linux/drivers/scsi/cxlflash/vlun.h
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   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
  52struct 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
  66struct 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 */
  76struct 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