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 "btt.h"
#include "nd.h"

enum log_ent_request {
	LOG_NEW_ENT = 0,
	LOG_OLD_ENT
};

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

	/* arena offsets are 4K from the base of the device */
	offset += SZ_4K;
	return nvdimm_read_bytes(ndns, offset, buf, n);
}

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

	/* arena offsets are 4K from the base of the device */
	offset += SZ_4K;
	return nvdimm_write_bytes(ndns, offset, buf, n);
}

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

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

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

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

/*
 * '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)
{
	u64 ns_off = arena->mapoff + (lba * MAP_ENT_SIZE);

	WARN_ON(lba >= arena->external_nlba);
	return arena_write_bytes(arena, ns_off, &mapping, MAP_ENT_SIZE);
}

static int btt_map_write(struct arena_info *arena, u32 lba, u32 mapping,
			u32 z_flag, u32 e_flag)
{
	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 &= MAP_LBA_MASK;

	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
		 */
		WARN_ONCE(1, "Invalid use of Z and E flags\n");
		return -EIO;
	}

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

static int btt_map_read(struct arena_info *arena, u32 lba, u32 *mapping,
			int *trim, int *error)
{
	int ret;
	__le32 in;
	u32 raw_mapping, postmap, ze, z_flag, e_flag;
	u64 ns_off = arena->mapoff + (lba * MAP_ENT_SIZE);

	WARN_ON(lba >= arena->external_nlba);

	ret = arena_read_bytes(arena, ns_off, &in, MAP_ENT_SIZE);
	if (ret)
		return ret;

	raw_mapping = le32_to_cpu(in);

	z_flag = (raw_mapping & MAP_TRIM_MASK) >> MAP_TRIM_SHIFT;
	e_flag = (raw_mapping & MAP_ERR_MASK) >> MAP_ERR_SHIFT;
	ze = (z_flag << 1) + e_flag;
	postmap = raw_mapping & MAP_LBA_MASK;

	/* Reuse the {z,e}_flag variables for *trim and *error */
	z_flag = 0;
	e_flag = 0;

	switch (ze) {
	case 0:
		/* Initial state. Return postmap = premap */
		*mapping = lba;
		break;
	case 1:
		*mapping = postmap;
		e_flag = 1;
		break;
	case 2:
		*mapping = postmap;
		z_flag = 1;
		break;
	case 3:
		*mapping = postmap;
		break;
	default:
		return -EIO;
	}

	if (trim)
		*trim = z_flag;
	if (error)
		*error = e_flag;

	return ret;
}

static int btt_log_group_read(struct arena_info *arena, u32 lane,
			struct log_group *log)
{
	WARN_ON(!log);
	return arena_read_bytes(arena,
			arena->logoff + (lane * LOG_GRP_SIZE), log,
			LOG_GRP_SIZE);
}

static struct dentry *debugfs_root;

static void arena_debugfs_init(struct arena_info *a, struct dentry *parent,
				int idx)
{
	char dirname[32];
	struct dentry *d;

	/* If for some reason, parent bttN was not created, exit */
	if (!parent)
		return;

	snprintf(dirname, 32, "arena%d", idx);
	d = debugfs_create_dir(dirname, parent);
	if (IS_ERR_OR_NULL(d))
		return;
	a->debugfs_dir = d;

	debugfs_create_x64("size", S_IRUGO, d, &a->size);
	debugfs_create_x64("external_lba_start", S_IRUGO, d,
				&a->external_lba_start);
	debugfs_create_x32("internal_nlba", S_IRUGO, d, &a->internal_nlba);
	debugfs_create_u32("internal_lbasize", S_IRUGO, d,
				&a->internal_lbasize);
	debugfs_create_x32("external_nlba", S_IRUGO, d, &a->external_nlba);
	debugfs_create_u32("external_lbasize", S_IRUGO, d,
				&a->external_lbasize);
	debugfs_create_u32("nfree", S_IRUGO, d, &a->nfree);
	debugfs_create_u16("version_major", S_IRUGO, d, &a->version_major);
	debugfs_create_u16("version_minor", S_IRUGO, d, &a->version_minor);
	debugfs_create_x64("nextoff", S_IRUGO, d, &a->nextoff);
	debugfs_create_x64("infooff", S_IRUGO, d, &a->infooff);
	debugfs_create_x64("dataoff", S_IRUGO, d, &a->dataoff);
	debugfs_create_x64("mapoff", S_IRUGO, d, &a->mapoff);
	debugfs_create_x64("logoff", S_IRUGO, d, &a->logoff);
	debugfs_create_x64("info2off", S_IRUGO, d, &a->info2off);
	debugfs_create_x32("flags", S_IRUGO, d, &a->flags);
	debugfs_create_u32("log_index_0", S_IRUGO, d, &a->log_index[0]);
	debugfs_create_u32("log_index_1", S_IRUGO, d, &a->log_index[1]);
}

static void btt_