xref: /openbmc/linux/drivers/nvdimm/btt.h (revision d4e4e583)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Block Translation Table library
4  * Copyright (c) 2014-2015, Intel Corporation.
5  */
6 
7 #ifndef _LINUX_BTT_H
8 #define _LINUX_BTT_H
9 
10 #include <linux/types.h>
11 
12 #define BTT_SIG_LEN 16
13 #define BTT_SIG "BTT_ARENA_INFO\0"
14 #define MAP_ENT_SIZE 4
15 #define MAP_TRIM_SHIFT 31
16 #define MAP_TRIM_MASK (1 << MAP_TRIM_SHIFT)
17 #define MAP_ERR_SHIFT 30
18 #define MAP_ERR_MASK (1 << MAP_ERR_SHIFT)
19 #define MAP_LBA_MASK (~((1 << MAP_TRIM_SHIFT) | (1 << MAP_ERR_SHIFT)))
20 #define MAP_ENT_NORMAL 0xC0000000
21 #define LOG_GRP_SIZE sizeof(struct log_group)
22 #define LOG_ENT_SIZE sizeof(struct log_entry)
23 #define ARENA_MIN_SIZE (1UL << 24)	/* 16 MB */
24 #define ARENA_MAX_SIZE (1ULL << 39)	/* 512 GB */
25 #define RTT_VALID (1UL << 31)
26 #define RTT_INVALID 0
27 #define BTT_PG_SIZE 4096
28 #define BTT_DEFAULT_NFREE ND_MAX_LANES
29 #define LOG_SEQ_INIT 1
30 
31 #define IB_FLAG_ERROR 0x00000001
32 #define IB_FLAG_ERROR_MASK 0x00000001
33 
34 #define ent_lba(ent) (ent & MAP_LBA_MASK)
35 #define ent_e_flag(ent) (!!(ent & MAP_ERR_MASK))
36 #define ent_z_flag(ent) (!!(ent & MAP_TRIM_MASK))
37 #define set_e_flag(ent) (ent |= MAP_ERR_MASK)
38 /* 'normal' is both e and z flags set */
39 #define ent_normal(ent) (ent_e_flag(ent) && ent_z_flag(ent))
40 
41 enum btt_init_state {
42 	INIT_UNCHECKED = 0,
43 	INIT_NOTFOUND,
44 	INIT_READY
45 };
46 
47 /*
48  * A log group represents one log 'lane', and consists of four log entries.
49  * Two of the four entries are valid entries, and the remaining two are
50  * padding. Due to an old bug in the padding location, we need to perform a
51  * test to determine the padding scheme being used, and use that scheme
52  * thereafter.
53  *
54  * In kernels prior to 4.15, 'log group' would have actual log entries at
55  * indices (0, 2) and padding at indices (1, 3), where as the correct/updated
56  * format has log entries at indices (0, 1) and padding at indices (2, 3).
57  *
58  * Old (pre 4.15) format:
59  * +-----------------+-----------------+
60  * |      ent[0]     |      ent[1]     |
61  * |       16B       |       16B       |
62  * | lba/old/new/seq |       pad       |
63  * +-----------------------------------+
64  * |      ent[2]     |      ent[3]     |
65  * |       16B       |       16B       |
66  * | lba/old/new/seq |       pad       |
67  * +-----------------+-----------------+
68  *
69  * New format:
70  * +-----------------+-----------------+
71  * |      ent[0]     |      ent[1]     |
72  * |       16B       |       16B       |
73  * | lba/old/new/seq | lba/old/new/seq |
74  * +-----------------------------------+
75  * |      ent[2]     |      ent[3]     |
76  * |       16B       |       16B       |
77  * |       pad       |       pad       |
78  * +-----------------+-----------------+
79  *
80  * We detect during start-up which format is in use, and set
81  * arena->log_index[(0, 1)] with the detected format.
82  */
83 
84 struct log_entry {
85 	__le32 lba;
86 	__le32 old_map;
87 	__le32 new_map;
88 	__le32 seq;
89 };
90 
91 struct log_group {
92 	struct log_entry ent[4];
93 };
94 
95 struct btt_sb {
96 	u8 signature[BTT_SIG_LEN];
97 	u8 uuid[16];
98 	u8 parent_uuid[16];
99 	__le32 flags;
100 	__le16 version_major;
101 	__le16 version_minor;
102 	__le32 external_lbasize;
103 	__le32 external_nlba;
104 	__le32 internal_lbasize;
105 	__le32 internal_nlba;
106 	__le32 nfree;
107 	__le32 infosize;
108 	__le64 nextoff;
109 	__le64 dataoff;
110 	__le64 mapoff;
111 	__le64 logoff;
112 	__le64 info2off;
113 	u8 padding[3968];
114 	__le64 checksum;
115 };
116 
117 struct free_entry {
118 	u32 block;
119 	u8 sub;
120 	u8 seq;
121 	u8 has_err;
122 };
123 
124 struct aligned_lock {
125 	union {
126 		spinlock_t lock;
127 		u8 cacheline_padding[L1_CACHE_BYTES];
128 	};
129 };
130 
131 /**
132  * struct arena_info - handle for an arena
133  * @size:		Size in bytes this arena occupies on the raw device.
134  *			This includes arena metadata.
135  * @external_lba_start:	The first external LBA in this arena.
136  * @internal_nlba:	Number of internal blocks available in the arena
137  *			including nfree reserved blocks
138  * @internal_lbasize:	Internal and external lba sizes may be different as
139  *			we can round up 'odd' external lbasizes such as 520B
140  *			to be aligned.
141  * @external_nlba:	Number of blocks contributed by the arena to the number
142  *			reported to upper layers. (internal_nlba - nfree)
143  * @external_lbasize:	LBA size as exposed to upper layers.
144  * @nfree:		A reserve number of 'free' blocks that is used to
145  *			handle incoming writes.
146  * @version_major:	Metadata layout version major.
147  * @version_minor:	Metadata layout version minor.
148  * @sector_size:	The Linux sector size - 512 or 4096
149  * @nextoff:		Offset in bytes to the start of the next arena.
150  * @infooff:		Offset in bytes to the info block of this arena.
151  * @dataoff:		Offset in bytes to the data area of this arena.
152  * @mapoff:		Offset in bytes to the map area of this arena.
153  * @logoff:		Offset in bytes to the log area of this arena.
154  * @info2off:		Offset in bytes to the backup info block of this arena.
155  * @freelist:		Pointer to in-memory list of free blocks
156  * @rtt:		Pointer to in-memory "Read Tracking Table"
157  * @map_locks:		Spinlocks protecting concurrent map writes
158  * @nd_btt:		Pointer to parent nd_btt structure.
159  * @list:		List head for list of arenas
160  * @debugfs_dir:	Debugfs dentry
161  * @flags:		Arena flags - may signify error states.
162  * @err_lock:		Mutex for synchronizing error clearing.
163  * @log_index:		Indices of the valid log entries in a log_group
164  *
165  * arena_info is a per-arena handle. Once an arena is narrowed down for an
166  * IO, this struct is passed around for the duration of the IO.
167  */
168 struct arena_info {
169 	u64 size;			/* Total bytes for this arena */
170 	u64 external_lba_start;
171 	u32 internal_nlba;
172 	u32 internal_lbasize;
173 	u32 external_nlba;
174 	u32 external_lbasize;
175 	u32 nfree;
176 	u16 version_major;
177 	u16 version_minor;
178 	u32 sector_size;
179 	/* Byte offsets to the different on-media structures */
180 	u64 nextoff;
181 	u64 infooff;
182 	u64 dataoff;
183 	u64 mapoff;
184 	u64 logoff;
185 	u64 info2off;
186 	/* Pointers to other in-memory structures for this arena */
187 	struct free_entry *freelist;
188 	u32 *rtt;
189 	struct aligned_lock *map_locks;
190 	struct nd_btt *nd_btt;
191 	struct list_head list;
192 	struct dentry *debugfs_dir;
193 	/* Arena flags */
194 	u32 flags;
195 	struct mutex err_lock;
196 	int log_index[2];
197 };
198 
199 struct badblocks;
200 
201 /**
202  * struct btt - handle for a BTT instance
203  * @btt_disk:		Pointer to the gendisk for BTT device
204  * @arena_list:		Head of the list of arenas
205  * @debugfs_dir:	Debugfs dentry
206  * @nd_btt:		Parent nd_btt struct
207  * @nlba:		Number of logical blocks exposed to the	upper layers
208  *			after removing the amount of space needed by metadata
209  * @rawsize:		Total size in bytes of the available backing device
210  * @lbasize:		LBA size as requested and presented to upper layers.
211  *			This is sector_size + size of any metadata.
212  * @sector_size:	The Linux sector size - 512 or 4096
213  * @lanes:		Per-lane spinlocks
214  * @init_lock:		Mutex used for the BTT initialization
215  * @init_state:		Flag describing the initialization state for the BTT
216  * @num_arenas:		Number of arenas in the BTT instance
217  * @phys_bb:		Pointer to the namespace's badblocks structure
218  */
219 struct btt {
220 	struct gendisk *btt_disk;
221 	struct list_head arena_list;
222 	struct dentry *debugfs_dir;
223 	struct nd_btt *nd_btt;
224 	u64 nlba;
225 	unsigned long long rawsize;
226 	u32 lbasize;
227 	u32 sector_size;
228 	struct nd_region *nd_region;
229 	struct mutex init_lock;
230 	int init_state;
231 	int num_arenas;
232 	struct badblocks *phys_bb;
233 };
234 
235 bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
236 int nd_btt_version(struct nd_btt *nd_btt, struct nd_namespace_common *ndns,
237 		struct btt_sb *btt_sb);
238 
239 #endif
240