/*
 * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
 * Copyright (C) 2009 - 2010 Bart Van Assche <bvanassche@acm.org>.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */

#ifndef IB_SRPT_H
#define IB_SRPT_H

#include <linux/types.h>
#include <linux/list.h>
#include <linux/wait.h>

#include <rdma/ib_verbs.h>
#include <rdma/ib_sa.h>
#include <rdma/ib_cm.h>
#include <rdma/rw.h>

#include <scsi/srp.h>

#include "ib_dm_mad.h"

/*
 * The prefix the ServiceName field must start with in the device management
 * ServiceEntries attribute pair. See also the SRP specification.
 */
#define SRP_SERVICE_NAME_PREFIX         "SRP.T10:"

enum {
        /*
         * SRP IOControllerProfile attributes for SRP target ports that have
         * not been defined in <scsi/srp.h>. Source: section B.7, table B.7
         * in the SRP specification.
         */
        SRP_PROTOCOL = 0x0108,
        SRP_PROTOCOL_VERSION = 0x0001,
        SRP_IO_SUBCLASS = 0x609e,
        SRP_SEND_TO_IOC = 0x01,
        SRP_SEND_FROM_IOC = 0x02,
        SRP_RDMA_READ_FROM_IOC = 0x08,
        SRP_RDMA_WRITE_FROM_IOC = 0x20,

        /*
         * srp_login_cmd.req_flags bitmasks. See also table 9 in the SRP
         * specification.
         */
        SRP_MTCH_ACTION = 0x03, /* MULTI-CHANNEL ACTION */
        SRP_LOSOLNT = 0x10, /* logout solicited notification */
        SRP_CRSOLNT = 0x20, /* credit request solicited notification */
        SRP_AESOLNT = 0x40, /* asynchronous event solicited notification */

        /*
         * srp_cmd.sol_nt / srp_tsk_mgmt.sol_not bitmasks. See also tables
         * 18 and 20 in the SRP specification.
         */
        SRP_SCSOLNT = 0x02, /* SCSOLNT = successful solicited notification */
        SRP_UCSOLNT = 0x04, /* UCSOLNT = unsuccessful solicited notification */

        /*
         * srp_rsp.sol_not / srp_t_logout.sol_not bitmasks. See also tables
         * 16 and 22 in the SRP specification.
         */
        SRP_SOLNT = 0x01, /* SOLNT = solicited notification */

        /* See also table 24 in the SRP specification. */
        SRP_TSK_MGMT_SUCCESS = 0x00,
        SRP_TSK_MGMT_FUNC_NOT_SUPP = 0x04,
        SRP_TSK_MGMT_FAILED = 0x05,

        /* See also table 21 in the SRP specification. */
        SRP_CMD_SIMPLE_Q = 0x0,
        SRP_CMD_HEAD_OF_Q = 0x1,
        SRP_CMD_ORDERED_Q = 0x2,
        SRP_CMD_ACA = 0x4,

        SRP_LOGIN_RSP_MULTICHAN_NO_CHAN = 0x0,
        SRP_LOGIN_RSP_MULTICHAN_TERMINATED = 0x1,
        SRP_LOGIN_RSP_MULTICHAN_MAINTAINED = 0x2,

        SRPT_DEF_SG_TABLESIZE = 128,
        /*
         * An experimentally determined value that avoids that QP creation
         * fails due to "swiotlb buffer is full" on systems using the swiotlb.
         */
        SRPT_MAX_SG_PER_WQE = 16,

        MIN_SRPT_SQ_SIZE = 16,
        DEF_SRPT_SQ_SIZE = 4096,
        SRPT_RQ_SIZE = 128,
        MIN_SRPT_SRQ_SIZE = 4,
        DEFAULT_SRPT_SRQ_SIZE = 4095,
        MAX_SRPT_SRQ_SIZE = 65535,
        MAX_SRPT_RDMA_SIZE = 1U << 24,
        MAX_SRPT_RSP_SIZE = 1024,

        MIN_MAX_REQ_SIZE = 996,
        DEFAULT_MAX_REQ_SIZE
                = sizeof(struct srp_cmd)/*48*/
                + sizeof(struct srp_indirect_buf)/*20*/
                + 128 * sizeof(struct srp_direct_buf)/*16*/,

        MIN_MAX_RSP_SIZE = sizeof(struct srp_rsp)/*36*/ + 4,
        DEFAULT_MAX_RSP_SIZE = 256, /* leaves 220 bytes for sense data */

        DEFAULT_MAX_RDMA_SIZE = 65536,
};

/**
 * enum srpt_command_state - SCSI command state managed by SRPT.
 * @SRPT_STATE_NEW:           New command arrived and is being processed.
 * @SRPT_STATE_NEED_DATA:     Processing a write or bidir command and waiting
 *                            for data arrival.
 * @SRPT_STATE_DATA_IN:       Data for the write or bidir command arrived and is
 *                            being processed.
 * @SRPT_STATE_CMD_RSP_SENT:  SRP_RSP for SRP_CMD has been sent.
 * @SRPT_STATE_MGMT:          Processing a SCSI task management command.
 * @SRPT_STATE_MGMT_RSP_SENT: SRP_RSP for SRP_TSK_MGMT has been sent.
 * @SRPT_STATE_DONE:          Command processing finished successfully, command
 *                            processing has been aborted or command processing
 *                            failed.
 */
enum srpt_command_state {
        SRPT_STATE_NEW           = 0,
        SRPT_STATE_NEED_DATA     = 1,
        SRPT_STATE_DATA_IN       = 2,
        SRPT_STATE_CMD_RSP_SENT  = 3,
        SRPT_STATE_MGMT          = 4,
        SRPT_STATE_MGMT_RSP_SENT = 5,
        SRPT_STATE_DONE          = 6,
};

/**
 * struct srpt_ioctx - Shared SRPT I/O context information.
 * @buf:   Pointer to the buffer.
 * @dma:   DMA address of the buffer.
 * @index: Index of the I/O context in its ioctx_ring array.
 */
struct srpt_ioctx {
        struct ib_cqe           cqe;
        void                    *buf;
        dma_addr_t              dma;
        uint32_t                index;
};

/**
 * struct srpt_recv_ioctx - SRPT receive I/O context.
 * @ioctx:     See above.
 * @wait_list: Node for insertion in srpt_rdma_ch.cmd_wait_list.
 */
struct srpt_recv_ioctx {
        struct srpt_ioctx       ioctx;
        struct list_head        wait_list;
};
        
struct srpt_rw_ctx {
        struct rdma_rw_ctx      rw;
        struct scatterlist      *sg;
        unsigned int            nents;
};

/**
 * struct srpt_send_ioctx - SRPT send I/O context.
 * @ioctx:       See above.
 * @ch:          Channel pointer.
 * @spinlock:    Protects 'state'.
 * @state:       I/O context state.
 * @cmd:         Target core command data structure.
 * @sense_data:  SCSI sense data.
 */
struct srpt_send_ioctx {
        struct srpt_ioctx       ioctx;
        struct srpt_rdma_ch     *ch;

        struct srpt_rw_ctx      s_rw_ctx;
        struct srpt_rw_ctx      *rw_ctxs;

        struct ib_cqe           rdma_cqe;
        struct list_head        free_list;
        spinlock_t              spinlock;
        enum srpt_command_state state;
        struct se_cmd           cmd;
        struct completion       tx_done;
        u8                      n_rdma;
        u8                      n_rw_ctx;
        bool                    queue_status_only;
        u8                      sense_data[TRANSPORT_SENSE_BUFFER];
};

/**
 * enum rdma_ch_state - SRP channel state.
 * @CH_CONNECTING:    QP is in RTR state; waiting for RTU.
 * @CH_LIVE:          QP is in RTS state.
 * @CH_DISCONNECTING: DREQ has been sent and waiting for DREP or DREQ has
 *                    been received.
 * @CH_DRAINING:      DREP has been received or waiting for DREP timed out
 *                    and last work request has been queued.
 * @CH_DISCONNECTED:  Last completion has been received.
 */
enum rdma_ch_state {
        CH_CONNECTING,
        CH_LIVE,
        CH_DISCONNECTING,
        CH_DRAINING,
        CH_DISCONNECTED,
};

/**
 * struct srpt_rdma_ch - RDMA channel.
 * @cm_id:         IB CM ID associated with the channel.
 * @qp:            IB queue pair used for communicating over this channel.
 * @cq:            IB completion queue for this channel.
 * @rq_size:       IB receive queue size.
 * @rsp_size       IB response message size in bytes.
 * @sq_wr_avail:   number of work requests available in the send queue.
 * @sport:         pointer to the information of the HCA port used by this
 *                 channel.
 * @i_port_id:     128-bit initiator port identifier copied from SRP_LOGIN_REQ.
 * @t_port_id:     128-bit target port identifier copied from SRP_LOGIN_REQ.
 * @max_ti_iu_len: maximum target-to-initiator information unit length.
 * @req_lim:       request limit: maximum number of requests that may be sent
 *                 by the initiator without having received a response.
 * @req_lim_delta: Number of credits not yet sent back to the initiator.
 * @spinlock:      Protects free_list and state.
 * @free_list:     Head of list with free send I/O contexts.
 * @state:         channel state. See also enum rdma_ch_state.
 * @ioctx_ring:    Send ring.
 * @list:          Node for insertion in the srpt_device.rch_list list.
 * @cmd_wait_list: List of SCSI commands that arrived before the RTU event. This
 *                 list contains struct srpt_ioctx elements and is protected
 *                 against concurrent modification by the cm_id spinlock.
 * @sess:          Session information associated with this SRP channel.
 * @sess_name:     Session name.
 * @ini_guid:      Initiator port GUID.
 * @release_work:  Allows scheduling of srpt_release_channel().
 * @release_done:  Enables waiting for srpt_release_channel() completion.
 */
struct srpt_rdma_ch {
        struct ib_cm_id         *cm_id;
        struct ib_qp            *qp;
        struct ib_cq            *cq;
        struct ib_cqe           zw_cqe;
        struct kref             kref;
        int                     rq_size;
        u32                     rsp_size;
        atomic_t                sq_wr_avail;
        struct srpt_port        *sport;
        u8                      i_port_id[16];
        u8                      t_port_id[16];
        int                     max_ti_iu_len;
        atomic_t                req_lim;
        atomic_t                req_lim_delta;
        spinlock_t              spinlock;
        struct list_head        free_list;
        enum rdma_ch_state      state;
        struct srpt_send_ioctx  **ioctx_ring;
        struct list_head        list;
        struct list_head        cmd_wait_list;
        struct se_session       *sess;
        u8                      sess_name[36];
        u8                      ini_guid[24];
        struct work_struct      release_work;
        struct completion       *release_done;
};

/**
 * struct srpt_port_attib - Attributes for SRPT port
 * @srp_max_rdma_size: Maximum size of SRP RDMA transfers for new connections.
 * @srp_max_rsp_size: Maximum size of SRP response messages in bytes.
 * @srp_sq_size: Shared receive queue (SRQ) size.
 */
struct srpt_port_attrib {
        u32                     srp_max_rdma_size;
        u32                     srp_max_rsp_size;
        u32                     srp_sq_size;
};

/**
 * struct srpt_port - Information associated by SRPT with a single IB port.
 * @sdev:      backpointer to the HCA information.
 * @mad_agent: per-port management datagram processing information.
 * @enabled:   Whether or not this target port is enabled.
 * @port_guid: ASCII representation of Port GUID
 * @port_gid:  ASCII representation of Port GID
 * @port:      one-based port number.
 * @sm_lid:    cached value of the port's sm_lid.
 * @lid:       cached value of the port's lid.
 * @gid:       cached value of the port's gid.
 * @port_acl_lock spinlock for port_acl_list:
 * @work:      work structure for refreshing the aforementioned cached values.
 * @port_guid_tpg: TPG associated with target port GUID.
 * @port_guid_wwn: WWN associated with target port GUID.
 * @port_gid_tpg:  TPG associated with target port GID.
 * @port_gid_wwn:  WWN associated with target port GID.
 * @port_acl_list: Head of the list with all node ACLs for this port.
 */
struct srpt_port {
        struct srpt_device      *sdev;
        struct ib_mad_agent     *mad_agent;
        bool                    enabled;
        u8                      port_guid[24];
        u8                      port_gid[64];
        u8                      port;
        u32                     sm_lid;
        u32                     lid;
        union ib_gid            gid;
        struct work_struct      work;
        struct se_portal_group  port_guid_tpg;
        struct se_wwn           port_guid_wwn;
        struct se_portal_group  port_gid_tpg;
        struct se_wwn           port_gid_wwn;
        struct srpt_port_attrib port_attrib;
};

/**
 * struct srpt_device - Information associated by SRPT with a single HCA.
 * @device:        Backpointer to the struct ib_device managed by the IB core.
 * @pd:            IB protection domain.
 * @mr:            L_Key (local key) with write access to all local memory.
 * @srq:           Per-HCA SRQ (shared receive queue).
 * @cm_id:         Connection identifier.
 * @srq_size:      SRQ size.
 * @ioctx_ring:    Per-HCA SRQ.
 * @rch_list:      Per-device channel list -- see also srpt_rdma_ch.list.
 * @ch_releaseQ:   Enables waiting for removal from rch_list.
 * @mutex:         Protects rch_list.
 * @port:          Information about the ports owned by this HCA.
 * @event_handler: Per-HCA asynchronous IB event handler.
 * @list:          Node in srpt_dev_list.
 */
struct srpt_device {
        struct ib_device        *device;
        struct ib_pd            *pd;
        struct ib_srq           *srq;
        struct ib_cm_id         *cm_id;
        int                     srq_size;
        struct srpt_recv_ioctx  **ioctx_ring;
        struct list_head        rch_list;
        wait_queue_head_t       ch_releaseQ;
        struct mutex            mutex;
        struct srpt_port        port[2];
        struct ib_event_handler event_handler;
        struct list_head        list;
};

#endif                          /* IB_SRPT_H */