LXR linux/include/uapi/linux/target_core

   1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2#ifndef __TARGET_CORE_USER_H
   3#define __TARGET_CORE_USER_H
   4
   5/* This header will be used by application too */
   6
   7#include <linux/types.h>
   8#include <linux/uio.h>
   9
  10#define TCMU_VERSION "2.0"
  11
  12/*
  13 * Ring Design
  14 * -----------
  15 *
  16 * The mmaped area is divided into three parts:
  17 * 1) The mailbox (struct tcmu_mailbox, below)
  18 * 2) The command ring
  19 * 3) Everything beyond the command ring (data)
  20 *
  21 * The mailbox tells userspace the offset of the command ring from the
  22 * start of the shared memory region, and how big the command ring is.
  23 *
  24 * The kernel passes SCSI commands to userspace by putting a struct
  25 * tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
  26 * userspace via uio's interrupt mechanism.
  27 *
  28 * tcmu_cmd_entry contains a header. If the header type is PAD,
  29 * userspace should skip hdr->length bytes (mod cmdr_size) to find the
  30 * next cmd_entry.
  31 *
  32 * Otherwise, the entry will contain offsets into the mmaped area that
  33 * contain the cdb and data buffers -- the latter accessible via the
  34 * iov array. iov addresses are also offsets into the shared area.
  35 *
  36 * When userspace is completed handling the command, set
  37 * entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
  38 * and also set mailbox->cmd_tail equal to the old cmd_tail plus
  39 * hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
  40 * should process the next packet the same way, and so on.
  41 */
  42
  43#define TCMU_MAILBOX_VERSION 2
  44#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
  45#define TCMU_MAILBOX_FLAG_CAP_OOOC (1 << 0) /* Out-of-order completions */
  46
  47struct tcmu_mailbox {
  48        __u16 version;
  49        __u16 flags;
  50        __u32 cmdr_off;
  51        __u32 cmdr_size;
  52
  53        __u32 cmd_head;
  54
  55        /* Updated by user. On its own cacheline */
  56        __u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
  57
  58} __packed;
  59
  60enum tcmu_opcode {
  61        TCMU_OP_PAD = 0,
  62        TCMU_OP_CMD,
  63};
  64
  65/*
  66 * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
  67 */
  68struct tcmu_cmd_entry_hdr {
  69        __u32 len_op;
  70        __u16 cmd_id;
  71        __u8 kflags;
  72#define TCMU_UFLAG_UNKNOWN_OP 0x1
  73        __u8 uflags;
  74
  75} __packed;
  76
  77#define TCMU_OP_MASK 0x7
  78
  79static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
  80{
  81        return len_op & TCMU_OP_MASK;
  82}
  83
  84static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
  85{
  86        *len_op &= ~TCMU_OP_MASK;
  87        *len_op |= (op & TCMU_OP_MASK);
  88}
  89
  90static inline __u32 tcmu_hdr_get_len(__u32 len_op)
  91{
  92        return len_op & ~TCMU_OP_MASK;
  93}
  94
  95static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
  96{
  97        *len_op &= TCMU_OP_MASK;
  98        *len_op |= len;
  99}
 100
 101/* Currently the same as SCSI_SENSE_BUFFERSIZE */
 102#define TCMU_SENSE_BUFFERSIZE 96
 103
 104struct tcmu_cmd_entry {
 105        struct tcmu_cmd_entry_hdr hdr;
 106
 107        union {
 108                struct {
 109                        __u32 iov_cnt;
 110                        __u32 iov_bidi_cnt;
 111                        __u32 iov_dif_cnt;
 112                        __u64 cdb_off;
 113                        __u64 __pad1;
 114                        __u64 __pad2;
 115                        struct iovec iov[0];
 116                } req;
 117                struct {
 118                        __u8 scsi_status;
 119                        __u8 __pad1;
 120                        __u16 __pad2;
 121                        __u32 __pad3;
 122                        char sense_buffer[TCMU_SENSE_BUFFERSIZE];
 123                } rsp;
 124        };
 125
 126} __packed;
 127
 128#define TCMU_OP_ALIGN_SIZE sizeof(__u64)
 129
 130enum tcmu_genl_cmd {
 131        TCMU_CMD_UNSPEC,
 132        TCMU_CMD_ADDED_DEVICE,
 133        TCMU_CMD_REMOVED_DEVICE,
 134        TCMU_CMD_RECONFIG_DEVICE,
 135        TCMU_CMD_ADDED_DEVICE_DONE,
 136        TCMU_CMD_REMOVED_DEVICE_DONE,
 137        TCMU_CMD_RECONFIG_DEVICE_DONE,
 138        TCMU_CMD_SET_FEATURES,
 139        __TCMU_CMD_MAX,
 140};
 141#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
 142
 143enum tcmu_genl_attr {
 144        TCMU_ATTR_UNSPEC,
 145        TCMU_ATTR_DEVICE,
 146        TCMU_ATTR_MINOR,
 147        TCMU_ATTR_PAD,
 148        TCMU_ATTR_DEV_CFG,
 149        TCMU_ATTR_DEV_SIZE,
 150        TCMU_ATTR_WRITECACHE,
 151        TCMU_ATTR_CMD_STATUS,
 152        TCMU_ATTR_DEVICE_ID,
 153        TCMU_ATTR_SUPP_KERN_CMD_REPLY,
 154        __TCMU_ATTR_MAX,
 155};
 156#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
 157
 158#endif
 159