* \author Francesco Sacchi <batt@develer.com>
*
* \brief KBlock interface
+ *
+ * $WIZ$ module_name = "kblock"
*/
#ifndef IO_KBLOCK_H
struct KBlock;
/**
- * \name Prototypes for KBlock access functions.
+ * \name Prototypes for KBlock low level access functions.
*
- * A KBlock user can choose which function subset to implement,
- * but has to set to NULL unimplemented features.
+ * When writing a driver implementing the KBlock interface you can choose which
+ * function subset to implement, but you have to set to NULL unimplemented
+ * features.
*
* \{
*/
-typedef size_t (* kblock_read_direct_t) (struct KBlock *b, block_idx_t index, void *buf, size_t offset, size_t size);
-typedef int (* kblock_write_block_t) (struct KBlock *b, block_idx_t index, const void *buf);
+typedef size_t (* kblock_read_direct_t) (struct KBlock *b, block_idx_t index, void *buf, size_t offset, size_t size);
+typedef size_t (* kblock_write_direct_t) (struct KBlock *b, block_idx_t index, const void *buf, size_t offset, size_t size);
typedef size_t (* kblock_read_t) (struct KBlock *b, void *buf, size_t offset, size_t size);
typedef size_t (* kblock_write_t) (struct KBlock *b, const void *buf, size_t offset, size_t size);
typedef int (* kblock_store_t) (struct KBlock *b, block_idx_t index);
typedef int (* kblock_error_t) (struct KBlock *b);
-typedef int (* kblock_clearerr_t) (struct KBlock *b);
+typedef void (* kblock_clearerr_t) (struct KBlock *b);
typedef int (* kblock_close_t) (struct KBlock *b);
/* \} */
-/**
+/*
* Table of interface functions for a KBlock device.
*/
typedef struct KBlockVTable
{
kblock_read_direct_t readDirect;
- kblock_write_block_t writeBlock;
-
+ kblock_write_direct_t writeDirect;
+
kblock_read_t readBuf;
kblock_write_t writeBuf;
kblock_load_t load;
kblock_store_t store;
-
- kblock_error_t error; ///< \sa kblock_error()
- kblock_clearerr_t clearerr; ///< \sa kblock_clearerr()
- kblock_close_t close; ///< \sa kblock_close()
+ kblock_error_t error; // \sa kblock_error()
+ kblock_clearerr_t clearerr; // \sa kblock_clearerr()
+
+ kblock_close_t close; // \sa kblock_close()
} KBlockVTable;
-#define KB_BUFFERED BV(0)
-#define KB_CACHE_DIRTY BV(1)
+#define KB_BUFFERED BV(0) ///< Internal flag: true if the KBlock has a buffer
+#define KB_CACHE_DIRTY BV(1) ///< Internal flag: true if the cache is dirty
+#define KB_PARTIAL_WRITE BV(2) ///< Internal flag: true if the device allows partial block write
-/**
+
+/*
* KBlock private members.
- * These are the private members of the KBlock class, please do not
+ * These are the private members of the KBlock interface, please do not
* access these directly, use the KBlock API.
*/
typedef struct KBlockPriv
{
- DB(id_t type); ///< Used to keep track, at runtime, of the class type.
- int flags; ///< Status and error flags.
- void *buf;
- block_idx_t blk_start; ///< Start block number when the device is trimmed. \sa kblock_trim()
- block_idx_t curr_blk;
+ DB(id_t type); // Used to keep track, at runtime, of the class type.
+ int flags; // Status and error flags.
+ void *buf; // Pointer to the page buffer for RAM-cached KBlocks.
+ block_idx_t blk_start; // Start block number when the device is trimmed. \sa kblock_trim().
+ block_idx_t curr_blk; // Current cached block number in cached KBlocks.
- const struct KBlockVTable *vt; ///< Virtual table of interface functions.
+ const struct KBlockVTable *vt; // Virtual table of interface functions.
} KBlockPriv;
/**
* \code
* //...init KBlock device dev
* kblock_trim(dev, 200, 1500); // Restrict access to the 200-1700 physical block range.
- * kblock_load(dev, 0); // Load the physical block #200.
+ * kblock_read(dev, 0, buf, 0, dev->blk_size); // Read from physical block #200.
* kblock_trim(dev, 0, 300); // Restrict access to the 200-500 physical block range.
* \endcode
*
*
* \param b KBlock device.
*
- * \return 0 on success, EOF on errors.
*
* \sa kblock_error()
*/
-INLINE int kblock_clearerr(struct KBlock *b)
+INLINE void kblock_clearerr(struct KBlock *b)
{
KB_ASSERT_METHOD(b, clearerr);
- return b->priv.vt->clearerr(b);
+ b->priv.vt->clearerr(b);
}
+
+/**
+ * Flush the cache (if any) to the device.
+ *
+ * This function will write any pending modifications to the device.
+ * If the device does not have a cache, this function will do nothing.
+ *
+ * \return 0 if all is OK, EOF on errors.
+ * \sa kblock_read(), kblock_write(), kblock_buffered().
+ */
+int kblock_flush(struct KBlock *b);
+
/**
* Close the device.
*
INLINE int kblock_close(struct KBlock *b)
{
KB_ASSERT_METHOD(b, close);
- return b->priv.vt->close(b);
+ return kblock_flush(b) | b->priv.vt->close(b);
}
-INLINE bool kblock_cacheDirty(struct KBlock *b)
+/**
+ * \return true if the device \a b is buffered, false otherwise.
+ * \param b KBlock device.
+ * \sa kblock_cachedBlock(), kblock_cacheDirty().
+ */
+INLINE bool kblock_buffered(struct KBlock *b)
{
ASSERT(b);
- return (b->priv.flags & KB_CACHE_DIRTY);
+ return (b->priv.flags & KB_BUFFERED);
}
+
+/**
+ * \return The current cached block number if the device is buffered.
+ * \param b KBlock device.
+ * \note This function will throw an ASSERT if called on a non buffered KBlock.
+ * \sa kblock_buffered(), kblock_cacheDirty().
+ */
INLINE block_idx_t kblock_cachedBlock(struct KBlock *b)
{
+ ASSERT(kblock_buffered(b));
return b->priv.curr_blk;
}
-INLINE bool kblock_buffered(struct KBlock *b)
+
+/**
+ * Return the status of the internal cache.
+ *
+ * \param b KBlock device.
+ * \return If the device supports buffering, returns true if the cache is dirty,
+ * false if the cache is clean and coherent with device content.
+ * \note This function will throw an ASSERT if called on a non buffered KBlock.
+ * \sa kblock_cachedBlock(), kblock_buffered().
+ */
+INLINE bool kblock_cacheDirty(struct KBlock *b)
+{
+ ASSERT(kblock_buffered(b));
+ return kblock_buffered(b) && (b->priv.flags & KB_CACHE_DIRTY);
+}
+
+/**
+ * \return true if the device \a b supports partial block write. That is, you
+ * can call kblock_write() with a size which is lesser than the block
+ * size.
+ * \param b KBlock device.
+ * \sa kblock_write().
+ */
+INLINE bool kblock_partialWrite(struct KBlock *b)
{
ASSERT(b);
- return (b->priv.flags & KB_BUFFERED);
+ return (b->priv.flags & KB_PARTIAL_WRITE);
}
+/**
+ * Read data from the block device.
+ *
+ * This function will read \a size bytes from block \a idx starting at
+ * address \a offset inside the block.
+ *
+ * Most block devices (almost all flash memories, for instance),
+ * can efficiently read even a part of the block.
+ *
+ * \note This function can be slow if you try to partial read a block from
+ * a device which does not support partial block reads and is opened
+ * in unbuffered mode.
+ *
+ * \param b KBlock device.
+ * \param idx the block number where you want to read.
+ * \param buf a buffer where the data will be read.
+ * \param offset the offset inside the block from which data reading will start.
+ * \param size the size of data to be read.
+ *
+ * \return the number of bytes read.
+ *
+ * \sa kblock_write().
+ */
size_t kblock_read(struct KBlock *b, block_idx_t idx, void *buf, size_t offset, size_t size);
-size_t kblock_write(struct KBlock *b, block_idx_t idx, const void *buf, size_t offset, size_t size);
-int kblock_flush(struct KBlock *b);
+/**
+ * Write data to the block device.
+ *
+ * This function will write \a size bytes to block \a idx starting at
+ * address \a offset inside the block.
+ *
+ * \note Partial block writes are supported only on certain devices.
+ * You can use kblock_partialWrite() in order to check if the device
+ * has this feature or not.
+ *
+ * \note If the device is opened in buffered mode, this function will use
+ * efficiently and trasparently the cache provided.
+ * In order to be sure that all modifications are actually written
+ * to the device you have to call kblock_flush().
+ *
+ * \param b KBlock device.
+ * \param idx the block number where you want to write.
+ * \param buf a pointer to the data to be written.
+ * \param offset the offset inside the block from which data writing will start.
+ * \param size the size of data to be written.
+ *
+ * \return the number of bytes written.
+ *
+ * \sa kblock_read(), kblock_flush(), kblock_buffered(), kblock_partialWrite().
+ */
+size_t kblock_write(struct KBlock *b, block_idx_t idx, const void *buf, size_t offset, size_t size);
-int kblock_copy(struct KBlock *b, block_idx_t idx1, block_idx_t idx2);
+/**
+ * Copy one block to another.
+ *
+ * This function will copy the content of block \a src to block \a dest.
+ *
+ * \note This function is available only on devices which support partial
+ * block write or are opened in buffered mode.
+ *
+ * \param b KBlock device.
+ * \param src source block number.
+ * \param dest destination block number.
+ *
+ * \return 0 if all is OK, EOF on errors.
+ */
+int kblock_copy(struct KBlock *b, block_idx_t src, block_idx_t dest);
int kblock_swLoad(struct KBlock *b, block_idx_t index);
int kblock_swStore(struct KBlock *b, block_idx_t index);
size_t kblock_swReadBuf(struct KBlock *b, void *buf, size_t offset, size_t size);
size_t kblock_swWriteBuf(struct KBlock *b, const void *buf, size_t offset, size_t size);
+int kblock_swClose(struct KBlock *b);
#endif /* IO_KBLOCK_H */
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