Working

bertos/io/kblock.h

@@ -0,0 +1,400 @@
+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2009 Develer S.r.l. (http://www.develer.com/)
+ *
+ * -->
+ *
+ * \defgroup io_kblock KBlock interface
+ * \ingroup core
+ * \{
+ *
+ * \brief KBlock interface
+ *
+ * A block device is a device which can only be read/written
+ * with data blocks of constant size: flash memories,
+ * SD cards, hard disks, etc...
+ * This interface is designed to adapt to most block devices and
+ * use peculiar features in order to save CPU time and memory space.
+ *
+ * There is no init function because you do not have to use this
+ * structure directly, specific implementations will supply their own init
+ * functions.
+ *
+ * Error handling is done in a way similar to standard C library: whenever a
+ * function (eg. kblock_flush()) returns error, you need to check the error
+ * code, which is implementation specific.
+ *
+ * Example of code flow:
+ * \code
+ * // init a KBlock-derived class
+ * Flash fls;
+ * flash_init(&fls.blk, 0);
+ *
+ * // use kblock_* functions to access the derived class
+ * kblock_write(&fls.blk, ...);
+ * if (kblock_flush(&fls.blk) == EOF)
+ * {
+ *     // oops, error occurred!
+ *     int err = kblock_error(&fls.blk);
+ *     // handle Flash specific error conditions
+ *     // ...
+ *     // clear error condition
+ *     kblock_clearerr(&fls.blk);
+ * }
+ * \endcode
+ *
+ * \note The KBlock interface is optimized for block reads. If you need a
+ * file-like access, you can use \ref kfile_block.
+ *
+ * \author Francesco Sacchi <batt@develer.com>
+ *
+ * $WIZ$ module_name = "kblock"
+ */
+
+#ifndef IO_KBLOCK_H
+#define IO_KBLOCK_H
+
+#include <cfg/compiler.h>
+#include <cfg/debug.h>
+#include <cfg/macros.h>
+
+/** Type for addressing blocks in the device. */
+typedef uint32_t block_idx_t;
+
+// Fwd Declaration
+struct KBlock;
+
+/**
+ * \name Prototypes for KBlock low level access functions.
+ *
+ * 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 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_load_t)        (struct KBlock *b, block_idx_t index);
+typedef int    (* kblock_store_t)       (struct KBlock *b, block_idx_t index);
+
+typedef int    (* kblock_error_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_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()
+} KBlockVTable;
+
+
+#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 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;             // 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.
+} KBlockPriv;
+
+/**
+ * KBlock: interface for a generic block device.
+ *
+ */
+typedef struct KBlock
+{
+	KBlockPriv priv;         ///< Interface private data, do not use directly.
+
+	/* Public access members */
+	size_t blk_size;         ///< Block size.
+	block_idx_t blk_cnt;     ///< Number of blocks available in the device.
+} KBlock;
+
+
+/**
+ * Use a subset of the blocks on the device.
+ *
+ * This function is useful for partitioning a device and use it for
+ * different purposes at the same time.
+ *
+ * This function will limit the number of blocks used on the device by setting
+ * a start index and a number of blocks to be used counting from that index.
+ *
+ * The blocks outside this range are no more accessible.
+ *
+ * Logical block indexes will be mapped to physical indexes inside this new
+ * range automatically. Even following calls to kblock_trim() will use logical
+ * indexes, so, once trimmed, access can only be limited further and never
+ * expanded back.
+ *
+ * Example:
+ * \code
+ * //...init KBlock device dev
+ * kblock_trim(dev, 200, 1500); // Restrict access to the 200-1700 physical block range.
+ * 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.
+ * \param start The index of the start block for the limiting window in logical addressing units.
+ * \param count The number of blocks to be used.
+ *
+ * \return 0 if all is OK, EOF on errors.
+ */
+int kblock_trim(struct KBlock *b, block_idx_t start, block_idx_t count);
+
+
+#define KB_ASSERT_METHOD(b, method) \
+	do \
+	{ \
+		ASSERT(b); \
+		ASSERT((b)->priv.vt); \
+		ASSERT((b)->priv.vt->method); \
+	} \
+	while (0)
+
+
+/**
+ * Get the current errors for the device.
+ *
+ * \note Calling this function will not clear the errors.
+ *
+ * \param b KBlock device.
+ *
+ * \return 0 if no error is present, a driver specific mask of errors otherwise.
+ *
+ * \sa kblock_clearerr()
+ */
+INLINE int kblock_error(struct KBlock *b)
+{
+	KB_ASSERT_METHOD(b, error);
+	return b->priv.vt->error(b);
+}
+
+/**
+ * Clear the errors of the device.
+ *
+ * \param b KBlock device.
+ *
+ *
+ * \sa kblock_error()
+ */
+INLINE void kblock_clearerr(struct KBlock *b)
+{
+	KB_ASSERT_METHOD(b, clearerr);
+	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.
+ *
+ * \param b KBlock device.
+ *
+ * \return 0 on success, EOF on errors.
+ */
+INLINE int kblock_close(struct KBlock *b)
+{
+	KB_ASSERT_METHOD(b, close);
+	return kblock_flush(b) | b->priv.vt->close(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_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;
+}
+
+
+/**
+ * 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_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);
+
+
+/**
+ * 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);
+
+/**
+ * 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);
+
+/** \} */ //defgroup io_kblock
+
+
+#endif /* IO_KBLOCK_H */