1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef FWH_LOCK_H
3#define FWH_LOCK_H
4
5
6enum fwh_lock_state {
7        FWH_UNLOCKED   = 0,
8	FWH_DENY_WRITE = 1,
9	FWH_IMMUTABLE  = 2,
10	FWH_DENY_READ  = 4,
11};
12
13struct fwh_xxlock_thunk {
14	enum fwh_lock_state val;
15	flstate_t state;
16};
17
18
19#define FWH_XXLOCK_ONEBLOCK_LOCK   ((struct fwh_xxlock_thunk){ FWH_DENY_WRITE, FL_LOCKING})
20#define FWH_XXLOCK_ONEBLOCK_UNLOCK ((struct fwh_xxlock_thunk){ FWH_UNLOCKED,   FL_UNLOCKING})
21
22/*
23 * This locking/unlock is specific to firmware hub parts.  Only one
24 * is known that supports the Intel command set.    Firmware
25 * hub parts cannot be interleaved as they are on the LPC bus
26 * so this code has not been tested with interleaved chips,
27 * and will likely fail in that context.
28 */
29static int fwh_xxlock_oneblock(struct map_info *map, struct flchip *chip,
30	unsigned long adr, int len, void *thunk)
31{
32	struct cfi_private *cfi = map->fldrv_priv;
33	struct fwh_xxlock_thunk *xxlt = (struct fwh_xxlock_thunk *)thunk;
34	int ret;
35
36	/* Refuse the operation if the we cannot look behind the chip */
37	if (chip->start < 0x400000) {
38		pr_debug( "MTD %s(): chip->start: %lx wanted >= 0x400000\n",
39			__func__, chip->start );
40		return -EIO;
41	}
42	/*
43	 * lock block registers:
44	 * - on 64k boundariesand
45	 * - bit 1 set high
46	 * - block lock registers are 4MiB lower - overflow subtract (danger)
47	 *
48	 * The address manipulation is first done on the logical address
49	 * which is 0 at the start of the chip, and then the offset of
50	 * the individual chip is addted to it.  Any other order a weird
51	 * map offset could cause problems.
52	 */
53	adr = (adr & ~0xffffUL) | 0x2;
54	adr += chip->start - 0x400000;
55
56	/*
57	 * This is easy because these are writes to registers and not writes
58	 * to flash memory - that means that we don't have to check status
59	 * and timeout.
60	 */
61	mutex_lock(&chip->mutex);
62	ret = get_chip(map, chip, adr, FL_LOCKING);
63	if (ret) {
64		mutex_unlock(&chip->mutex);
65		return ret;
66	}
67
68	chip->oldstate = chip->state;
69	chip->state = xxlt->state;
70	map_write(map, CMD(xxlt->val), adr);
71
72	/* Done and happy. */
73	chip->state = chip->oldstate;
74	put_chip(map, chip, adr);
75	mutex_unlock(&chip->mutex);
76	return 0;
77}
78
79
80static int fwh_lock_varsize(struct mtd_info *mtd, loff_t ofs, uint64_t len)
81{
82	int ret;
83
84	ret = cfi_varsize_frob(mtd, fwh_xxlock_oneblock, ofs, len,
85		(void *)&FWH_XXLOCK_ONEBLOCK_LOCK);
86
87	return ret;
88}
89
90
91static int fwh_unlock_varsize(struct mtd_info *mtd, loff_t ofs, uint64_t len)
92{
93	int ret;
94
95	ret = cfi_varsize_frob(mtd, fwh_xxlock_oneblock, ofs, len,
96		(void *)&FWH_XXLOCK_ONEBLOCK_UNLOCK);
97
98	return ret;
99}
100
101static void fixup_use_fwh_lock(struct mtd_info *mtd)
102{
103	printk(KERN_NOTICE "using fwh lock/unlock method\n");
104	/* Setup for the chips with the fwh lock method */
105	mtd->_lock   = fwh_lock_varsize;
106	mtd->_unlock = fwh_unlock_varsize;
107}
108#endif /* FWH_LOCK_H */
109