xref: /openbmc/linux/drivers/scsi/cxlflash/vlun.h (revision fb574682)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * CXL Flash Device Driver
4  *
5  * Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
6  *             Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
7  *
8  * Copyright (C) 2015 IBM Corporation
9  */
10 
11 #ifndef _CXLFLASH_VLUN_H
12 #define _CXLFLASH_VLUN_H
13 
14 /* RHT - Resource Handle Table */
15 #define MC_RHT_NMASK      16	/* in bits */
16 #define MC_CHUNK_SHIFT    MC_RHT_NMASK	/* shift to go from LBA to chunk# */
17 
18 #define HIBIT             (BITS_PER_LONG - 1)
19 
20 #define MAX_AUN_CLONE_CNT 0xFF
21 
22 /*
23  * LXT - LBA Translation Table
24  *
25  * +-------+-------+-------+-------+-------+-------+-------+---+---+
26  * | RLBA_BASE                                     |LUN_IDX| P |SEL|
27  * +-------+-------+-------+-------+-------+-------+-------+---+---+
28  *
29  * The LXT Entry contains the physical LBA where the chunk starts (RLBA_BASE).
30  * AFU ORes the low order bits from the virtual LBA (offset into the chunk)
31  * with RLBA_BASE. The result is the physical LBA to be sent to storage.
32  * The LXT Entry also contains an index to a LUN TBL and a bitmask of which
33  * outgoing (FC) * ports can be selected. The port select bit-mask is ANDed
34  * with a global port select bit-mask maintained by the driver.
35  * In addition, it has permission bits that are ANDed with the
36  * RHT permissions to arrive at the final permissions for the chunk.
37  *
38  * LXT tables are allocated dynamically in groups. This is done to avoid
39  * a malloc/free overhead each time the LXT has to grow or shrink.
40  *
41  * Based on the current lxt_cnt (used), it is always possible to know
42  * how many are allocated (used+free). The number of allocated entries is
43  * not stored anywhere.
44  *
45  * The LXT table is re-allocated whenever it needs to cross into another group.
46  */
47 #define LXT_GROUP_SIZE          8
48 #define LXT_NUM_GROUPS(lxt_cnt) (((lxt_cnt) + 7)/8)	/* alloc'ed groups */
49 #define LXT_LUNIDX_SHIFT  8	/* LXT entry, shift for LUN index */
50 #define LXT_PERM_SHIFT    4	/* LXT entry, shift for permission bits */
51 
52 struct ba_lun_info {
53 	u64 *lun_alloc_map;
54 	u32 lun_bmap_size;
55 	u32 total_aus;
56 	u64 free_aun_cnt;
57 
58 	/* indices to be used for elevator lookup of free map */
59 	u32 free_low_idx;
60 	u32 free_curr_idx;
61 	u32 free_high_idx;
62 
63 	u8 *aun_clone_map;
64 };
65 
66 struct ba_lun {
67 	u64 lun_id;
68 	u64 wwpn;
69 	size_t lsize;		/* LUN size in number of LBAs             */
70 	size_t lba_size;	/* LBA size in number of bytes            */
71 	size_t au_size;		/* Allocation Unit size in number of LBAs */
72 	struct ba_lun_info *ba_lun_handle;
73 };
74 
75 /* Block Allocator */
76 struct blka {
77 	struct ba_lun ba_lun;
78 	u64 nchunk;		/* number of chunks */
79 	struct mutex mutex;
80 };
81 
82 #endif /* ifndef _CXLFLASH_SUPERPIPE_H */
83