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, mode: FL_LOCKING);
63 if (ret) {
64 mutex_unlock(lock: &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(lock: &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, frob: fwh_xxlock_oneblock, ofs, len,
85 thunk: (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, frob: fwh_xxlock_oneblock, ofs, len,
96 thunk: (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

source code of linux/drivers/mtd/chips/fwh_lock.h