xref: /linux/include/scsi/scsi_cmnd.h (revision 42fda66387daa53538ae13a2c858396aaf037158)
1 #ifndef _SCSI_SCSI_CMND_H
2 #define _SCSI_SCSI_CMND_H
3 
4 #include <linux/dma-mapping.h>
5 #include <linux/list.h>
6 #include <linux/types.h>
7 #include <linux/timer.h>
8 
9 struct request;
10 struct scatterlist;
11 struct Scsi_Host;
12 struct scsi_device;
13 
14 
15 /* embedded in scsi_cmnd */
16 struct scsi_pointer {
17 	char *ptr;		/* data pointer */
18 	int this_residual;	/* left in this buffer */
19 	struct scatterlist *buffer;	/* which buffer */
20 	int buffers_residual;	/* how many buffers left */
21 
22         dma_addr_t dma_handle;
23 
24 	volatile int Status;
25 	volatile int Message;
26 	volatile int have_data_in;
27 	volatile int sent_command;
28 	volatile int phase;
29 };
30 
31 struct scsi_cmnd {
32 	struct scsi_device *device;
33 	struct list_head list;  /* scsi_cmnd participates in queue lists */
34 	struct list_head eh_entry; /* entry for the host eh_cmd_q */
35 	int eh_eflags;		/* Used by error handlr */
36 
37 	/*
38 	 * A SCSI Command is assigned a nonzero serial_number before passed
39 	 * to the driver's queue command function.  The serial_number is
40 	 * cleared when scsi_done is entered indicating that the command
41 	 * has been completed.  It is a bug for LLDDs to use this number
42 	 * for purposes other than printk (and even that is only useful
43 	 * for debugging).
44 	 */
45 	unsigned long serial_number;
46 
47 	/*
48 	 * This is set to jiffies as it was when the command was first
49 	 * allocated.  It is used to time how long the command has
50 	 * been outstanding
51 	 */
52 	unsigned long jiffies_at_alloc;
53 
54 	int retries;
55 	int allowed;
56 	int timeout_per_command;
57 
58 	unsigned char cmd_len;
59 	enum dma_data_direction sc_data_direction;
60 
61 	/* These elements define the operation we are about to perform */
62 #define MAX_COMMAND_SIZE	16
63 	unsigned char cmnd[MAX_COMMAND_SIZE];
64 	unsigned request_bufflen;	/* Actual request size */
65 
66 	struct timer_list eh_timeout;	/* Used to time out the command. */
67 	void *request_buffer;		/* Actual requested buffer */
68 
69 	/* These elements define the operation we ultimately want to perform */
70 	unsigned short use_sg;	/* Number of pieces of scatter-gather */
71 	unsigned short sglist_len;	/* size of malloc'd scatter-gather list */
72 
73 	unsigned underflow;	/* Return error if less than
74 				   this amount is transferred */
75 
76 	unsigned transfersize;	/* How much we are guaranteed to
77 				   transfer with each SCSI transfer
78 				   (ie, between disconnect /
79 				   reconnects.   Probably == sector
80 				   size */
81 
82 	int resid;		/* Number of bytes requested to be
83 				   transferred less actual number
84 				   transferred (0 if not supported) */
85 
86 	struct request *request;	/* The command we are
87 				   	   working on */
88 
89 #define SCSI_SENSE_BUFFERSIZE 	96
90 	unsigned char sense_buffer[SCSI_SENSE_BUFFERSIZE];
91 				/* obtained by REQUEST SENSE when
92 				 * CHECK CONDITION is received on original
93 				 * command (auto-sense) */
94 
95 	/* Low-level done function - can be used by low-level driver to point
96 	 *        to completion function.  Not used by mid/upper level code. */
97 	void (*scsi_done) (struct scsi_cmnd *);
98 
99 	/*
100 	 * The following fields can be written to by the host specific code.
101 	 * Everything else should be left alone.
102 	 */
103 	struct scsi_pointer SCp;	/* Scratchpad used by some host adapters */
104 
105 	unsigned char *host_scribble;	/* The host adapter is allowed to
106 					 * call scsi_malloc and get some memory
107 					 * and hang it here.  The host adapter
108 					 * is also expected to call scsi_free
109 					 * to release this memory.  (The memory
110 					 * obtained by scsi_malloc is guaranteed
111 					 * to be at an address < 16Mb). */
112 
113 	int result;		/* Status code from lower level driver */
114 
115 	unsigned char tag;	/* SCSI-II queued command tag */
116 };
117 
118 extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
119 extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t);
120 extern void scsi_put_command(struct scsi_cmnd *);
121 extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
122 			       struct device *);
123 extern void scsi_finish_command(struct scsi_cmnd *cmd);
124 extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
125 
126 extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
127 				 size_t *offset, size_t *len);
128 extern void scsi_kunmap_atomic_sg(void *virt);
129 
130 extern struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
131 extern void scsi_free_sgtable(struct scatterlist *, int);
132 
133 extern int scsi_dma_map(struct scsi_cmnd *cmd);
134 extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
135 
136 #define scsi_sg_count(cmd) ((cmd)->use_sg)
137 #define scsi_sglist(cmd) ((struct scatterlist *)(cmd)->request_buffer)
138 #define scsi_bufflen(cmd) ((cmd)->request_bufflen)
139 
140 static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
141 {
142 	cmd->resid = resid;
143 }
144 
145 static inline int scsi_get_resid(struct scsi_cmnd *cmd)
146 {
147 	return cmd->resid;
148 }
149 
150 #define scsi_for_each_sg(cmd, sg, nseg, __i)			\
151 	for (__i = 0, sg = scsi_sglist(cmd); __i < (nseg); __i++, (sg)++)
152 
153 #endif /* _SCSI_SCSI_CMND_H */
154