/*
   * Copyright(c) 2013-2015 Intel Corporation. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of version 2 of the GNU General Public License as
   * published by the Free Software Foundation.
   *
   * 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.
   */
  #include <linux/blkdev.h>
  #include <linux/device.h>
  #include <linux/genhd.h>
  #include <linux/sizes.h>
  #include <linux/slab.h>
  #include <linux/fs.h>
  #include <linux/mm.h>
  #include "nd-core.h"
  #include "btt.h"
  #include "nd.h"
  
  static void nd_btt_release(struct device *dev)
  {
  	struct nd_region *nd_region = to_nd_region(dev->parent);
  	struct nd_btt *nd_btt = to_nd_btt(dev);
  
  	dev_dbg(dev, "%s
  ", __func__);
  	nd_detach_ndns(&nd_btt->dev, &nd_btt->ndns);
  	ida_simple_remove(&nd_region->btt_ida, nd_btt->id);
  	kfree(nd_btt->uuid);
  	kfree(nd_btt);
  }
  
  static struct device_type nd_btt_device_type = {
  	.name = "nd_btt",
  	.release = nd_btt_release,
  };
  
  bool is_nd_btt(struct device *dev)
  {
  	return dev->type == &nd_btt_device_type;
  }
  EXPORT_SYMBOL(is_nd_btt);
  
  struct nd_btt *to_nd_btt(struct device *dev)
  {
  	struct nd_btt *nd_btt = container_of(dev, struct nd_btt, dev);
  
  	WARN_ON(!is_nd_btt(dev));
  	return nd_btt;
  }
  EXPORT_SYMBOL(to_nd_btt);
  
  static const unsigned long btt_lbasize_supported[] = { 512, 520, 528,
  	4096, 4104, 4160, 4224, 0 };
  
  static ssize_t sector_size_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct nd_btt *nd_btt = to_nd_btt(dev);
  
  	return nd_sector_size_show(nd_btt->lbasize, btt_lbasize_supported, buf);
  }
  
  static ssize_t sector_size_store(struct device *dev,
  		struct device_attribute *attr, const char *buf, size_t len)
  {
  	struct nd_btt *nd_btt = to_nd_btt(dev);
  	ssize_t rc;
  
  	device_lock(dev);
  	nvdimm_bus_lock(dev);
  	rc = nd_sector_size_store(dev, buf, &nd_btt->lbasize,
  			btt_lbasize_supported);
  	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
  			rc, buf, buf[len - 1] == '
  ' ? "" : "
  ");
  	nvdimm_bus_unlock(dev);
  	device_unlock(dev);
  
  	return rc ? rc : len;
  }
  static DEVICE_ATTR_RW(sector_size);
  
  static ssize_t uuid_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct nd_btt *nd_btt = to_nd_btt(dev);
  
  	if (nd_btt->uuid)
  		return sprintf(buf, "%pUb
  ", nd_btt->uuid);
  	return sprintf(buf, "
  ");
  }
  
  static ssize_t uuid_store(struct device *dev,
  		struct device_attribute *attr, const char *buf, size_t len)
  {
  	struct nd_btt *nd_btt = to_nd_btt(dev);
  	ssize_t rc;
  
  	device_lock(dev);
  	rc = nd_uuid_store(dev, &nd_btt->uuid, buf, len);
  	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
  			rc, buf, buf[len - 1] == '
  ' ? "" : "
  ");
  	device_unlock(dev);
  
  	return rc ? rc : len;
  }
  static DEVICE_ATTR_RW(uuid);
  
  static ssize_t namespace_show(struct device *dev,
  		struct device_attribute *attr, char *buf)
  {
  	struct nd_btt *nd_btt = to_nd_btt(dev);
  	ssize_t rc;
  
  	nvdimm_bus_lock(dev);
  	rc = sprintf(buf, "%s
  ", nd_btt->ndns
  			? dev_name(&nd_btt->ndns->dev) : "");
  	nvdimm_bus_unlock(dev);
  	return rc;
  }
  
  static ssize_t namespace_store(struct device *dev,
  		struct device_attribute *attr, const char *buf, size_t len)
  {
  	struct nd_btt *nd_btt = to_nd_btt(dev);
  	ssize_t rc;
  
  	device_lock(dev);
  	nvdimm_bus_lock(dev);
  	rc = nd_namespace_store(dev, &nd_btt->ndns, buf, len);
  	dev_dbg(dev, "%s: result: %zd wrote: %s%s", __func__,
  			rc, buf, buf[len - 1] == '
  ' ? "" : "
  ");
  	nvdimm_bus_unlock(dev);
  	device_unlock(dev);
  
  	return rc;
  }
  static DEVICE_ATTR_RW(namespace);
  
  static struct attribute *nd_btt_attributes[] = {
  	&dev_attr_sector_size.attr,
  	&dev_attr_namespace.attr,
  	&dev_attr_uuid.attr,
  	NULL,
  };
  
  static struct attribute_group nd_btt_attribute_group = {
  	.attrs = nd_btt_attributes,
  };
  
  static const struct attribute_group *nd_btt_attribute_groups[] = {
  	&nd_btt_attribute_group,
  	&nd_device_attribute_group,
  	&nd_numa_attribute_group,
  	NULL,
  };
  
  static struct device *__nd_btt_create(struct nd_region *nd_region,
  		unsigned long lbasize, u8 *uuid,
  		struct nd_namespace_common *ndns)
  {
  	struct nd_btt *nd_btt;
  	struct device *dev;
  
  	nd_btt = kzalloc(sizeof(*nd_btt), GFP_KERNEL);
  	if (!nd_btt)
  		return NULL;
  
  	nd_btt->id = ida_simple_get(&nd_region->btt_ida, 0, 0, GFP_KERNEL);
  	if (nd_btt->id < 0) {
  		kfree(nd_btt);
  		return NULL;
  	}
  
  	nd_btt->lbasize = lbasize;
  	if (uuid)
  		uuid = kmemdup(uuid, 16, GFP_KERNEL);
  	nd_btt->uuid = uuid;
  	dev = &nd_btt->dev;
  	dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id);
  	dev->parent = &nd_region->dev;
  	dev->type = &nd_btt_device_type;
  	dev->groups = nd_btt_attribute_groups;
  	device_initialize(&nd_btt->dev);
  	if (ndns && !__nd_attach_ndns(&nd_btt->dev, ndns, &nd_btt->ndns)) {
  		dev_dbg(&ndns->dev, "%s failed, already claimed by %s
  ",
  				__func__, dev_name(ndns->claim));
  		put_device(dev);
  		return NULL;
  	}
  	return dev;
  }
  
  struct device *nd_btt_create(struct nd_region *nd_region)
  {
  	struct device *dev = __nd_btt_create(nd_region, 0, NULL, NULL);
  
  	if (dev)
  		__nd_device_register(dev);
  	return dev;
  }
  
  static bool uuid_is_null(u8 *uuid)
  {
  	static const u8 null_uuid[16];
  
  	return (memcmp(uuid, null_uuid, 16) == 0);
  }
  
  /**
   * nd_btt_arena_is_valid - check if the metadata layout is valid
   * @nd_btt:	device with BTT geometry and backing device info
   * @super:	pointer to the arena's info block being tested
   *
   * Check consistency of the btt info block with itself by validating
   * the checksum, and with the parent namespace by verifying the
   * parent_uuid contained in the info block with the one supplied in.
   *
   * Returns:
   * false for an invalid info block, true for a valid one
   */
  bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)
  {
  	const u8 *parent_uuid = nd_dev_to_uuid(&nd_btt->ndns->dev);
  	u64 checksum;
  
  	if (memcmp(super->signature, BTT_SIG, BTT_SIG_LEN) != 0)
  		return false;
  
  	if (!uuid_is_null(super->parent_uuid))
  		if (memcmp(super->parent_uuid, parent_uuid, 16) != 0)
  			return false;
  
  	checksum = le64_to_cpu(super->checksum);
  	super->checksum = 0;
  	if (checksum != nd_sb_checksum((struct nd_gen_sb *) super))
  		return false;
  	super->checksum = cpu_to_le64(checksum);
  
  	/* TODO: figure out action for this */
  	if ((le32_to_cpu(super->flags) & IB_FLAG_ERROR_MASK) != 0)
  		dev_info(&nd_btt->dev, "Found arena with an error flag
  ");
  
  	return true;
  }
  EXPORT_SYMBOL(nd_btt_arena_is_valid);
  
  static int __nd_btt_probe(struct nd_btt *nd_btt,
  		struct nd_namespace_common *ndns, struct btt_sb *btt_sb)
  {
  	if (!btt_sb || !ndns || !nd_btt)
  		return -ENODEV;
  
  	if (nvdimm_read_bytes(ndns, SZ_4K, btt_sb, sizeof(*btt_sb)))
  		return -ENXIO;
  
  	if (nvdimm_namespace_capacity(ndns) < SZ_16M)
  		return -ENXIO;
  
  	if (!nd_btt_arena_is_valid(nd_btt, btt_sb))
  		return -ENODEV;
  
  	nd_btt->lbasize = le32_to_cpu(btt_sb->external_lbasize);
  	nd_btt->uuid = kmemdup(btt_sb->uuid, 16, GFP_KERNEL);
  	if (!nd_btt->uuid)
  		return -ENOMEM;
  
  	__nd_device_register(&nd_btt->dev);
  
  	return 0;
  }
  
  int nd_btt_probe(struct nd_namespace_common *ndns, void *drvdata)
  {
  	int rc;
  	struct device *dev;
  	struct btt_sb *btt_sb;
  	struct nd_region *nd_region = to_nd_region(ndns->dev.parent);
  
  	if (ndns->force_raw)
  		return -ENODEV;
  
  	nvdimm_bus_lock(&ndns->dev);
  	dev = __nd_btt_create(nd_region, 0, NULL, ndns);
  	nvdimm_bus_unlock(&ndns->dev);
  	if (!dev)
  		return -ENOMEM;
  	dev_set_drvdata(dev, drvdata);
  	btt_sb = kzalloc(sizeof(*btt_sb), GFP_KERNEL);
  	rc = __nd_btt_probe(to_nd_btt(dev), ndns, btt_sb);
  	kfree(btt_sb);
  	dev_dbg(&ndns->dev, "%s: btt: %s
  ", __func__,
  			rc == 0 ? dev_name(dev) : "<none>");
  	if (rc < 0) {
  		struct nd_btt *nd_btt = to_nd_btt(dev);
  
  		__nd_detach_ndns(dev, &nd_btt->ndns);
  		put_device(dev);
  	}
  
  	return rc;
  }
  EXPORT_SYMBOL(nd_btt_probe);