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Add support for physical LUN segmentation (virtual LUNs) to device driver supporting the IBM CXL Flash adapter. This patch allows user space applications to virtually segment a physical LUN into N virtual LUNs, taking advantage of the translation features provided by this adapter. Signed-off-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Signed-off-by: Manoj N. Kumar <manoj@linux.vnet.ibm.com> Reviewed-by: Michael Neuling <mikey@neuling.org> Reviewed-by: Wen Xiong <wenxiong@linux.vnet.ibm.com> Signed-off-by: James Bottomley <JBottomley@Odin.com>
87 lines
2.8 KiB
C
87 lines
2.8 KiB
C
/*
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* CXL Flash Device Driver
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*
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* Written by: Manoj N. Kumar <manoj@linux.vnet.ibm.com>, IBM Corporation
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* Matthew R. Ochs <mrochs@linux.vnet.ibm.com>, IBM Corporation
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*
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* Copyright (C) 2015 IBM Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _CXLFLASH_VLUN_H
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#define _CXLFLASH_VLUN_H
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/* RHT - Resource Handle Table */
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#define MC_RHT_NMASK 16 /* in bits */
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#define MC_CHUNK_SHIFT MC_RHT_NMASK /* shift to go from LBA to chunk# */
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#define HIBIT (BITS_PER_LONG - 1)
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#define MAX_AUN_CLONE_CNT 0xFF
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/*
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* LXT - LBA Translation Table
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*
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* +-------+-------+-------+-------+-------+-------+-------+---+---+
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* | RLBA_BASE |LUN_IDX| P |SEL|
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* +-------+-------+-------+-------+-------+-------+-------+---+---+
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*
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* The LXT Entry contains the physical LBA where the chunk starts (RLBA_BASE).
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* AFU ORes the low order bits from the virtual LBA (offset into the chunk)
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* with RLBA_BASE. The result is the physical LBA to be sent to storage.
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* The LXT Entry also contains an index to a LUN TBL and a bitmask of which
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* outgoing (FC) * ports can be selected. The port select bit-mask is ANDed
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* with a global port select bit-mask maintained by the driver.
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* In addition, it has permission bits that are ANDed with the
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* RHT permissions to arrive at the final permissions for the chunk.
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*
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* LXT tables are allocated dynamically in groups. This is done to avoid
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* a malloc/free overhead each time the LXT has to grow or shrink.
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*
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* Based on the current lxt_cnt (used), it is always possible to know
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* how many are allocated (used+free). The number of allocated entries is
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* not stored anywhere.
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*
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* The LXT table is re-allocated whenever it needs to cross into another group.
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*/
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#define LXT_GROUP_SIZE 8
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#define LXT_NUM_GROUPS(lxt_cnt) (((lxt_cnt) + 7)/8) /* alloc'ed groups */
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#define LXT_LUNIDX_SHIFT 8 /* LXT entry, shift for LUN index */
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#define LXT_PERM_SHIFT 4 /* LXT entry, shift for permission bits */
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struct ba_lun_info {
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u64 *lun_alloc_map;
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u32 lun_bmap_size;
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u32 total_aus;
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u64 free_aun_cnt;
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/* indices to be used for elevator lookup of free map */
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u32 free_low_idx;
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u32 free_curr_idx;
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u32 free_high_idx;
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u8 *aun_clone_map;
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};
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struct ba_lun {
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u64 lun_id;
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u64 wwpn;
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size_t lsize; /* LUN size in number of LBAs */
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size_t lba_size; /* LBA size in number of bytes */
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size_t au_size; /* Allocation Unit size in number of LBAs */
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struct ba_lun_info *ba_lun_handle;
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};
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/* Block Allocator */
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struct blka {
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struct ba_lun ba_lun;
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u64 nchunk; /* number of chunks */
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struct mutex mutex;
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};
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#endif /* ifndef _CXLFLASH_SUPERPIPE_H */
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