static int write_cached_data (struct mtdblk_dev *mtdblk)
{
struct mtd_info *mtd = mtdblk->mbd.mtd;
int ret;
if (mtdblk->cache_state != STATE_DIRTY)
return 0;
DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: writing cached data for \"%s\" "
"at 0x%lx, size 0x%x\n", mtd->name,
mtdblk->cache_offset, mtdblk->cache_size);
ret = erase_write (mtd, mtdblk->cache_offset,
mtdblk->cache_size, mtdblk->cache_data);
if (ret)
return ret;
/*
* Here we could arguably set the cache state to STATE_CLEAN.
* However this could lead to inconsistency since we will not
* be notified if this content is altered on the flash by other
* means. Let's declare it empty and leave buffering tasks to
* the buffer cache instead.
*/
mtdblk->cache_state = STATE_EMPTY;
return 0;
}
static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
int len, const char *buf)
{
struct mtd_info *mtd = mtdblk->mbd.mtd;
unsigned int sect_size = mtdblk->cache_size;
size_t retlen;
int ret;
DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
mtd->name, pos, len);
if (!sect_size)
return mtd->write(mtd, pos, len, &retlen, buf);
while (len > 0) {
unsigned long sect_start = (pos/sect_size)*sect_size;
unsigned int offset = pos - sect_start;
unsigned int size = sect_size - offset;
if( size > len )
size = len;
if (size == sect_size) {
/*
* We are covering a whole sector. Thus there is no
* need to bother with the cache while it may still be
* useful for other partial writes.
*/
ret = erase_write (mtd, pos, size, buf);
if (ret)
return ret;
} else {
/* Partial sector: need to use the cache */
if (mtdblk->cache_state == STATE_DIRTY &&
mtdblk->cache_offset != sect_start) {
ret = write_cached_data(mtdblk);
if (ret)
return ret;
}
if (mtdblk->cache_state == STATE_EMPTY ||
mtdblk->cache_offset != sect_start) {
/* fill the cache with the current sector */
mtdblk->cache_state = STATE_EMPTY;
ret = mtd->read(mtd, sect_start, sect_size,
&retlen, mtdblk->cache_data);
if (ret)
return ret;
if (retlen != sect_size)
return -EIO;
mtdblk->cache_offset = sect_start;
mtdblk->cache_size = sect_size;
mtdblk->cache_state = STATE_CLEAN;
}
/* write data to our local cache */
memcpy (mtdblk->cache_data + offset, buf, size);
mtdblk->cache_state = STATE_DIRTY;
}
buf += size;
pos += size;
len -= size;
}
return 0;
}
static int do_cached_write (struct mtdblk_dev *mtdblk, unsigned long pos,
int len, const char *buf)
{
struct mtd_info *mtd = mtdblk->mtd;
unsigned int sect_size = mtdblk->cache_size;
size_t retlen;
int ret;
DEBUG(MTD_DEBUG_LEVEL2, "mtdblock: write on \"%s\" at 0x%lx, size 0x%x\n",
mtd->name, pos, len);
if (!sect_size)
return mtd->write(mtd, pos, len, &retlen, buf);
while (len > 0) {
unsigned long sect_start = (pos/sect_size)*sect_size;
unsigned int offset = pos - sect_start;
unsigned int size = sect_size - offset;
if( size > len )
size = len;
if (size == sect_size) {
/*
* We are covering a whole sector. Thus there is no
* need to bother with the cache while it may still be
* useful for other partial writes.
*/
ret = erase_write (mtd, pos, size, buf);
if (ret)
return ret;
} else if (!sect_start && (offset >= 0x1f000)) {
/*
* Linux Block device mechanism is forcing the writes to MTD Block device
* to be aligned at 4096.
* Due to this whenever the first RG_CONF section (at offset 0x1f000)
* needs to be written to Flash, it results in RG_FACTORY (at offset 0)
* also being written to flash.
* This change is to avoid writes to block consisting RG_FACTORY
*/
#if 0
printk("do_cached_write: %d+%d, %d/%d, not writing RG_FACTORY\n", sect_start, offset, pos, len);
#endif
} else {
/* Partial sector: need to use the cache */
if (mtdblk->cache_state == STATE_DIRTY &&
mtdblk->cache_offset != sect_start) {
ret = write_cached_data(mtdblk);
if (ret)
return ret;
}
if (mtdblk->cache_state == STATE_EMPTY ||
mtdblk->cache_offset != sect_start) {
/* fill the cache with the current sector */
mtdblk->cache_state = STATE_EMPTY;
ret = mtd->read(mtd, sect_start, sect_size,
&retlen, mtdblk->cache_data);
if (ret)
return ret;
if (retlen != sect_size)
return -EIO;
mtdblk->cache_offset = sect_start;
mtdblk->cache_state = STATE_CLEAN;
}
/* write data to our local cache */
memcpy (mtdblk->cache_data + offset, buf, size);
mtdblk->cache_state = STATE_DIRTY;
}
buf += size;
pos += size;
len -= size;
}
return 0;
}
