1 /*
2  * Testing block device, wraps filebd and rambd while providing a bunch
3  * of hooks for testing littlefs in various conditions.
4  *
5  * Copyright (c) 2022, The littlefs authors.
6  * Copyright (c) 2017, Arm Limited. All rights reserved.
7  * SPDX-License-Identifier: BSD-3-Clause
8  */
9 #ifndef LFS_TESTBD_H
10 #define LFS_TESTBD_H
11 
12 #include "lfs.h"
13 #include "lfs_util.h"
14 #include "bd/lfs_rambd.h"
15 #include "bd/lfs_filebd.h"
16 
17 #ifdef __cplusplus
18 extern "C"
19 {
20 #endif
21 
22 
23 // Block device specific tracing
24 #ifdef LFS_TESTBD_YES_TRACE
25 #define LFS_TESTBD_TRACE(...) LFS_TRACE(__VA_ARGS__)
26 #else
27 #define LFS_TESTBD_TRACE(...)
28 #endif
29 
30 // Mode determining how "bad blocks" behave during testing. This simulates
31 // some real-world circumstances such as progs not sticking (prog-noop),
32 // a readonly disk (erase-noop), and ECC failures (read-error).
33 //
34 // Not that read-noop is not allowed. Read _must_ return a consistent (but
35 // may be arbitrary) value on every read.
36 enum lfs_testbd_badblock_behavior {
37     LFS_TESTBD_BADBLOCK_PROGERROR,
38     LFS_TESTBD_BADBLOCK_ERASEERROR,
39     LFS_TESTBD_BADBLOCK_READERROR,
40     LFS_TESTBD_BADBLOCK_PROGNOOP,
41     LFS_TESTBD_BADBLOCK_ERASENOOP,
42 };
43 
44 // Type for measuring wear
45 typedef uint32_t lfs_testbd_wear_t;
46 typedef int32_t  lfs_testbd_swear_t;
47 
48 // testbd config, this is required for testing
49 struct lfs_testbd_config {
50     // 8-bit erase value to use for simulating erases. -1 does not simulate
51     // erases, which can speed up testing by avoiding all the extra block-device
52     // operations to store the erase value.
53     int32_t erase_value;
54 
55     // Number of erase cycles before a block becomes "bad". The exact behavior
56     // of bad blocks is controlled by the badblock_mode.
57     uint32_t erase_cycles;
58 
59     // The mode determining how bad blocks fail
60     uint8_t badblock_behavior;
61 
62     // Number of write operations (erase/prog) before forcefully killing
63     // the program with exit. Simulates power-loss. 0 disables.
64     uint32_t power_cycles;
65 
66     // Optional buffer for RAM block device.
67     void *buffer;
68 
69     // Optional buffer for wear
70     void *wear_buffer;
71 };
72 
73 // testbd state
74 typedef struct lfs_testbd {
75     union {
76         struct {
77             lfs_filebd_t bd;
78             struct lfs_filebd_config cfg;
79         } file;
80         struct {
81             lfs_rambd_t bd;
82             struct lfs_rambd_config cfg;
83         } ram;
84     } u;
85 
86     bool persist;
87     uint32_t power_cycles;
88     lfs_testbd_wear_t *wear;
89 
90     const struct lfs_testbd_config *cfg;
91 } lfs_testbd_t;
92 
93 
94 /// Block device API ///
95 
96 // Create a test block device using the geometry in lfs_config
97 //
98 // Note that filebd is used if a path is provided, if path is NULL
99 // testbd will use rambd which can be much faster.
100 int lfs_testbd_create(const struct lfs_config *cfg, const char *path);
101 int lfs_testbd_createcfg(const struct lfs_config *cfg, const char *path,
102         const struct lfs_testbd_config *bdcfg);
103 
104 // Clean up memory associated with block device
105 int lfs_testbd_destroy(const struct lfs_config *cfg);
106 
107 // Read a block
108 int lfs_testbd_read(const struct lfs_config *cfg, lfs_block_t block,
109         lfs_off_t off, void *buffer, lfs_size_t size);
110 
111 // Program a block
112 //
113 // The block must have previously been erased.
114 int lfs_testbd_prog(const struct lfs_config *cfg, lfs_block_t block,
115         lfs_off_t off, const void *buffer, lfs_size_t size);
116 
117 // Erase a block
118 //
119 // A block must be erased before being programmed. The
120 // state of an erased block is undefined.
121 int lfs_testbd_erase(const struct lfs_config *cfg, lfs_block_t block);
122 
123 // Sync the block device
124 int lfs_testbd_sync(const struct lfs_config *cfg);
125 
126 
127 /// Additional extended API for driving test features ///
128 
129 // Get simulated wear on a given block
130 lfs_testbd_swear_t lfs_testbd_getwear(const struct lfs_config *cfg,
131         lfs_block_t block);
132 
133 // Manually set simulated wear on a given block
134 int lfs_testbd_setwear(const struct lfs_config *cfg,
135         lfs_block_t block, lfs_testbd_wear_t wear);
136 
137 
138 #ifdef __cplusplus
139 } /* extern "C" */
140 #endif
141 
142 #endif
143