fs_flash.c

支持nvram盘

/*
 * FLASH low-level FS driver
 */

/*** BeginHeader fs_block_init */

/* size of the block */
#ifndef FS_BLOCK_SIZE
	#define FS_BLOCK_SIZE 4096L
#endif

#ifndef FS_PHYSICAL_OFFSET
	#define FS_PHYSICAL_OFFSET	0x40000
#endif

#define FS_SECTOR_SIZE FD->sector_size
#define FS_SECTORS_PER_BLOCK (((int)FS_BLOCK_SIZE)/FS_SECTOR_SIZE)

#define FS_TEMPBUF_SIZE	1024
#define FS_BUFS_PER_BLOCK	(((int)FS_BLOCK_SIZE)/FS_TEMPBUF_SIZE)

int fs_block_init(long baseaddress, int num_blocks);
int fs_block_read(int block_num, int offset, char *buf, int len);
int fs_block_write(int block_num, char *buf, int len);
int fs_block_move(long to, int block, int offset, int len);
char *fs_block_pushxpc(int block_num);

#use "flash.lib"

extern FlashDescriptor *FD;

/*** EndHeader */

FlashDescriptor FlashDescrip;
FlashDescriptor *FD;

long fs_block_baseaddress;
int fs_block_num_blocks;
int fs_sector_offset;

/*
 * Initilize the low-level driver, starting at baseaddress (relative to start of flash),
 * with num_blocks blocks of size FS_BLOCK_SIZE
 */
nodebug
int fs_block_init(long baseaddress, int num_blocks)
{
	/* sanity check these values? */

	FD = &FlashDescrip;
	
#ifdef FS_DEBUG_FLASH
	printf("Initilizing FLASH fs driver\n");
#endif
	fs_block_baseaddress = baseaddress;
	fs_block_num_blocks = num_blocks;

	if(flash_init(FD,0xC2,NULL)) {
#ifdef FS_DEBUG_FLASH
		printf("Error initilizing 2nd flash!\n");
#endif
		return 1;
	}
	
	/* verify the 256 byte sector boundary */
	fs_sector_offset = (int)(baseaddress / FS_SECTOR_SIZE); /* offset into flash, in sectors */
	if(((long)fs_sector_offset)*FS_SECTOR_SIZE != baseaddress) {
#ifdef FS_DEBUG_FLASH
		printf("Not on sector boundary!\n");
#endif
		return 1; /* not on FS_SECTOR_SIZE boundary */
	}

	if((FD->number_sectors - fs_sector_offset) < (num_blocks * FS_SECTORS_PER_BLOCK)) {
#ifdef FS_DEBUG_FLASH
		printf("Not enough sectors in flash!\n");
#endif
		return 1;
	}

#ifdef FS_DEBUG_FLASH
	printf("Flash sector size == %d\n",FS_SECTOR_SIZE);
#endif
			
	return 0;
}

/*
 * read from block_num/offset into buf/len
 * offset == number of bytes from beginning of the block
 */
nodebug
int fs_block_read(int block_num, int offset, char *buf, int len)
{
	auto int sector, temp;

	/*
	 * check the checksum here
	 *
	 * crc == block[16] & block[17]
	 * first byte == block[2] & block[3]
	 * last byte == block[4] & block[5]
	 */

	sector = FS_SECTORS_PER_BLOCK * block_num;

#ifdef FS_DEBUG_FLASH
	if(offset != 0)
		printf("FLASH> Reading from block %d, offset %d, len %d\n",block_num,offset,len);
#endif
	
	/* find the beginning of where to read. */
	while(offset > FS_SECTOR_SIZE) {
		offset -= FS_SECTOR_SIZE;
		sector++;
	}

	/* first partial sector */
	temp = FS_SECTOR_SIZE - offset;
	if(temp > len)
		temp = len;
#ifdef FS_DEBUG_FLASH
	if(offset != 0)
		printf("FLASH> !!!! Reading sector %d, offset %d, len %d\n",sector,offset,temp);
#endif
	if(flash_read(FD,sector,offset,paddr(buf),temp)) {
#ifdef FS_DEBUG_FLASH
		printf("FLASH> Error in read (1)!\n");
#endif
		return 1;
	}
	sector++;
	offset = temp;

	/* remaining sectors */
	while(offset < len) {
		if((len - offset) >= FS_SECTOR_SIZE) {
			temp = FS_SECTOR_SIZE;
		} else {
			temp = len - offset;
		}
#ifdef FS_DEBUG_FLASH
		printf("FLASH> Reading sector %d, len %d\n",sector,temp);
#endif
		if(flash_read(FD,sector,0,paddr(buf + offset),temp)) {
#ifdef FS_DEBUG_FLASH
			printf("FLASH> Error in read (2)!\n");
#endif
			return 1;
		}
		sector++;
		offset += temp;
	}
	
	return 0;
}

/*
 * Replacement for xmem2xmem() - move a block of data from flash to xmem
 */
nodebug
int fs_block_move(long to, int block, int offset, int len)
{
	auto int sector, temp;
	sector = FS_SECTORS_PER_BLOCK * block;

#ifdef FS_DEBUG_FLASH
	printf("FLASH> Moving from block %d, offset %d\n",block,offset);
#endif
	
	/* find the beginning of where to read. */
	while(offset > FS_SECTOR_SIZE) {
		offset -= FS_SECTOR_SIZE;
		sector++;
	}

	/* first partial sector */
	temp = FS_SECTOR_SIZE - offset;
	if(temp > len)
		temp = len;
	if(flash_read(FD,sector,offset,to,temp)) {
#ifdef FS_DEBUG_FLASH
		printf("FLASH> Error in move (1)!\n");
#endif
		return 1;
	}
	sector++;
	offset = temp;

	/* remaining sectors */
	while(offset < len) {
		if((offset - len) >= FS_SECTOR_SIZE) {
			temp = FS_SECTOR_SIZE;
		} else {
			temp = len;
		}
		if(flash_read(FD,sector,0,to+offset,temp)) {
#ifdef FS_DEBUG_FLASH
			printf("FLASH> Error in move (2)!\n");
#endif
			return 1;
		}
		sector++;
		offset += temp;
	}
	
	return 0;
}

/*
 * Write the given block (described in buf/len),
 * to block number block_num (always start at offset=0 in the block)
 */
nodebug
int fs_block_write(int block_num, char *buf, int len)
{
	auto int sector, offset, temp;
	sector = FS_SECTORS_PER_BLOCK * block_num;

#ifdef FS_DEBUG_FLASH
	printf("FLASH> Writing to block %d, len %d (first sector = %d)\n",block_num,len,sector);
#endif
	
	offset = 0;
	while(offset < len) {
		if((len - offset) > FS_SECTOR_SIZE) {
			temp = FS_SECTOR_SIZE;
		} else {
			temp = len - offset;
		}
#ifdef FS_DEBUG_FLASH
		printf("FLASH> Writing sector %d\n",sector);
#endif
		if(flash_writesector(FD, sector, paddr(buf + offset))) {
#ifdef FS_DEBUG_FLASH
			printf("FLASH> Error writing sector!\n");
#endif
			return 1;
		}
		sector++;
		offset += temp;
	}

	return 0;
}

/*
 *	write a sector out. (buf is a physical address, probably in xmem)
 */
nodebug
int fs_writesector(int sector, long buf, int len)
{
#ifdef FS_DEBUG_FLASH
	printf("FLASH> Writing sector %d\n",sector);
#endif

	if(flash_writesector(FD, sector, buf)) {
#ifdef FS_DEBUG_FLASH
		printf("Error writing sector!\n");
#endif
		return 1;
   }
   return 0;
}

/*
 * set the XPC such that the given block is in the window, and
 * return a pointer to the beginning of the block, as accessable
 * through the xpc window.
 */
nodebug
root char *fs_block_pushxpc(int block_num)
{
	return flash_sector2xwindow(FD, block_num * FS_SECTORS_PER_BLOCK);
}