logical.c File Reference

#include <flash.h>
#include <string.h>
#include <memory.h>

Functions
devcall	logicalRead (struct flash *flash, uchar *buffer, ulong block)
devcall	logicalWrite (struct flash *flash, uchar *buffer, ulong block)
struct flash_block	logicalMap (struct flash *flash, ulong block)

Detailed Description

This provides a more proper interface between driver calls and the physical layer of flash. It is possible to split the entire flash device into logical blocks of n bytes and this file provides the mappings from physical address to logical block.

Function Documentation

struct flash_block logicalMap	(	struct flash *	flash,
		ulong	block
	)

Given a flash structure and a logical block, this method will discover the physical erase-block (and region) of that block. Once the physical mapping is found it will return an incomplete flash_block structure with the region and erase-block filled in.

Parameters

*flash	flash device to discover on.
block	logical block to find.

Returns

flash_block structure with start_pos and size

devcall logicalRead	(	struct flash *	flash,
		uchar *	buffer,
		ulong	block
	)

With a logical block address, read in the contents of the block into the buffer. This will check if the erase-block is already in memory and if so simply read from the cached copy, if it is not read it into memory and read the specified block. If there is no more room in memory to store an erase-block it will automatically write to the oldest erase-block to flash and read in the requested block.

Parameters

*flash	flash device to read on.
*buffer	buffer to read into.
block	block to read on device.

Returns

number of bytes read or SYSERR on failure

devcall logicalWrite	(	struct flash *	flash,
		uchar *	buffer,
		ulong	block
	)

Translate a logical block number to a physical portion of flash and write the data. This function will check if the erase-block is in memory and store changes to the memory location to prevent too many writes to flash. If no more room is available it will evict the oldest erase-block and write it to flash.

Parameters

*flash	flash device to write to
*buffer	buffer holding new data
block	block to write to device

Returns

number of bytes written or SYSERR on failure