/*
 * Copyright (c) 2005 Cisco Systems.  All rights reserved.
 *
 * 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_SRP_H
#define IB_SRP_H

#include <linux/types.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/scatterlist.h>

#include <scsi/scsi_host.h>
#include <scsi/scsi_cmnd.h>

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

enum {
        SRP_PATH_REC_TIMEOUT_MS = 1000,
        SRP_ABORT_TIMEOUT_MS    = 5000,

        SRP_PORT_REDIRECT       = 1,
        SRP_DLID_REDIRECT       = 2,
        SRP_STALE_CONN          = 3,

        SRP_DEF_SG_TABLESIZE    = 12,

        SRP_DEFAULT_QUEUE_SIZE  = 1 << 6,
        SRP_RSP_SQ_SIZE         = 1,
        SRP_TSK_MGMT_SQ_SIZE    = 1,
        SRP_DEFAULT_CMD_SQ_SIZE = SRP_DEFAULT_QUEUE_SIZE - SRP_RSP_SQ_SIZE -
                                  SRP_TSK_MGMT_SQ_SIZE,

        SRP_MAX_PAGES_PER_MR    = 512,

        SRP_MAX_ADD_CDB_LEN     = 16,

        SRP_MAX_IMM_SGE         = 2,
        SRP_MAX_SGE             = SRP_MAX_IMM_SGE + 1,
        /*
         * Choose the immediate data offset such that a 32 byte CDB still fits.
         */
        SRP_IMM_DATA_OFFSET     = sizeof(struct srp_cmd) +
                                  SRP_MAX_ADD_CDB_LEN +
                                  sizeof(struct srp_imm_buf),
};

enum {
        SRP_TAG_NO_REQ          = ~0U,
        SRP_TAG_TSK_MGMT        = BIT(31),
};

enum srp_target_state {
        SRP_TARGET_SCANNING,
        SRP_TARGET_LIVE,
        SRP_TARGET_REMOVED,
};

enum srp_iu_type {
        SRP_IU_CMD,
        SRP_IU_TSK_MGMT,
        SRP_IU_RSP,
};

/*
 * RDMA adapter in the initiator system.
 *
 * @dev_list: List of RDMA ports associated with this RDMA adapter (srp_host).
 * @mr_page_mask: HCA memory registration page mask.
 * @mr_page_size: HCA memory registration page size.
 * @mr_max_size: Maximum size in bytes of a single FR registration request.
 */
struct srp_device {
        struct list_head        dev_list;
        struct ib_device       *dev;
        struct ib_pd           *pd;
        u32                     global_rkey;
        u64                     mr_page_mask;
        int                     mr_page_size;
        int                     mr_max_size;
        int                     max_pages_per_mr;
        bool                    has_fr;
        bool                    use_fast_reg;
};

/*
 * One port of an RDMA adapter in the initiator system.
 *
 * @target_list: List of connected target ports (struct srp_target_port).
 * @target_lock: Protects @target_list.
 */
struct srp_host {
        struct srp_device      *srp_dev;
        u32                     port;
        struct device           dev;
        struct list_head        target_list;
        spinlock_t              target_lock;
        struct list_head        list;
        struct mutex            add_target_mutex;
};

struct srp_request {
        struct scsi_cmnd       *scmnd;
        struct srp_iu          *cmd;
        struct srp_fr_desc     **fr_list;
        struct srp_direct_buf  *indirect_desc;
        dma_addr_t              indirect_dma_addr;
        short                   nmdesc;
        struct ib_cqe           reg_cqe;
};

/**
 * struct srp_rdma_ch
 * @comp_vector: Completion vector used by this RDMA channel.
 * @max_it_iu_len: Maximum initiator-to-target information unit length.
 * @max_ti_iu_len: Maximum target-to-initiator information unit length.
 */
struct srp_rdma_ch {
        /* These are RW in the hot path, and commonly used together */
        struct list_head        free_tx;
        spinlock_t              lock;
        s32                     req_lim;

        /* These are read-only in the hot path */
        struct srp_target_port *target ____cacheline_aligned_in_smp;
        struct ib_cq           *send_cq;
        struct ib_cq           *recv_cq;
        struct ib_qp           *qp;
        struct srp_fr_pool     *fr_pool;
        uint32_t                max_it_iu_len;
        uint32_t                max_ti_iu_len;
        u8                      max_imm_sge;
        bool                    use_imm_data;

        /* Everything above this point is used in the hot path of
         * command processing. Try to keep them packed into cachelines.
         */

        struct completion       done;
        int                     status;

        union {
                struct ib_cm {
                        struct sa_path_rec      path;
                        struct ib_sa_query      *path_query;
                        int                     path_query_id;
                        struct ib_cm_id         *cm_id;
                } ib_cm;
                struct rdma_cm {
                        struct rdma_cm_id       *cm_id;
                } rdma_cm;
        };

        struct srp_iu         **tx_ring;
        struct srp_iu         **rx_ring;
        int                     comp_vector;

        u64                     tsk_mgmt_tag;
        struct completion       tsk_mgmt_done;
        u8                      tsk_mgmt_status;
        bool                    connected;
};

/**
 * struct srp_target_port - RDMA port in the SRP target system
 * @comp_vector: Completion vector used by the first RDMA channel created for
 *   this target port.
 */
struct srp_target_port {
        /* read and written in the hot path */
        spinlock_t              lock;

        /* read only in the hot path */
        u32                     global_rkey;
        struct srp_rdma_ch      *ch;
        struct net              *net;
        u32                     ch_count;
        u32                     lkey;
        enum srp_target_state   state;
        uint32_t                max_it_iu_size;
        unsigned int            cmd_sg_cnt;
        unsigned int            indirect_size;
        bool                    allow_ext_sg;

        /* other member variables */
        union ib_gid            sgid;
        __be64                  id_ext;
        __be64                  ioc_guid;
        __be64                  initiator_ext;
        u16                     io_class;
        struct srp_host        *srp_host;
        struct Scsi_Host       *scsi_host;
        struct srp_rport       *rport;
        char                    target_name[32];
        unsigned int            scsi_id;
        unsigned int            sg_tablesize;
        unsigned int            target_can_queue;
        int                     mr_pool_size;
        int                     mr_per_cmd;
        int                     queue_size;
        int                     comp_vector;
        int                     tl_retry_count;

        bool                    using_rdma_cm;

        union {
                struct {
                        __be64                  service_id;
                        union ib_gid            orig_dgid;
                        __be16                  pkey;
                } ib_cm;
                struct {
                        union {
                                struct sockaddr_in      ip4;
                                struct sockaddr_in6     ip6;
                                struct sockaddr         sa;
                                struct sockaddr_storage ss;
                        } src;
                        union {
                                struct sockaddr_in      ip4;
                                struct sockaddr_in6     ip6;
                                struct sockaddr         sa;
                                struct sockaddr_storage ss;
                        } dst;
                        bool src_specified;
                } rdma_cm;
        };

        u32                     rq_tmo_jiffies;

        int                     zero_req_lim;

        struct work_struct      tl_err_work;
        struct work_struct      remove_work;

        struct list_head        list;
        bool                    qp_in_error;
};

struct srp_iu {
        struct list_head        list;
        u64                     dma;
        void                   *buf;
        size_t                  size;
        enum dma_data_direction direction;
        u32                     num_sge;
        struct ib_sge           sge[SRP_MAX_SGE];
        struct ib_cqe           cqe;
};

/**
 * struct srp_fr_desc - fast registration work request arguments
 * @entry: Entry in srp_fr_pool.free_list.
 * @mr:    Memory region.
 * @frpl:  Fast registration page list.
 */
struct srp_fr_desc {
        struct list_head                entry;
        struct ib_mr                    *mr;
};

/**
 * struct srp_fr_pool - pool of fast registration descriptors
 *
 * An entry is available for allocation if and only if it occurs in @free_list.
 *
 * @size:      Number of descriptors in this pool.
 * @max_page_list_len: Maximum fast registration work request page list length.
 * @lock:      Protects free_list.
 * @free_list: List of free descriptors.
 * @desc:      Fast registration descriptor pool.
 */
struct srp_fr_pool {
        int                     size;
        int                     max_page_list_len;
        spinlock_t              lock;
        struct list_head        free_list;
        struct srp_fr_desc      desc[] __counted_by(size);
};

/**
 * struct srp_map_state - per-request DMA memory mapping state
 * @desc:           Pointer to the element of the SRP buffer descriptor array
 *                  that is being filled in.
 * @pages:          Array with DMA addresses of pages being considered for
 *                  memory registration.
 * @base_dma_addr:  DMA address of the first page that has not yet been mapped.
 * @dma_len:        Number of bytes that will be registered with the next FR
 *                  memory registration call.
 * @total_len:      Total number of bytes in the sg-list being mapped.
 * @npages:         Number of page addresses in the pages[] array.
 * @nmdesc:         Number of FR memory descriptors used for mapping.
 * @ndesc:          Number of SRP buffer descriptors that have been filled in.
 */
struct srp_map_state {
        union {
                struct {
                        struct srp_fr_desc **next;
                        struct srp_fr_desc **end;
                } fr;
                struct {
                        void               **next;
                        void               **end;
                } gen;
        };
        struct srp_direct_buf  *desc;
        union {
                u64                     *pages;
                struct scatterlist      *sg;
        };
        dma_addr_t              base_dma_addr;
        u32                     dma_len;
        u32                     total_len;
        unsigned int            npages;
        unsigned int            nmdesc;
        unsigned int            ndesc;
};

#endif /* IB_SRP_H */