LXR linux/include/uapi/linux/target_core

   1#ifndef __TARGET_CORE_USER_H
   2#define __TARGET_CORE_USER_H
   3
   4/* This header will be used by application too */
   5
   6#include <linux/types.h>
   7#include <linux/uio.h>
   8
   9#define TCMU_VERSION "2.0"
  10
  11/*
  12 * Ring Design
  13 * -----------
  14 *
  15 * The mmaped area is divided into three parts:
  16 * 1) The mailbox (struct tcmu_mailbox, below)
  17 * 2) The command ring
  18 * 3) Everything beyond the command ring (data)
  19 *
  20 * The mailbox tells userspace the offset of the command ring from the
  21 * start of the shared memory region, and how big the command ring is.
  22 *
  23 * The kernel passes SCSI commands to userspace by putting a struct
  24 * tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
  25 * userspace via uio's interrupt mechanism.
  26 *
  27 * tcmu_cmd_entry contains a header. If the header type is PAD,
  28 * userspace should skip hdr->length bytes (mod cmdr_size) to find the
  29 * next cmd_entry.
  30 *
  31 * Otherwise, the entry will contain offsets into the mmaped area that
  32 * contain the cdb and data buffers -- the latter accessible via the
  33 * iov array. iov addresses are also offsets into the shared area.
  34 *
  35 * When userspace is completed handling the command, set
  36 * entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
  37 * and also set mailbox->cmd_tail equal to the old cmd_tail plus
  38 * hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
  39 * should process the next packet the same way, and so on.
  40 */
  41
  42#define TCMU_MAILBOX_VERSION 2
  43#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
  44#define TCMU_MAILBOX_FLAG_CAP_OOOC (1 << 0) /* Out-of-order completions */
  45
  46struct tcmu_mailbox {
  47        __u16 version;
  48        __u16 flags;
  49        __u32 cmdr_off;
  50        __u32 cmdr_size;
  51
  52        __u32 cmd_head;
  53
  54        /* Updated by user. On its own cacheline */
  55        __u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
  56
  57} __packed;
  58
  59enum tcmu_opcode {
  60        TCMU_OP_PAD = 0,
  61        TCMU_OP_CMD,
  62};
  63
  64/*
  65 * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
  66 */
  67struct tcmu_cmd_entry_hdr {
  68        __u32 len_op;
  69        __u16 cmd_id;
  70        __u8 kflags;
  71#define TCMU_UFLAG_UNKNOWN_OP 0x1
  72        __u8 uflags;
  73
  74} __packed;
  75
  76#define TCMU_OP_MASK 0x7
  77
  78static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
  79{
  80        return len_op & TCMU_OP_MASK;
  81}
  82
  83static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
  84{
  85        *len_op &= ~TCMU_OP_MASK;
  86        *len_op |= (op & TCMU_OP_MASK);
  87}
  88
  89static inline __u32 tcmu_hdr_get_len(__u32 len_op)
  90{
  91        return len_op & ~TCMU_OP_MASK;
  92}
  93
  94static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
  95{
  96        *len_op &= TCMU_OP_MASK;
  97        *len_op |= len;
  98}
  99
 100/* Currently the same as SCSI_SENSE_BUFFERSIZE */
 101#define TCMU_SENSE_BUFFERSIZE 96
 102
 103struct tcmu_cmd_entry {
 104        struct tcmu_cmd_entry_hdr hdr;
 105
 106        union {
 107                struct {
 108                        uint32_t iov_cnt;
 109                        uint32_t iov_bidi_cnt;
 110                        uint32_t iov_dif_cnt;
 111                        uint64_t cdb_off;
 112                        uint64_t __pad1;
 113                        uint64_t __pad2;
 114                        struct iovec iov[0];
 115                } req;
 116                struct {
 117                        uint8_t scsi_status;
 118                        uint8_t __pad1;
 119                        uint16_t __pad2;
 120                        uint32_t __pad3;
 121                        char sense_buffer[TCMU_SENSE_BUFFERSIZE];
 122                } rsp;
 123        };
 124
 125} __packed;
 126
 127#define TCMU_OP_ALIGN_SIZE sizeof(uint64_t)
 128
 129enum tcmu_genl_cmd {
 130        TCMU_CMD_UNSPEC,
 131        TCMU_CMD_ADDED_DEVICE,
 132        TCMU_CMD_REMOVED_DEVICE,
 133        __TCMU_CMD_MAX,
 134};
 135#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
 136
 137enum tcmu_genl_attr {
 138        TCMU_ATTR_UNSPEC,
 139        TCMU_ATTR_DEVICE,
 140        TCMU_ATTR_MINOR,
 141        __TCMU_ATTR_MAX,
 142};
 143#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
 144
 145#endif
 146