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FAT cache now uses static memory

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@789 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Björn Stenberg 2002-05-29 11:56:42 +00:00
parent d2a90d2d32
commit 3ad66b95fb
1 changed files with 18 additions and 35 deletions
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53
firmware/drivers/fat.c
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@ -24,7 +24,7 @@
#include <ctype.h> #include <ctype.h>
#include <time.h> #include <time.h>
#include <sys/timeb.h> #include <sys/timeb.h>
#include <stdbool.h>
#include "fat.h" #include "fat.h"
#include "ata.h" #include "ata.h"
#include "debug.h" #include "debug.h"
@ -132,12 +132,13 @@ struct bpb fat_bpb;
struct fat_cache_entry struct fat_cache_entry
{ {
unsigned char *ptr;
int secnum; int secnum;
int dirty; bool inuse;
bool dirty;
}; };
struct fat_cache_entry fat_cache[FAT_CACHE_SIZE]; static char fat_cache_sectors[FAT_CACHE_SIZE][SECTOR_SIZE];
static struct fat_cache_entry fat_cache[FAT_CACHE_SIZE];
/* sectors cache for longname use */ /* sectors cache for longname use */
static unsigned char lastsector[SECTOR_SIZE]; static unsigned char lastsector[SECTOR_SIZE];
@ -182,16 +183,11 @@ int fat_mount(int startsector)
int countofclusters; int countofclusters;
int i; int i;
/* Clear the cache. Be aware! The bss section MUST have been cleared
at boot. Otherwise we will free() garbage pointers here */
for(i = 0;i < FAT_CACHE_SIZE;i++) for(i = 0;i < FAT_CACHE_SIZE;i++)
{ {
if(fat_cache[i].ptr)
{
free(fat_cache[i].ptr);
}
fat_cache[i].secnum = 8; /* We use a "safe" sector just in case */ fat_cache[i].secnum = 8; /* We use a "safe" sector just in case */
fat_cache[i].dirty = 0; fat_cache[i].inuse = false;
fat_cache[i].dirty = false;
} }
/* Read the sector */ /* Read the sector */
@ -329,12 +325,10 @@ static int bpb_is_sane(void)
static void *cache_fat_sector(int secnum) static void *cache_fat_sector(int secnum)
{ {
int cache_index = secnum & FAT_CACHE_MASK; int cache_index = secnum & FAT_CACHE_MASK;
unsigned char *sec;
sec = fat_cache[cache_index].ptr;
/* Delete the cache entry if it isn't the sector we want */ /* Delete the cache entry if it isn't the sector we want */
if(sec && fat_cache[cache_index].secnum != secnum) if(fat_cache[cache_index].inuse &&
fat_cache[cache_index].secnum != secnum)
{ {
#ifdef WRITE #ifdef WRITE
/* Write back if it is dirty */ /* Write back if it is dirty */
@ -347,36 +341,25 @@ static void *cache_fat_sector(int secnum)
secnum); secnum);
} }
} }
#endif
free(sec);
fat_cache[cache_index].ptr = NULL;
fat_cache[cache_index].secnum = 8; /* Normally an unused sector */ fat_cache[cache_index].secnum = 8; /* Normally an unused sector */
fat_cache[cache_index].dirty = 0; fat_cache[cache_index].dirty = false;
sec = NULL; #endif
fat_cache[cache_index].inuse = false;
} }
/* Load the sector if it is not cached */ /* Load the sector if it is not cached */
if(!sec) if(!fat_cache[cache_index].inuse)
{ {
sec = malloc(fat_bpb.bpb_bytspersec); if(ata_read_sectors(secnum + fat_bpb.startsector,1,
if(!sec) fat_cache_sectors[cache_index]))
{ {
DEBUGF( "cache_fat_sector() - Out of memory\n"); DEBUGF( "cache_fat_sector() - Could not read sector %d\n", secnum);
return NULL; return NULL;
} }
if(ata_read_sectors(secnum + fat_bpb.startsector,1,sec)) fat_cache[cache_index].inuse = true;
{
DEBUGF( "cache_fat_sector() - Could"
" not read sector %d\n",
secnum);
free(sec);
return NULL;
}
fat_cache[cache_index].ptr = sec;
fat_cache[cache_index].secnum = secnum; fat_cache[cache_index].secnum = secnum;
} }
return sec; return fat_cache_sectors[cache_index];
} }
#ifdef DISK_WRITE #ifdef DISK_WRITE