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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 size_t (* kblock_write_direct_t) (struct KBlock *b, block_idx_t index, const void *buf, size_t offset, size_t size);
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 void (* 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_direct_t writeDirect;
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
95 #define KB_PARTIAL_WRITE BV(2) ///< Internal flag: true if the device allows partial block write
98 * KBlock private members.
99 * These are the private members of the KBlock interface, please do not
100 * access these directly, use the KBlock API.
102 typedef struct KBlockPriv
104 DB(id_t type); ///< Used to keep track, at runtime, of the class type.
105 int flags; ///< Status and error flags.
106 void *buf; ///< Pointer to the page buffer for RAM-cached KBlocks.
107 block_idx_t blk_start; ///< Start block number when the device is trimmed. \sa kblock_trim().
108 block_idx_t curr_blk; ///< Current cached block number in cached KBlocks.
110 const struct KBlockVTable *vt; ///< Virtual table of interface functions.
114 * KBlock: interface for a generic block device.
116 * A block device is a device which can only be read/written
117 * with data blocks of constant size: flash memories,
118 * SD cards, hard disks, etc...
120 * This interface is designed to adapt to most block devices and
121 * use peculiar features in order to save CPU time and memory space.
123 * You do not have to use this structure directly, specific implementations
124 * will be supplied in the peripheral drivers.
126 typedef struct KBlock
128 KBlockPriv priv; ///< Interface private data, do not use directly.
130 /* Public access members */
131 size_t blk_size; ///< Block size.
132 block_idx_t blk_cnt; ///< Number of blocks available in the device.
137 * Use a subset of the blocks on the device.
139 * This function is useful for partitioning a device and use it for
140 * different purposes at the same time.
142 * This function will limit the number of blocks used on the device by setting
143 * a start index and a number of blocks to be used counting from that index.
145 * The blocks outside this range are no more accessible.
147 * Logical block indexes will be mapped to physical indexes inside this new
148 * range automatically. Even following calls to kblock_trim() will use logical
149 * indexes, so, once trimmed, access can only be limited further and never
154 * //...init KBlock device dev
155 * kblock_trim(dev, 200, 1500); // Restrict access to the 200-1700 physical block range.
156 * kblock_read(dev, 0, buf, 0, dev->blk_size); // Read from physical block #200.
157 * kblock_trim(dev, 0, 300); // Restrict access to the 200-500 physical block range.
160 * \param b KBlock device.
161 * \param start The index of the start block for the limiting window in logical addressing units.
162 * \param count The number of blocks to be used.
165 INLINE void kblock_trim(struct KBlock *b, block_idx_t start, block_idx_t count)
167 ASSERT(start + count <= b->blk_cnt);
168 b->priv.blk_start += start;
173 #define KB_ASSERT_METHOD(b, method) \
177 ASSERT((b)->priv.vt); \
178 ASSERT((b)->priv.vt->method); \
184 * Get the current errors for the device.
186 * \note Calling this function will not clear the errors.
188 * \param b KBlock device.
190 * \return 0 if no error is present, a driver specific mask of errors otherwise.
192 * \sa kblock_clearerr()
194 INLINE int kblock_error(struct KBlock *b)
196 KB_ASSERT_METHOD(b, error);
197 return b->priv.vt->error(b);
201 * Clear the errors of the device.
203 * \param b KBlock device.
208 INLINE void kblock_clearerr(struct KBlock *b)
210 KB_ASSERT_METHOD(b, clearerr);
211 b->priv.vt->clearerr(b);
216 * Flush the cache (if any) to the device.
218 * This function will write any pending modifications to the device.
219 * If the device does not have a cache, this function will do nothing.
221 * \return 0 if all is OK, EOF on errors.
222 * \sa kblock_read(), kblock_write(), kblock_buffered().
224 int kblock_flush(struct KBlock *b);
229 * \param b KBlock device.
231 * \return 0 on success, EOF on errors.
233 INLINE int kblock_close(struct KBlock *b)
235 KB_ASSERT_METHOD(b, close);
236 return kblock_flush(b) | b->priv.vt->close(b);
240 * \return true if the device \a b is buffered, false otherwise.
241 * \param b KBlock device.
242 * \sa kblock_cachedBlock(), kblock_cacheDirty().
244 INLINE bool kblock_buffered(struct KBlock *b)
247 return (b->priv.flags & KB_BUFFERED);
252 * \return The current cached block number if the device is buffered.
253 * \param b KBlock device.
254 * \note This function will throw an ASSERT if called on a non buffered KBlock.
255 * \sa kblock_buffered(), kblock_cacheDirty().
257 INLINE block_idx_t kblock_cachedBlock(struct KBlock *b)
259 ASSERT(kblock_buffered(b));
260 return b->priv.curr_blk;
265 * Return the status of the internal cache.
267 * \param b KBlock device.
268 * \return If the device supports buffering, returns true if the cache is dirty,
269 * false if the cache is clean and coherent with device content.
270 * \note This function will throw an ASSERT if called on a non buffered KBlock.
271 * \sa kblock_cachedBlock(), kblock_buffered().
273 INLINE bool kblock_cacheDirty(struct KBlock *b)
275 ASSERT(kblock_buffered(b));
276 return kblock_buffered(b) && (b->priv.flags & KB_CACHE_DIRTY);
280 * \return true if the device \a b supports partial block write. That is, you
281 * can call kblock_write() with a size which is lesser than the block
283 * \param b KBlock device.
284 * \sa kblock_write().
286 INLINE bool kblock_partialWrite(struct KBlock *b)
289 return (b->priv.flags & KB_PARTIAL_WRITE);
293 * Read data from the block device.
295 * This function will read \a size bytes from block \a idx starting at
296 * address \a offset inside the block.
298 * Most block devices (almost all flash memories, for instance),
299 * can efficiently read even a part of the block.
301 * \note This function can be slow if you try to partial read a block from
302 * a device which does not support partial block reads and is opened
303 * in unbuffered mode.
305 * \param b KBlock device.
306 * \param idx the block number where you want to read.
307 * \param buf a buffer where the data will be read.
308 * \param offset the offset inside the block from which data reading will start.
309 * \param size the size of data to be read.
311 * \return the number of bytes read.
313 * \sa kblock_write().
315 size_t kblock_read(struct KBlock *b, block_idx_t idx, void *buf, size_t offset, size_t size);
319 * Write data to the block device.
321 * This function will write \a size bytes to block \a idx starting at
322 * address \a offset inside the block.
324 * \note Partial block writes are supported only on certain devices.
325 * You can use kblock_partialWrite() in order to check if the device
326 * has this feature or not.
328 * \note If the device is opened in buffered mode, this function will use
329 * efficiently and trasparently the cache provided.
330 * In order to be sure that all modifications are actually written
331 * to the device you have to call kblock_flush().
333 * \param b KBlock device.
334 * \param idx the block number where you want to write.
335 * \param buf a pointer to the data to be written.
336 * \param offset the offset inside the block from which data writing will start.
337 * \param size the size of data to be written.
339 * \return the number of bytes written.
341 * \sa kblock_read(), kblock_flush(), kblock_buffered(), kblock_partialWrite().
343 size_t kblock_write(struct KBlock *b, block_idx_t idx, const void *buf, size_t offset, size_t size);
346 * Copy one block to another.
348 * This function will copy the content of block \a src to block \a dest.
350 * \note This function is available only on devices which support partial
351 * block write or are opened in buffered mode.
353 * \param b KBlock device.
354 * \param src source block number.
355 * \param dest destination block number.
357 * \return 0 if all is OK, EOF on errors.
359 int kblock_copy(struct KBlock *b, block_idx_t src, block_idx_t dest);
361 int kblock_swLoad(struct KBlock *b, block_idx_t index);
362 int kblock_swStore(struct KBlock *b, block_idx_t index);
363 size_t kblock_swReadBuf(struct KBlock *b, void *buf, size_t offset, size_t size);
364 size_t kblock_swWriteBuf(struct KBlock *b, const void *buf, size_t offset, size_t size);
366 #endif /* IO_KBLOCK_H */