/*
 * iSER transport for the Open iSCSI Initiator & iSER transport internals
 *
 * Copyright (C) 2004 Dmitry Yusupov
 * Copyright (C) 2004 Alex Aizman
 * Copyright (C) 2005 Mike Christie
 * based on code maintained by open-iscsi@googlegroups.com
 *
 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
 * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
 * Copyright (c) 2013-2014 Mellanox Technologies. 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 __ISCSI_ISER_H__
#define __ISCSI_ISER_H__

#include <linux/types.h>
#include <linux/net.h>
#include <linux/printk.h>
#include <scsi/libiscsi.h>
#include <scsi/scsi_transport_iscsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>

#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/dma-mapping.h>
#include <linux/mutex.h>
#include <linux/mempool.h>
#include <linux/uio.h>

#include <linux/socket.h>
#include <linux/in.h>
#include <linux/in6.h>

#include <rdma/ib_verbs.h>
#include <rdma/ib_fmr_pool.h>
#include <rdma/rdma_cm.h>

#define DRV_NAME	"iser"
#define PFX		DRV_NAME ": "
#define DRV_VER		"1.4"

#define iser_dbg(fmt, arg...)				\
	do {						\
		if (iser_debug_level > 2)		\
			printk(KERN_DEBUG PFX "%s:" fmt,\
				__func__ , ## arg);	\
	} while (0)

#define iser_warn(fmt, arg...)				\
	do {						\
		if (iser_debug_level > 0)		\
			pr_warn(PFX "%s:" fmt,          \
				__func__ , ## arg);	\
	} while (0)

#define iser_info(fmt, arg...)				\
	do {						\
		if (iser_debug_level > 1)		\
			pr_info(PFX "%s:" fmt,          \
				__func__ , ## arg);	\
	} while (0)

#define iser_err(fmt, arg...)				\
	do {						\
		printk(KERN_ERR PFX "%s:" fmt,          \
		       __func__ , ## arg);		\
	} while (0)

#define SHIFT_4K	12
#define SIZE_4K	(1ULL << SHIFT_4K)
#define MASK_4K	(~(SIZE_4K-1))

					/* support up to 512KB in one RDMA */
#define ISCSI_ISER_SG_TABLESIZE         (0x80000 >> SHIFT_4K)
#define ISER_DEF_XMIT_CMDS_DEFAULT		512
#if ISCSI_DEF_XMIT_CMDS_MAX > ISER_DEF_XMIT_CMDS_DEFAULT
	#define ISER_DEF_XMIT_CMDS_MAX		ISCSI_DEF_XMIT_CMDS_MAX
#else
	#define ISER_DEF_XMIT_CMDS_MAX		ISER_DEF_XMIT_CMDS_DEFAULT
#endif
#define ISER_DEF_CMD_PER_LUN		ISER_DEF_XMIT_CMDS_MAX

/* QP settings */
/* Maximal bounds on received asynchronous PDUs */
#define ISER_MAX_RX_MISC_PDUS		4 /* NOOP_IN(2) , ASYNC_EVENT(2)   */

#define ISER_MAX_TX_MISC_PDUS		6 /* NOOP_OUT(2), TEXT(1),         *
					   * SCSI_TMFUNC(2), LOGOUT(1) */

#define ISER_QP_MAX_RECV_DTOS		(ISER_DEF_XMIT_CMDS_MAX)

#define ISER_MIN_POSTED_RX		(ISER_DEF_XMIT_CMDS_MAX >> 2)

/* the max TX (send) WR supported by the iSER QP is defined by                 *
 * max_send_wr = T * (1 + D) + C ; D is how many inflight dataouts we expect   *
 * to have at max for SCSI command. The tx posting & completion handling code  *
 * supports -EAGAIN scheme where tx is suspended till the QP has room for more *
 * send WR. D=8 comes from 64K/8K                                              */

#define ISER_INFLIGHT_DATAOUTS		8

#define ISER_QP_MAX_REQ_DTOS		(ISER_DEF_XMIT_CMDS_MAX *    \
					(1 + ISER_INFLIGHT_DATAOUTS) + \
					ISER_MAX_TX_MISC_PDUS        + \
					ISER_MAX_RX_MISC_PDUS)

/* Max registration work requests per command */
#define ISER_MAX_REG_WR_PER_CMD		5

/* For Signature we don't support DATAOUTs so no need to make room for them */
#define ISER_QP_SIG_MAX_REQ_DTOS	(ISER_DEF_XMIT_CMDS_MAX	*       \
					(1 + ISER_MAX_REG_WR_PER_CMD) + \
					ISER_MAX_TX_MISC_PDUS         + \
					ISER_MAX_RX_MISC_PDUS)

#define ISER_VER			0x10
#define ISER_WSV			0x08
#define ISER_RSV			0x04

#define ISER_FASTREG_LI_WRID		0xffffffffffffffffULL

struct iser_hdr {
	u8      flags;
	u8      rsvd[3];
	__be32  write_stag; /* write rkey */
	__be64  write_va;
	__be32  read_stag;  /* read rkey */
	__be64  read_va;
} __attribute__((packed));


#define ISER_ZBVA_NOT_SUPPORTED		0x80
#define ISER_SEND_W_INV_NOT_SUPPORTED	0x40

struct iser_cm_hdr {
	u8      flags;
	u8      rsvd[3];
} __packed;

/* Constant PDU lengths calculations */
#define ISER_HEADERS_LEN  (sizeof(struct iser_hdr) + sizeof(struct iscsi_hdr))

#define ISER_RECV_DATA_SEG_LEN	128
#define ISER_RX_PAYLOAD_SIZE	(ISER_HEADERS_LEN + ISER_RECV_DATA_SEG_LEN)
#define ISER_RX_LOGIN_SIZE	(ISER_HEADERS_LEN + ISCSI_DEF_MAX_RECV_SEG_LEN)

/* Length of an object name string */
#define ISER_OBJECT_NAME_SIZE		    64

enum iser_ib_conn_state {
	ISER_CONN_INIT,		   /* descriptor allocd, no conn          */
	ISER_CONN_PENDING,	   /* in the process of being established */
	ISER_CONN_UP,		   /* up and running                      */
	ISER_CONN_TERMINATING,	   /* in the process of being terminated  */
	ISER_CONN_DOWN,		   /* shut down                           */
	ISER_CONN_STATES_NUM
};

enum iser_task_status {
	ISER_TASK_STATUS_INIT = 0,
	ISER_TASK_STATUS_STARTED,
	ISER_TASK_STATUS_COMPLETED
};

enum iser_data_dir {
	ISER_DIR_IN = 0,	   /* to initiator */
	ISER_DIR_OUT,		   /* from initiator */
	ISER_DIRS_NUM
};

struct iser_data_buf {
	void               *buf;      /* pointer to the sg list               */
	unsigned int       size;      /* num entries of this sg               */
	unsigned long      data_len;  /* total data len                       */
	unsigned int       dma_nents; /* returned by dma_map_sg               */
	char       	   *copy_buf; /* allocated copy buf for SGs unaligned *
	                               * for rdma which are copied            */
	struct scatterlist sg_single; /* SG-ified clone of a non SG SC or     *
				       * unaligned SG                         */
  };

/* fwd declarations */
struct iser_device;
struct iser_cq_desc;
struct iscsi_iser_task;
struct iscsi_endpoint;

struct iser_mem_reg {
	u32  lkey;
	u32  rkey;
	u64  va;
	u64  len;
	void *mem_h;
	int  is_mr;
};

struct iser_regd_buf {
	struct iser_mem_reg     reg;        /* memory registration info        */
	void                    *virt_addr;
	struct iser_device      *device;    /* device->device for dma_unmap    */
	enum dma_data_direction direction;  /* direction for dma_unmap	       */
	unsigned int            data_size;
};

enum iser_desc_type {
	ISCSI_TX_CONTROL ,
	ISCSI_TX_SCSI_COMMAND,
	ISCSI_TX_DATAOUT
};

struct iser_tx_desc {
	struct iser_hdr              iser_header;
	struct iscsi_hdr             iscsi_header;
	enum   iser_desc_type        type;
	u64		             dma_addr;
	/* sg[0] points to iser/iscsi headers, sg[1] optionally points to either
	of immediate data, unsolicited data-out or control (login,text) */
	struct ib_sge		     tx_sg[2];
	int                          num_sge;
};

#define ISER_RX_PAD_SIZE	(256 - (ISER_RX_PAYLOAD_SIZE + \
					sizeof(u64) + sizeof(struct ib_sge)))
struct iser_rx_desc {
	struct iser_hdr              iser_header;
	struct iscsi_hdr             iscsi_header;
	char		             data[ISER_RECV_DATA_SEG_LEN];
	u64		             dma_addr;
	struct ib_sge		     rx_sg;
	char		             pad[ISER_RX_PAD_SIZE];
} __attribute__((packed));

#define ISER_MAX_CQ 4

struct iser_conn;
struct iscsi_iser_task;

struct iser_device {
	struct ib_device             *ib_device;
	struct ib_pd	             *pd;
	struct ib_device_attr	     dev_attr;
	struct ib_cq	             *rx_cq[ISER_MAX_CQ];
	struct ib_cq	             *tx_cq[ISER_MAX_CQ];
	struct ib_mr	             *mr;
	struct tasklet_struct	     cq_tasklet[ISER_MAX_CQ];
	struct ib_event_handler      event_handler;
	struct list_head             ig_list; /* entry in ig devices list */
	int                          refcount;
	int                          cq_active_qps[ISER_MAX_CQ];
	int			     cqs_used;
	struct iser_cq_desc	     *cq_desc;
	int                          (*iser_alloc_rdma_reg_res)(struct iser_conn *ib_conn,
								unsigned cmds_max);
	void                         (*iser_free_rdma_reg_res)(struct iser_conn *ib_conn);
	int                          (*iser_reg_rdma_mem)(struct iscsi_iser_task *iser_task,
							  enum iser_data_dir cmd_dir);
	void                         (*iser_unreg_rdma_mem)(struct iscsi_iser_task *iser_task,
							    enum iser_data_dir cmd_dir);
};

#define ISER_CHECK_GUARD	0xc0
#define ISER_CHECK_REFTAG	0x0f
#define ISER_CHECK_APPTAG	0x30

enum iser_reg_indicator {
	ISER_DATA_KEY_VALID	= 1 << 0,
	ISER_PROT_KEY_VALID	= 1 << 1,
	ISER_SIG_KEY_VALID	= 1 << 2,
	ISER_FASTREG_PROTECTED	= 1 << 3,
};

struct iser_pi_context {
	struct ib_mr                   *prot_mr;
	struct ib_fast_reg_page_list   *prot_frpl;
	struct ib_mr                   *sig_mr;
};

struct fast_reg_descriptor {
	struct list_head		  list;
	/* For fast registration - FRWR */
	struct ib_mr			 *data_mr;
	struct ib_fast_reg_page_list     *data_frpl;
	struct iser_pi_context		 *pi_ctx;
	/* registration indicators container */
	u8				  reg_indicators;
};

struct iser_conn {
	struct iscsi_conn	     *iscsi_conn;
	struct iscsi_endpoint	     *ep;
	enum iser_ib_conn_state	     state;	    /* rdma connection state   */
	atomic_t		     refcount;
	spinlock_t		     lock;	    /* used for state changes  */
	struct iser_device           *device;       /* device context          */
	struct rdma_cm_id            *cma_id;       /* CMA ID		       */
	struct ib_qp	             *qp;           /* QP 		       */
	wait_queue_head_t	     wait;          /* waitq for conn/disconn  */
	unsigned		     qp_max_recv_dtos; /* num of rx buffers */
	unsigned		     qp_max_recv_dtos_mask; /* above minus 1 */
	unsigned		     min_posted_rx; /* qp_max_recv_dtos >> 2 */
	int                          post_recv_buf_count; /* posted rx count  */
	atomic_t                     post_send_buf_count; /* posted tx count   */
	char 			     name[ISER_OBJECT_NAME_SIZE];
	struct work_struct	     release_work;
	struct completion	     stop_completion;
	struct list_head	     conn_list;       /* entry in ig conn list */

	char  			     *login_buf;
	char			     *login_req_buf, *login_resp_buf;
	u64			     login_req_dma, login_resp_dma;
	unsigned int 		     rx_desc_head;
	struct iser_rx_desc	     *rx_descs;
	struct ib_recv_wr	     rx_wr[ISER_MIN_POSTED_RX];
	bool			     pi_support;

	/* Connection memory registration pool */
	union {
		struct {
			struct ib_fmr_pool      *pool;	   /* pool of IB FMRs         */
			struct iser_page_vec	*page_vec; /* represents SG to fmr maps*
							    * maps serialized as tx is*/
		} fmr;
		struct {
			struct list_head	pool;
			int			pool_size;
		} fastreg;
	};
};

struct iscsi_iser_task {
	struct iser_tx_desc          desc;
	struct iser_conn	     *ib_conn;
	enum iser_task_status 	     status;
	struct scsi_cmnd	     *sc;
	int                          command_sent;  /* set if command  sent  */
	int                          dir[ISER_DIRS_NUM];      /* set if dir use*/
	struct iser_regd_buf         rdma_regd[ISER_DIRS_NUM];/* regd rdma buf */
	struct iser_data_buf         data[ISER_DIRS_NUM];     /* orig. data des*/
	struct iser_data_buf         data_copy[ISER_DIRS_NUM];/* contig. copy  */
	struct iser_data_buf         prot[ISER_DIRS_NUM];     /* prot desc     */
	struct iser_data_buf         prot_copy[ISER_DIRS_NUM];/* prot copy     */
};

struct iser_page_vec {
	u64 *pages;
	int length;
	int offset;
	int data_size;
};

struct iser_cq_desc {
	struct iser_device           *device;
	int                          cq_index;
};

struct iser_global {
	struct mutex      device_list_mutex;/*                   */
	struct list_head  device_list;	     /* all iSER devices */
	struct mutex      connlist_mutex;
	struct list_head  connlist;		/* all iSER IB connections */

	struct kmem_cache *desc_cache;
};

extern struct iser_global ig;
extern int iser_debug_level;
extern bool iser_pi_enable;
extern int iser_pi_guard;

/* allocate connection resources needed for rdma functionality */
int iser_conn_set_full_featured_mode(struct iscsi_conn *conn);

int iser_send_control(struct iscsi_conn *conn,
		      struct iscsi_task *task);

int iser_send_command(struct iscsi_conn *conn,
		      struct iscsi_task *task);

int iser_send_data_out(struct iscsi_conn *conn,
		       struct iscsi_task *task,
		       struct iscsi_data *hdr);

void iscsi_iser_recv(struct iscsi_conn *conn,
		     struct iscsi_hdr       *hdr,
		     char                   *rx_data,
		     int                    rx_data_len);

void iser_conn_init(struct iser_conn *ib_conn);

void iser_conn_release(struct iser_conn *ib_conn);

void iser_conn_terminate(struct iser_conn *ib_conn);

void iser_release_work(struct work_struct *work);

void iser_rcv_completion(struct iser_rx_desc *desc,
			 unsigned long    dto_xfer_len,
			struct iser_conn *ib_conn);

void iser_snd_completion(struct iser_tx_desc *desc, struct iser_conn *ib_conn);

void iser_task_rdma_init(struct iscsi_iser_task *task);

void iser_task_rdma_finalize(struct iscsi_iser_task *task);

void iser_free_rx_descriptors(struct iser_conn *ib_conn);

void iser_finalize_rdma_unaligned_sg(struct iscsi_iser_task *iser_task,
				     struct iser_data_buf *mem,
				     struct iser_data_buf *mem_copy,
				     enum iser_data_dir cmd_dir);

int  iser_reg_rdma_mem_fmr(struct iscsi_iser_task *task,
			   enum iser_data_dir cmd_dir);
int  iser_reg_rdma_mem_fastreg(struct iscsi_iser_task *task,
			       enum iser_data_dir cmd_dir);

int  iser_connect(struct iser_conn   *ib_conn,
		  struct sockaddr_in *src_addr,
		  struct sockaddr_in *dst_addr,
		  int                non_blocking);

int  iser_reg_page_vec(struct iser_conn     *ib_conn,
		       struct iser_page_vec *page_vec,
		       struct iser_mem_reg  *mem_reg);

void iser_unreg_mem_fmr(struct iscsi_iser_task *iser_task,
			enum iser_data_dir cmd_dir);
void iser_unreg_mem_fastreg(struct iscsi_iser_task *iser_task,
			    enum iser_data_dir cmd_dir);

int  iser_post_recvl(struct iser_conn *ib_conn);
int  iser_post_recvm(struct iser_conn *ib_conn, int count);
int  iser_post_send(struct iser_conn *ib_conn, struct iser_tx_desc *tx_desc);

int iser_dma_map_task_data(struct iscsi_iser_task *iser_task,
			    struct iser_data_buf       *data,
			    enum   iser_data_dir       iser_dir,
			    enum   dma_data_direction  dma_dir);

void iser_dma_unmap_task_data(struct iscsi_iser_task *iser_task,
			      struct iser_data_buf *data);
int  iser_initialize_task_headers(struct iscsi_task *task,
			struct iser_tx_desc *tx_desc);
int iser_alloc_rx_descriptors(struct iser_conn *ib_conn, struct iscsi_session *session);
int iser_create_fmr_pool(struct iser_conn *ib_conn, unsigned cmds_max);
void iser_free_fmr_pool(struct iser_conn *ib_conn);
int iser_create_fastreg_pool(struct iser_conn *ib_conn, unsigned cmds_max);
void iser_free_fastreg_pool(struct iser_conn *ib_conn);
u8 iser_check_task_pi_status(struct iscsi_iser_task *iser_task,
			     enum iser_data_dir cmd_dir, sector_t *sector);
#endif