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1 /*
2 * hosts.h Copyright (C) 1992 Drew Eckhardt
3 * mid to low-level SCSI driver interface header by
4 * Drew Eckhardt
5 *
6 * <drew@colorado.edu>
7 *
8 * Modified by Eric Youngdale eric@tantalus.nrl.navy.mil to
9 * add scatter-gather, multiple outstanding request, and other
10 * enhancements.
11 *
12 * Further modified by Eric Youngdale to support multiple host adapters
13 * of the same type.
14 */
15
16 #ifndef _HOSTS_H
17 #define _HOSTS_H
18
19 /*
20 $Header: /usr/src/linux/kernel/blk_drv/scsi/RCS/hosts.h,v 1.3 1993/09/24 12:21:00 drew Exp drew $
21 */
22
23
24 #define SG_NONE 0
25 #define SG_ALL 0x7fff
26
27 #define DISABLE_CLUSTERING 0
28 #define ENABLE_CLUSTERING 1
29
30 /* The various choices mean:
31 NONE: Self evident. Host adapter is not capable of scatter-gather.
32 ALL: Means that the host adapter module can do scatter-gather,
33 and that there is no limit to the size of the table to which
34 we scatter/gather data.
35 Anything else: Indicates the maximum number of chains that can be
36 used in one scatter-gather request.
37 */
38
39 /*
40 The Scsi_Host_Template type has all that is needed to interface with a SCSI
41 host in a device independant matter. There is one entry for each different
42 type of host adapter that is supported on the system.
43 */
44
45 typedef struct
46 {
47 /*
48 The name pointer is a pointer to the name of the SCSI
49 device detected.
50 */
51
52 char *name;
53
54 /*
55 The detect function shall return non zero on detection,
56 indicating the number of host adapters of this particular
57 type were found. It should also
58 initialize all data necessary for this particular
59 SCSI driver. It is passed the host number, so this host
60 knows where the first entry is in the scsi_hosts[] array.
61
62 Note that the detect routine MUST not call any of the mid level
63 functions to queue commands because things are not guaranteed
64 to be set up yet. The detect routine can send commands to
65 the host adapter as long as the program control will not be
66 passed to scsi.c in the processesing of the command. Note
67 especially that scsi_malloc/scsi_free must not be called.
68 */
69
70 int (* detect)(int);
71
72 /*
73 The info function will return whatever useful
74 information the developer sees fit.
75 */
76
77 const char *(* info)(void);
78
79 /*
80 The command function takes a target, a command (this is a SCSI
81 command formatted as per the SCSI spec, nothing strange), a
82 data buffer pointer, and data buffer length pointer. The return
83 is a status int, bit fielded as follows :
84 Byte What
85 0 SCSI status code
86 1 SCSI 1 byte message
87 2 host error return.
88 3 mid level error return
89 */
90
91 int (* command)(Scsi_Cmnd *);
92
93 /*
94 The QueueCommand function works in a similar manner
95 to the command function. It takes an additional parameter,
96 void (* done)(int host, int code) which is passed the host
97 # and exit result when the command is complete.
98 Host number is the POSITION IN THE hosts array of THIS
99 host adapter.
100 */
101
102 int (* queuecommand)(Scsi_Cmnd *, void (*done)(Scsi_Cmnd *));
103
104 /*
105 Since the mid level driver handles time outs, etc, we want to
106 be able to abort the current command. Abort returns 0 if the
107 abortion was successful. The field SCpnt->abort reason
108 can be filled in with the appropriate reason why we wanted
109 the abort in the first place, and this will be used
110 in the mid-level code instead of the host_byte().
111 If non-zero, the code passed to it
112 will be used as the return code, otherwise
113 DID_ABORT should be returned.
114
115 Note that the scsi driver should "clean up" after itself,
116 resetting the bus, etc. if necessary.
117 */
118
119 int (* abort)(Scsi_Cmnd *);
120
121 /*
122 The reset function will reset the SCSI bus. Any executing
123 commands should fail with a DID_RESET in the host byte.
124 The Scsi_Cmnd is passed so that the reset routine can figure
125 out which host adapter should be reset, and also which command
126 within the command block was responsible for the reset in
127 the first place. Some hosts do not implement a reset function,
128 and these hosts must call scsi_request_sense(SCpnt) to keep
129 the command alive.
130 */
131
132 int (* reset)(Scsi_Cmnd *);
133 /*
134 This function is used to select synchronous communications,
135 which will result in a higher data throughput. Not implemented
136 yet.
137 */
138
139 int (* slave_attach)(int, int);
140 /*
141 This function determines the bios parameters for a given
142 harddisk. These tend to be numbers that are made up by
143 the host adapter. Parameters:
144 size, device number, list (heads, sectors, cylinders)
145 */
146
147 int (* bios_param)(int, int, int []);
148
149 /*
150 This determines if we will use a non-interrupt driven
151 or an interrupt driven scheme, It is set to the maximum number
152 of simulataneous commands a given host adapter will accept.
153 */
154 int can_queue;
155
156 /*
157 In many instances, especially where disconnect / reconnect are
158 supported, our host also has an ID on the SCSI bus. If this is
159 the case, then it must be reserved. Please set this_id to -1 if
160 your settup is in single initiator mode, and the host lacks an
161 ID.
162 */
163
164 int this_id;
165
166 /*
167 This determines the degree to which the host adapter is capable
168 of scatter-gather.
169 */
170
171 short unsigned int sg_tablesize;
172
173 /*
174 True if this host adapter can make good use of linked commands.
175 This will allow more than one command to be queued to a given
176 unit on a given host. Set this to the maximum number of command
177 blocks to be provided for each device. Set this to 1 for one
178 command block per lun, 2 for two, etc. Do not set this to 0.
179 You should make sure that the host adapter will do the right thing
180 before you try setting this above 1.
181 */
182
183 short cmd_per_lun;
184 /*
185 present contains counter indicating how many boards of this
186 type were found when we did the scan.
187 */
188
189 unsigned char present;
190 /*
191 true if this host adapter uses unchecked DMA onto an ISA bus.
192 */
193 unsigned unchecked_isa_dma:1;
194 /*
195 true if this host adapter can make good use of clustering.
196 I originally thought that if the tablesize was large that it
197 was a waste of CPU cycles to prepare a cluster list, but
198 it works out that the Buslogic is faster if you use a smaller
199 number of segments (i.e. use clustering). I guess it is
200 inefficient.
201 */
202 unsigned use_clustering:1;
203 } Scsi_Host_Template;
204
205 /*
206 The scsi_hosts array is the array containing the data for all
207 possible <supported> scsi hosts. This is similar to the
208 Scsi_Host_Template, except that we have one entry for each
209 actual physical host adapter on the system, stored as a linked
210 list. Note that if there are 2 aha1542 boards, then there will
211 be two Scsi_Host entries, but only 1 Scsi_Host_Template entries.
212 */
213
214 struct Scsi_Host
215 {
216 struct Scsi_Host * next;
217 volatile unsigned char host_busy;
218 char host_no; /* Used for IOCTL_GET_IDLUN */
219 int last_reset;
220 struct wait_queue *host_wait;
221 Scsi_Cmnd *host_queue;
222 Scsi_Host_Template * hostt;
223
224 /* These parameters should be set by the detect routine */
225 unsigned char *base;
226 short unsigned int io_port;
227 unsigned char irq;
228 unsigned char dma_channel;
229 /*
230 The rest can be copied from the template, or specifically
231 initialized, as required.
232 */
233
234 int this_id;
235 short unsigned int sg_tablesize;
236 unsigned unchecked_isa_dma:1;
237 int hostdata[0]; /* Used for storage of host specific stuff */
238 };
239
240 extern struct Scsi_Host * scsi_hostlist;
241
242 extern Scsi_Host_Template scsi_hosts[];
243
244 /*
245 scsi_init initializes the scsi hosts.
246 */
247
248
249 unsigned int scsi_init(unsigned long memory_start,unsigned long memory_end);
250 extern struct Scsi_Host * scsi_register(int i, int j);
251 extern void scsi_unregister(struct Scsi_Host * i, int j);
252
253 #define BLANK_HOST {"", 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
254 #endif
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