xref: /openbmc/linux/drivers/mtd/chips/fwh_lock.h (revision 9cfc5c90)
1 #ifndef FWH_LOCK_H
2 #define FWH_LOCK_H
3 
4 
5 enum fwh_lock_state {
6         FWH_UNLOCKED   = 0,
7 	FWH_DENY_WRITE = 1,
8 	FWH_IMMUTABLE  = 2,
9 	FWH_DENY_READ  = 4,
10 };
11 
12 struct fwh_xxlock_thunk {
13 	enum fwh_lock_state val;
14 	flstate_t state;
15 };
16 
17 
18 #define FWH_XXLOCK_ONEBLOCK_LOCK   ((struct fwh_xxlock_thunk){ FWH_DENY_WRITE, FL_LOCKING})
19 #define FWH_XXLOCK_ONEBLOCK_UNLOCK ((struct fwh_xxlock_thunk){ FWH_UNLOCKED,   FL_UNLOCKING})
20 
21 /*
22  * This locking/unlock is specific to firmware hub parts.  Only one
23  * is known that supports the Intel command set.    Firmware
24  * hub parts cannot be interleaved as they are on the LPC bus
25  * so this code has not been tested with interleaved chips,
26  * and will likely fail in that context.
27  */
28 static int fwh_xxlock_oneblock(struct map_info *map, struct flchip *chip,
29 	unsigned long adr, int len, void *thunk)
30 {
31 	struct cfi_private *cfi = map->fldrv_priv;
32 	struct fwh_xxlock_thunk *xxlt = (struct fwh_xxlock_thunk *)thunk;
33 	int ret;
34 
35 	/* Refuse the operation if the we cannot look behind the chip */
36 	if (chip->start < 0x400000) {
37 		pr_debug( "MTD %s(): chip->start: %lx wanted >= 0x400000\n",
38 			__func__, chip->start );
39 		return -EIO;
40 	}
41 	/*
42 	 * lock block registers:
43 	 * - on 64k boundariesand
44 	 * - bit 1 set high
45 	 * - block lock registers are 4MiB lower - overflow subtract (danger)
46 	 *
47 	 * The address manipulation is first done on the logical address
48 	 * which is 0 at the start of the chip, and then the offset of
49 	 * the individual chip is addted to it.  Any other order a weird
50 	 * map offset could cause problems.
51 	 */
52 	adr = (adr & ~0xffffUL) | 0x2;
53 	adr += chip->start - 0x400000;
54 
55 	/*
56 	 * This is easy because these are writes to registers and not writes
57 	 * to flash memory - that means that we don't have to check status
58 	 * and timeout.
59 	 */
60 	mutex_lock(&chip->mutex);
61 	ret = get_chip(map, chip, adr, FL_LOCKING);
62 	if (ret) {
63 		mutex_unlock(&chip->mutex);
64 		return ret;
65 	}
66 
67 	chip->oldstate = chip->state;
68 	chip->state = xxlt->state;
69 	map_write(map, CMD(xxlt->val), adr);
70 
71 	/* Done and happy. */
72 	chip->state = chip->oldstate;
73 	put_chip(map, chip, adr);
74 	mutex_unlock(&chip->mutex);
75 	return 0;
76 }
77 
78 
79 static int fwh_lock_varsize(struct mtd_info *mtd, loff_t ofs, uint64_t len)
80 {
81 	int ret;
82 
83 	ret = cfi_varsize_frob(mtd, fwh_xxlock_oneblock, ofs, len,
84 		(void *)&FWH_XXLOCK_ONEBLOCK_LOCK);
85 
86 	return ret;
87 }
88 
89 
90 static int fwh_unlock_varsize(struct mtd_info *mtd, loff_t ofs, uint64_t len)
91 {
92 	int ret;
93 
94 	ret = cfi_varsize_frob(mtd, fwh_xxlock_oneblock, ofs, len,
95 		(void *)&FWH_XXLOCK_ONEBLOCK_UNLOCK);
96 
97 	return ret;
98 }
99 
100 static void fixup_use_fwh_lock(struct mtd_info *mtd)
101 {
102 	printk(KERN_NOTICE "using fwh lock/unlock method\n");
103 	/* Setup for the chips with the fwh lock method */
104 	mtd->_lock   = fwh_lock_varsize;
105 	mtd->_unlock = fwh_unlock_varsize;
106 }
107 #endif /* FWH_LOCK_H */
108