/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _SCSI_SCSI_CMND_H
#define _SCSI_SCSI_CMND_H

#include <linux/dma-mapping.h>
#include <linux/blkdev.h>
#include <linux/t10-pi.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/timer.h>
#include <linux/scatterlist.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_request.h>

struct Scsi_Host;
struct scsi_driver;

/*
 * MAX_COMMAND_SIZE is:
 * The longest fixed-length SCSI CDB as per the SCSI standard.
 * fixed-length means: commands that their size can be determined
 * by their opcode and the CDB does not carry a length specifier, (unlike
 * the VARIABLE_LENGTH_CMD(0x7f) command). This is actually not exactly
 * true and the SCSI standard also defines extended commands and
 * vendor specific commands that can be bigger than 16 bytes. The kernel
 * will support these using the same infrastructure used for VARLEN CDB's.
 * So in effect MAX_COMMAND_SIZE means the maximum size command scsi-ml
 * supports without specifying a cmd_len by ULD's
 */
#define MAX_COMMAND_SIZE 16
#if (MAX_COMMAND_SIZE > BLK_MAX_CDB)
# error MAX_COMMAND_SIZE can not be bigger than BLK_MAX_CDB
#endif

struct scsi_data_buffer {
        struct sg_table table;
        unsigned length;
};

/* embedded in scsi_cmnd */
struct scsi_pointer {
        char *ptr;              /* data pointer */
        int this_residual;      /* left in this buffer */
        struct scatterlist *buffer;     /* which buffer */
        int buffers_residual;   /* how many buffers left */

        dma_addr_t dma_handle;

        volatile int Status;
        volatile int Message;
        volatile int have_data_in;
        volatile int sent_command;
        volatile int phase;
};

/* for scmd->flags */
#define SCMD_TAGGED             (1 << 0)
#define SCMD_INITIALIZED        (1 << 1)
#define SCMD_LAST               (1 << 2)
/* flags preserved across unprep / reprep */
#define SCMD_PRESERVED_FLAGS    (SCMD_INITIALIZED)

/* for scmd->state */
#define SCMD_STATE_COMPLETE     0
#define SCMD_STATE_INFLIGHT     1

struct scsi_cmnd {
        struct scsi_request req;
        struct scsi_device *device;
        struct list_head eh_entry; /* entry for the host eh_cmd_q */
        struct delayed_work abort_work;

        struct rcu_head rcu;

        int eh_eflags;          /* Used by error handlr */

        int budget_token;

        /*
         * This is set to jiffies as it was when the command was first
         * allocated.  It is used to time how long the command has
         * been outstanding
         */
        unsigned long jiffies_at_alloc;

        int retries;
        int allowed;

        unsigned char prot_op;
        unsigned char prot_type;
        unsigned char prot_flags;

        unsigned short cmd_len;
        enum dma_data_direction sc_data_direction;

        /* These elements define the operation we are about to perform */
        unsigned char *cmnd;


        /* These elements define the operation we ultimately want to perform */
        struct scsi_data_buffer sdb;
        struct scsi_data_buffer *prot_sdb;

        unsigned underflow;     /* Return error if less than
                                   this amount is transferred */

        unsigned transfersize;  /* How much we are guaranteed to
                                   transfer with each SCSI transfer
                                   (ie, between disconnect / 
                                   reconnects.   Probably == sector
                                   size */

        unsigned char *sense_buffer;
                                /* obtained by REQUEST SENSE when
                                 * CHECK CONDITION is received on original
                                 * command (auto-sense). Length must be
                                 * SCSI_SENSE_BUFFERSIZE bytes. */

        /* Low-level done function - can be used by low-level driver to point
         *        to completion function.  Not used by mid/upper level code. */
        void (*scsi_done) (struct scsi_cmnd *);

        /*
         * The following fields can be written to by the host specific code. 
         * Everything else should be left alone. 
         */
        struct scsi_pointer SCp;        /* Scratchpad used by some host adapters */

        unsigned char *host_scribble;   /* The host adapter is allowed to
                                         * call scsi_malloc and get some memory
                                         * and hang it here.  The host adapter
                                         * is also expected to call scsi_free
                                         * to release this memory.  (The memory
                                         * obtained by scsi_malloc is guaranteed
                                         * to be at an address < 16Mb). */

        int result;             /* Status code from lower level driver */
        int flags;              /* Command flags */
        unsigned long state;    /* Command completion state */

        unsigned int extra_len; /* length of alignment and padding */
};

/* Variant of blk_mq_rq_from_pdu() that verifies the type of its argument. */
static inline struct request *scsi_cmd_to_rq(struct scsi_cmnd *scmd)
{
        return blk_mq_rq_from_pdu(scmd);
}

/*
 * Return the driver private allocation behind the command.
 * Only works if cmd_size is set in the host template.
 */
static inline void *scsi_cmd_priv(struct scsi_cmnd *cmd)
{
        return cmd + 1;
}

/* make sure not to use it with passthrough commands */
static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
{
        struct request *rq = scsi_cmd_to_rq(cmd);

        return *(struct scsi_driver **)rq->rq_disk->private_data;
}

extern void scsi_finish_command(struct scsi_cmnd *cmd);

extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
                                 size_t *offset, size_t *len);
extern void scsi_kunmap_atomic_sg(void *virt);

blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd);
void scsi_free_sgtables(struct scsi_cmnd *cmd);

#ifdef CONFIG_SCSI_DMA
extern int scsi_dma_map(struct scsi_cmnd *cmd);
extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
#else /* !CONFIG_SCSI_DMA */
static inline int scsi_dma_map(struct scsi_cmnd *cmd) { return -ENOSYS; }
static inline void scsi_dma_unmap(struct scsi_cmnd *cmd) { }
#endif /* !CONFIG_SCSI_DMA */

static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
{
        return cmd->sdb.table.nents;
}

static inline struct scatterlist *scsi_sglist(struct scsi_cmnd *cmd)
{
        return cmd->sdb.table.sgl;
}

static inline unsigned scsi_bufflen(struct scsi_cmnd *cmd)
{
        return cmd->sdb.length;
}

static inline void scsi_set_resid(struct scsi_cmnd *cmd, unsigned int resid)
{
        cmd->req.resid_len = resid;
}

static inline unsigned int scsi_get_resid(struct scsi_cmnd *cmd)
{
        return cmd->req.resid_len;
}

#define scsi_for_each_sg(cmd, sg, nseg, __i)                    \
        for_each_sg(scsi_sglist(cmd), sg, nseg, __i)

static inline int scsi_sg_copy_from_buffer(struct scsi_cmnd *cmd,
                                           void *buf, int buflen)
{
        return sg_copy_from_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
                                   buf, buflen);
}

static inline int scsi_sg_copy_to_buffer(struct scsi_cmnd *cmd,
                                         void *buf, int buflen)
{
        return sg_copy_to_buffer(scsi_sglist(cmd), scsi_sg_count(cmd),
                                 buf, buflen);
}

static inline sector_t scsi_get_sector(struct scsi_cmnd *scmd)
{
        return blk_rq_pos(scsi_cmd_to_rq(scmd));
}

static inline sector_t scsi_get_lba(struct scsi_cmnd *scmd)
{
        unsigned int shift = ilog2(scmd->device->sector_size) - SECTOR_SHIFT;

        return blk_rq_pos(scsi_cmd_to_rq(scmd)) >> shift;
}

static inline unsigned int scsi_logical_block_count(struct scsi_cmnd *scmd)
{
        unsigned int shift = ilog2(scmd->device->sector_size) - SECTOR_SHIFT;

        return blk_rq_bytes(scsi_cmd_to_rq(scmd)) >> shift;
}

/*
 * The operations below are hints that tell the controller driver how
 * to handle I/Os with DIF or similar types of protection information.
 */
enum scsi_prot_operations {
        /* Normal I/O */
        SCSI_PROT_NORMAL = 0,

        /* OS-HBA: Protected, HBA-Target: Unprotected */
        SCSI_PROT_READ_INSERT,
        SCSI_PROT_WRITE_STRIP,

        /* OS-HBA: Unprotected, HBA-Target: Protected */
        SCSI_PROT_READ_STRIP,
        SCSI_PROT_WRITE_INSERT,

        /* OS-HBA: Protected, HBA-Target: Protected */
        SCSI_PROT_READ_PASS,
        SCSI_PROT_WRITE_PASS,
};

static inline void scsi_set_prot_op(struct scsi_cmnd *scmd, unsigned char op)
{
        scmd->prot_op = op;
}

static inline unsigned char scsi_get_prot_op(struct scsi_cmnd *scmd)
{
        return scmd->prot_op;
}

enum scsi_prot_flags {
        SCSI_PROT_TRANSFER_PI           = 1 << 0,
        SCSI_PROT_GUARD_CHECK           = 1 << 1,
        SCSI_PROT_REF_CHECK             = 1 << 2,
        SCSI_PROT_REF_INCREMENT         = 1 << 3,
        SCSI_PROT_IP_CHECKSUM           = 1 << 4,
};

/*
 * The controller usually does not know anything about the target it
 * is communicating with.  However, when DIX is enabled the controller
 * must be know target type so it can verify the protection
 * information passed along with the I/O.
 */
enum scsi_prot_target_type {
        SCSI_PROT_DIF_TYPE0 = 0,
        SCSI_PROT_DIF_TYPE1,
        SCSI_PROT_DIF_TYPE2,
        SCSI_PROT_DIF_TYPE3,
};

static inline void scsi_set_prot_type(struct scsi_cmnd *scmd, unsigned char type)
{
        scmd->prot_type = type;
}

static inline unsigned char scsi_get_prot_type(struct scsi_cmnd *scmd)
{
        return scmd->prot_type;
}

static inline u32 scsi_prot_ref_tag(struct scsi_cmnd *scmd)
{
        struct request *rq = blk_mq_rq_from_pdu(scmd);

        return t10_pi_ref_tag(rq);
}

static inline unsigned int scsi_prot_interval(struct scsi_cmnd *scmd)
{
        return scmd->device->sector_size;
}

static inline unsigned scsi_prot_sg_count(struct scsi_cmnd *cmd)
{
        return cmd->prot_sdb ? cmd->prot_sdb->table.nents : 0;
}

static inline struct scatterlist *scsi_prot_sglist(struct scsi_cmnd *cmd)
{
        return cmd->prot_sdb ? cmd->prot_sdb->table.sgl : NULL;
}

static inline struct scsi_data_buffer *scsi_prot(struct scsi_cmnd *cmd)
{
        return cmd->prot_sdb;
}

#define scsi_for_each_prot_sg(cmd, sg, nseg, __i)               \
        for_each_sg(scsi_prot_sglist(cmd), sg, nseg, __i)

static inline void set_status_byte(struct scsi_cmnd *cmd, char status)
{
        cmd->result = (cmd->result & 0xffffff00) | status;
}

static inline u8 get_status_byte(struct scsi_cmnd *cmd)
{
        return cmd->result & 0xff;
}

static inline void set_host_byte(struct scsi_cmnd *cmd, char status)
{
        cmd->result = (cmd->result & 0xff00ffff) | (status << 16);
}

static inline u8 get_host_byte(struct scsi_cmnd *cmd)
{
        return (cmd->result >> 16) & 0xff;
}

/**
 * scsi_msg_to_host_byte() - translate message byte
 *
 * Translate the SCSI parallel message byte to a matching
 * host byte setting. A message of COMMAND_COMPLETE indicates
 * a successful command execution, any other message indicate
 * an error. As the messages themselves only have a meaning
 * for the SCSI parallel protocol this function translates
 * them into a matching host byte value for SCSI EH.
 */
static inline void scsi_msg_to_host_byte(struct scsi_cmnd *cmd, u8 msg)
{
        switch (msg) {
        case COMMAND_COMPLETE:
                break;
        case ABORT_TASK_SET:
                set_host_byte(cmd, DID_ABORT);
                break;
        case TARGET_RESET:
                set_host_byte(cmd, DID_RESET);
                break;
        default:
                set_host_byte(cmd, DID_ERROR);
                break;
        }
}

static inline unsigned scsi_transfer_length(struct scsi_cmnd *scmd)
{
        unsigned int xfer_len = scmd->sdb.length;
        unsigned int prot_interval = scsi_prot_interval(scmd);

        if (scmd->prot_flags & SCSI_PROT_TRANSFER_PI)
                xfer_len += (xfer_len >> ilog2(prot_interval)) * 8;

        return xfer_len;
}

extern void scsi_build_sense(struct scsi_cmnd *scmd, int desc,
                             u8 key, u8 asc, u8 ascq);

#endif /* _SCSI_SCSI_CMND_H */