File: /usr/src/linux/drivers/scsi/hosts.c
1 /*
2 * hosts.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995 Eric Youngdale
4 *
5 * mid to lowlevel SCSI driver interface
6 * Initial versions: Drew Eckhardt
7 * Subsequent revisions: Eric Youngdale
8 *
9 * <drew@colorado.edu>
10 *
11 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
12 * Added QLOGIC QLA1280 SCSI controller kernel host support.
13 * August 4, 1999 Fred Lewis, Intel DuPont
14 *
15 * Updated to reflect the new initialization scheme for the higher
16 * level of scsi drivers (sd/sr/st)
17 * September 17, 2000 Torben Mathiasen <tmm@image.dk>
18 */
19
20
21 /*
22 * This file contains the medium level SCSI
23 * host interface initialization, as well as the scsi_hosts array of SCSI
24 * hosts currently present in the system.
25 */
26
27 #define __NO_VERSION__
28 #include <linux/module.h>
29 #include <linux/blk.h>
30 #include <linux/kernel.h>
31 #include <linux/string.h>
32 #include <linux/mm.h>
33 #include <linux/proc_fs.h>
34 #include <linux/init.h>
35
36 #define __KERNEL_SYSCALLS__
37
38 #include <linux/unistd.h>
39
40 #include "scsi.h"
41 #include "hosts.h"
42
43 /*
44 static const char RCSid[] = "$Header: /vger/u4/cvs/linux/drivers/scsi/hosts.c,v 1.20 1996/12/12 19:18:32 davem Exp $";
45 */
46
47 /*
48 * The scsi host entries should be in the order you wish the
49 * cards to be detected. A driver may appear more than once IFF
50 * it can deal with being detected (and therefore initialized)
51 * with more than one simultaneous host number, can handle being
52 * reentrant, etc.
53 *
54 * They may appear in any order, as each SCSI host is told which host
55 * number it is during detection.
56 */
57
58 /* This is a placeholder for controllers that are not configured into
59 * the system - we do this to ensure that the controller numbering is
60 * always consistent, no matter how the kernel is configured. */
61
62 #define NO_CONTROLLER {NULL, NULL, NULL, NULL, NULL, NULL, NULL, \
63 NULL, NULL, 0, 0, 0, 0, 0, 0}
64
65 /*
66 * When figure is run, we don't want to link to any object code. Since
67 * the macro for each host will contain function pointers, we cannot
68 * use it and instead must use a "blank" that does no such
69 * idiocy.
70 */
71
72 Scsi_Host_Template * scsi_hosts;
73
74
75 /*
76 * Our semaphores and timeout counters, where size depends on
77 * MAX_SCSI_HOSTS here.
78 */
79
80 Scsi_Host_Name * scsi_host_no_list;
81 struct Scsi_Host * scsi_hostlist;
82 struct Scsi_Device_Template * scsi_devicelist;
83
84 int max_scsi_hosts;
85 int next_scsi_host;
86
87 void
88 scsi_unregister(struct Scsi_Host * sh){
89 struct Scsi_Host * shpnt;
90 Scsi_Host_Name *shn;
91
92 if(scsi_hostlist == sh)
93 scsi_hostlist = sh->next;
94 else {
95 shpnt = scsi_hostlist;
96 while(shpnt->next != sh) shpnt = shpnt->next;
97 shpnt->next = shpnt->next->next;
98 }
99
100 /*
101 * We have to unregister the host from the scsi_host_no_list as well.
102 * Decide by the host_no not by the name because most host drivers are
103 * able to handle more than one adapters from the same kind (or family).
104 */
105 for ( shn=scsi_host_no_list; shn && (sh->host_no != shn->host_no);
106 shn=shn->next);
107 if (shn) shn->host_registered = 0;
108 /* else {} : This should not happen, we should panic here... */
109
110 /* If we are removing the last host registered, it is safe to reuse
111 * its host number (this avoids "holes" at boot time) (DB)
112 * It is also safe to reuse those of numbers directly below which have
113 * been released earlier (to avoid some holes in numbering).
114 */
115 if(sh->host_no == max_scsi_hosts - 1) {
116 while(--max_scsi_hosts >= next_scsi_host) {
117 shpnt = scsi_hostlist;
118 while(shpnt && shpnt->host_no != max_scsi_hosts - 1)
119 shpnt = shpnt->next;
120 if(shpnt)
121 break;
122 }
123 }
124 next_scsi_host--;
125 kfree((char *) sh);
126 }
127
128 /* We call this when we come across a new host adapter. We only do this
129 * once we are 100% sure that we want to use this host adapter - it is a
130 * pain to reverse this, so we try to avoid it
131 */
132
133 struct Scsi_Host * scsi_register(Scsi_Host_Template * tpnt, int j){
134 struct Scsi_Host * retval, *shpnt, *o_shp;
135 Scsi_Host_Name *shn, *shn2;
136 int flag_new = 1;
137 const char * hname;
138 size_t hname_len;
139 retval = (struct Scsi_Host *)kmalloc(sizeof(struct Scsi_Host) + j,
140 (tpnt->unchecked_isa_dma && j ?
141 GFP_DMA : 0) | GFP_ATOMIC);
142 if(retval == NULL)
143 {
144 printk("scsi: out of memory in scsi_register.\n");
145 return NULL;
146 }
147
148 memset(retval, 0, sizeof(struct Scsi_Host) + j);
149
150 /* trying to find a reserved entry (host_no) */
151 hname = (tpnt->proc_name) ? tpnt->proc_name : "";
152 hname_len = strlen(hname);
153 for (shn = scsi_host_no_list;shn;shn = shn->next) {
154 if (!(shn->host_registered) &&
155 (hname_len > 0) && (0 == strncmp(hname, shn->name, hname_len))) {
156 flag_new = 0;
157 retval->host_no = shn->host_no;
158 shn->host_registered = 1;
159 shn->loaded_as_module = 1;
160 break;
161 }
162 }
163 atomic_set(&retval->host_active,0);
164 retval->host_busy = 0;
165 retval->host_failed = 0;
166 if(j > 0xffff) panic("Too many extra bytes requested\n");
167 retval->extra_bytes = j;
168 retval->loaded_as_module = 1;
169 if (flag_new) {
170 shn = (Scsi_Host_Name *) kmalloc(sizeof(Scsi_Host_Name), GFP_ATOMIC);
171 if (!shn) {
172 kfree(retval);
173 printk(KERN_ERR "scsi: out of memory(2) in scsi_register.\n");
174 return NULL;
175 }
176 shn->name = kmalloc(hname_len + 1, GFP_ATOMIC);
177 if (hname_len > 0)
178 strncpy(shn->name, hname, hname_len);
179 shn->name[hname_len] = 0;
180 shn->host_no = max_scsi_hosts++;
181 shn->host_registered = 1;
182 shn->loaded_as_module = 1;
183 shn->next = NULL;
184 if (scsi_host_no_list) {
185 for (shn2 = scsi_host_no_list;shn2->next;shn2 = shn2->next)
186 ;
187 shn2->next = shn;
188 }
189 else
190 scsi_host_no_list = shn;
191 retval->host_no = shn->host_no;
192 }
193 next_scsi_host++;
194 retval->host_queue = NULL;
195 init_waitqueue_head(&retval->host_wait);
196 retval->resetting = 0;
197 retval->last_reset = 0;
198 retval->irq = 0;
199 retval->dma_channel = 0xff;
200
201 /* These three are default values which can be overridden */
202 retval->max_channel = 0;
203 retval->max_id = 8;
204 retval->max_lun = 8;
205
206 /*
207 * All drivers right now should be able to handle 12 byte commands.
208 * Every so often there are requests for 16 byte commands, but individual
209 * low-level drivers need to certify that they actually do something
210 * sensible with such commands.
211 */
212 retval->max_cmd_len = 12;
213
214 retval->unique_id = 0;
215 retval->io_port = 0;
216 retval->hostt = tpnt;
217 retval->next = NULL;
218 retval->in_recovery = 0;
219 retval->ehandler = NULL; /* Initial value until the thing starts up. */
220 retval->eh_notify = NULL; /* Who we notify when we exit. */
221
222
223 retval->host_blocked = FALSE;
224 retval->host_self_blocked = FALSE;
225
226 #ifdef DEBUG
227 printk("Register %x %x: %d\n", (int)retval, (int)retval->hostt, j);
228 #endif
229
230 /* The next six are the default values which can be overridden
231 * if need be */
232 retval->this_id = tpnt->this_id;
233 retval->can_queue = tpnt->can_queue;
234 retval->sg_tablesize = tpnt->sg_tablesize;
235 retval->cmd_per_lun = tpnt->cmd_per_lun;
236 retval->unchecked_isa_dma = tpnt->unchecked_isa_dma;
237 retval->use_clustering = tpnt->use_clustering;
238
239 retval->select_queue_depths = tpnt->select_queue_depths;
240 retval->max_sectors = tpnt->max_sectors;
241
242 if(!scsi_hostlist)
243 scsi_hostlist = retval;
244 else {
245 shpnt = scsi_hostlist;
246 if (retval->host_no < shpnt->host_no) {
247 retval->next = shpnt;
248 wmb(); /* want all to see these writes in this order */
249 scsi_hostlist = retval;
250 }
251 else {
252 for (o_shp = shpnt, shpnt = shpnt->next; shpnt;
253 o_shp = shpnt, shpnt = shpnt->next) {
254 if (retval->host_no < shpnt->host_no) {
255 retval->next = shpnt;
256 wmb();
257 o_shp->next = retval;
258 break;
259 }
260 }
261 if (! shpnt)
262 o_shp->next = retval;
263 }
264 }
265
266 return retval;
267 }
268
269 int
270 scsi_register_device(struct Scsi_Device_Template * sdpnt)
271 {
272 if(sdpnt->next) panic("Device already registered");
273 sdpnt->next = scsi_devicelist;
274 scsi_devicelist = sdpnt;
275 return 0;
276 }
277
278 /*
279 * Overrides for Emacs so that we follow Linus's tabbing style.
280 * Emacs will notice this stuff at the end of the file and automatically
281 * adjust the settings for this buffer only. This must remain at the end
282 * of the file.
283 * ---------------------------------------------------------------------------
284 * Local variables:
285 * c-indent-level: 4
286 * c-brace-imaginary-offset: 0
287 * c-brace-offset: -4
288 * c-argdecl-indent: 4
289 * c-label-offset: -4
290 * c-continued-statement-offset: 4
291 * c-continued-brace-offset: 0
292 * indent-tabs-mode: nil
293 * tab-width: 8
294 * End:
295 */
296