xref: /openbmc/linux/drivers/nvdimm/btt.h (revision 3805e6a1)
1 /*
2  * Block Translation Table library
3  * Copyright (c) 2014-2015, Intel Corporation.
4  *
5  * This program is free software; you can redistribute it and/or modify it
6  * under the terms and conditions of the GNU General Public License,
7  * version 2, as published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope it will be useful, but WITHOUT
10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
12  * more details.
13  */
14 
15 #ifndef _LINUX_BTT_H
16 #define _LINUX_BTT_H
17 
18 #include <linux/types.h>
19 
20 #define BTT_SIG_LEN 16
21 #define BTT_SIG "BTT_ARENA_INFO\0"
22 #define MAP_ENT_SIZE 4
23 #define MAP_TRIM_SHIFT 31
24 #define MAP_TRIM_MASK (1 << MAP_TRIM_SHIFT)
25 #define MAP_ERR_SHIFT 30
26 #define MAP_ERR_MASK (1 << MAP_ERR_SHIFT)
27 #define MAP_LBA_MASK (~((1 << MAP_TRIM_SHIFT) | (1 << MAP_ERR_SHIFT)))
28 #define MAP_ENT_NORMAL 0xC0000000
29 #define LOG_ENT_SIZE sizeof(struct log_entry)
30 #define ARENA_MIN_SIZE (1UL << 24)	/* 16 MB */
31 #define ARENA_MAX_SIZE (1ULL << 39)	/* 512 GB */
32 #define RTT_VALID (1UL << 31)
33 #define RTT_INVALID 0
34 #define BTT_PG_SIZE 4096
35 #define BTT_DEFAULT_NFREE ND_MAX_LANES
36 #define LOG_SEQ_INIT 1
37 
38 #define IB_FLAG_ERROR 0x00000001
39 #define IB_FLAG_ERROR_MASK 0x00000001
40 
41 enum btt_init_state {
42 	INIT_UNCHECKED = 0,
43 	INIT_NOTFOUND,
44 	INIT_READY
45 };
46 
47 struct log_entry {
48 	__le32 lba;
49 	__le32 old_map;
50 	__le32 new_map;
51 	__le32 seq;
52 	__le64 padding[2];
53 };
54 
55 struct btt_sb {
56 	u8 signature[BTT_SIG_LEN];
57 	u8 uuid[16];
58 	u8 parent_uuid[16];
59 	__le32 flags;
60 	__le16 version_major;
61 	__le16 version_minor;
62 	__le32 external_lbasize;
63 	__le32 external_nlba;
64 	__le32 internal_lbasize;
65 	__le32 internal_nlba;
66 	__le32 nfree;
67 	__le32 infosize;
68 	__le64 nextoff;
69 	__le64 dataoff;
70 	__le64 mapoff;
71 	__le64 logoff;
72 	__le64 info2off;
73 	u8 padding[3968];
74 	__le64 checksum;
75 };
76 
77 struct free_entry {
78 	u32 block;
79 	u8 sub;
80 	u8 seq;
81 };
82 
83 struct aligned_lock {
84 	union {
85 		spinlock_t lock;
86 		u8 cacheline_padding[L1_CACHE_BYTES];
87 	};
88 };
89 
90 /**
91  * struct arena_info - handle for an arena
92  * @size:		Size in bytes this arena occupies on the raw device.
93  *			This includes arena metadata.
94  * @external_lba_start:	The first external LBA in this arena.
95  * @internal_nlba:	Number of internal blocks available in the arena
96  *			including nfree reserved blocks
97  * @internal_lbasize:	Internal and external lba sizes may be different as
98  *			we can round up 'odd' external lbasizes such as 520B
99  *			to be aligned.
100  * @external_nlba:	Number of blocks contributed by the arena to the number
101  *			reported to upper layers. (internal_nlba - nfree)
102  * @external_lbasize:	LBA size as exposed to upper layers.
103  * @nfree:		A reserve number of 'free' blocks that is used to
104  *			handle incoming writes.
105  * @version_major:	Metadata layout version major.
106  * @version_minor:	Metadata layout version minor.
107  * @nextoff:		Offset in bytes to the start of the next arena.
108  * @infooff:		Offset in bytes to the info block of this arena.
109  * @dataoff:		Offset in bytes to the data area of this arena.
110  * @mapoff:		Offset in bytes to the map area of this arena.
111  * @logoff:		Offset in bytes to the log area of this arena.
112  * @info2off:		Offset in bytes to the backup info block of this arena.
113  * @freelist:		Pointer to in-memory list of free blocks
114  * @rtt:		Pointer to in-memory "Read Tracking Table"
115  * @map_locks:		Spinlocks protecting concurrent map writes
116  * @nd_btt:		Pointer to parent nd_btt structure.
117  * @list:		List head for list of arenas
118  * @debugfs_dir:	Debugfs dentry
119  * @flags:		Arena flags - may signify error states.
120  *
121  * arena_info is a per-arena handle. Once an arena is narrowed down for an
122  * IO, this struct is passed around for the duration of the IO.
123  */
124 struct arena_info {
125 	u64 size;			/* Total bytes for this arena */
126 	u64 external_lba_start;
127 	u32 internal_nlba;
128 	u32 internal_lbasize;
129 	u32 external_nlba;
130 	u32 external_lbasize;
131 	u32 nfree;
132 	u16 version_major;
133 	u16 version_minor;
134 	/* Byte offsets to the different on-media structures */
135 	u64 nextoff;
136 	u64 infooff;
137 	u64 dataoff;
138 	u64 mapoff;
139 	u64 logoff;
140 	u64 info2off;
141 	/* Pointers to other in-memory structures for this arena */
142 	struct free_entry *freelist;
143 	u32 *rtt;
144 	struct aligned_lock *map_locks;
145 	struct nd_btt *nd_btt;
146 	struct list_head list;
147 	struct dentry *debugfs_dir;
148 	/* Arena flags */
149 	u32 flags;
150 };
151 
152 /**
153  * struct btt - handle for a BTT instance
154  * @btt_disk:		Pointer to the gendisk for BTT device
155  * @btt_queue:		Pointer to the request queue for the BTT device
156  * @arena_list:		Head of the list of arenas
157  * @debugfs_dir:	Debugfs dentry
158  * @nd_btt:		Parent nd_btt struct
159  * @nlba:		Number of logical blocks exposed to the	upper layers
160  *			after removing the amount of space needed by metadata
161  * @rawsize:		Total size in bytes of the available backing device
162  * @lbasize:		LBA size as requested and presented to upper layers.
163  *			This is sector_size + size of any metadata.
164  * @sector_size:	The Linux sector size - 512 or 4096
165  * @lanes:		Per-lane spinlocks
166  * @init_lock:		Mutex used for the BTT initialization
167  * @init_state:		Flag describing the initialization state for the BTT
168  * @num_arenas:		Number of arenas in the BTT instance
169  */
170 struct btt {
171 	struct gendisk *btt_disk;
172 	struct request_queue *btt_queue;
173 	struct list_head arena_list;
174 	struct dentry *debugfs_dir;
175 	struct nd_btt *nd_btt;
176 	u64 nlba;
177 	unsigned long long rawsize;
178 	u32 lbasize;
179 	u32 sector_size;
180 	struct nd_region *nd_region;
181 	struct mutex init_lock;
182 	int init_state;
183 	int num_arenas;
184 };
185 
186 bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
187 
188 #endif
189