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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
37 * $WIZ$ module_name = "kblock"
43 #include <cfg/compiler.h>
44 #include <cfg/debug.h>
45 #include <cfg/macros.h>
47 /** Type for addressing blocks in the device. */
48 typedef uint32_t block_idx_t;
54 * \name Prototypes for KBlock low level access functions.
56 * When writing a driver implementing the KBlock interface you can choose which
57 * function subset to implement, but you have to set to NULL unimplemented
62 typedef size_t (* kblock_read_direct_t) (struct KBlock *b, block_idx_t index, void *buf, size_t offset, size_t size);
63 typedef size_t (* kblock_write_direct_t) (struct KBlock *b, block_idx_t index, const void *buf, size_t offset, size_t size);
65 typedef size_t (* kblock_read_t) (struct KBlock *b, void *buf, size_t offset, size_t size);
66 typedef size_t (* kblock_write_t) (struct KBlock *b, const void *buf, size_t offset, size_t size);
67 typedef int (* kblock_load_t) (struct KBlock *b, block_idx_t index);
68 typedef int (* kblock_store_t) (struct KBlock *b, block_idx_t index);
70 typedef int (* kblock_error_t) (struct KBlock *b);
71 typedef void (* kblock_clearerr_t) (struct KBlock *b);
72 typedef int (* kblock_close_t) (struct KBlock *b);
76 * Table of interface functions for a KBlock device.
78 typedef struct KBlockVTable
80 kblock_read_direct_t readDirect;
81 kblock_write_direct_t writeDirect;
83 kblock_read_t readBuf;
84 kblock_write_t writeBuf;
88 kblock_error_t error; ///< \sa kblock_error()
89 kblock_clearerr_t clearerr; ///< \sa kblock_clearerr()
91 kblock_close_t close; ///< \sa kblock_close()
95 #define KB_BUFFERED BV(0) ///< Internal flag: true if the KBlock has a buffer
96 #define KB_CACHE_DIRTY BV(1) ///< Internal flag: true if the cache is dirty
97 #define KB_PARTIAL_WRITE BV(2) ///< Internal flag: true if the device allows partial block write
99 #define KB_WRITE_ONCE BV(3) ///< Allow only the one write on select block.
100 #define KB_OPEN_BUFF BV(4) ///< Open flash memory using page caching, allowing the modification and partial write.
101 #define KB_OPEN_UNBUFF BV(5) ///< Open flash memory whitout memory caching.
104 * KBlock private members.
105 * These are the private members of the KBlock interface, please do not
106 * access these directly, use the KBlock API.
108 typedef struct KBlockPriv
110 DB(id_t type); ///< Used to keep track, at runtime, of the class type.
111 int flags; ///< Status and error flags.
112 void *buf; ///< Pointer to the page buffer for RAM-cached KBlocks.
113 block_idx_t blk_start; ///< Start block number when the device is trimmed. \sa kblock_trim().
114 block_idx_t curr_blk; ///< Current cached block number in cached KBlocks.
116 const struct KBlockVTable *vt; ///< Virtual table of interface functions.
120 * KBlock: interface for a generic block device.
122 * A block device is a device which can only be read/written
123 * with data blocks of constant size: flash memories,
124 * SD cards, hard disks, etc...
126 * This interface is designed to adapt to most block devices and
127 * use peculiar features in order to save CPU time and memory space.
129 * You do not have to use this structure directly, specific implementations
130 * will be supplied in the peripheral drivers.
132 typedef struct KBlock
134 KBlockPriv priv; ///< Interface private data, do not use directly.
136 /* Public access members */
137 size_t blk_size; ///< Block size.
138 block_idx_t blk_cnt; ///< Number of blocks available in the device.
143 * Use a subset of the blocks on the device.
145 * This function is useful for partitioning a device and use it for
146 * different purposes at the same time.
148 * This function will limit the number of blocks used on the device by setting
149 * a start index and a number of blocks to be used counting from that index.
151 * The blocks outside this range are no more accessible.
153 * Logical block indexes will be mapped to physical indexes inside this new
154 * range automatically. Even following calls to kblock_trim() will use logical
155 * indexes, so, once trimmed, access can only be limited further and never
160 * //...init KBlock device dev
161 * kblock_trim(dev, 200, 1500); // Restrict access to the 200-1700 physical block range.
162 * kblock_read(dev, 0, buf, 0, dev->blk_size); // Read from physical block #200.
163 * kblock_trim(dev, 0, 300); // Restrict access to the 200-500 physical block range.
166 * \param b KBlock device.
167 * \param start The index of the start block for the limiting window in logical addressing units.
168 * \param count The number of blocks to be used.
171 INLINE void kblock_trim(struct KBlock *b, block_idx_t start, block_idx_t count)
173 ASSERT(start + count <= b->blk_cnt);
174 b->priv.blk_start += start;
179 #define KB_ASSERT_METHOD(b, method) \
183 ASSERT((b)->priv.vt); \
184 ASSERT((b)->priv.vt->method); \
190 * Get the current errors for the device.
192 * \note Calling this function will not clear the errors.
194 * \param b KBlock device.
196 * \return 0 if no error is present, a driver specific mask of errors otherwise.
198 * \sa kblock_clearerr()
200 INLINE int kblock_error(struct KBlock *b)
202 KB_ASSERT_METHOD(b, error);
203 return b->priv.vt->error(b);
207 * Clear the errors of the device.
209 * \param b KBlock device.
214 INLINE void kblock_clearerr(struct KBlock *b)
216 KB_ASSERT_METHOD(b, clearerr);
217 b->priv.vt->clearerr(b);
222 * Flush the cache (if any) to the device.
224 * This function will write any pending modifications to the device.
225 * If the device does not have a cache, this function will do nothing.
227 * \return 0 if all is OK, EOF on errors.
228 * \sa kblock_read(), kblock_write(), kblock_buffered().
230 int kblock_flush(struct KBlock *b);
235 * \param b KBlock device.
237 * \return 0 on success, EOF on errors.
239 INLINE int kblock_close(struct KBlock *b)
241 KB_ASSERT_METHOD(b, close);
242 return kblock_flush(b) | b->priv.vt->close(b);
246 * \return true if the device \a b is buffered, false otherwise.
247 * \param b KBlock device.
248 * \sa kblock_cachedBlock(), kblock_cacheDirty().
250 INLINE bool kblock_buffered(struct KBlock *b)
253 return (b->priv.flags & KB_BUFFERED);
258 * \return The current cached block number if the device is buffered.
259 * \param b KBlock device.
260 * \note This function will throw an ASSERT if called on a non buffered KBlock.
261 * \sa kblock_buffered(), kblock_cacheDirty().
263 INLINE block_idx_t kblock_cachedBlock(struct KBlock *b)
265 ASSERT(kblock_buffered(b));
266 return b->priv.curr_blk;
271 * Return the status of the internal cache.
273 * \param b KBlock device.
274 * \return If the device supports buffering, returns true if the cache is dirty,
275 * false if the cache is clean and coherent with device content.
276 * \note This function will throw an ASSERT if called on a non buffered KBlock.
277 * \sa kblock_cachedBlock(), kblock_buffered().
279 INLINE bool kblock_cacheDirty(struct KBlock *b)
281 ASSERT(kblock_buffered(b));
282 return kblock_buffered(b) && (b->priv.flags & KB_CACHE_DIRTY);
286 * \return true if the device \a b supports partial block write. That is, you
287 * can call kblock_write() with a size which is lesser than the block
289 * \param b KBlock device.
290 * \sa kblock_write().
292 INLINE bool kblock_partialWrite(struct KBlock *b)
295 return (b->priv.flags & KB_PARTIAL_WRITE);
299 * Read data from the block device.
301 * This function will read \a size bytes from block \a idx starting at
302 * address \a offset inside the block.
304 * Most block devices (almost all flash memories, for instance),
305 * can efficiently read even a part of the block.
307 * \note This function can be slow if you try to partial read a block from
308 * a device which does not support partial block reads and is opened
309 * in unbuffered mode.
311 * \param b KBlock device.
312 * \param idx the block number where you want to read.
313 * \param buf a buffer where the data will be read.
314 * \param offset the offset inside the block from which data reading will start.
315 * \param size the size of data to be read.
317 * \return the number of bytes read.
319 * \sa kblock_write().
321 size_t kblock_read(struct KBlock *b, block_idx_t idx, void *buf, size_t offset, size_t size);
325 * Write data to the block device.
327 * This function will write \a size bytes to block \a idx starting at
328 * address \a offset inside the block.
330 * \note Partial block writes are supported only on certain devices.
331 * You can use kblock_partialWrite() in order to check if the device
332 * has this feature or not.
334 * \note If the device is opened in buffered mode, this function will use
335 * efficiently and trasparently the cache provided.
336 * In order to be sure that all modifications are actually written
337 * to the device you have to call kblock_flush().
339 * \param b KBlock device.
340 * \param idx the block number where you want to write.
341 * \param buf a pointer to the data to be written.
342 * \param offset the offset inside the block from which data writing will start.
343 * \param size the size of data to be written.
345 * \return the number of bytes written.
347 * \sa kblock_read(), kblock_flush(), kblock_buffered(), kblock_partialWrite().
349 size_t kblock_write(struct KBlock *b, block_idx_t idx, const void *buf, size_t offset, size_t size);
352 * Copy one block to another.
354 * This function will copy the content of block \a src to block \a dest.
356 * \note This function is available only on devices which support partial
357 * block write or are opened in buffered mode.
359 * \param b KBlock device.
360 * \param src source block number.
361 * \param dest destination block number.
363 * \return 0 if all is OK, EOF on errors.
365 int kblock_copy(struct KBlock *b, block_idx_t src, block_idx_t dest);
367 int kblock_swLoad(struct KBlock *b, block_idx_t index);
368 int kblock_swStore(struct KBlock *b, block_idx_t index);
369 size_t kblock_swReadBuf(struct KBlock *b, void *buf, size_t offset, size_t size);
370 size_t kblock_swWriteBuf(struct KBlock *b, const void *buf, size_t offset, size_t size);
371 int kblock_swClose(struct KBlock *b);
373 #endif /* IO_KBLOCK_H */