include/uapi/linux/target_core_user.h

   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
  45 struct tcmu_mailbox {
  46         __u16 version;
  47         __u16 flags;
  48         __u32 cmdr_off;
  49         __u32 cmdr_size;
  50
  51         __u32 cmd_head;
  52
  53         /* Updated by user. On its own cacheline */
  54         __u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
  55
  56 } __packed;
  57
  58 enum tcmu_opcode {
  59         TCMU_OP_PAD = 0,
  60         TCMU_OP_CMD,
  61 };
  62
  63 /*
  64  * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
  65  */
  66 struct tcmu_cmd_entry_hdr {
  67         __u32 len_op;
  68         __u16 cmd_id;
  69         __u8 kflags;
  70 #define TCMU_UFLAG_UNKNOWN_OP 0x1
  71         __u8 uflags;
  72
  73 } __packed;
  74
  75 #define TCMU_OP_MASK 0x7
  76
  77 static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
  78 {
  79         return len_op & TCMU_OP_MASK;
  80 }
  81
  82 static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
  83 {
  84         *len_op &= ~TCMU_OP_MASK;
  85         *len_op |= (op & TCMU_OP_MASK);
  86 }
  87
  88 static inline __u32 tcmu_hdr_get_len(__u32 len_op)
  89 {
  90         return len_op & ~TCMU_OP_MASK;
  91 }
  92
  93 static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
  94 {
  95         *len_op &= TCMU_OP_MASK;
  96         *len_op |= len;
  97 }
  98
  99 /* Currently the same as SCSI_SENSE_BUFFERSIZE */
 100 #define TCMU_SENSE_BUFFERSIZE 96
 101
 102 struct tcmu_cmd_entry {
 103         struct tcmu_cmd_entry_hdr hdr;
 104
 105         union {
 106                 struct {
 107                         uint32_t iov_cnt;
 108                         uint32_t iov_bidi_cnt;
 109                         uint32_t iov_dif_cnt;
 110                         uint64_t cdb_off;
 111                         uint64_t __pad1;
 112                         uint64_t __pad2;
 113                         struct iovec iov[0];
 114                 } req;
 115                 struct {
 116                         uint8_t scsi_status;
 117                         uint8_t __pad1;
 118                         uint16_t __pad2;
 119                         uint32_t __pad3;
 120                         char sense_buffer[TCMU_SENSE_BUFFERSIZE];
 121                 } rsp;
 122         };
 123
 124 } __packed;
 125
 126 #define TCMU_OP_ALIGN_SIZE sizeof(uint64_t)
 127
 128 enum tcmu_genl_cmd {
 129         TCMU_CMD_UNSPEC,
 130         TCMU_CMD_ADDED_DEVICE,
 131         TCMU_CMD_REMOVED_DEVICE,
 132         __TCMU_CMD_MAX,
 133 };
 134 #define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
 135
 136 enum tcmu_genl_attr {
 137         TCMU_ATTR_UNSPEC,
 138         TCMU_ATTR_DEVICE,
 139         TCMU_ATTR_MINOR,
 140         __TCMU_ATTR_MAX,
 141 };
 142 #define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
 143
 144 #endif