text: /* 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_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
  
  enum scsi_cmnd_submitter {
  	SUBMITTED_BY_BLOCK_LAYER = 0,
  	SUBMITTED_BY_SCSI_ERROR_HANDLER = 1,
  	SUBMITTED_BY_SCSI_RESET_IOCTL = 2,
  } __packed;
  
  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;
  	enum scsi_cmnd_submitter submitter;
  
  	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. */
  
  	/*
  	 * 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;
  }
  
  void scsi_done(struct scsi_cmnd *cmd);
  
  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);
  
  struct request *scsi_alloc_request(struct request_queue *q,
  		unsigned int op, blk_mq_req_flags_t flags);
  
  #endif /* _SCSI_SCSI_CMND_H */
  