path: root/drivers/nvdimm/btt.c

/*
 * Block Translation Table
 * Copyright (c) 2014-2015, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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/highmem.h>
#include <linux/debugfs.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/hdreg.h>
#include <linux/genhd.h>
#include <linux/sizes.h>
#include <linux/ndctl.h>
#include <linux/fs.h>
#include <linux/nd.h>
#include <linux/backing-dev.h>
#include "btt.h"
#include "nd.h"

enum log_ent_request {
	LOG_NEW_ENT = 0,
	LOG_OLD_ENT
};

static struct device *to_dev(struct arena_info *arena)
{
	return &arena->nd_btt->dev;
}

static u64 adjust_initial_offset(struct nd_btt *nd_btt, u64 offset)
{
	return offset + nd_btt->initial_offset;
}

static int arena_read_bytes(struct arena_info *arena, resource_size_t offset,
		void *buf, size_t n, unsigned long flags)
{
	struct nd_btt *nd_btt = arena->nd_btt;
	struct nd_namespace_common *ndns = nd_btt->ndns;

	/* arena offsets may be shifted from the base of the device */
	offset = adjust_initial_offset(nd_btt, offset);
	return nvdimm_read_bytes(ndns, offset, buf, n, flags);
}

static int arena_write_bytes(struct arena_info *arena, resource_size_t offset,
		void *buf, size_t n, unsigned long flags)
{
	struct nd_btt *nd_btt = arena->nd_btt;
	struct nd_namespace_common *ndns = nd_btt->ndns;

	/* arena offsets may be shifted from the base of the device */
	offset = adjust_initial_offset(nd_btt, offset);
	return nvdimm_write_bytes(ndns, offset, buf, n, flags);
}

static int btt_info_write(struct arena_info *arena, struct btt_sb *super)
{
	int ret;

	/*
	 * infooff and info2off should always be at least 512B aligned.
	 * We rely on that to make sure rw_bytes does error clearing
	 * correctly, so make sure that is the case.
	 */
	dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->infooff, 512),
		"arena->infooff: %#llx is unaligned\n", arena->infooff);
	dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->info2off, 512),
		"arena->info2off: %#llx is unaligned\n", arena->info2off);

	ret = arena_write_bytes(arena, arena->info2off, super,
			sizeof(struct btt_sb), 0);
	if (ret)
		return ret;

	return arena_write_bytes(arena, arena->infooff, super,
			sizeof(struct btt_sb), 0);
}

static int btt_info_read(struct arena_info *arena, struct btt_sb *super)
{
	return arena_read_bytes(arena, arena->infooff, super,
			sizeof(struct btt_sb), 0);
}

/*
 * 'raw' version of btt_map write
 * Assumptions:
 *   mapping is in little-endian
 *   mapping contains 'E' and 'Z' flags as desired
 */
static int __btt_map_write(struct arena_info *arena, u32 lba, __le32 mapping,
		unsigned long flags)
{
	u64 ns_off = arena->mapoff + (lba * MAP_ENT_SIZE);

	if (unlikely(lba >= arena->external_nlba))
		dev_err_ratelimited(to_dev(arena),
			"%s: lba %#x out of range (max: %#x)\n",
			__func__, lba, arena->external_nlba);
	return arena_write_bytes(arena, ns_off, &mapping, MAP_ENT_SIZE, flags);
}

static int btt_map_write(struct arena_info *arena, u32 lba, u32 mapping,
			u32 z_flag, u32 e_flag, unsigned long rwb_flags)
{
	u32 ze;
	__le32 mapping_le;

	/*
	 * This 'mapping' is supposed to be just the LBA mapping, without
	 * any flags set, so strip the flag bits.
	 */
	mapping = ent_lba(mapping);

	ze = (z_flag << 1) + e_flag;
	switch (ze) {
	case 0:
		/*
		 * We want to set neither of the Z or E flags, and
		 * in the actual layout, this means setting the bit
		 * positions of both to '1' to indicate a 'normal'
		 * map entry
		 */
		mapping |= MAP_ENT_NORMAL;
		break;
	case 1:
		mapping |= (1 << MAP_ERR_SHIFT);
		break;
	case 2:
		mapping |= (1 << MAP_TRIM_SHIFT);
		break;
	default:
		/*
		 * The case where Z and E are both sent in as '1' could be
		 * construed as a valid 'normal' case, but we decide not to,
		 * to avoid confusion
		 */
		dev_err_ratelimited(to_dev(arena),
			"Invalid use of Z and E flags\n");
		return -EIO;
	}

	mapping_le = cpu_to_le32(mapping);
	return __btt_map_write(arena, lba, mapping_le, rwb_flags);
}

static int btt_map_read(struct arena_info *arena, u