fwh_lock.h
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef FWH_LOCK_H
#define FWH_LOCK_H
enum fwh_lock_state {
FWH_UNLOCKED = 0,
FWH_DENY_WRITE = 1,
FWH_IMMUTABLE = 2,
FWH_DENY_READ = 4,
};
struct fwh_xxlock_thunk {
enum fwh_lock_state val;
flstate_t state;
};
#define FWH_XXLOCK_ONEBLOCK_LOCK ((struct fwh_xxlock_thunk){ FWH_DENY_WRITE, FL_LOCKING})
#define FWH_XXLOCK_ONEBLOCK_UNLOCK ((struct fwh_xxlock_thunk){ FWH_UNLOCKED, FL_UNLOCKING})
/*
* This locking/unlock is specific to firmware hub parts. Only one
* is known that supports the Intel command set. Firmware
* hub parts cannot be interleaved as they are on the LPC bus
* so this code has not been tested with interleaved chips,
* and will likely fail in that context.
*/
static int fwh_xxlock_oneblock(struct map_info *map, struct flchip *chip,
unsigned long adr, int len, void *thunk)
{
struct cfi_private *cfi = map->fldrv_priv;
struct fwh_xxlock_thunk *xxlt = (struct fwh_xxlock_thunk *)thunk;
int ret;
/* Refuse the operation if the we cannot look behind the chip */
if (chip->start < 0x400000) {
pr_debug( "MTD %s(): chip->start: %lx wanted >= 0x400000\n",
__func__, chip->start );
return -EIO;
}
/*
* lock block registers:
* - on 64k boundariesand
* - bit 1 set high
* - block lock registers are 4MiB lower - overflow subtract (danger)
*
* The address manipulation is first done on the logical address
* which is 0 at the start of the chip, and then the offset of
* the individual chip is addted to it. Any other order a weird
* map offset could cause problems.
*/
adr = (adr & ~0xffffUL) | 0x2;
adr += chip->start - 0x400000;
/*
* This is easy because these are writes to registers and not writes
* to flash memory - that means that we don't have to check status
* and timeout.
*/
mutex_lock(&chip->mutex);
ret = get_chip(map, chip, adr, FL_LOCKING);
if (ret) {
mutex_unlock(&chip->mutex);
return ret;
}
chip->oldstate = chip->state;
chip->state = xxlt->state;
map_write(map, CMD(xxlt->val), adr);
/* Done and happy. */
chip->state = chip->oldstate;
put_chip(map, chip, adr);
mutex_unlock(&chip->mutex);
return 0;
}
static int fwh_lock_varsize(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
int ret;
ret = cfi_varsize_frob(mtd, fwh_xxlock_oneblock, ofs, len,
(void *)&FWH_XXLOCK_ONEBLOCK_LOCK);
return ret;
}
static int fwh_unlock_varsize(struct mtd_info *mtd, loff_t ofs, uint64_t len)
{
int ret;
ret = cfi_varsize_frob(mtd, fwh_xxlock_oneblock, ofs, len,
(void *)&FWH_XXLOCK_ONEBLOCK_UNLOCK);
return ret;
}
static void fixup_use_fwh_lock(struct mtd_info *mtd)
{
printk(KERN_NOTICE "using fwh lock/unlock method\n");
/* Setup for the chips with the fwh lock method */
mtd->_lock = fwh_lock_varsize;
mtd->_unlock = fwh_unlock_varsize;
}
#endif /* FWH_LOCK_H */