xref: /linux/include/scsi/scsi_cmnd.h (revision c537b994505099b7197e7d3125b942ecbcc51eb6)
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 	void (*done) (struct scsi_cmnd *);	/* Mid-level done function */
37 
38 	/*
39 	 * A SCSI Command is assigned a nonzero serial_number before passed
40 	 * to the driver's queue command function.  The serial_number is
41 	 * cleared when scsi_done is entered indicating that the command
42 	 * has been completed.  It currently doesn't have much use other
43 	 * than printk's.  Some lldd's use this number for other purposes.
44 	 * It's almost certain that such usages are either incorrect or
45 	 * meaningless.  Please kill all usages other than printk's.  Also,
46 	 * as this number is always identical to ->pid, please convert
47 	 * printk's to use ->pid, so that we can kill this field.
48 	 */
49 	unsigned long serial_number;
50 	/*
51 	 * This is set to jiffies as it was when the command was first
52 	 * allocated.  It is used to time how long the command has
53 	 * been outstanding
54 	 */
55 	unsigned long jiffies_at_alloc;
56 
57 	int retries;
58 	int allowed;
59 	int timeout_per_command;
60 
61 	unsigned char cmd_len;
62 	enum dma_data_direction sc_data_direction;
63 
64 	/* These elements define the operation we are about to perform */
65 #define MAX_COMMAND_SIZE	16
66 	unsigned char cmnd[MAX_COMMAND_SIZE];
67 	unsigned request_bufflen;	/* Actual request size */
68 
69 	struct timer_list eh_timeout;	/* Used to time out the command. */
70 	void *request_buffer;		/* Actual requested buffer */
71 
72 	/* These elements define the operation we ultimately want to perform */
73 	unsigned short use_sg;	/* Number of pieces of scatter-gather */
74 	unsigned short sglist_len;	/* size of malloc'd scatter-gather list */
75 
76 	/* offset in cmd we are at (for multi-transfer tgt cmds) */
77 	unsigned offset;
78 
79 	unsigned underflow;	/* Return error if less than
80 				   this amount is transferred */
81 
82 	unsigned transfersize;	/* How much we are guaranteed to
83 				   transfer with each SCSI transfer
84 				   (ie, between disconnect /
85 				   reconnects.   Probably == sector
86 				   size */
87 
88 	int resid;		/* Number of bytes requested to be
89 				   transferred less actual number
90 				   transferred (0 if not supported) */
91 
92 	struct request *request;	/* The command we are
93 				   	   working on */
94 
95 #define SCSI_SENSE_BUFFERSIZE 	96
96 	unsigned char sense_buffer[SCSI_SENSE_BUFFERSIZE];
97 				/* obtained by REQUEST SENSE when
98 				 * CHECK CONDITION is received on original
99 				 * command (auto-sense) */
100 
101 	/* Low-level done function - can be used by low-level driver to point
102 	 *        to completion function.  Not used by mid/upper level code. */
103 	void (*scsi_done) (struct scsi_cmnd *);
104 
105 	/*
106 	 * The following fields can be written to by the host specific code.
107 	 * Everything else should be left alone.
108 	 */
109 	struct scsi_pointer SCp;	/* Scratchpad used by some host adapters */
110 
111 	unsigned char *host_scribble;	/* The host adapter is allowed to
112 					 * call scsi_malloc and get some memory
113 					 * and hang it here.  The host adapter
114 					 * is also expected to call scsi_free
115 					 * to release this memory.  (The memory
116 					 * obtained by scsi_malloc is guaranteed
117 					 * to be at an address < 16Mb). */
118 
119 	int result;		/* Status code from lower level driver */
120 
121 	unsigned char tag;	/* SCSI-II queued command tag */
122 	unsigned long pid;	/* Process ID, starts at 0. Unique per host. */
123 };
124 
125 extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
126 extern struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *, gfp_t);
127 extern void scsi_put_command(struct scsi_cmnd *);
128 extern void __scsi_put_command(struct Scsi_Host *, struct scsi_cmnd *,
129 			       struct device *);
130 extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
131 extern void scsi_finish_command(struct scsi_cmnd *cmd);
132 extern void scsi_req_abort_cmd(struct scsi_cmnd *cmd);
133 
134 extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
135 				 size_t *offset, size_t *len);
136 extern void scsi_kunmap_atomic_sg(void *virt);
137 
138 extern struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
139 extern void scsi_free_sgtable(struct scatterlist *, int);
140 
141 #endif /* _SCSI_SCSI_CMND_H */
142