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- cleaned up cache code. reverted access policy to what it was before.

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- _FAT_fat_linkFreeClusterCleared must go thru cache aswell.
This commit is contained in:
Michael Wiedenbauer 2009-06-06 16:06:42 +00:00
parent 22f3dea64f
commit 806fc418e0
4 changed files with 93 additions and 220 deletions
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303
source/cache.c
View File

@ -101,151 +101,94 @@ void _FAT_cache_destructor (CACHE* cache) {
_FAT_mem_free (cache); _FAT_mem_free (cache);
} }
/*
static u32 accessCounter = 0; static u32 accessCounter = 0;
static u32 accessTime(){ static u32 accessTime(){
accessCounter++; accessCounter++;
return accessCounter; return accessCounter;
} }
/*
Retrieve a sector's page from the cache. If it is not found in the cache,
load it into the cache and return the page it was loaded to.
Return CACHE_FREE on error.
*/ */
static unsigned int _FAT_cache_getSector (CACHE* cache, sec_t sector, void* buffer) {
static CACHE_ENTRY* _FAT_cache_getPage(CACHE *cache,sec_t sector)
{
unsigned int i; unsigned int i;
CACHE_ENTRY* cacheEntries = cache->cacheEntries; CACHE_ENTRY* cacheEntries = cache->cacheEntries;
unsigned int numberOfPages = cache->numberOfPages; unsigned int numberOfPages = cache->numberOfPages;
unsigned int sectorsPerPage = cache->sectorsPerPage; unsigned int sectorsPerPage = cache->sectorsPerPage;
bool foundFree = false;
unsigned int oldUsed = 0; unsigned int oldUsed = 0;
unsigned int oldAccess = cacheEntries[0].last_access; unsigned int oldAccess = UINT_MAX;
for (i = 0; i < numberOfPages ; i++) { for(i=0;i<numberOfPages;i++) {
if ( sector>=cacheEntries[i].sector && sector < cacheEntries[i].sector+cacheEntries[i].count) { if(sector>=cacheEntries[i].sector && sector<(cacheEntries[i].sector + cacheEntries[i].count)) {
cacheEntries[i].last_access = accessTime(); cacheEntries[i].last_access++;
memcpy(buffer, cacheEntries[i].cache + ((sector - cacheEntries[i].sector)*BYTES_PER_READ), BYTES_PER_READ); return &(cacheEntries[i]);
return true;
} }
// While searching for the desired sector, also search for the least recently used page
if ( (cacheEntries[i].sector == CACHE_FREE) || (cacheEntries[i].last_access < oldAccess) ) { if(foundFree==false && (cacheEntries[i].sector==CACHE_FREE || cacheEntries[i].last_access<oldAccess)) {
if(cacheEntries[i].sector==CACHE_FREE) foundFree = true;
oldUsed = i; oldUsed = i;
oldAccess = cacheEntries[i].last_access; oldAccess = cacheEntries[i].last_access;
} }
} }
if(foundFree==false && cacheEntries[oldUsed].dirty==true) {
// If it didn't, replace the least used cache page with the desired sector if(!_FAT_disc_writeSectors(cache->disc,cacheEntries[oldUsed].sector,cacheEntries[oldUsed].count,cacheEntries[oldUsed].cache)) return NULL;
if ((cacheEntries[oldUsed].sector != CACHE_FREE) && (cacheEntries[oldUsed].dirty == true)) {
// Write the page back to disc if it has been written to
if (!_FAT_disc_writeSectors (cache->disc, cacheEntries[oldUsed].sector, cacheEntries[oldUsed].count, cacheEntries[oldUsed].cache)) {
return false;
}
cacheEntries[oldUsed].dirty = false; cacheEntries[oldUsed].dirty = false;
} }
// Load the new sector into the cache if(!_FAT_disc_readSectors(cache->disc,sector,sectorsPerPage,cacheEntries[oldUsed].cache)) return NULL;
if (!_FAT_disc_readSectors (cache->disc, sector, sectorsPerPage, cacheEntries[oldUsed].cache)) {
return false;
}
cacheEntries[oldUsed].sector = sector; cacheEntries[oldUsed].sector = sector;
cacheEntries[oldUsed].count = sectorsPerPage; cacheEntries[oldUsed].count = sectorsPerPage;
// Increment the usage count, don't reset it cacheEntries[oldUsed].last_access++;
// This creates a paging policy of least recently used PAGE, not sector
cacheEntries[oldUsed].last_access = accessTime(); return &(cacheEntries[oldUsed]);
memcpy(buffer, cacheEntries[oldUsed].cache, BYTES_PER_READ);
return true;
} }
bool _FAT_cache_getSectors (CACHE* cache, sec_t sector, sec_t numSectors, void* buffer) { bool _FAT_cache_readSectors(CACHE *cache,sec_t sector,sec_t numSectors,void *buffer)
unsigned int i; {
CACHE_ENTRY* cacheEntries = cache->cacheEntries;
unsigned int numberOfPages = cache->numberOfPages;
sec_t sec; sec_t sec;
sec_t secs_to_read; sec_t secs_to_read;
CACHE_ENTRY *entry;
uint8_t *dest = buffer;
unsigned int oldUsed = 0; while(numSectors>0) {
unsigned int oldAccess = cacheEntries[0].last_access; entry = _FAT_cache_getPage(cache,sector);
if(entry==NULL) return false;
while(numSectors>0) sec = sector - entry->sector;
{ secs_to_read = entry->count - sec;
i=0; if(secs_to_read>numSectors) secs_to_read = numSectors;
while (i < numberOfPages ) {
if ( sector>=cacheEntries[i].sector && sector < cacheEntries[i].sector+cacheEntries[i].count) {
sec=sector-cacheEntries[i].sector;
secs_to_read=cacheEntries[i].count-sec;
if(secs_to_read>numSectors)secs_to_read=numSectors;
memcpy(buffer,cacheEntries[i].cache + (sec*BYTES_PER_READ), secs_to_read*BYTES_PER_READ);
cacheEntries[i].last_access = accessTime();
numSectors=numSectors-secs_to_read;
if(numSectors==0) return true;
buffer+=secs_to_read*BYTES_PER_READ;
sector+=secs_to_read;
i=-1; // recheck all pages again
oldUsed = 0;
oldAccess = cacheEntries[0].last_access;
} memcpy(dest,entry->cache + (sec*BYTES_PER_READ),(secs_to_read*BYTES_PER_READ));
else // While searching for the desired sector, also search for the least recently used page
if ( (cacheEntries[i].sector == CACHE_FREE) || (cacheEntries[i].last_access < oldAccess) ) {
oldUsed = i;
oldAccess = cacheEntries[i].last_access;
}
i++;
}
// If it didn't, replace the least recently used cache page with the desired sector
if ((cacheEntries[oldUsed].sector != CACHE_FREE) && (cacheEntries[oldUsed].dirty == true)) {
// Write the page back to disc if it has been written to
if (!_FAT_disc_writeSectors (cache->disc, cacheEntries[oldUsed].sector, cacheEntries[oldUsed].count, cacheEntries[oldUsed].cache)) {
return false;
}
cacheEntries[oldUsed].dirty = false;
}
cacheEntries[oldUsed].sector = sector; dest += (secs_to_read*BYTES_PER_READ);
cacheEntries[oldUsed].count = cache->sectorsPerPage; sector += secs_to_read;
numSectors -= secs_to_read;
if (!_FAT_disc_readSectors (cache->disc, sector, cacheEntries[oldUsed].count, cacheEntries[oldUsed].cache)) {
return false;
}
// Increment the usage count, don't reset it
// This creates a paging policy of least used PAGE, not sector
cacheEntries[oldUsed].last_access = accessTime();
sec=0;
secs_to_read=cacheEntries[oldUsed].count-sec;
if(secs_to_read>numSectors)secs_to_read=numSectors;
memcpy(buffer,cacheEntries[oldUsed].cache + (sec*BYTES_PER_READ), secs_to_read*BYTES_PER_READ);
numSectors=numSectors-secs_to_read;
if(numSectors==0) return true;
buffer+=secs_to_read*BYTES_PER_READ;
sector+=secs_to_read;
oldUsed = 0;
oldAccess = cacheEntries[0].last_access;
} }
return false;
return true;
} }
/* /*
Reads some data from a cache page, determined by the sector number Reads some data from a cache page, determined by the sector number
*/ */
bool _FAT_cache_readPartialSector (CACHE* cache, void* buffer, sec_t sector, unsigned int offset, size_t size) { bool _FAT_cache_readPartialSector (CACHE* cache, void* buffer, sec_t sector, unsigned int offset, size_t size)
void* sec; {
sec_t sec;
CACHE_ENTRY *entry;
if (offset + size > BYTES_PER_READ) return false;
entry = _FAT_cache_getPage(cache,sector);
if(entry==NULL) return false;
sec = sector - entry->sector;
memcpy(buffer,entry->cache + ((sec*BYTES_PER_READ) + offset),size);
if (offset + size > BYTES_PER_READ) {
return false;
}
sec = (void*) _FAT_mem_align ( BYTES_PER_READ );
if(sec == NULL) return false;
if(! _FAT_cache_getSector(cache, sector, sec) ) {
_FAT_mem_free(sec);
return false;
}
memcpy(buffer, sec + offset, size);
_FAT_mem_free(sec);
return true; return true;
} }
@ -265,35 +208,21 @@ bool _FAT_cache_readLittleEndianValue (CACHE* cache, uint32_t *value, sec_t sect
/* /*
Writes some data to a cache page, making sure it is loaded into memory first. Writes some data to a cache page, making sure it is loaded into memory first.
*/ */
bool _FAT_cache_writePartialSector (CACHE* cache, const void* buffer, sec_t sector, unsigned int offset, size_t size) { bool _FAT_cache_writePartialSector (CACHE* cache, const void* buffer, sec_t sector, unsigned int offset, size_t size)
unsigned int i; {
void* sec; sec_t sec;
CACHE_ENTRY* cacheEntries = cache->cacheEntries; CACHE_ENTRY *entry;
unsigned int numberOfPages = cache->numberOfPages;
if (offset + size > BYTES_PER_READ) { if (offset + size > BYTES_PER_READ) return false;
return false;
}
//To be sure sector is in cache entry = _FAT_cache_getPage(cache,sector);
sec = (void*) _FAT_mem_align ( BYTES_PER_READ ); if(entry==NULL) return false;
if(sec == NULL) return false;
if(! _FAT_cache_getSector(cache, sector, sec) ) {
_FAT_mem_free(sec);
return false;
}
_FAT_mem_free(sec);
//Find where sector is and write sec = sector - entry->sector;
for (i = 0; i < numberOfPages ; i++) { memcpy(entry->cache + ((sec*BYTES_PER_READ) + offset),buffer,size);
if ( sector>=cacheEntries[i].sector && sector < cacheEntries[i].sector+cacheEntries[i].count) {
cacheEntries[i].last_access = accessTime(); entry->dirty = true;
memcpy (cacheEntries[i].cache + ((sector-cacheEntries[i].sector)*BYTES_PER_READ) + offset, buffer, size); return true;
cache->cacheEntries[i].dirty = true;
return true;
}
}
return false;
} }
bool _FAT_cache_writeLittleEndianValue (CACHE* cache, const uint32_t value, sec_t sector, unsigned int offset, int size) { bool _FAT_cache_writeLittleEndianValue (CACHE* cache, const uint32_t value, sec_t sector, unsigned int offset, int size) {
@ -312,105 +241,49 @@ bool _FAT_cache_writeLittleEndianValue (CACHE* cache, const uint32_t value, sec_
/* /*
Writes some data to a cache page, zeroing out the page first Writes some data to a cache page, zeroing out the page first
*/ */
bool _FAT_cache_eraseWritePartialSector (CACHE* cache, const void* buffer, sec_t sector, unsigned int offset, size_t size) { bool _FAT_cache_eraseWritePartialSector (CACHE* cache, const void* buffer, sec_t sector, unsigned int offset, size_t size)
unsigned int i; {
void* sec; sec_t sec;
CACHE_ENTRY* cacheEntries = cache->cacheEntries; CACHE_ENTRY *entry;
unsigned int numberOfPages = cache->numberOfPages;
if (offset + size > BYTES_PER_READ) { if (offset + size > BYTES_PER_READ) return false;
return false;
}
//To be sure sector is in cache entry = _FAT_cache_getPage(cache,sector);
sec = (void*) _FAT_mem_align ( BYTES_PER_READ ); if(entry==NULL) return false;
if(sec == NULL) return false;
if(! _FAT_cache_getSector(cache, sector, sec) ) {
_FAT_mem_free(sec);
return false;
}
_FAT_mem_free(sec);
//Find where sector is and write sec = sector - entry->sector;
for (i = 0; i < numberOfPages ; i++) { memset(entry->cache + (sec*BYTES_PER_READ),0,BYTES_PER_READ);
if ( sector>=cacheEntries[i].sector && sector < cacheEntries[i].sector+cacheEntries[i].count) { memcpy(entry->cache + ((sec*BYTES_PER_READ) + offset),buffer,size);
cacheEntries[i].last_access = accessTime();
memset (cacheEntries[i].cache + ((sector-cacheEntries[i].sector)*BYTES_PER_READ), 0, BYTES_PER_READ); entry->dirty = true;
memcpy (cacheEntries[i].cache + ((sector-cacheEntries[i].sector)*BYTES_PER_READ) + offset, buffer, size); return true;
cache->cacheEntries[i].dirty = true;
return true;
}
}
return false;
} }
bool _FAT_cache_writeSectors (CACHE* cache, sec_t sector, sec_t numSectors, const void* buffer) { bool _FAT_cache_writeSectors (CACHE* cache, sec_t sector, sec_t numSectors, const void* buffer)
unsigned int i; {
CACHE_ENTRY* cacheEntries = cache->cacheEntries;
unsigned int numberOfPages = cache->numberOfPages;
sec_t sec; sec_t sec;
sec_t secs_to_write; sec_t secs_to_write;
CACHE_ENTRY* entry;
unsigned int oldUsed = 0; const uint8_t *src = buffer;
unsigned int oldAccess = cacheEntries[0].last_access;
while(numSectors>0) while(numSectors>0)
{ {
i=0; entry = _FAT_cache_getPage(cache,sector);
while (i < numberOfPages ) { if(entry==NULL) return false;
if ( (sector>=cacheEntries[i].sector && sector < cacheEntries[i].sector+cacheEntries[i].count) ||
(sector == cacheEntries[i].sector+cacheEntries[i].count && cacheEntries[i].count < cache->sectorsPerPage)) {
sec=sector-cacheEntries[i].sector;
secs_to_write=cache->sectorsPerPage-sec;
if(secs_to_write>numSectors)secs_to_write=numSectors;
memcpy(cacheEntries[i].cache + (sec*BYTES_PER_READ), buffer, secs_to_write*BYTES_PER_READ);
cacheEntries[i].last_access = accessTime();
cacheEntries[i].dirty = true;
cacheEntries[i].count = sec + secs_to_write;
numSectors=numSectors-secs_to_write;
if(numSectors==0) return true;
buffer+=secs_to_write*BYTES_PER_READ;
sector+=secs_to_write;
i=-1; // recheck all pages again
oldUsed = 0;
oldAccess = cacheEntries[0].last_access;
} sec = sector - entry->sector;
else // While searching for the desired sector, also search for the least recently used page secs_to_write = entry->count - sec;
if ( (cacheEntries[i].sector == CACHE_FREE) || (cacheEntries[i].last_access < oldAccess) ) { if(secs_to_write>numSectors) secs_to_write = numSectors;
oldUsed = i;
oldAccess = cacheEntries[i].last_access;
}
i++;
}
// If it didn't, replace the least recently used cache page with the desired sector
if ((cacheEntries[oldUsed].sector != CACHE_FREE) && (cacheEntries[oldUsed].dirty == true)) {
// Write the page back to disc if it has been written to
if (!_FAT_disc_writeSectors (cache->disc, cacheEntries[oldUsed].sector, cacheEntries[oldUsed].count, cacheEntries[oldUsed].cache)) {
return false;
}
cacheEntries[oldUsed].dirty = false;
}
secs_to_write=numSectors; memcpy(entry->cache + (sec*BYTES_PER_READ),src,(secs_to_write*BYTES_PER_READ));
if(secs_to_write>cache->sectorsPerPage)secs_to_write=cache->sectorsPerPage;
cacheEntries[oldUsed].sector = sector;
cacheEntries[oldUsed].count = secs_to_write;
memcpy(cacheEntries[oldUsed].cache, buffer, secs_to_write*BYTES_PER_READ); src += (secs_to_write*BYTES_PER_READ);
buffer+=secs_to_write*BYTES_PER_READ; sector += secs_to_write;
sector+=secs_to_write; numSectors -= secs_to_write;
numSectors=numSectors-secs_to_write;
// Increment the usage count, don't reset it entry->dirty = true;
// This creates a paging policy of least used PAGE, not sector
cacheEntries[oldUsed].last_access = accessTime();
cacheEntries[oldUsed].dirty = true;
if(numSectors==0) return true;
oldUsed = 0;
oldAccess = cacheEntries[0].last_access;
} }
return false; return true;
} }
/* /*

2
source/cache.h
View File

@ -93,7 +93,7 @@ bool _FAT_cache_eraseWritePartialSector (CACHE* cache, const void* buffer, sec_t
/* /*
Read several sectors from the cache Read several sectors from the cache
*/ */
bool _FAT_cache_getSectors (CACHE* cache, sec_t sector, sec_t numSectors, void* buffer); bool _FAT_cache_readSectors (CACHE* cache, sec_t sector, sec_t numSectors, void* buffer);
/* /*
Read a full sector from the cache Read a full sector from the cache

6
source/fatfile.c
View File

@ -411,7 +411,7 @@ ssize_t _FAT_read_r (struct _reent *r, int fd, char *ptr, size_t len) {
} }
if ((tempVar > 0) && flagNoError) { if ((tempVar > 0) && flagNoError) {
if (! _FAT_cache_getSectors (cache, _FAT_fat_clusterToSector (partition, position.cluster) + position.sector, if (! _FAT_cache_readSectors (cache, _FAT_fat_clusterToSector (partition, position.cluster) + position.sector,
tempVar, ptr)) tempVar, ptr))
{ {
flagNoError = false; flagNoError = false;
@ -454,7 +454,7 @@ ssize_t _FAT_read_r (struct _reent *r, int fd, char *ptr, size_t len) {
#endif #endif
(chunkSize + partition->bytesPerCluster <= remain)); (chunkSize + partition->bytesPerCluster <= remain));
if (!_FAT_cache_getSectors (cache, _FAT_fat_clusterToSector (partition, position.cluster), if (!_FAT_cache_readSectors (cache, _FAT_fat_clusterToSector (partition, position.cluster),
chunkSize / BYTES_PER_READ, ptr)) chunkSize / BYTES_PER_READ, ptr))
{ {
flagNoError = false; flagNoError = false;
@ -480,7 +480,7 @@ ssize_t _FAT_read_r (struct _reent *r, int fd, char *ptr, size_t len) {
// Read remaining sectors // Read remaining sectors
tempVar = remain / BYTES_PER_READ; // Number of sectors left tempVar = remain / BYTES_PER_READ; // Number of sectors left
if ((tempVar > 0) && flagNoError) { if ((tempVar > 0) && flagNoError) {
if (!_FAT_cache_getSectors (cache, _FAT_fat_clusterToSector (partition, position.cluster), if (!_FAT_cache_readSectors (cache, _FAT_fat_clusterToSector (partition, position.cluster),
tempVar, ptr)) tempVar, ptr))
{ {
flagNoError = false; flagNoError = false;

2
source/file_allocation_table.c
View File

@ -278,7 +278,7 @@ uint32_t _FAT_fat_linkFreeClusterCleared (PARTITION* partition, uint32_t cluster
// Clear all the sectors within the cluster // Clear all the sectors within the cluster
memset (emptySector, 0, BYTES_PER_READ); memset (emptySector, 0, BYTES_PER_READ);
for (i = 0; i < partition->sectorsPerCluster; i++) { for (i = 0; i < partition->sectorsPerCluster; i++) {
_FAT_disc_writeSectors (partition->disc, _FAT_cache_writeSectors (partition->disc,
_FAT_fat_clusterToSector (partition, newCluster) + i, _FAT_fat_clusterToSector (partition, newCluster) + i,
1, emptySector); 1, emptySector);
} }