139 lines
3.2 KiB
C
139 lines
3.2 KiB
C
#ifndef __TARGET_CORE_USER_H
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#define __TARGET_CORE_USER_H
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/* This header will be used by application too */
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#include <linux/types.h>
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#include <linux/uio.h>
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#define TCMU_VERSION "1.0"
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/*
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* Ring Design
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* -----------
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*
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* The mmaped area is divided into three parts:
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* 1) The mailbox (struct tcmu_mailbox, below)
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* 2) The command ring
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* 3) Everything beyond the command ring (data)
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*
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* The mailbox tells userspace the offset of the command ring from the
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* start of the shared memory region, and how big the command ring is.
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*
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* The kernel passes SCSI commands to userspace by putting a struct
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* tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
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* userspace via uio's interrupt mechanism.
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*
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* tcmu_cmd_entry contains a header. If the header type is PAD,
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* userspace should skip hdr->length bytes (mod cmdr_size) to find the
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* next cmd_entry.
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*
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* Otherwise, the entry will contain offsets into the mmaped area that
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* contain the cdb and data buffers -- the latter accessible via the
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* iov array. iov addresses are also offsets into the shared area.
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*
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* When userspace is completed handling the command, set
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* entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
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* and also set mailbox->cmd_tail equal to the old cmd_tail plus
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* hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
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* should process the next packet the same way, and so on.
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*/
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#define TCMU_MAILBOX_VERSION 1
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#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
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struct tcmu_mailbox {
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__u16 version;
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__u16 flags;
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__u32 cmdr_off;
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__u32 cmdr_size;
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__u32 cmd_head;
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/* Updated by user. On its own cacheline */
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__u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
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} __packed;
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enum tcmu_opcode {
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TCMU_OP_PAD = 0,
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TCMU_OP_CMD,
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};
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/*
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* Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
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*/
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struct tcmu_cmd_entry_hdr {
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__u32 len_op;
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} __packed;
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#define TCMU_OP_MASK 0x7
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static inline enum tcmu_opcode tcmu_hdr_get_op(struct tcmu_cmd_entry_hdr *hdr)
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{
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return hdr->len_op & TCMU_OP_MASK;
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}
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static inline void tcmu_hdr_set_op(struct tcmu_cmd_entry_hdr *hdr, enum tcmu_opcode op)
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{
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hdr->len_op &= ~TCMU_OP_MASK;
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hdr->len_op |= (op & TCMU_OP_MASK);
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}
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static inline __u32 tcmu_hdr_get_len(struct tcmu_cmd_entry_hdr *hdr)
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{
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return hdr->len_op & ~TCMU_OP_MASK;
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}
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static inline void tcmu_hdr_set_len(struct tcmu_cmd_entry_hdr *hdr, __u32 len)
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{
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hdr->len_op &= TCMU_OP_MASK;
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hdr->len_op |= len;
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}
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/* Currently the same as SCSI_SENSE_BUFFERSIZE */
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#define TCMU_SENSE_BUFFERSIZE 96
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struct tcmu_cmd_entry {
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struct tcmu_cmd_entry_hdr hdr;
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uint16_t cmd_id;
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uint16_t __pad1;
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union {
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struct {
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uint64_t cdb_off;
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uint64_t iov_cnt;
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struct iovec iov[0];
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} req;
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struct {
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uint8_t scsi_status;
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uint8_t __pad1;
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uint16_t __pad2;
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uint32_t __pad3;
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char sense_buffer[TCMU_SENSE_BUFFERSIZE];
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} rsp;
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};
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} __packed;
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#define TCMU_OP_ALIGN_SIZE sizeof(uint64_t)
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enum tcmu_genl_cmd {
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TCMU_CMD_UNSPEC,
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TCMU_CMD_ADDED_DEVICE,
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TCMU_CMD_REMOVED_DEVICE,
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__TCMU_CMD_MAX,
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};
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#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
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enum tcmu_genl_attr {
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TCMU_ATTR_UNSPEC,
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TCMU_ATTR_DEVICE,
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TCMU_ATTR_MINOR,
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__TCMU_ATTR_MAX,
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};
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#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
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#endif
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