1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_T10_PI_H
3 #define _LINUX_T10_PI_H
4 
5 #include <linux/types.h>
6 #include <linux/blk-mq.h>
7 
8 /*
9  * A T10 PI-capable target device can be formatted with different
10  * protection schemes.	Currently 0 through 3 are defined:
11  *
12  * Type 0 is regular (unprotected) I/O
13  *
14  * Type 1 defines the contents of the guard and reference tags
15  *
16  * Type 2 defines the contents of the guard and reference tags and
17  * uses 32-byte commands to seed the latter
18  *
19  * Type 3 defines the contents of the guard tag only
20  */
21 enum t10_dif_type {
22 	T10_PI_TYPE0_PROTECTION = 0x0,
23 	T10_PI_TYPE1_PROTECTION = 0x1,
24 	T10_PI_TYPE2_PROTECTION = 0x2,
25 	T10_PI_TYPE3_PROTECTION = 0x3,
26 };
27 
28 /*
29  * T10 Protection Information tuple.
30  */
31 struct t10_pi_tuple {
32 	__be16 guard_tag;	/* Checksum */
33 	__be16 app_tag;		/* Opaque storage */
34 	__be32 ref_tag;		/* Target LBA or indirect LBA */
35 };
36 
37 #define T10_PI_APP_ESCAPE cpu_to_be16(0xffff)
38 #define T10_PI_REF_ESCAPE cpu_to_be32(0xffffffff)
39 
t10_pi_ref_tag(struct request * rq)40 static inline u32 t10_pi_ref_tag(struct request *rq)
41 {
42 	unsigned int shift = ilog2(queue_logical_block_size(rq->q));
43 
44 #ifdef CONFIG_BLK_DEV_INTEGRITY
45 	if (rq->q->integrity.interval_exp)
46 		shift = rq->q->integrity.interval_exp;
47 #endif
48 	return blk_rq_pos(rq) >> (shift - SECTOR_SHIFT) & 0xffffffff;
49 }
50 
51 extern const struct blk_integrity_profile t10_pi_type1_crc;
52 extern const struct blk_integrity_profile t10_pi_type1_ip;
53 extern const struct blk_integrity_profile t10_pi_type3_crc;
54 extern const struct blk_integrity_profile t10_pi_type3_ip;
55 
56 struct crc64_pi_tuple {
57 	__be64 guard_tag;
58 	__be16 app_tag;
59 	__u8   ref_tag[6];
60 };
61 
62 /**
63  * lower_48_bits() - return bits 0-47 of a number
64  * @n: the number we're accessing
65  */
lower_48_bits(u64 n)66 static inline u64 lower_48_bits(u64 n)
67 {
68 	return n & ((1ull << 48) - 1);
69 }
70 
ext_pi_ref_tag(struct request * rq)71 static inline u64 ext_pi_ref_tag(struct request *rq)
72 {
73 	unsigned int shift = ilog2(queue_logical_block_size(rq->q));
74 
75 #ifdef CONFIG_BLK_DEV_INTEGRITY
76 	if (rq->q->integrity.interval_exp)
77 		shift = rq->q->integrity.interval_exp;
78 #endif
79 	return lower_48_bits(blk_rq_pos(rq) >> (shift - SECTOR_SHIFT));
80 }
81 
82 extern const struct blk_integrity_profile ext_pi_type1_crc64;
83 extern const struct blk_integrity_profile ext_pi_type3_crc64;
84 
85 #endif
86