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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
27 /* It is senseless to set SG_ALL any higher than this - the performance
28 * does not get any better, and it wastes memory
29 */
30 #define SG_NONE 0
31 #define SG_ALL 0xff
32
33 #define DISABLE_CLUSTERING 0
34 #define ENABLE_CLUSTERING 1
35
36 /* The various choices mean:
37 * NONE: Self evident. Host adapter is not capable of scatter-gather.
38 * ALL: Means that the host adapter module can do scatter-gather,
39 * and that there is no limit to the size of the table to which
40 * we scatter/gather data.
41 * Anything else: Indicates the maximum number of chains that can be
42 * used in one scatter-gather request.
43 */
44
45 /*
46 * The Scsi_Host_Template type has all that is needed to interface with a SCSI
47 * host in a device independent matter. There is one entry for each different
48 * type of host adapter that is supported on the system.
49 */
50
51 typedef struct scsi_disk Disk;
52
53 typedef struct SHT
54 {
55
56 /* Used with loadable modules so we can construct a linked list. */
57 struct SHT * next;
58
59 /* Used with loadable modules so that we know when it is safe to unload */
60 int * usage_count;
61
62 /* proc-fs info function.
63 * Can be used to export driver statistics and other infos to the world
64 * outside the kernel ie. userspace and it also provides an interface
65 * to feed the driver with information. Check eata_dma_proc.c for reference.
66 */
67 int (*proc_info)(char *, char **, off_t, int, int, int);
68
69 /* driver name that will appear in the /proc/scsi directory */
70 const char *procname;
71
72 /* low_ino of the drivers /proc/scsi entry. Defined in proc_fs.h */
73 unsigned short low_ino;
74
75 /*
76 * The name pointer is a pointer to the name of the SCSI
77 * device detected.
78 */
79 const char *name;
80
81 /*
82 * The detect function shall return non zero on detection,
83 * indicating the number of host adapters of this particular
84 * type were found. It should also
85 * initialize all data necessary for this particular
86 * SCSI driver. It is passed the host number, so this host
87 * knows where the first entry is in the scsi_hosts[] array.
88 *
89 * Note that the detect routine MUST not call any of the mid level
90 * functions to queue commands because things are not guaranteed
91 * to be set up yet. The detect routine can send commands to
92 * the host adapter as long as the program control will not be
93 * passed to scsi.c in the processing of the command. Note
94 * especially that scsi_malloc/scsi_free must not be called.
95 */
96 int (* detect)(struct SHT *);
97
98 /* Used with loadable modules to unload the host structures. Note:
99 * there is a default action built into the modules code which may
100 * be sufficient for most host adapters. Thus you may not have to supply
101 * this at all.
102 */
103 int (*release)(struct Scsi_Host *);
104
105 /*
106 * The info function will return whatever useful
107 * information the developer sees fit. If not provided, then
108 * the name field will be used instead.
109 */
110 const char *(* info)(struct Scsi_Host *);
111
112 /*
113 * The command function takes a target, a command (this is a SCSI
114 * command formatted as per the SCSI spec, nothing strange), a
115 * data buffer pointer, and data buffer length pointer. The return
116 * is a status int, bit fielded as follows :
117 * Byte What
118 * 0 SCSI status code
119 * 1 SCSI 1 byte message
120 * 2 host error return.
121 * 3 mid level error return
122 */
123 int (* command)(Scsi_Cmnd *);
124
125 /*
126 * The QueueCommand function works in a similar manner
127 * to the command function. It takes an additional parameter,
128 * void (* done)(int host, int code) which is passed the host
129 * # and exit result when the command is complete.
130 * Host number is the POSITION IN THE hosts array of THIS
131 * host adapter.
132 */
133 int (* queuecommand)(Scsi_Cmnd *, void (*done)(Scsi_Cmnd *));
134
135 /*
136 * Since the mid level driver handles time outs, etc, we want to
137 * be able to abort the current command. Abort returns 0 if the
138 * abortion was successful. The field SCpnt->abort reason
139 * can be filled in with the appropriate reason why we wanted
140 * the abort in the first place, and this will be used
141 * in the mid-level code instead of the host_byte().
142 * If non-zero, the code passed to it
143 * will be used as the return code, otherwise
144 * DID_ABORT should be returned.
145 *
146 * Note that the scsi driver should "clean up" after itself,
147 * resetting the bus, etc. if necessary.
148 */
149 int (* abort)(Scsi_Cmnd *);
150
151 /*
152 * The reset function will reset the SCSI bus. Any executing
153 * commands should fail with a DID_RESET in the host byte.
154 * The Scsi_Cmnd is passed so that the reset routine can figure
155 * out which host adapter should be reset, and also which command
156 * within the command block was responsible for the reset in
157 * the first place. Some hosts do not implement a reset function,
158 * and these hosts must call scsi_request_sense(SCpnt) to keep
159 * the command alive.
160 */
161 int (* reset)(Scsi_Cmnd *);
162
163 /*
164 * This function is used to select synchronous communications,
165 * which will result in a higher data throughput. Not implemented
166 * yet.
167 */
168 int (* slave_attach)(int, int);
169
170 /*
171 * This function determines the bios parameters for a given
172 * harddisk. These tend to be numbers that are made up by
173 * the host adapter. Parameters:
174 * size, device number, list (heads, sectors, cylinders)
175 */
176 int (* bios_param)(Disk *, int, int []);
177
178 /*
179 * This determines if we will use a non-interrupt driven
180 * or an interrupt driven scheme, It is set to the maximum number
181 * of simultaneous commands a given host adapter will accept.
182 */
183 int can_queue;
184
185 /*
186 * In many instances, especially where disconnect / reconnect are
187 * supported, our host also has an ID on the SCSI bus. If this is
188 * the case, then it must be reserved. Please set this_id to -1 if
189 * your setup is in single initiator mode, and the host lacks an
190 * ID.
191 */
192 int this_id;
193
194 /*
195 * This determines the degree to which the host adapter is capable
196 * of scatter-gather.
197 */
198 short unsigned int sg_tablesize;
199
200 /*
201 * True if this host adapter can make good use of linked commands.
202 * This will allow more than one command to be queued to a given
203 * unit on a given host. Set this to the maximum number of command
204 * blocks to be provided for each device. Set this to 1 for one
205 * command block per lun, 2 for two, etc. Do not set this to 0.
206 * You should make sure that the host adapter will do the right thing
207 * before you try setting this above 1.
208 */
209 short cmd_per_lun;
210
211 /*
212 * present contains counter indicating how many boards of this
213 * type were found when we did the scan.
214 */
215 unsigned char present;
216
217 /*
218 * true if this host adapter uses unchecked DMA onto an ISA bus.
219 */
220 unsigned unchecked_isa_dma:1;
221
222 /*
223 * true if this host adapter can make good use of clustering.
224 * I originally thought that if the tablesize was large that it
225 * was a waste of CPU cycles to prepare a cluster list, but
226 * it works out that the Buslogic is faster if you use a smaller
227 * number of segments (i.e. use clustering). I guess it is
228 * inefficient.
229 */
230 unsigned use_clustering:1;
231
232 } Scsi_Host_Template;
233
234 /*
235 * The scsi_hosts array is the array containing the data for all
236 * possible <supported> scsi hosts. This is similar to the
237 * Scsi_Host_Template, except that we have one entry for each
238 * actual physical host adapter on the system, stored as a linked
239 * list. Note that if there are 2 aha1542 boards, then there will
240 * be two Scsi_Host entries, but only 1 Scsi_Host_Template entries.
241 */
242
243 struct Scsi_Host
244 {
245 struct Scsi_Host * next;
246 unsigned short extra_bytes;
247 volatile unsigned char host_busy;
248 char host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
249 int last_reset;
250 struct wait_queue *host_wait;
251 Scsi_Cmnd *host_queue;
252 Scsi_Host_Template * hostt;
253
254 /*
255 * These three parameters can be used to allow for wide scsi,
256 * and for host adapters that support multiple busses
257 * The first two should be set to 1 more than the actual max id
258 * or lun (i.e. 8 for normal systems).
259 */
260 unsigned int max_id;
261 unsigned int max_lun;
262 unsigned int max_channel;
263
264 /*
265 * Pointer to a circularly linked list - this indicates the hosts
266 * that should be locked out of performing I/O while we have an active
267 * command on this host.
268 */
269 struct Scsi_Host * block;
270 unsigned wish_block:1;
271
272 /* These parameters should be set by the detect routine */
273 unsigned char *base;
274 unsigned int io_port;
275 unsigned char n_io_port;
276 unsigned char irq;
277 unsigned char dma_channel;
278
279 /*
280 * This is a unique identifier that must be assigned so that we
281 * have some way of identifying each detected host adapter properly
282 * and uniquely. For hosts that do not support more than one card
283 * in the system at one time, this does not need to be set. It is
284 * initialized to 0 in scsi_register.
285 */
286 unsigned int unique_id;
287
288 /*
289 * Set these if there are conflicts between memory
290 * in the < 1mb region and regions at 16mb multiples.
291 * The address must be on a page boundary.
292 */
293 unsigned long forbidden_addr;
294 unsigned long forbidden_size;
295
296 /*
297 * The rest can be copied from the template, or specifically
298 * initialized, as required.
299 */
300
301 int this_id;
302 int can_queue;
303 short cmd_per_lun;
304 short unsigned int sg_tablesize;
305 unsigned unchecked_isa_dma:1;
306 unsigned use_clustering:1;
307 /*
308 * True if this host was loaded as a loadable module
309 */
310 unsigned loaded_as_module:1;
311
312 /*
313 * True when we call the low-level reset function, and
314 * the midlevel code suggests a full bus reset.
315 */
316 unsigned suggest_bus_reset:1;
317
318 int hostdata[0]; /* Used for storage of host specific stuff */
319 };
320
321 extern struct Scsi_Host * scsi_hostlist;
322 extern struct Scsi_Device_Template * scsi_devicelist;
323
324 extern Scsi_Host_Template * scsi_hosts;
325
326 /*
327 * scsi_init initializes the scsi hosts.
328 */
329
330 /*
331 * We use these goofy things because the MM is not set up when we init
332 * the scsi subsystem. By using these functions we can write code that
333 * looks normal. Also, it makes it possible to use the same code for a
334 * loadable module.
335 */
336
337 extern void * scsi_init_malloc(unsigned int size, int priority);
338 extern void scsi_init_free(char * ptr, unsigned int size);
339
340 void scan_scsis (struct Scsi_Host * shpnt, unchar hardcoded,
341 unchar hchannel, unchar hid, unchar hlun);
342
343 extern int next_scsi_host;
344
345 extern int scsi_loadable_module_flag;
346 unsigned int scsi_init(void);
347 extern struct Scsi_Host * scsi_register(Scsi_Host_Template *, int j);
348 extern void scsi_unregister(struct Scsi_Host * i);
349
350 #define BLANK_HOST {"", 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
351
352 struct Scsi_Device_Template
353 {
354 struct Scsi_Device_Template * next;
355 const char * name;
356 const char * tag;
357 int * usage_count; /* Used for loadable modules */
358 unsigned char scsi_type;
359 unsigned char major;
360 unsigned char nr_dev; /* Number currently attached */
361 unsigned char dev_noticed; /* Number of devices detected. */
362 unsigned char dev_max; /* Current size of arrays */
363 unsigned blk:1; /* 0 if character device */
364 int (*detect)(Scsi_Device *); /* Returns 1 if we can attach this device */
365 int (*init)(void); /* Sizes arrays based upon number of devices
366 * detected */
367 void (*finish)(void); /* Perform initialization after attachment */
368 int (*attach)(Scsi_Device *); /* Attach devices to arrays */
369 void (*detach)(Scsi_Device *);
370 };
371
372 extern struct Scsi_Device_Template sd_template;
373 extern struct Scsi_Device_Template st_template;
374 extern struct Scsi_Device_Template sr_template;
375 extern struct Scsi_Device_Template sg_template;
376
377 int scsi_register_device(struct Scsi_Device_Template * sdpnt);
378
379 /* These are used by loadable modules */
380 extern int scsi_register_module(int, void *);
381 extern void scsi_unregister_module(int, void *);
382
383 /* The different types of modules that we can load and unload */
384 #define MODULE_SCSI_HA 1
385 #define MODULE_SCSI_CONST 2
386 #define MODULE_SCSI_IOCTL 3
387 #define MODULE_SCSI_DEV 4
388
389
390 /*
391 * This is an ugly hack. If we expect to be able to load devices at run time,
392 * we need to leave extra room in some of the data structures. Doing a
393 * realloc to enlarge the structures would be riddled with race conditions,
394 * so until a better solution is discovered, we use this crude approach
395 */
396 #define SD_EXTRA_DEVS 2
397 #define ST_EXTRA_DEVS 2
398 #define SR_EXTRA_DEVS 2
399 #define SG_EXTRA_DEVS (SD_EXTRA_DEVS + SR_EXTRA_DEVS + ST_EXTRA_DEVS)
400
401 #endif
402 /*
403 * Overrides for Emacs so that we follow Linus's tabbing style.
404 * Emacs will notice this stuff at the end of the file and automatically
405 * adjust the settings for this buffer only. This must remain at the end
406 * of the file.
407 * ---------------------------------------------------------------------------
408 * Local variables:
409 * c-indent-level: 4
410 * c-brace-imaginary-offset: 0
411 * c-brace-offset: -4
412 * c-argdecl-indent: 4
413 * c-label-offset: -4
414 * c-continued-statement-offset: 4
415 * c-continued-brace-offset: 0
416 * indent-tabs-mode: nil
417 * tab-width: 8
418 * End:
419 */
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