--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef __TARGET_CORE_USER_H
+#define __TARGET_CORE_USER_H
+
+/* This header will be used by application too */
+
+#include <linux/types.h>
+#include <linux/uio.h>
+
+#define TCMU_VERSION "2.0"
+
+/**
+ * DOC: Ring Design
+ * Ring Design
+ * -----------
+ *
+ * The mmaped area is divided into three parts:
+ * 1) The mailbox (struct tcmu_mailbox, below);
+ * 2) The command ring;
+ * 3) Everything beyond the command ring (data).
+ *
+ * The mailbox tells userspace the offset of the command ring from the
+ * start of the shared memory region, and how big the command ring is.
+ *
+ * The kernel passes SCSI commands to userspace by putting a struct
+ * tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
+ * userspace via UIO's interrupt mechanism.
+ *
+ * tcmu_cmd_entry contains a header. If the header type is PAD,
+ * userspace should skip hdr->length bytes (mod cmdr_size) to find the
+ * next cmd_entry.
+ *
+ * Otherwise, the entry will contain offsets into the mmaped area that
+ * contain the cdb and data buffers -- the latter accessible via the
+ * iov array. iov addresses are also offsets into the shared area.
+ *
+ * When userspace is completed handling the command, set
+ * entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
+ * and also set mailbox->cmd_tail equal to the old cmd_tail plus
+ * hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
+ * should process the next packet the same way, and so on.
+ */
+
+#define TCMU_MAILBOX_VERSION 2
+#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
+#define TCMU_MAILBOX_FLAG_CAP_OOOC (1 << 0) /* Out-of-order completions */
+#define TCMU_MAILBOX_FLAG_CAP_READ_LEN (1 << 1) /* Read data length */
+
+struct tcmu_mailbox {
+ __u16 version;
+ __u16 flags;
+ __u32 cmdr_off;
+ __u32 cmdr_size;
+
+ __u32 cmd_head;
+
+ /* Updated by user. On its own cacheline */
+ __u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
+
+} __attribute__((packed));
+
+enum tcmu_opcode {
+ TCMU_OP_PAD = 0,
+ TCMU_OP_CMD,
+};
+
+/*
+ * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
+ */
+struct tcmu_cmd_entry_hdr {
+ __u32 len_op;
+ __u16 cmd_id;
+ __u8 kflags;
+#define TCMU_UFLAG_UNKNOWN_OP 0x1
+#define TCMU_UFLAG_READ_LEN 0x2
+ __u8 uflags;
+
+} __attribute__((packed));
+
+#define TCMU_OP_MASK 0x7
+
+static __inline__ enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
+{
+ return len_op & TCMU_OP_MASK;
+}
+
+static __inline__ void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
+{
+ *len_op &= ~TCMU_OP_MASK;
+ *len_op |= (op & TCMU_OP_MASK);
+}
+
+static __inline__ __u32 tcmu_hdr_get_len(__u32 len_op)
+{
+ return len_op & ~TCMU_OP_MASK;
+}
+
+static __inline__ void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
+{
+ *len_op &= TCMU_OP_MASK;
+ *len_op |= len;
+}
+
+/* Currently the same as SCSI_SENSE_BUFFERSIZE */
+#define TCMU_SENSE_BUFFERSIZE 96
+
+struct tcmu_cmd_entry {
+ struct tcmu_cmd_entry_hdr hdr;
+
+ union {
+ struct {
+ __u32 iov_cnt;
+ __u32 iov_bidi_cnt;
+ __u32 iov_dif_cnt;
+ __u64 cdb_off;
+ __u64 __pad1;
+ __u64 __pad2;
+ struct iovec iov[0];
+ } req;
+ struct {
+ __u8 scsi_status;
+ __u8 __pad1;
+ __u16 __pad2;
+ __u32 read_len;
+ char sense_buffer[TCMU_SENSE_BUFFERSIZE];
+ } rsp;
+ };
+
+} __attribute__((packed));
+
+#define TCMU_OP_ALIGN_SIZE sizeof(__u64)
+
+enum tcmu_genl_cmd {
+ TCMU_CMD_UNSPEC,
+ TCMU_CMD_ADDED_DEVICE,
+ TCMU_CMD_REMOVED_DEVICE,
+ TCMU_CMD_RECONFIG_DEVICE,
+ TCMU_CMD_ADDED_DEVICE_DONE,
+ TCMU_CMD_REMOVED_DEVICE_DONE,
+ TCMU_CMD_RECONFIG_DEVICE_DONE,
+ TCMU_CMD_SET_FEATURES,
+ __TCMU_CMD_MAX,
+};
+#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
+
+enum tcmu_genl_attr {
+ TCMU_ATTR_UNSPEC,
+ TCMU_ATTR_DEVICE,
+ TCMU_ATTR_MINOR,
+ TCMU_ATTR_PAD,
+ TCMU_ATTR_DEV_CFG,
+ TCMU_ATTR_DEV_SIZE,
+ TCMU_ATTR_WRITECACHE,
+ TCMU_ATTR_CMD_STATUS,
+ TCMU_ATTR_DEVICE_ID,
+ TCMU_ATTR_SUPP_KERN_CMD_REPLY,
+ __TCMU_ATTR_MAX,
+};
+#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
+
+#endif
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