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1 /*
2 * hosts.h Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995 Eric Youngdale
4 *
5 * mid to low-level SCSI driver interface header
6 * Initial versions: Drew Eckhardt
7 * Subsequent revisions: Eric Youngdale
8 *
9 * <drew@colorado.edu>
10 *
11 * Modified by Eric Youngdale eric@aib.com to
12 * add scatter-gather, multiple outstanding request, and other
13 * enhancements.
14 *
15 * Further modified by Eric Youngdale to support multiple host adapters
16 * of the same type.
17 */
18
19 #ifndef _HOSTS_H
20 #define _HOSTS_H
21
22 /*
23 $Header: /usr/src/linux/kernel/blk_drv/scsi/RCS/hosts.h,v 1.3 1993/09/24 12:21:00 drew Exp drew $
24 */
25
26 #include <linux/proc_fs.h>
27
28 /* It is senseless to set SG_ALL any higher than this - the performance
29 * does not get any better, and it wastes memory
30 */
31 #define SG_NONE 0
32 #define SG_ALL 0xff
33
34 #define DISABLE_CLUSTERING 0
35 #define ENABLE_CLUSTERING 1
36
37 /* The various choices mean:
38 * NONE: Self evident. Host adapter is not capable of scatter-gather.
39 * ALL: Means that the host adapter module can do scatter-gather,
40 * and that there is no limit to the size of the table to which
41 * we scatter/gather data.
42 * Anything else: Indicates the maximum number of chains that can be
43 * used in one scatter-gather request.
44 */
45
46 /*
47 * The Scsi_Host_Template type has all that is needed to interface with a SCSI
48 * host in a device independent matter. There is one entry for each different
49 * type of host adapter that is supported on the system.
50 */
51
52 typedef struct scsi_disk Disk;
53
54 typedef struct SHT
55 {
56
57 /* Used with loadable modules so we can construct a linked list. */
58 struct SHT * next;
59
60 /* Used with loadable modules so that we know when it is safe to unload */
61 long * usage_count;
62
63 /* The pointer to the /proc/scsi directory entry */
64 struct proc_dir_entry *proc_dir;
65
66 /* proc-fs info function.
67 * Can be used to export driver statistics and other infos to the world
68 * outside the kernel ie. userspace and it also provides an interface
69 * to feed the driver with information. Check eata_dma_proc.c for reference
70 */
71 int (*proc_info)(char *, char **, off_t, int, int, int);
72
73 /*
74 * The name pointer is a pointer to the name of the SCSI
75 * device detected.
76 */
77 const char *name;
78
79 /*
80 * The detect function shall return non zero on detection,
81 * indicating the number of host adapters of this particular
82 * type were found. It should also
83 * initialize all data necessary for this particular
84 * SCSI driver. It is passed the host number, so this host
85 * knows where the first entry is in the scsi_hosts[] array.
86 *
87 * Note that the detect routine MUST not call any of the mid level
88 * functions to queue commands because things are not guaranteed
89 * to be set up yet. The detect routine can send commands to
90 * the host adapter as long as the program control will not be
91 * passed to scsi.c in the processing of the command. Note
92 * especially that scsi_malloc/scsi_free must not be called.
93 */
94 int (* detect)(struct SHT *);
95
96 /* Used with loadable modules to unload the host structures. Note:
97 * there is a default action built into the modules code which may
98 * be sufficient for most host adapters. Thus you may not have to supply
99 * this at all.
100 */
101 int (*release)(struct Scsi_Host *);
102
103 /*
104 * The info function will return whatever useful
105 * information the developer sees fit. If not provided, then
106 * the name field will be used instead.
107 */
108 const char *(* info)(struct Scsi_Host *);
109
110 /*
111 * The command function takes a target, a command (this is a SCSI
112 * command formatted as per the SCSI spec, nothing strange), a
113 * data buffer pointer, and data buffer length pointer. The return
114 * is a status int, bit fielded as follows :
115 * Byte What
116 * 0 SCSI status code
117 * 1 SCSI 1 byte message
118 * 2 host error return.
119 * 3 mid level error return
120 */
121 int (* command)(Scsi_Cmnd *);
122
123 /*
124 * The QueueCommand function works in a similar manner
125 * to the command function. It takes an additional parameter,
126 * void (* done)(int host, int code) which is passed the host
127 * # and exit result when the command is complete.
128 * Host number is the POSITION IN THE hosts array of THIS
129 * host adapter.
130 */
131 int (* queuecommand)(Scsi_Cmnd *, void (*done)(Scsi_Cmnd *));
132
133 /*
134 * Since the mid level driver handles time outs, etc, we want to
135 * be able to abort the current command. Abort returns 0 if the
136 * abortion was successful. The field SCpnt->abort reason
137 * can be filled in with the appropriate reason why we wanted
138 * the abort in the first place, and this will be used
139 * in the mid-level code instead of the host_byte().
140 * If non-zero, the code passed to it
141 * will be used as the return code, otherwise
142 * DID_ABORT should be returned.
143 *
144 * Note that the scsi driver should "clean up" after itself,
145 * resetting the bus, etc. if necessary.
146 */
147 int (* abort)(Scsi_Cmnd *);
148
149 /*
150 * The reset function will reset the SCSI bus. Any executing
151 * commands should fail with a DID_RESET in the host byte.
152 * The Scsi_Cmnd is passed so that the reset routine can figure
153 * out which host adapter should be reset, and also which command
154 * within the command block was responsible for the reset in
155 * the first place. Some hosts do not implement a reset function,
156 * and these hosts must call scsi_request_sense(SCpnt) to keep
157 * the command alive.
158 */
159 int (* reset)(Scsi_Cmnd *);
160
161 /*
162 * This function is used to select synchronous communications,
163 * which will result in a higher data throughput. Not implemented
164 * yet.
165 */
166 int (* slave_attach)(int, int);
167
168 /*
169 * This function determines the bios parameters for a given
170 * harddisk. These tend to be numbers that are made up by
171 * the host adapter. Parameters:
172 * size, device number, list (heads, sectors, cylinders)
173 */
174 int (* bios_param)(Disk *, kdev_t, int []);
175
176 /*
177 * This determines if we will use a non-interrupt driven
178 * or an interrupt driven scheme, It is set to the maximum number
179 * of simultaneous commands a given host adapter will accept.
180 */
181 int can_queue;
182
183 /*
184 * In many instances, especially where disconnect / reconnect are
185 * supported, our host also has an ID on the SCSI bus. If this is
186 * the case, then it must be reserved. Please set this_id to -1 if
187 * your setup is in single initiator mode, and the host lacks an
188 * ID.
189 */
190 int this_id;
191
192 /*
193 * This determines the degree to which the host adapter is capable
194 * of scatter-gather.
195 */
196 short unsigned int sg_tablesize;
197
198 /*
199 * True if this host adapter can make good use of linked commands.
200 * This will allow more than one command to be queued to a given
201 * unit on a given host. Set this to the maximum number of command
202 * blocks to be provided for each device. Set this to 1 for one
203 * command block per lun, 2 for two, etc. Do not set this to 0.
204 * You should make sure that the host adapter will do the right thing
205 * before you try setting this above 1.
206 */
207 short cmd_per_lun;
208
209 /*
210 * present contains counter indicating how many boards of this
211 * type were found when we did the scan.
212 */
213 unsigned char present;
214
215 /*
216 * true if this host adapter uses unchecked DMA onto an ISA bus.
217 */
218 unsigned unchecked_isa_dma:1;
219
220 /*
221 * true if this host adapter can make good use of clustering.
222 * I originally thought that if the tablesize was large that it
223 * was a waste of CPU cycles to prepare a cluster list, but
224 * it works out that the Buslogic is faster if you use a smaller
225 * number of segments (i.e. use clustering). I guess it is
226 * inefficient.
227 */
228 unsigned use_clustering:1;
229
230 } Scsi_Host_Template;
231
232 /*
233 * The scsi_hosts array is the array containing the data for all
234 * possible <supported> scsi hosts. This is similar to the
235 * Scsi_Host_Template, except that we have one entry for each
236 * actual physical host adapter on the system, stored as a linked
237 * list. Note that if there are 2 aha1542 boards, then there will
238 * be two Scsi_Host entries, but only 1 Scsi_Host_Template entries.
239 */
240
241 struct Scsi_Host
242 {
243 struct Scsi_Host * next;
244 unsigned short extra_bytes;
245 volatile unsigned char host_busy;
246 char host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
247 int last_reset;
248 struct wait_queue *host_wait;
249 Scsi_Cmnd *host_queue;
250 Scsi_Host_Template * hostt;
251
252 /*
253 * These three parameters can be used to allow for wide scsi,
254 * and for host adapters that support multiple busses
255 * The first two should be set to 1 more than the actual max id
256 * or lun (i.e. 8 for normal systems).
257 */
258 unsigned int max_id;
259 unsigned int max_lun;
260 unsigned int max_channel;
261
262 /*
263 * Pointer to a circularly linked list - this indicates the hosts
264 * that should be locked out of performing I/O while we have an active
265 * command on this host.
266 */
267 struct Scsi_Host * block;
268 unsigned wish_block:1;
269
270 /* These parameters should be set by the detect routine */
271 unsigned char *base;
272 unsigned int io_port;
273 unsigned char n_io_port;
274 unsigned char irq;
275 unsigned char dma_channel;
276
277 /*
278 * This is a unique identifier that must be assigned so that we
279 * have some way of identifying each detected host adapter properly
280 * and uniquely. For hosts that do not support more than one card
281 * in the system at one time, this does not need to be set. It is
282 * initialized to 0 in scsi_register.
283 */
284 unsigned int unique_id;
285
286 /*
287 * The rest can be copied from the template, or specifically
288 * initialized, as required.
289 */
290
291 int this_id;
292 int can_queue;
293 short cmd_per_lun;
294 short unsigned int sg_tablesize;
295 unsigned unchecked_isa_dma:1;
296 unsigned use_clustering:1;
297 /*
298 * True if this host was loaded as a loadable module
299 */
300 unsigned loaded_as_module:1;
301
302 /*
303 * True when we call the low-level reset function, and
304 * the midlevel code suggests a full bus reset.
305 */
306 unsigned suggest_bus_reset:1;
307
308 unsigned long hostdata[0]; /* Used for storage of host specific stuff */
309 };
310
311 extern struct Scsi_Host * scsi_hostlist;
312 extern struct Scsi_Device_Template * scsi_devicelist;
313
314 extern Scsi_Host_Template * scsi_hosts;
315
316 extern void build_proc_dir_entries(Scsi_Host_Template *);
317
318
319 /*
320 * scsi_init initializes the scsi hosts.
321 */
322
323 /*
324 * We use these goofy things because the MM is not set up when we init
325 * the scsi subsystem. By using these functions we can write code that
326 * looks normal. Also, it makes it possible to use the same code for a
327 * loadable module.
328 */
329
330 extern void * scsi_init_malloc(unsigned int size, int priority);
331 extern void scsi_init_free(char * ptr, unsigned int size);
332
333 extern int next_scsi_host;
334
335 extern int scsi_loadable_module_flag;
336 unsigned int scsi_init(void);
337 extern struct Scsi_Host * scsi_register(Scsi_Host_Template *, int j);
338 extern void scsi_unregister(struct Scsi_Host * i);
339
340 #define BLANK_HOST {"", 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
341
342 struct Scsi_Device_Template
343 {
344 struct Scsi_Device_Template * next;
345 const char * name;
346 const char * tag;
347 long * usage_count; /* Used for loadable modules */
348 unsigned char scsi_type;
349 unsigned char major;
350 unsigned char nr_dev; /* Number currently attached */
351 unsigned char dev_noticed; /* Number of devices detected. */
352 unsigned char dev_max; /* Current size of arrays */
353 unsigned blk:1; /* 0 if character device */
354 int (*detect)(Scsi_Device *); /* Returns 1 if we can attach this device */
355 int (*init)(void); /* Sizes arrays based upon number of devices
356 * detected */
357 void (*finish)(void); /* Perform initialization after attachment */
358 int (*attach)(Scsi_Device *); /* Attach devices to arrays */
359 void (*detach)(Scsi_Device *);
360 };
361
362 extern struct Scsi_Device_Template sd_template;
363 extern struct Scsi_Device_Template st_template;
364 extern struct Scsi_Device_Template sr_template;
365 extern struct Scsi_Device_Template sg_template;
366
367 int scsi_register_device(struct Scsi_Device_Template * sdpnt);
368
369 /* These are used by loadable modules */
370 extern int scsi_register_module(int, void *);
371 extern void scsi_unregister_module(int, void *);
372
373 /* The different types of modules that we can load and unload */
374 #define MODULE_SCSI_HA 1
375 #define MODULE_SCSI_CONST 2
376 #define MODULE_SCSI_IOCTL 3
377 #define MODULE_SCSI_DEV 4
378
379
380 /*
381 * This is an ugly hack. If we expect to be able to load devices at run time,
382 * we need to leave extra room in some of the data structures. Doing a
383 * realloc to enlarge the structures would be riddled with race conditions,
384 * so until a better solution is discovered, we use this crude approach
385 */
386 #define SD_EXTRA_DEVS 2
387 #define ST_EXTRA_DEVS 2
388 #define SR_EXTRA_DEVS 2
389 #define SG_EXTRA_DEVS (SD_EXTRA_DEVS + SR_EXTRA_DEVS + ST_EXTRA_DEVS)
390
391 #endif
392 /*
393 * Overrides for Emacs so that we follow Linus's tabbing style.
394 * Emacs will notice this stuff at the end of the file and automatically
395 * adjust the settings for this buffer only. This must remain at the end
396 * of the file.
397 * ---------------------------------------------------------------------------
398 * Local variables:
399 * c-indent-level: 4
400 * c-brace-imaginary-offset: 0
401 * c-brace-offset: -4
402 * c-argdecl-indent: 4
403 * c-label-offset: -4
404 * c-continued-statement-offset: 4
405 * c-continued-brace-offset: 0
406 * indent-tabs-mode: nil
407 * tab-width: 8
408 * End:
409 */
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