size >>= 2;
  
  	if (index >= (size / (2*cells)))
  		return 0;
  
  	reg = of_read_number(&prop[index * cells * 2], cells);
  	cnt = of_read_number(&prop[index * cells * 2 + cells], cells);
  
  	ret = scom_map(parent, reg, cnt);
  	of_node_put(parent);
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(scom_map_device);
  
  #ifdef CONFIG_SCOM_DEBUGFS
  struct scom_debug_entry {
  	struct device_node *dn;
  	struct debugfs_blob_wrapper path;
  	char name[16];
  };
  
  static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
  			       size_t count, loff_t *ppos)
  {
  	struct scom_debug_entry *ent = filp->private_data;
  	u64 __user *ubuf64 = (u64 __user *)ubuf;
  	loff_t off = *ppos;
  	ssize_t done = 0; 
  	u64 reg, reg_cnt, val;
  	scom_map_t map;
  	int rc;
  
  	if (off < 0 || (off & 7) || (count & 7))
  		return -EINVAL;
  	reg = off >> 3;
  	reg_cnt = count >> 3;
  
  	map = scom_map(ent->dn, reg, reg_cnt);
  	if (!scom_map_ok(map))
  		return -ENXIO;
  
  	for (reg = 0; reg < reg_cnt; reg++) {
  		rc = scom_read(map, reg, &val);
  		if (!rc)
  			rc = put_user(val, ubuf64);
  		if (rc) {
  			if (!done)
  				done = rc;
  			break;
  		}
  		ubuf64++;
  		*ppos += 8;
  		done += 8;
  	}
  	scom_unmap(map);
  	return done;
  }
  
  static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
  				size_t count, loff_t *ppos)
  {
  	struct scom_debug_entry *ent = filp->private_data;
  	u64 __user *ubuf64 = (u64 __user *)ubuf;
  	loff_t off = *ppos;
  	ssize_t done = 0; 
  	u64 reg, reg_cnt, val;
  	scom_map_t map;
  	int rc;
  
  	if (off < 0 || (off & 7) || (count & 7))
  		return -EINVAL;
  	reg = off >> 3;
  	reg_cnt = count >> 3;
  
  	map = scom_map(ent->dn, reg, reg_cnt);
  	if (!scom_map_ok(map))
  		return -ENXIO;
  
  	for (reg = 0; reg < reg_cnt; reg++) {
  		rc = get_user(val, ubuf64);
  		if (!rc)
  			rc = scom_write(map, reg,  val);
  		if (rc) {
  			if (!done)
  				done = rc;
  			break;
  		}
  		ubuf64++;
  		done += 8;
  	}
  	scom_unmap(map);
  	return done;
  }
  
  static const struct file_operations scom_debug_fops = {
  	.read =		scom_debug_read,
  	.write =	scom_debug_write,
  	.open =		simple_open,
  	.llseek =	default_llseek,
  };
  
  static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
  			       int i)
  {
  	struct scom_debug_entry *ent;
  	struct dentry *dir;
  
  	ent = kzalloc(sizeof(*ent), GFP_KERNEL);
  	if (!ent)
  		return -ENOMEM;
  
  	ent->dn = of_node_get(dn);
  	snprintf(ent->name, 16, "%08x", i);
  	ent->path.data = (void*) dn->full_name;
  	ent->path.size = strlen(dn->full_name);
  
  	dir = debugfs_create_dir(ent->name, root);
  	if (!dir) {
  		of_node_put(dn);
  		kfree(ent);
  		return -1;
  	}
  
  	debugfs_create_blob("devspec", 0400, dir, &ent->path);
  	debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
  
  	return 0;
  }
  
  static int scom_debug_init(void)
  {
  	struct device_node *dn;
  	struct dentry *root;
  	int i, rc;
  
  	root = debugfs_create_dir("scom", powerpc_debugfs_root);
  	if (!root)
  		return -1;
  
  	i = rc = 0;
  	for_each_node_with_property(dn, "scom-controller") {
  		int id = of_get_ibm_chip_id(dn);
  		if (id == -1)
  			id = i;
  		rc |= scom_debug_init_one(root, dn, id);
  		i++;
  	}
  
  	return rc;
  }
  device_initcall(scom_debug_init);
  #endif /* CONFIG_SCOM_DEBUGFS */