xref: /openbmc/linux/drivers/mtd/chips/fwh_lock.h (revision b2441318)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef FWH_LOCK_H
3 #define FWH_LOCK_H
4 
5 
6 enum fwh_lock_state {
7         FWH_UNLOCKED   = 0,
8 	FWH_DENY_WRITE = 1,
9 	FWH_IMMUTABLE  = 2,
10 	FWH_DENY_READ  = 4,
11 };
12 
13 struct 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  */
fwh_xxlock_oneblock(struct map_info * map,struct flchip * chip,unsigned long adr,int len,void * thunk)29 static 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 
fwh_lock_varsize(struct mtd_info * mtd,loff_t ofs,uint64_t len)80 static 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 
fwh_unlock_varsize(struct mtd_info * mtd,loff_t ofs,uint64_t len)91 static 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 
fixup_use_fwh_lock(struct mtd_info * mtd)101 static 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