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/*
* COPYRIGHT (c) 2010 Chris Johns <chrisj@rtems.org>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*
* $Id$
*/
/**
* @file
*
* @ingroup rtems-rfs
*
* RTEMS File Systems Buffer Management.
*
* These functions map blocks to the media interface layers.
*/
#if !defined (_RTEMS_RFS_BUFFER_H_)
#define _RTEMS_RFS_BUFFER_H_
#include <errno.h>
#include <rtems/rfs/rtems-rfs-file-system-fwd.h>
#include <rtems/rfs/rtems-rfs-trace.h>
/**
* Define the method used to interface to the buffers. It can be libblock or
* device I/O. The libblock interface is to the RTEMS cache and block devices
* and device I/O accesses the media via a device file handle.
*/
#if defined (__rtems__)
#define RTEMS_RFS_USE_LIBBLOCK 1
#endif
/**
* The RTEMS RFS I/O Layering.
*/
#if RTEMS_RFS_USE_LIBBLOCK
#include <rtems/bdbuf.h>
#include <rtems/error.h>
typedef rtems_blkdev_bnum rtems_rfs_buffer_block;
typedef rtems_bdbuf_buffer rtems_rfs_buffer;
#define rtems_rfs_buffer_io_request rtems_rfs_buffer_bdbuf_request
#define rtems_rfs_buffer_io_release rtems_rfs_buffer_bdbuf_release
/**
* Request a buffer from the RTEMS libblock BD buffer cache.
*/
int rtems_rfs_buffer_bdbuf_request (rtems_rfs_file_system* fs,
rtems_rfs_buffer_block block,
bool read,
rtems_rfs_buffer** buffer);
/**
* Release a buffer to the RTEMS libblock BD buffer cache.
*/
int rtems_rfs_buffer_bdbuf_release (rtems_rfs_buffer* handle,
bool modified);
#else /* Device I/O */
typedef uint32_t rtems_rfs_buffer_block;
typedef struct _rtems_rfs_buffer
{
rtems_chain_node link;
rtems_rfs_buffer_block user;
void* buffer;
size_t size;
uint32_t references;
} rtems_rfs_buffer;
#define rtems_rfs_buffer_io_request rtems_rfs_buffer_devceio_request
#define rtems_rfs_buffer_io_release rtems_rfs_uffer_deviceio_release
/**
* Request a buffer from the device I/O.
*/
int rtems_rfs_buffer_deviceio_request (rtems_rfs_file_system* fs,
rtems_rfs_buffer_block block,
bool read,
rtems_rfs_buffer* buffer);
/**
* Release a buffer to the RTEMS libblock BD buffer cache.
*/
int rtems_rfs_buffer_deviceio_release (rtems_rfs_buffer* handle,
bool modified);
#endif
/**
* RFS Buffer handle.
*/
typedef struct rtems_rfs_buffer_handle_t
{
/**
* Has the buffer been modifed?
*/
bool dirty;
/**
* Block number. The lower layer block number may be absolute and we maybe
* relative to an offset in the disk so hold locally.
*/
rtems_rfs_buffer_block bnum;
/**
* Reference the buffer descriptor.
*/
rtems_rfs_buffer* buffer;
} rtems_rfs_buffer_handle;
/**
* The buffer linkage.
*/
#define rtems_rfs_buffer_link(_h) (&(_h)->buffer->link)
/**
* Return the start of the data area of the buffer given a handle.
*/
#define rtems_rfs_buffer_data(_h) ((void*)((_h)->buffer->buffer))
/**
* Return the size of the buffer given a handle.
*/
#define rtems_rfs_buffer_size(_h) ((_h)->buffer->size)
/**
* Return the block number.
*/
#define rtems_rfs_buffer_bnum(_h) ((_h)->bnum)
/**
* Return the buffer dirty status.
*/
#define rtems_rfs_buffer_dirty(_h) ((_h)->dirty)
/**
* Does the handle have a valid block attached ?
*/
#define rtems_rfs_buffer_handle_has_block(_h) ((_h)->buffer ? true : false)
/**
* Mark the buffer as dirty.
*/
#define rtems_rfs_buffer_mark_dirty(_h) ((_h)->dirty = true)
/**
* Return the reference count.
*/
#define rtems_rfs_buffer_refs(_h) ((_h)->buffer->references)
/**
* Increment the reference count.
*/
#define rtems_rfs_buffer_refs_up(_h) ((_h)->buffer->references += 1)
/**
* Decrement the reference count.
*/
#define rtems_rfs_buffer_refs_down(_h) ((_h)->buffer->references -= 1)
/**
* Request a buffer. The buffer can be filled with data from the media (read ==
* true) or you can request a buffer to fill with data.
*
* @param fs The file system data.
* @param handle The handle the requested buffer is attached to.
* @param block The block number.
* @param read Read the data from the disk.
* @return int The error number (errno). No error if 0.
*/
int rtems_rfs_buffer_handle_request (rtems_rfs_file_system* fs,
rtems_rfs_buffer_handle* handle,
rtems_rfs_buffer_block block,
bool read);
/**
* Release a buffer. If the buffer is dirty the buffer is written to disk. The
* result does not indicate if the data was successfully written to the disk as
* this operation may be performed in asynchronously to this release.
*
* @param fs The file system data.
* @param handle The handle the requested buffer is attached to.
* @return int The error number (errno). No error if 0.
*/
int rtems_rfs_buffer_handle_release (rtems_rfs_file_system* fs,
rtems_rfs_buffer_handle* handle);
/**
* Open a handle.
*
* @param fs The file system data.
* @param handle The buffer handle to open.
* @return int The error number (errno). No error if 0.
*/
static inline int
rtems_rfs_buffer_handle_open (rtems_rfs_file_system* fs,
rtems_rfs_buffer_handle* handle)
{
handle->dirty = false;
handle->bnum = 0;
handle->buffer = NULL;
return 0;
}
/**
* Close a handle.
*
* @param fs The file system data.
* @param handle The buffer handle to close.
* @return int The error number (errno). No error if 0.
*/
static inline int
rtems_rfs_buffer_handle_close (rtems_rfs_file_system* fs,
rtems_rfs_buffer_handle* handle)
{
rtems_rfs_buffer_handle_release (fs, handle);
handle->dirty = false;
handle->bnum = 0;
handle->buffer = NULL;
return 0;
}
/**
* Open the buffer interface.
*
* @param name The device name to the media.
* @param fs Pointer to the file system data.
* @return int The error number (errno). No error if 0.
*/
int rtems_rfs_buffer_open (const char* name, rtems_rfs_file_system* fs);
/**
* Close the buffer interface.
*
* @param fs Pointer to the file system data.
* @return int The error number (errno). No error if 0.
*/
int rtems_rfs_buffer_close (rtems_rfs_file_system* fs);
/**
* Sync all buffers to the media.
*
* @param fs Pointer to the file system data.
* @return int The error number (errno). No error if 0.
*/
int rtems_rfs_buffer_sync (rtems_rfs_file_system* fs);
/**
* Set the block size of the device.
*
* @param fs Pointer to the file system data.
* @param size The new block size.
* @return int The error number (errno). No error if 0.
*/
int rtems_rfs_buffer_setblksize (rtems_rfs_file_system* fs, size_t size);
/**
* Release any chained buffers.
*
* @param fs The file system data.
* @return int The error number (errno). No error if 0.
*/
int rtems_rfs_buffers_release (rtems_rfs_file_system* fs);
#endif
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