gint/src/fs/fygue/fat/flash/cmap.c

/*
** fygue/flash/cmap	- flash cluster map
*/
#include <stdlib.h>
#include <string.h>

#include <gint/defs/attributes.h>

#include "flash.h"

//---
// Internals
//---

/* fygue_flash_cmap_update()  - update the cluster redirection map
 *
 * notes
 *   Since Casio uses its own methods to handle flash sector and cluster we
 *   need to rebuild the translation page between "logical cluster"
 *   (lcluster) and "flash cluster" (fcluster).
 *
 *   Casio does not erase systematically each sector when they become
 *   outdated, instead, they use a `version` mechanism which indicates
 *   "when"  the cluster has been created to keep the more recent one.
 *
 * return
 *   -1   if the provided information is not valid
 *    0   if the provided lcluster exists and has not been updated
 *    1   if the provided lcluster has been created
 *    2   if the provided lcluster exists and has been updated */
static int fygue_flash_cmap_update(
	struct fygue_flash_cmap *cmap,
	struct fygue_flash_cluster *fcluster
) {
	struct fygue_flash_cmap_entry *entry;
	int i;

	if (cmap == NULL || fcluster == NULL)
		return -1;
	if (fcluster->kind != 0x11)
		return -1;
	if (cmap->lcluster_id_max > fcluster->lcluster_id)
	{
		if (
			cmap->lcluster[fcluster->lcluster_id].version != 0xffffffff &&
			cmap->lcluster[fcluster->lcluster_id].version
				< fcluster->version
		) {
			return 1;
		}
	} else {
		cmap->lcluster = reallocarray(
			cmap->lcluster,
			(fcluster->lcluster_id + 1),
			sizeof(struct fygue_flash_cmap_entry)
		);
		for (
			i = cmap->lcluster_id_max ;
			i < fcluster->lcluster_id ;
			i++
		) {
			cmap->lcluster[i].fcluster_id	   = 0xffff;
			cmap->lcluster[i].fcluster_id_bfile = 0xffff;
			cmap->lcluster[i].fcluster_addr	 = 0xffffffff;
			cmap->lcluster[i].version		   = 0xffffffff;
		}
		cmap->lcluster_id_max = fcluster->lcluster_id + 1;
	}
	entry = &(cmap->lcluster[fcluster->lcluster_id]);
	entry->fcluster_id	   = fcluster->fcluster_id;
	entry->fcluster_id_bfile = fcluster->fcluster_id_bfile;
	entry->fcluster_addr	 = fcluster->data_addr;
	entry->version		   = fcluster->version;
	return 0;
}

/* _fygue_flash_cmap_discover(): discover flash information */
static int _fygue_flash_cmap_discover(
	struct fygue_flash *flash,
	struct fygue_flash_cmap *cmap
) {
	struct fygue_flash_cluster fcluster;
	int fsector_id;
	int fsector;
	int rc;
	int j;

	fsector_id = 0;
	for (
		fsector = 0 ;
		fsector < flash->geometry.fsector_count ;
		fsector++
	) {
		if (fsector != 0)
			fsector_id += flash->geometry.fcluster_per_fsector;
		if (fygue_flash_cluster_get(flash, &fcluster, fsector_id) != 0)
			continue;
		if (fcluster.kind != 0x22)
			continue;
		for (j = 1 ; j < (flash->geometry.fcluster_per_fsector - 1) ; j++)
		{
			rc = fygue_flash_cluster_get(flash, &fcluster, fsector_id + j);
			if (rc != 0)
				continue;
			if (fcluster.kind != 0x11)
				continue;
			fygue_flash_cmap_update(cmap, &fcluster);
		}
	}
	return 0;
}

//---
// Public
//---

/* fygue_flash_cmap_lsector_get_addr() - get logical sector address */
int fygue_flash_cmap_lsector_get_addr(
	struct fygue_flash *flash,
	struct fygue_flash_cmap *cmap,
	uintptr_t *sector,
	uint16_t lsector_id
) {
	uintptr_t fsector_addr;
	uint16_t lcluster_id;

	if (flash == NULL  || sector == NULL || cmap == NULL)
		return -1;
	if (cmap->lcluster == NULL)
		return -1;
	lcluster_id = lsector_id / 8;
	if (
		cmap->lcluster_id_max < lcluster_id ||
		cmap->lcluster[lcluster_id].fcluster_id == 0xffff
	) {
		return -2;
	}
	fsector_addr  = cmap->lcluster[lcluster_id].fcluster_addr;
	fsector_addr += (lsector_id % 8) * 512;
	*sector = fsector_addr;
	return 0;
}

/* fygue_flash_cmap_init() - initialize fcluster translation
 *
 * notes:
 *   Casio has its own flash handling layer that hooks Fugue primitives to
 *   control how/when the hardware will perform IO operations
 *   (read,write,erase). This because the Flash used in recent devices use
 *   sector of 128ko which implies, when you want to update one byte of
 *   memory, you need to:
 *    - copy the whole page in RAM
 *    - perform the modification
 *    - write the new page information
 *
 *   todo: docs
 *
 * returns:
 *   -1 if the sector 0 is not found
 *    0 success */
int fygue_flash_cmap_initialize(
	struct fygue_flash *flash,
	struct fygue_flash_cmap *cmap
) {
	if (flash == NULL || cmap == NULL)
		return -1;
	memset(cmap, 0x00, sizeof(struct fygue_flash_cmap));
	if (_fygue_flash_cmap_discover(flash, cmap) != 0)
		return -1;
	if (cmap->lcluster == NULL)
		return -2;
	if (cmap->lcluster[0].fcluster_id == 0xffff)
		return -3;
	return 0;
}

/* fygue_flash_cmap_sync() - sync the fcluster redirection map */
int fygue_flash_cmap_sync(
	struct fygue_flash *flash,
	struct fygue_flash_cmap *cmap
) {
	if (flash == NULL || cmap == NULL)
		return -1;
	for (int i = 0 ; i < cmap->lcluster_id_max ; i++)
		cmap->lcluster[i].version = 0xffffffff;
	if (_fygue_flash_cmap_discover(flash, cmap) != 0)
		return -2;
	return 0;
}