[deliverable/linux.git] / include / uapi / linux / target_core_user.h

#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"

/*
 * 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 */

/* See https://gcc.gnu.org/onlinedocs/cpp/Stringification.html */
#define xstr(s) str(s)
#define str(s) #s

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)));

} __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
	__u8 uflags;

} __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 {
			uint32_t iov_cnt;
			uint32_t iov_bidi_cnt;
			uint32_t iov_dif_cnt;
			uint64_t cdb_off;
			uint64_t __pad1;
			uint64_t __pad2;
			struct iovec iov[0];
		} req;
		struct {
			uint8_t scsi_status;
			uint8_t __pad1;
			uint16_t __pad2;
			uint32_t __pad3;
			char sense_buffer[TCMU_SENSE_BUFFERSIZE];
		} rsp;
	};

} __packed;

#define TCMU_OP_ALIGN_SIZE sizeof(uint64_t)

enum tcmu_genl_cmd {
	TCMU_CMD_UNSPEC,
	TCMU_CMD_ADDED_DEVICE,
	TCMU_CMD_REMOVED_DEVICE,
	__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_MAX,
};
#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)

#endif
Commit	Line	Data
7c9e7a6f AG	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
0ad46af8	9	#define TCMU_VERSION "2.0"
7c9e7a6f AG	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
0ad46af8	42	#define TCMU_MAILBOX_VERSION 2
7c9e7a6f AG	43	#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
7c9e7a6f AG	44
0ad46af8 AG	45	/* See https://gcc.gnu.org/onlinedocs/cpp/Stringification.html */
	46	#define xstr(s) str(s)
	47	#define str(s) #s
	48
7c9e7a6f AG	49	struct tcmu_mailbox {
	50	__u16 version;
	51	__u16 flags;
	52	__u32 cmdr_off;
	53	__u32 cmdr_size;
	54
	55	__u32 cmd_head;
	56
	57	/* Updated by user. On its own cacheline */
	58	__u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
	59
	60	} __packed;
	61
	62	enum tcmu_opcode {
	63	TCMU_OP_PAD = 0,
	64	TCMU_OP_CMD,
	65	};
	66
	67	/*
	68	* Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
	69	*/
	70	struct tcmu_cmd_entry_hdr {
0ad46af8 AG	71	__u32 len_op;
	72	__u16 cmd_id;
	73	__u8 kflags;
	74	#define TCMU_UFLAG_UNKNOWN_OP 0x1
	75	__u8 uflags;
	76
7c9e7a6f AG	77	} __packed;
	78
	79	#define TCMU_OP_MASK 0x7
	80
0ad46af8	81	static inline enum tcmu_opcode tcmu_hdr_get_op(__u32 len_op)
7c9e7a6f	82	{
0ad46af8	83	return len_op & TCMU_OP_MASK;
7c9e7a6f AG	84	}
7c9e7a6f AG	85
0ad46af8	86	static inline void tcmu_hdr_set_op(__u32 *len_op, enum tcmu_opcode op)
7c9e7a6f	87	{
0ad46af8 AG	88	*len_op &= ~TCMU_OP_MASK;
0ad46af8 AG	89	*len_op \|= (op & TCMU_OP_MASK);
7c9e7a6f AG	90	}
7c9e7a6f AG	91
0ad46af8	92	static inline __u32 tcmu_hdr_get_len(__u32 len_op)
7c9e7a6f	93	{
0ad46af8	94	return len_op & ~TCMU_OP_MASK;
7c9e7a6f AG	95	}
7c9e7a6f AG	96
0ad46af8	97	static inline void tcmu_hdr_set_len(__u32 *len_op, __u32 len)
7c9e7a6f	98	{
0ad46af8 AG	99	*len_op &= TCMU_OP_MASK;
0ad46af8 AG	100	*len_op \|= len;
7c9e7a6f AG	101	}
	102
	103	/* Currently the same as SCSI_SENSE_BUFFERSIZE */
	104	#define TCMU_SENSE_BUFFERSIZE 96
	105
	106	struct tcmu_cmd_entry {
	107	struct tcmu_cmd_entry_hdr hdr;
	108
7c9e7a6f AG	109	union {
7c9e7a6f AG	110	struct {
0ad46af8 AG	111	uint32_t iov_cnt;
	112	uint32_t iov_bidi_cnt;
	113	uint32_t iov_dif_cnt;
7c9e7a6f	114	uint64_t cdb_off;
0ad46af8 AG	115	uint64_t __pad1;
0ad46af8 AG	116	uint64_t __pad2;
7c9e7a6f AG	117	struct iovec iov[0];
	118	} req;
	119	struct {
	120	uint8_t scsi_status;
	121	uint8_t __pad1;
	122	uint16_t __pad2;
	123	uint32_t __pad3;
	124	char sense_buffer[TCMU_SENSE_BUFFERSIZE];
	125	} rsp;
	126	};
	127
	128	} __packed;
	129
	130	#define TCMU_OP_ALIGN_SIZE sizeof(uint64_t)
	131
	132	enum tcmu_genl_cmd {
	133	TCMU_CMD_UNSPEC,
	134	TCMU_CMD_ADDED_DEVICE,
	135	TCMU_CMD_REMOVED_DEVICE,
	136	__TCMU_CMD_MAX,
	137	};
	138	#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
	139
	140	enum tcmu_genl_attr {
	141	TCMU_ATTR_UNSPEC,
	142	TCMU_ATTR_DEVICE,
	143	TCMU_ATTR_MINOR,
	144	__TCMU_ATTR_MAX,
	145	};
	146	#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
	147
	148	#endif