84 lines
2.9 KiB
C
84 lines
2.9 KiB
C
|
/***************************************************************************
|
||
|
|
* __________ __ ___.
|
||
|
|
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
|
||
|
|
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
|
||
|
|
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
|
||
|
|
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
|
||
|
|
* \/ \/ \/ \/ \/
|
||
|
|
* $Id$
|
||
|
|
*
|
||
|
|
* Copyright (C) 2014 by Michael Sevakis
|
||
|
|
*
|
||
|
|
* This program 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
|
||
|
|
* KIND, either express or implied.
|
||
|
|
*
|
||
|
|
****************************************************************************/
|
||
|
|
#ifndef DISK_CACHE_H
|
||
|
|
#define DISK_CACHE_H
|
||
|
|
|
||
|
|
/* This needs enough for all file handles to have a buffer in the worst case
|
||
|
|
* plus at least one reserved exclusively for the cache client and a couple
|
||
|
|
* for other file system code. The buffers are put to use by the cache if not
|
||
|
|
* taken for another purpose (meaning nothing is wasted sitting fallow).
|
||
|
|
*
|
||
|
|
* One map per volume is maintained in order to avoid collisions between
|
||
|
|
* volumes that would slow cache probing. DC_MAP_NUM_ENTRIES is the number
|
||
|
|
* for each map per volume. The buffers themselves are shared.
|
||
|
|
*/
|
||
|
|
#if MEMORYSIZE < 8
|
||
|
|
#define DC_NUM_ENTRIES 32
|
||
|
|
#define DC_MAP_NUM_ENTRIES 128
|
||
|
|
#elif MEMORYSIZE <= 32
|
||
|
|
#define DC_NUM_ENTRIES 48
|
||
|
|
#define DC_MAP_NUM_ENTRIES 128
|
||
|
|
#else /* MEMORYSIZE > 32 */
|
||
|
|
#define DC_NUM_ENTRIES 64
|
||
|
|
#define DC_MAP_NUM_ENTRIES 256
|
||
|
|
#endif /* MEMORYSIZE */
|
||
|
|
|
||
|
|
/* this _could_ be larger than a sector if that would ever be useful */
|
||
|
|
#define DC_CACHE_BUFSIZE SECTOR_SIZE
|
||
|
|
|
||
|
|
#include "mutex.h"
|
||
|
|
#include "mv.h"
|
||
|
|
|
||
|
|
static inline void dc_lock_cache(void)
|
||
|
|
{
|
||
|
|
extern struct mutex disk_cache_mutex;
|
||
|
|
mutex_lock(&disk_cache_mutex);
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline void dc_unlock_cache(void)
|
||
|
|
{
|
||
|
|
extern struct mutex disk_cache_mutex;
|
||
|
|
mutex_unlock(&disk_cache_mutex);
|
||
|
|
}
|
||
|
|
|
||
|
|
void * dc_cache_probe(IF_MV(int volume,) unsigned long secnum,
|
||
|
|
unsigned int *flags);
|
||
|
|
void dc_dirty_buf(void *buf);
|
||
|
|
void dc_discard_buf(void *buf);
|
||
|
|
void dc_commit_all(IF_MV_NONVOID(int volume));
|
||
|
|
void dc_discard_all(IF_MV_NONVOID(int volume));
|
||
|
|
|
||
|
|
void dc_init(void) INIT_ATTR;
|
||
|
|
|
||
|
|
/* in addition to filling, writeback is implemented by the client */
|
||
|
|
extern void dc_writeback_callback(IF_MV(int volume, ) unsigned long sector,
|
||
|
|
void *buf);
|
||
|
|
|
||
|
|
|
||
|
|
/** These synchronize and can be called by anyone **/
|
||
|
|
|
||
|
|
/* expropriate a buffer from the cache of DC_CACHE_BUFSIZE bytes */
|
||
|
|
void * dc_get_buffer(void);
|
||
|
|
/* return buffer to the cache by buffer */
|
||
|
|
void dc_release_buffer(void *buf);
|
||
|
|
|
||
|
|
#endif /* DISK_CACHE_H */
|