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29 * Copyright 2009 Develer S.r.l. (http://www.develer.com/)
33 * \author Francesco Sacchi <batt@develer.com>
35 * \brief KBlock interface
41 #include <cfg/compiler.h>
42 #include <cfg/debug.h>
43 #include <cfg/macros.h>
45 /** Type for addressing blocks in the device. */
46 typedef uint32_t block_idx_t;
52 * \name Prototypes for KBlock low level access functions.
54 * When writing a driver implementing the KBlock interface you can choose which
55 * function subset to implement, but you have to set to NULL unimplemented
60 typedef size_t (* kblock_read_direct_t) (struct KBlock *b, block_idx_t index, void *buf, size_t offset, size_t size);
61 typedef int (* kblock_write_block_t) (struct KBlock *b, block_idx_t index, const void *buf);
63 typedef size_t (* kblock_read_t) (struct KBlock *b, void *buf, size_t offset, size_t size);
64 typedef size_t (* kblock_write_t) (struct KBlock *b, const void *buf, size_t offset, size_t size);
65 typedef int (* kblock_load_t) (struct KBlock *b, block_idx_t index);
66 typedef int (* kblock_store_t) (struct KBlock *b, block_idx_t index);
68 typedef int (* kblock_error_t) (struct KBlock *b);
69 typedef int (* kblock_clearerr_t) (struct KBlock *b);
70 typedef int (* kblock_close_t) (struct KBlock *b);
74 * Table of interface functions for a KBlock device.
76 typedef struct KBlockVTable
78 kblock_read_direct_t readDirect;
79 kblock_write_block_t writeBlock;
81 kblock_read_t readBuf;
82 kblock_write_t writeBuf;
86 kblock_error_t error; ///< \sa kblock_error()
87 kblock_clearerr_t clearerr; ///< \sa kblock_clearerr()
89 kblock_close_t close; ///< \sa kblock_close()
93 #define KB_BUFFERED BV(0) ///< Internal flag: true if the KBlock has a buffer
94 #define KB_CACHE_DIRTY BV(1) ///< Internal flag: true if the cache is dirty
97 * KBlock private members.
98 * These are the private members of the KBlock interface, please do not
99 * access these directly, use the KBlock API.
101 typedef struct KBlockPriv
103 DB(id_t type); ///< Used to keep track, at runtime, of the class type.
104 int flags; ///< Status and error flags.
105 void *buf; ///< Pointer to the page buffer for RAM-cached KBlocks.
106 block_idx_t blk_start; ///< Start block number when the device is trimmed. \sa kblock_trim().
107 block_idx_t curr_blk; ///< Current cached block number in cached KBlocks.
109 const struct KBlockVTable *vt; ///< Virtual table of interface functions.
113 * KBlock: interface for a generic block device.
115 * A block device is a device which can only be read/written
116 * with data blocks of constant size: flash memories,
117 * SD cards, hard disks, etc...
119 * This interface is designed to adapt to most block devices and
120 * use peculiar features in order to save CPU time and memory space.
122 * You do not have to use this structure directly, specific implementations
123 * will be supplied in the peripheral drivers.
125 typedef struct KBlock
127 KBlockPriv priv; ///< Interface private data, do not use directly.
129 /* Public access members */
130 size_t blk_size; ///< Block size.
131 block_idx_t blk_cnt; ///< Number of blocks available in the device.
136 * Use a subset of the blocks on the device.
138 * This function is useful for partitioning a device and use it for
139 * different purposes at the same time.
141 * This function will limit the number of blocks used on the device by setting
142 * a start index and a number of blocks to be used counting from that index.
144 * The blocks outside this range are no more accessible.
146 * Logical block indexes will be mapped to physical indexes inside this new
147 * range automatically. Even following calls to kblock_trim() will use logical
148 * indexes, so, once trimmed, access can only be limited further and never
153 * //...init KBlock device dev
154 * kblock_trim(dev, 200, 1500); // Restrict access to the 200-1700 physical block range.
155 * kblock_read(dev, 0, buf, 0, dev->blk_size); // Read from physical block #200.
156 * kblock_trim(dev, 0, 300); // Restrict access to the 200-500 physical block range.
159 * \param b KBlock device.
160 * \param start The index of the start block for the limiting window in logical addressing units.
161 * \param count The number of blocks to be used.
164 INLINE void kblock_trim(struct KBlock *b, block_idx_t start, block_idx_t count)
166 ASSERT(start + count <= b->blk_cnt);
167 b->priv.blk_start += start;
172 #define KB_ASSERT_METHOD(b, method) \
176 ASSERT((b)->priv.vt); \
177 ASSERT((b)->priv.vt->method); \
183 * Get the current errors for the device.
185 * \note Calling this function will not clear the errors.
187 * \param b KBlock device.
189 * \return 0 if no error is present, a driver specific mask of errors otherwise.
191 * \sa kblock_clearerr()
193 INLINE int kblock_error(struct KBlock *b)
195 KB_ASSERT_METHOD(b, error);
196 return b->priv.vt->error(b);
200 * Clear the errors of the device.
202 * \param b KBlock device.
204 * \return 0 on success, EOF on errors.
208 INLINE int kblock_clearerr(struct KBlock *b)
210 KB_ASSERT_METHOD(b, clearerr);
211 return b->priv.vt->clearerr(b);
217 * \param b KBlock device.
219 * \return 0 on success, EOF on errors.
221 INLINE int kblock_close(struct KBlock *b)
223 KB_ASSERT_METHOD(b, close);
224 return b->priv.vt->close(b);
228 * \return true if the device \a b is buffered, false otherwise.
229 * \param b KBlock device.
230 * \sa kblock_cachedBlock(), kblock_cacheDirty().
232 INLINE bool kblock_buffered(struct KBlock *b)
235 return (b->priv.flags & KB_BUFFERED);
240 * \return The current cached block number if the device is buffered.
241 * \param b KBlock device.
242 * \note This function will throw an ASSERT if called on a non buffered KBlock.
243 * \sa kblock_buffered(), kblock_cacheDirty().
245 INLINE block_idx_t kblock_cachedBlock(struct KBlock *b)
247 ASSERT(kblock_buffered(b));
248 return b->priv.curr_blk;
253 * Return the status of the internal cache.
255 * \param b KBlock device.
256 * \return If the device supports buffering, returns true if the cache is dirty,
257 * false if the cache is clean and coherent with device content.
258 * \note This function will throw an ASSERT if called on a non buffered KBlock.
259 * \sa kblock_cachedBlock(), kblock_buffered().
261 INLINE bool kblock_cacheDirty(struct KBlock *b)
263 ASSERT(kblock_buffered(b));
264 return kblock_buffered(b) && (b->priv.flags & KB_CACHE_DIRTY);
269 * Read data from the block device.
271 * This function will read \a size bytes from block \a idx starting at
272 * address \a offset inside the block.
274 * Most block devices (almost all flash memories, for instance),
275 * can efficiently read even a part of the block.
277 * \note This function can be slow if you try to partial read a block from
278 * a device which does not support partial block reads and is opened
279 * in unbuffered mode.
281 * \param b KBlock device.
282 * \param idx the block number where you want to read.
283 * \param buf a buffer where the data will be read.
284 * \param offset the offset inside the block from which data reading will start.
285 * \param size the size of data to be read.
287 * \return the number of bytes read.
289 * \sa kblock_write().
291 size_t kblock_read(struct KBlock *b, block_idx_t idx, void *buf, size_t offset, size_t size);
295 * Write data to the block device.
297 * This function will write \a size bytes to block \a idx starting at
298 * address \a offset inside the block.
300 * \note Partial block writes are supported only if the device is opened in
301 * buffered mode. You can use kblock_buffered() to check if the device
302 * has an internal cache or not.
304 * \note If the device is opened in buffered mode, this function will use
305 * efficiently and trasparently the cache provided.
306 * In order to be sure that all modifications are actually written
307 * to the device you have to call kblock_flush().
309 * \param b KBlock device.
310 * \param idx the block number where you want to write.
311 * \param buf a pointer to the data to be written.
312 * \param offset the offset inside the block from which data writing will start.
313 * \param size the size of data to be written.
315 * \return the number of bytes written.
317 * \sa kblock_read(), kblock_flush(), kblock_buffered().
319 size_t kblock_write(struct KBlock *b, block_idx_t idx, const void *buf, size_t offset, size_t size);
323 * Flush the cache (if any) to the device.
325 * This function will write any pending modifications to the device.
326 * If the device does not have a cache, this function will do nothing.
328 * \return 0 if all is OK, EOF on errors.
329 * \sa kblock_read(), kblock_write(), kblock_buffered().
331 int kblock_flush(struct KBlock *b);
335 * Copy one block to another.
337 * This function will copy the content of block \a src to block \a dest.
339 * \note This function is available only on devices opened in buffered mode.
341 * \param b KBlock device.
342 * \param src source block number.
343 * \param dest destination block number.
345 * \return 0 if all is OK, EOF on errors.
347 int kblock_copy(struct KBlock *b, block_idx_t src, block_idx_t dest);
349 int kblock_swLoad(struct KBlock *b, block_idx_t index);
350 int kblock_swStore(struct KBlock *b, block_idx_t index);
351 size_t kblock_swReadBuf(struct KBlock *b, void *buf, size_t offset, size_t size);
352 size_t kblock_swWriteBuf(struct KBlock *b, const void *buf, size_t offset, size_t size);
354 #endif /* IO_KBLOCK_H */