path: root/include/linux/nvme-fc-driver.h

/*
 * Copyright (c) 2016, Avago Technologies
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 */

#ifndef _NVME_FC_DRIVER_H
#define _NVME_FC_DRIVER_H 1


/*
 * **********************  LLDD FC-NVME Host API ********************
 *
 *  For FC LLDD's that are the NVME Host role.
 *
 * ******************************************************************
 */



/* FC Port role bitmask - can merge with FC Port Roles in fc transport */
#define FC_PORT_ROLE_NVME_INITIATOR	0x10
#define FC_PORT_ROLE_NVME_TARGET	0x20
#define FC_PORT_ROLE_NVME_DISCOVERY	0x40


/**
 * struct nvme_fc_port_info - port-specific ids and FC connection-specific
 *                            data element used during NVME Host role
 *                            registrations
 *
 * Static fields describing the port being registered:
 * @node_name: FC WWNN for the port
 * @port_name: FC WWPN for the port
 * @port_role: What NVME roles are supported (see FC_PORT_ROLE_xxx)
 *
 * Initialization values for dynamic port fields:
 * @port_id:      FC N_Port_ID currently assigned the port. Upper 8 bits must
 *                be set to 0.
 */
struct nvme_fc_port_info {
	u64			node_name;
	u64			port_name;
	u32			port_role;
	u32			port_id;
};


/**
 * struct nvmefc_ls_req - Request structure passed from NVME-FC transport
 *                        to LLDD in order to perform a NVME FC-4 LS
 *                        request and obtain a response.
 *
 * Values set by the NVME-FC layer prior to calling the LLDD ls_req
 * entrypoint.
 * @rqstaddr: pointer to request buffer
 * @rqstdma:  PCI DMA address of request buffer
 * @rqstlen:  Length, in bytes, of request buffer
 * @rspaddr:  pointer to response buffer
 * @rspdma:   PCI DMA address of response buffer
 * @rsplen:   Length, in bytes, of response buffer
 * @timeout:  Maximum amount of time, in seconds, to wait for the LS response.
 *            If timeout exceeded, LLDD to abort LS exchange and complete
 *            LS request with error status.
 * @private:  pointer to memory allocated alongside the ls request structure
 *            that is specifically for the LLDD to use while processing the
 *            request. The length of the buffer corresponds to the
 *            lsrqst_priv_sz value specified in the nvme_fc_port_template
 *            supplied by the LLDD.
 * @done:     The callback routine the LLDD is to invoke upon completion of
 *            the LS request. req argument is the pointer to the original LS
 *            request structure. Status argument must be 0 upon success, a
 *            negative errno on failure (example: -ENXIO).
 */
struct nvmefc_ls_req {
	void			*rqstaddr;
	dma_addr_t		rqstdma;
	u32			rqstlen;
	void			*rspaddr;
	dma_addr_t		rspdma;
	u32			rsplen;
	u32			timeout;

	void			*private;

	void (*done)(struct nvmefc_ls_req *req, int status);

} __aligned(sizeof(u64));	/* alignment for other things alloc'd with */


enum nvmefc_fcp_datadir {
	NVMEFC_FCP_NODATA,	/* payload_length and sg_cnt will be zero */
	NVMEFC_FCP_WRITE,
	NVMEFC_FCP_READ,
};


#define NVME_FC_MAX_SEGMENTS		256

/**
 * struct nvmefc_fcp_req - Request structure passed from NVME-FC transport
 *                         to LLDD in order to perform a NVME FCP IO operation.
 *
 * Values set by the NVME-FC layer prior to calling the LLDD fcp_io
 * entrypoint.
 * @cmdaddr:   pointer to the FCP CMD IU buffer
 * @rspaddr:   pointer to the FCP RSP IU buffer
 * @cmddma:    PCI DMA address of the FCP CMD IU buffer
 * @rspdma:    PCI DMA address of the FCP RSP IU buffer
 * @cmdlen:    Length, in bytes, of the FCP CMD IU buffer
 * @rsplen:    Length, in bytes, of the FCP RSP IU buffer
 * @payload_length: Length of DATA_IN or DATA_OUT payload data to transfer
 * @sg_table:  scatter/gather structure for payload data
 * @first_sgl: memory for 1st scatter/gather list segment for payload data
 * @sg_cnt:    number of elements in the scatter/gather list
 * @io_dir:    direction of the FCP request (see NVMEFC_FCP_xxx)
 * @sqid:      The nvme SQID the command is being issued on
 * @done:      The callback routine the LLDD is to invoke upon completion of
 *             the FCP operation. req argument is the pointer to the original
 *             FCP IO operation.
 * @private:   pointer to memory allocated alongside the FCP operation
 *             request structure that is specifically for the LLDD to use
 *             while processing the operation. The length of the buffer
 *             corresponds to the fcprqst_priv_sz value specified in the
 *             nvme_fc_port_template supplied by the LLDD.
 *
 * Values set by the LLDD indicating completion status of the FCP operation.
 * Must be set prior to calling the done() callback.
 * @transferred_length: amount of payload data, in bytes, that were
 *             transferred. Should equal payload_length on success.
 * @rcv_rsplen: length, in bytes, of the FCP RSP IU received.
 * @status:    Completion status of the FCP operation. must be 0 upon success,
 *             negative errno value upon failure (ex: -EIO). Note: this is
 *             NOT a reflection of the NVME CQE completion status. Only the
 *             status of the FCP operation at the NVME-FC level.
 */
struct nvmefc_fcp_req {
	void			*cmdaddr;
	void			*rspaddr;
	dma_addr_t		cmddma;
	dma_addr_t		rspdma;
	u16			cmdlen;
	u16			rsplen;

	u32			payload_length;
	struct sg_table		sg_table;
	struct scatterlist	*first_sgl;
	int			sg_cnt;
	enum nvmefc_fcp_datadir	io_dir;

	__le16			sqid;

	void (*done)(struct nvmefc_fcp_req *req);

	void			*private;

	u32			transferred_length;
	u16			rcv_rsplen;
	u32			status;
} __aligned(sizeof(u64));	/* alignment for other things alloc'd with */


/*
 * Direct copy of fc_port_state enum. For later merging
 */
enum nvme_fc_obj_state {
	FC_OBJSTATE_UNKNOWN,
	FC_OBJSTATE_NOTPRESENT,
	FC_OBJSTATE_ONLINE,
	FC_OBJSTATE_OFFLINE,		/* User has taken Port Offline */
	FC_OBJSTATE_BLOCKED,
	FC_OBJSTATE_BYPASSED,
	FC_OBJSTATE_DIAGNOSTICS,
	FC_OBJSTATE_LINKDOWN,
	FC_OBJSTATE_ERROR,
	FC_OBJSTATE_LOOPBACK,
	FC_OBJSTATE_DELETED,
};


/**
 * struct nvme_fc_local_port - structure used between NVME-FC transport and
 *                 a LLDD to reference a local NVME host port.
 *                 Allocated/created by the nvme_fc_register_localport()
 *                 transport interface.
 *
 * Fields with static values for the port. Initialized by the
 * port_info struct supplied to the registration call.
 * @port_num:  NVME-FC transport host port number
 * @port_role: NVME roles are supported on the port (see FC_PORT_ROLE_xxx)
 * @node_name: FC WWNN for the port
 * @port_name: FC WWPN for the port
 * @private:   pointer to memory allocated alongside the local port
 *             structure that is specifically for the LLDD to use.
 *             The length of the buffer corresponds to the local_priv_sz
 *             value specified in the nvme_fc_port_template supplied by
 *             the LLDD.
 *
 * Fields with dynamic values. Values may change base on link state. LLDD
 * may reference fields directly to change them. Initialized by the
 * port_info struct supplied to the registration call.
 * @port_id:      FC N_Port_ID currently assigned the port. Upper 8 bits must
 *                be set to 0.
 * @port_state:   Operational state of the port.
 */
struct nvme_fc_local_port {
	/* static/read-only fields */
	u32 port_num;
	u32 port_role;
	u64 node_name;
	u64 port_name;

	void *private;

	/* dynamic fields */
	u32 port_id;
	enum nvme_fc_obj_state port_state;
} __aligned(sizeof(u64));	/* alignment for other things alloc'd with */


/**
 * struct nvme_fc_remote_port - structure used between NVME-FC transport and
 *                 a LLDD to reference a remote NVME subsystem port.
 *                 Allocated/created by the nvme_fc_register_remoteport()
 *                 transport interface.
 *
 * Fields with static values for the port. Initialized by the
 * port_info struct supplied to the registration call.
 * @port_num:  NVME-FC transport remote subsystem port number
 * @port_role: NVME roles are supported on the port (see FC_PORT_ROLE_xxx)
 * @node_name: FC WWNN for the port
 * @port_name: FC WWPN for the port
 * @localport: pointer to the NVME-FC local host port the subsystem is
 *             connected to.
 * @private:   pointer to memory allocated alongside the remote port
 *             structure that is specifically for the LLDD to use.
 *             The length of the buffer corresponds to the remote_priv_sz
 *             value specified in the nvme_fc_port_template supplied by
 *             the LLDD.
 *
 * Fields with dynamic values. Values may change base on link or login
 * state. LLDD may reference fields directly to change them. Initialized by
 * the port_info struct supplied to the registration call.
 * @port_id:      FC N_Port_ID currently assigned the port. Upper 8 bits must
 *                be set to 0.
 * @port_state:   Operational state of the remote port. Valid values are
 *                ONLINE or UNKNOWN.
 */
struct nvme_fc_remote_port {
	/* static fields */
	u32 port_num;
	u32 port_role;
	u64 node_name;
	u64 port_name;

	struct nvme_fc_local_port *localport;

	void *private;

	/* dynamic fields */
	u32 port_id;
	enum nvme_fc_obj_state port_state;
} __aligned(sizeof(u64));	/* alignment for other things alloc'd with */


/**
 * struct nvme_fc_port_template - structure containing static entrypoints and
 *                 operational parameters for an LLDD that supports NVME host
 *                 behavior. Passed by reference in port registrations.
 *                 NVME-FC transport remembers template reference and may
 *                 access it during runtime operation.
 *
 * Host/Initiator Transport Entrypoints/Parameters:
 *
 * @localport_delete:  The LLDD initiates deletion of a localport via
 *       nvme_fc_deregister_localport(). However, the teardown is
 *       asynchronous. This routine is called upon the completion of the
 *       teardown to inform the LLDD that the localport has been deleted.
 *       Entrypoint is Mandatory.
 *
 * @remoteport_delete:  The LLDD initiates deletion of a remoteport via
 *       nvme_fc_deregister_remoteport(). However, the teardown is
 *       asynchronous. This routine is called upon the completion of the
 *       teardown to inform the LLDD that the remoteport has been deleted.
 *       Entrypoint is Mandatory.
 *
 * @create_queue:  Upon creating a host<->controller association, queues are
 *       created such that they can be affinitized to cpus/cores. This
 *       callback into the LLDD to notify that a controller queue is being
 *       created.  The LLDD may choose to allocate an associated hw queue
 *       or map it onto a shared hw queue. Upon return from the call, the
 *       LLDD specifies a handle that will be given back to it for any
 *       command that is posted to the controller queue.  The handle can
 *       be used by the LLDD to map quickly to the proper hw queue for
 *       command execution.  The mask of cpu's that will map to this queue
 *       at the block-level is also passed in. The LLDD should use the
 *       queue id and/or cpu masks to ensure proper affinitization of the
 *       controller queue to the hw queue.
 *       Entrypoint is Optional.
 *
 * @delete_queue:  This is the inverse of the crete_queue. During
 *       host<->controller association teardown, this routine is called
 *       when a controller queue is being terminated. Any association with
 *       a hw queue should be termined. If there is a unique hw queue, the
 *       hw queue should be torn down.
 *       Entrypoint is Optional.
 *
 * @poll_queue:  Called to poll for the completion of an io on a blk queue.
 *       Entrypoint is Optional.
 *
 * @ls_req:  Called to issue a FC-NVME FC-4 LS service request.
 *       The nvme_fc_ls_req structure will fully describe the buffers for
 *       the request payload and where to place the response payload. The
 *       LLDD is to allocate an exchange, issue the LS request, obtain the
 *       LS response, and call the "done" routine specified in the request
 *       structure (argument to done is the ls request structure itself).
 *       Entrypoint is Mandatory.
 *
 * @fcp_io:  called to issue a FC-NVME I/O request.  The I/O may be for
 *       an admin queue or an i/o queue.  The nvmefc_fcp_req structure will
 *       fully describe the io: the buffer containing the FC-NVME CMD IU
 *       (which contains the SQE), the sg list for the payload if applicable,
 *       and the buffer to place the FC-NVME RSP IU into.  The LLDD will
 *       complete the i/o, indicating the amount of data transferred or
 *       any transport error, and call the "done" routine specified in the
 *       request structure (argument to done is the fcp request structure
 *       itself).
 *       Entrypoint is Mandatory.
 *
 * @ls_abort: called to request the LLDD to abort the indicated ls request.
 *       The call may return before the abort has completed. After aborting
 *       the request, the LLDD must still call the ls request done routine
 *       indicating an FC transport Aborted status.
 *       Entrypoint is Mandatory.
 *
 * @fcp_abort: called to request the LLDD to abort the indicated fcp request.
 *       The call may return before the abort has completed. After aborting
 *       the request, the LLDD must still call the fcp request done routine
 *       indicating an FC transport Aborted status.
 *       Entrypoint is Mandatory.
 *
 * @defer_rcv:  Called by the transport to signal the LLLD that it has
 *       begun processing of a previously received NVME CMD IU. The LLDD
 *       is now free to re-use the rcv buffer associated with the
 *       nvmefc_tgt_fcp_req.
 *
 * @max_hw_queues:  indicates the maximum number of hw queues the LLDD
 *       supports for cpu affinitization.
 *       Value is Mandatory. Must be at least 1.
 *
 * @max_sgl_segments:  indicates the maximum number of sgl segments supported
 *       by the LLDD
 *       Value is Mandatory. Must be at least 1. Recommend at least 256.
 *
 * @max_dif_sgl_segments:  indicates the maximum number of sgl segments
 *       supported by the LLDD for DIF operations.
 *       Value is Mandatory. Must be at least 1. Recommend at least 256.
 *
 * @dma_boundary:  indicates the dma address boundary where dma mappings
 *       will be split across.
 *       Value is Mandatory. Typical value is 0xFFFFFFFF to split across
 *       4Gig address boundarys
 *
 * @local_priv_sz: The LLDD sets this field to the amount of additional
 *       memory that it would like fc nvme layer to allocate on the LLDD's
 *       behalf whenever a localport is allocated.  The additional memory
 *       area solely for the of the LLDD and its location is specified by
 *       the localport->private pointer.
 *       Value is Mandatory. Allowed to be zero.
 *
 * @remote_priv_sz: The LLDD sets this field to the amount of additional
 *       memory that it would like fc nvme layer to allocate on the LLDD's
 *       behalf whenever a remoteport is allocated.  The additional memory
 *       area solely for the of the LLDD and its location is specified by
 *       the remoteport->private pointer.
 *       Value is Mandatory. Allowed to be zero.
 *
 * @lsrqst_priv_sz: The LLDD sets this field to the amount of additional
 *       memory that it would like fc nvme layer to allocate on the LLDD's
 *       behalf whenever a ls request structure is allocated. The additional
 *       memory area solely for the of the LLDD and its location is
 *       specified by the ls_request->private pointer.
 *       Value is Mandatory. Allowed to be zero.
 *
 * @fcprqst_priv_sz: The LLDD sets this field to the amount of additional
 *       memory that it would like fc nvme layer to allocate on the LLDD's
 *       behalf whenever a fcp request structure is allocated. The additional
 *       memory area solely for the of the LLDD and its location is
 *       specified by the fcp_request->private pointer.
 *       Value is Mandatory. Allowed to be zero.
 */
struct nvme_fc_port_template {
	/* initiator-based functions */
	void	(*localport_delete)(struct nvme_fc_local_port *);
	void	(*remoteport_delete)(struct nvme_fc_remote_port *);
	int	(*create_queue)(struct nvme_fc_local_port *,
				unsigned int qidx, u16 qsize,
				void **handle);
	void	(*delete_queue)(struct nvme_fc_local_port *,
				unsigned int qidx, void *handle);
	void	(*poll_queue)(struct nvme_fc_local_port *, void *handle);
	int	(*ls_req)(struct nvme_fc_local_port *,
				struct nvme_fc_remote_port *,
				struct nvmefc_ls_req *);
	int	(*fcp_io)(struct nvme_fc_local_port *,
				struct nvme_fc_remote_port *,
				void *hw_queue_handle,
				struct nvmefc_fcp_req *);
	void	(*ls_abort)(struct nvme_fc_local_port *,
				struct nvme_fc_remote_port *,
				struct nvmefc_ls_req *);
	void	(*fcp_abort)(struct nvme_fc_local_port *,
				struct nvme_fc_remote_port *,
				void *hw_queue_handle,
				struct nvmefc_fcp_req *);

	u32	max_hw_queues;
	u16	max_sgl_segments;
	u16	max_dif_sgl_segments;
	u64	dma_boundary;

	/* sizes of additional private data for data structures */
	u32	local_priv_sz;
	u32	remote_priv_sz;
	u32	lsrqst_priv_sz;
	u32	fcprqst_priv_sz;
};


/*
 * Initiator/Host functions
 */

int nvme_fc_register_localport(struct nvme_fc_port_info *pinfo,
			struct nvme_fc_port_template *template,
			struct device *dev,
			struct nvme_fc_local_port **lport_p);

int nvme_fc_unregister_localport(struct nvme_fc_local_port *localport);

int nvme_fc_register_remoteport(struct nvme_fc_local_port *localport,
			struct nvme_fc_port_info *pinfo,
			struct nvme_fc_remote_port **rport_p);

int nvme_fc_unregister_remoteport(struct nvme_fc_remote_port *remoteport);



/*
 * ***************  LLDD FC-NVME Target/Subsystem API ***************
 *
 *  For FC LLDD's that are the NVME Subsystem role
 *
 * ******************************************************************
 */

/**
 * struct nvmet_fc_port_info - port-specific ids and FC connection-specific
 *                             data element used during NVME Subsystem role
 *                             registrations
 *
 * Static fields describing the port being registered:
 * @node_name: FC WWNN for the port
 * @port_name: FC WWPN for the port
 *
 * Initialization values for dynamic port fields:
 * @port_id:      FC N_Port_ID currently assigned the port. Upper 8 bits must
 *                be set to 0.
 */
struct nvmet_fc_port_info {
	u64			node_name;
	u64			port_name;
	u32			port_id;
};


/**
 * struct nvmefc_tgt_ls_req - Structure used between LLDD and NVMET-FC
 *                            layer to represent the exchange context for
 *                            a FC-NVME Link Service (LS).
 *
 * The structure is allocated by the LLDD whenever a LS Request is received
 * from the FC link. The address of the structure is passed to the nvmet-fc
 * layer via the nvmet_fc_rcv_ls_req() call. The address of the structure
 * will be passed back to the LLDD when the response is to be transmit.
 * The LLDD is to use the address to map back to the LLDD exchange structure
 * which maintains information such as the targetport the LS was received
 * on, the remote FC NVME initiator that sent the LS, and any FC exchange
 * context.  Upon completion of the LS response transmit, the address of the
 * structure will be passed back to the LS rsp done() routine, allowing the
 * nvmet-fc layer to release dma resources. Upon completion of the done()
 * routine, no further access will be made by the nvmet-fc layer and the
 * LLDD can de-allocate the structure.
 *
 * Field initialization:
 *   At the time of the nvmet_fc_rcv_ls_req() call, there is no content that
 *     is valid in the structure.
 *
 *   When the structure is used for the LLDD->xmt_ls_rsp() call, the nvmet-fc
 *     layer will fully set the fields in order to specify the response
 *     payload buffer and its length as well as the done routine to be called
 *     upon compeletion of the transmit.  The nvmet-fc layer will also set a
 *     private pointer for its own use in the done routine.
 *
 * Values set by the NVMET-FC layer prior to calling the LLDD xmt_ls_rsp
 * entrypoint.
 * @rspbuf:   pointer to the LS response buffer
 * @rspdma:   PCI DMA address of the LS response buffer
 * @rsplen:   Length, in bytes, of the LS response buffer
 * @done:     The callback routine the LLDD is to invoke upon completion of
 *            transmitting the LS response. req argument is the pointer to
 *            the original ls request.
 * @nvmet_fc_private:  pointer to an internal NVMET-FC layer structure used
 *            as part of the NVMET-FC processing. The LLDD is not to access
 *            this pointer.
 */
struct nvmefc_tgt_ls_req {
	void		*rspbuf;
	dma_addr_t	rspdma;
	u16		rsplen;

	void (*done)(struct nvmefc_tgt_ls_req *req);
	void *nvmet_fc_private;		/* LLDD is not to access !! */
};

/* Operations that NVME-FC layer may request the LLDD to perform for FCP */
enum {
	NVMET_FCOP_READDATA	= 1,	/* xmt data to initiator */
	NVMET_FCOP_WRITEDATA	= 2,	/* xmt data from initiator */
	NVMET_FCOP_READDATA_RSP	= 3,	/* xmt data to initiator and send
					 * rsp as well
					 */
	NVMET_FCOP_RSP		= 4,	/* send rsp frame */
};

/**
 * struct nvmefc_tgt_fcp_req - Structure used between LLDD and NVMET-FC
 *                            layer to represent the exchange context and
 *                            the specific FC-NVME IU operation(s) to perform
 *                            for a FC-NVME FCP IO.
 *
 * Structure used between LLDD and nvmet-fc layer to represent the exchange
 * context for a FC-NVME FCP I/O operation (e.g. a nvme sqe, the sqe-related
 * memory transfers, and its assocated cqe transfer).
 *
 * The structure is allocated by the LLDD whenever a FCP CMD IU is received
 * from the FC link. The address of the structure is passed to the nvmet-fc
 * layer via the nvmet_fc_rcv_fcp_req() call. The address of the structure
 * will be passed back to the LLDD for the data operations and transmit of
 * the response. The LLDD is to use the address to map back to the LLDD
 * exchange structure which maintains information such as the targetport
 * the FCP I/O was received on, the remote FC NVME initiator that sent the
 * FCP I/O, and any FC exchange context.  Upon completion of the FCP target
 * operation, the address of the structure will be passed back to the FCP
 * op done() routine, allowing the nvmet-fc layer to release dma resources.
 * Upon completion of the done() routine for either RSP or ABORT ops, no
 * further access will be made by the nvmet-fc layer and the LLDD can
 * de-allocate the structure.
 *
 * Field initialization:
 *   At the time of the nvmet_fc_rcv_fcp_req() call, there is no content that
 *     is valid in the structure.
 *
 *   When the structure is used for an FCP target operation, the nvmet-fc
 *     layer will fully set the fields in order to specify the scattergather
 *     list, the transfer length, as well as the done routine to be called
 *     upon compeletion of the operation.  The nvmet-fc layer will also set a
 *     private pointer for its own use in the done routine.
 *
 * Values set by the NVMET-FC layer prior to calling the LLDD fcp_op
 * entrypoint.
 * @op:       Indicates the FCP IU operation to perform (see NVMET_FCOP_xxx)
 * @hwqid:    Specifies the hw queue index (0..N-1, where N is the
 *            max_hw_queues value from the LLD's nvmet_fc_target_template)
 *            that the operation is to use.
 * @offset:   Indicates the DATA_OUT/DATA_IN payload offset to be tranferred.
 *            Field is only valid on WRITEDATA, READDATA, or READDATA_RSP ops.
 * @timeout:  amount of time, in seconds, to wait for a response from the NVME
 *            host. A value of 0 is an infinite wait.
 *            Valid only for the following ops:
 *              WRITEDATA: caps the wait for data reception
 *              READDATA_RSP & RSP: caps wait for FCP_CONF reception (if used)
 * @transfer_length: the length, in bytes, of the DATA_OUT or DATA_IN payload
 *            that is to be transferred.
 *            Valid only for the WRITEDATA, READDATA, or READDATA_RSP ops.
 * @ba_rjt:   Contains the BA_RJT payload that is to be transferred.
 *            Valid only for the NVMET_FCOP_BA_RJT op.
 * @sg:       Scatter/gather list for the DATA_OUT/DATA_IN payload data.
 *            Valid only for the WRITEDATA, READDATA, or READDATA_RSP ops.
 * @sg_cnt:   Number of valid entries in the scatter/gather list.
 *            Valid only for the WRITEDATA, READDATA, or READDATA_RSP ops.
 * @rspaddr:  pointer to the FCP RSP IU buffer to be transmit
 *            Used by RSP and READDATA_RSP ops
 * @rspdma:   PCI DMA address of the FCP RSP IU buffer
 *            Used by RSP and READDATA_RSP ops
 * @rsplen:   Length, in bytes, of the FCP RSP IU buffer
 *            Used by RSP and READDATA_RSP ops
 * @done:     The callback routine the LLDD is to invoke upon completion of
 *            the operation. req argument is the pointer to the original
 *            FCP subsystem op request.
 * @nvmet_fc_private:  pointer to an internal NVMET-FC layer structure used
 *            as part of the NVMET-FC processing. The LLDD is not to
 *            reference this field.
 *
 * Values set by the LLDD indicating completion status of the FCP operation.
 * Must be set prior to calling the done() callback.
 * @transferred_length: amount of DATA_OUT payload data received by a
 *            a WRITEDATA operation. If not a WRITEDATA operation, value must
 *            be set to 0. Should equal transfer_length on success.
 * @fcp_error: status of the FCP operation. Must be 0 on success; on failure
 *            must be a NVME_SC_FC_xxxx value.
 */
struct nvmefc_tgt_fcp_req {
	u8			op;
	u16			hwqid;
	u32			offset;
	u32			timeout;
	u32			transfer_length;
	struct fc_ba_rjt	ba_rjt;
	struct scatterlist	sg[NVME_FC_MAX_SEGMENTS];
	int			sg_cnt;
	void			*rspaddr;
	dma_addr_t		rspdma;
	u16			rsplen;

	void (*done)(struct nvmefc_tgt_fcp_req *);

	void *nvmet_fc_private;		/* LLDD is not to access !! */

	u32			transferred_length;
	int			fcp_error;
};


/* Target Features (Bit fields) LLDD supports */
enum {
	NVMET_FCTGTFEAT_READDATA_RSP = (1 << 0),
		/* Bit 0: supports the NVMET_FCPOP_READDATA_RSP op, which
		 * sends (the last) Read Data sequence followed by the RSP
		 * sequence in one LLDD operation. Errors during Data
		 * sequence transmit must not allow RSP sequence to be sent.
		 */
	NVMET_FCTGTFEAT_CMD_IN_ISR = (1 << 1),
		/* Bit 2: When 0, the LLDD is calling the cmd rcv handler
		 * in a non-isr context, allowing the transport to finish
		 * op completion in the calling context. When 1, the LLDD
		 * is calling the cmd rcv handler in an ISR context,
		 * requiring the transport to transition to a workqueue
		 * for op completion.
		 */
	NVMET_FCTGTFEAT_OPDONE_IN_ISR = (1 << 2),
		/* Bit 3: When 0, the LLDD is calling the op done handler
		 * in a non-isr context, allowing the transport to finish
		 * op completion in the calling context. When 1, the LLDD
		 * is calling the op done handler in an ISR context,
		 * requiring the transport to transition to a workqueue
		 * for op completion.
		 */
};


/**
 * struct nvmet_fc_target_port - structure used between NVME-FC transport and
 *                 a LLDD to reference a local NVME subsystem port.
 *                 Allocated/created by the nvme_fc_register_targetport()
 *                 transport interface.
 *
 * Fields with static values for the port. Initialized by the
 * port_info struct supplied to the registration call.
 * @port_num:  NVME-FC transport subsytem port number
 * @node_name: FC WWNN for the port
 * @port_name: FC WWPN for the port
 * @private:   pointer to memory allocated alongside the local port
 *             structure that is specifically for the LLDD to use.
 *             The length of the buffer corresponds to the target_priv_sz
 *             value specified in the nvme_fc_target_template supplied by
 *             the LLDD.
 *
 * Fields with dynamic values. Values may change base on link state. LLDD
 * may reference fields directly to change them. Initialized by the
 * port_info struct supplied to the registration call.
 * @port_id:      FC N_Port_ID currently assigned the port. Upper 8 bits must
 *                be set to 0.
 * @port_state:   Operational state of the port.
 */
struct nvmet_fc_target_port {
	/* static/read-only fields */
	u32 port_num;
	u64 node_name;
	u64 port_name;

	void *private;

	/* dynamic fields */
	u32 port_id;
	enum nvme_fc_obj_state port_state;
} __aligned(sizeof(u64));	/* alignment for other things alloc'd with */


/**
 * struct nvmet_fc_target_template - structure containing static entrypoints
 *                 and operational parameters for an LLDD that supports NVME
 *                 subsystem behavior. Passed by reference in port
 *                 registrations. NVME-FC transport remembers template
 *                 reference and may access it during runtime operation.
 *
 * Subsystem/Target Transport Entrypoints/Parameters:
 *
 * @targetport_delete:  The LLDD initiates deletion of a targetport via
 *       nvmet_fc_unregister_targetport(). However, the teardown is
 *       asynchronous. This routine is called upon the completion of the
 *       teardown to inform the LLDD that the targetport has been deleted.
 *       Entrypoint is Mandatory.
 *
 * @xmt_ls_rsp:  Called to transmit the response to a FC-NVME FC-4 LS service.
 *       The nvmefc_tgt_ls_req structure is the same LLDD-supplied exchange
 *       structure specified in the nvmet_fc_rcv_ls_req() call made when
 *       the LS request was received.  The structure will fully describe
 *       the buffers for the response payload and the dma address of the
 *       payload. The LLDD is to transmit the response (or return a non-zero
 *       errno status), and upon completion of the transmit, call the
 *       "done" routine specified in the nvmefc_tgt_ls_req structure
 *       (argument to done is the ls reqwuest structure itself).
 *       After calling the done routine, the LLDD shall consider the
 *       LS handling complete and the nvmefc_tgt_ls_req structure may
 *       be freed/released.
 *       Entrypoint is Mandatory.
 *
 * @fcp_op:  Called to perform a data transfer or transmit a response.
 *       The nvmefc_tgt_fcp_req structure is the same LLDD-supplied
 *       exchange structure specified in the nvmet_fc_rcv_fcp_req() call
 *       made when the FCP CMD IU was received. The op field in the
 *       structure shall indicate the operation for the LLDD to perform
 *       relative to the io.
 *         NVMET_FCOP_READDATA operation: the LLDD is to send the
 *           payload data (described by sglist) to the host in 1 or
 *           more FC sequences (preferrably 1).  Note: the fc-nvme layer
 *           may call the READDATA operation multiple times for longer
 *           payloads.
 *         NVMET_FCOP_WRITEDATA operation: the LLDD is to receive the
 *           payload data (described by sglist) from the host via 1 or
 *           more FC sequences (preferrably 1). The LLDD is to generate
 *           the XFER_RDY IU(s) corresponding to the data being requested.
 *           Note: the FC-NVME layer may call the WRITEDATA operation
 *           multiple times for longer payloads.
 *         NVMET_FCOP_READDATA_RSP operation: the LLDD is to send the
 *           payload data (described by sglist) to the host in 1 or
 *           more FC sequences (preferrably 1). If an error occurs during
 *           payload data transmission, the LLDD is to set the
 *           nvmefc_tgt_fcp_req fcp_error and transferred_length field, then
 *           consider the operation complete. On error, the LLDD is to not
 *           transmit the FCP_RSP iu. If all payload data is transferred
 *           successfully, the LLDD is to update the nvmefc_tgt_fcp_req
 *           transferred_length field and may subsequently transmit the
 *           FCP_RSP iu payload (described by rspbuf, rspdma, rsplen).
 *           If FCP_CONF is supported, the LLDD is to await FCP_CONF
 *           reception to confirm the RSP reception by the host. The LLDD
 *           may retramsit the FCP_RSP iu if necessary per FC-NVME. Upon
 *           transmission of the FCP_RSP iu if FCP_CONF is not supported,
 *           or upon success/failure of FCP_CONF if it is supported, the
 *           LLDD is to set the nvmefc_tgt_fcp_req fcp_error field and
 *           consider the operation complete.
 *         NVMET_FCOP_RSP: the LLDD is to transmit the FCP_RSP iu payload
 *           (described by rspbuf, rspdma, rsplen). If FCP_CONF is
 *           supported, the LLDD is to await FCP_CONF reception to confirm
 *           the RSP reception by the host. The LLDD may retramsit the
 *           FCP_RSP iu if FCP_CONF is not received per FC-NVME. Upon
 *           transmission of the FCP_RSP iu if FCP_CONF is not supported,
 *           or upon success/failure of FCP_CONF if it is supported, the
 *           LLDD is to set the nvmefc_tgt_fcp_req fcp_error field and
 *           consider the operation complete.
 *       Upon completing the indicated operation, the LLDD is to set the
 *       status fields for the operation (tranferred_length and fcp_error
 *       status) in the request, then call the "done" routine
 *       indicated in the fcp request. After the operation completes,
 *       regardless of whether the FCP_RSP iu was successfully transmit,
 *       the LLDD-supplied exchange structure must remain valid until the
 *       transport calls the fcp_req_release() callback to return ownership
 *       of the exchange structure back to the LLDD so that it may be used
 *       for another fcp command.
 *       Note: when calling the done routine for READDATA or WRITEDATA
 *       operations, the fc-nvme layer may immediate convert, in the same
 *       thread and before returning to the LLDD, the fcp operation to
 *       the next operation for the fcp io and call the LLDDs fcp_op
 *       call again. If fields in the fcp request are to be accessed post
 *       the done call, the LLDD should save their values prior to calling
 *       the done routine, and inspect the save values after the done
 *       routine.
 *       Returns 0 on success, -<errno> on failure (Ex: -EIO)
 *       Entrypoint is Mandatory.
 *
 * @fcp_abort:  Called by the transport to abort an active command.
 *       The command may be in-between operations (nothing active in LLDD)
 *       or may have an active WRITEDATA operation pending. The LLDD is to
 *       initiate the ABTS process for the command and return from the
 *       callback. The ABTS does not need to be complete on the command.
 *       The fcp_abort callback inherently cannot fail. After the
 *       fcp_abort() callback completes, the transport will wait for any
 *       outstanding operation (if there was one) to complete, then will
 *       call the fcp_req_release() callback to return the command's
 *       exchange context back to the LLDD.
 *
 * @fcp_req_release:  Called by the transport to return a nvmefc_tgt_fcp_req
 *       to the LLDD after all operations on the fcp operation are complete.
 *       This may be due to the command completing or upon completion of
 *       abort cleanup.
 *
 * @max_hw_queues:  indicates the maximum number of hw queues the LLDD
 *       supports for cpu affinitization.
 *       Value is Mandatory. Must be at least 1.
 *
 * @max_sgl_segments:  indicates the maximum number of sgl segments supported
 *       by the LLDD
 *       Value is Mandatory. Must be at least 1. Recommend at least 256.
 *
 * @max_dif_sgl_segments:  indicates the maximum number of sgl segments
 *       supported by the LLDD for DIF operations.
 *       Value is Mandatory. Must be at least 1. Recommend at least 256.
 *
 * @dma_boundary:  indicates the dma address boundary where dma mappings
 *       will be split across.
 *       Value is Mandatory. Typical value is 0xFFFFFFFF to split across
 *       4Gig address boundarys
 *
 * @target_features: The LLDD sets bits in this field to correspond to
 *       optional features that are supported by the LLDD.
 *       Refer to the NVMET_FCTGTFEAT_xxx values.
 *       Value is Mandatory. Allowed to be zero.
 *
 * @target_priv_sz: The LLDD sets this field to the amount of additional
 *       memory that it would like fc nvme layer to allocate on the LLDD's
 *       behalf whenever a targetport is allocated.  The additional memory
 *       area solely for the of the LLDD and its location is specified by
 *       the targetport->private pointer.
 *       Value is Mandatory. Allowed to be zero.
 */
struct nvmet_fc_target_template {
	void (*targetport_delete)(struct nvmet_fc_target_port *tgtport);
	int (*xmt_ls_rsp)(struct nvmet_fc_target_port *tgtport,
				struct nvmefc_tgt_ls_req *tls_req);
	int (*fcp_op)(struct nvmet_fc_target_port *tgtport,
				struct nvmefc_tgt_fcp_req *fcpreq);
	void (*fcp_abort)(struct nvmet_fc_target_port *tgtport,
				struct nvmefc_tgt_fcp_req *fcpreq);
	void (*fcp_req_release)(struct nvmet_fc_target_port *tgtport,
				struct nvmefc_tgt_fcp_req *fcpreq);
	void (*defer_rcv)(struct nvmet_fc_target_port *tgtport,
				struct nvmefc_tgt_fcp_req *fcpreq);

	u32	max_hw_queues;
	u16	max_sgl_segments;
	u16	max_dif_sgl_segments;
	u64	dma_boundary;

	u32	target_features;

	u32	target_priv_sz;
};


int nvmet_fc_register_targetport(struct nvmet_fc_port_info *portinfo,
			struct nvmet_fc_target_template *template,
			struct device *dev,
			struct nvmet_fc_target_port **tgtport_p);

int nvmet_fc_unregister_targetport(struct nvmet_fc_target_port *tgtport);

int nvmet_fc_rcv_ls_req(struct nvmet_fc_target_port *tgtport,
			struct nvmefc_tgt_ls_req *lsreq,
			void *lsreqbuf, u32 lsreqbuf_len);

int nvmet_fc_rcv_fcp_req(struct nvmet_fc_target_port *tgtport,
			struct nvmefc_tgt_fcp_req *fcpreq,
			void *cmdiubuf, u32 cmdiubuf_len);

void nvmet_fc_rcv_fcp_abort(struct nvmet_fc_target_port *tgtport,
			struct nvmefc_tgt_fcp_req *fcpreq);

#endif /* _NVME_FC_DRIVER_H */