2 * hosts.c Copyright (C) 1992 Drew Eckhardt
3 * Copyright (C) 1993, 1994, 1995 Eric Youngdale
4 * Copyright (C) 2002-2003 Christoph Hellwig
6 * mid to lowlevel SCSI driver interface
7 * Initial versions: Drew Eckhardt
8 * Subsequent revisions: Eric Youngdale
12 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
13 * Added QLOGIC QLA1280 SCSI controller kernel host support.
14 * August 4, 1999 Fred Lewis, Intel DuPont
16 * Updated to reflect the new initialization scheme for the higher
17 * level of scsi drivers (sd/sr/st)
18 * September 17, 2000 Torben Mathiasen <tmm@image.dk>
20 * Restructured scsi_host lists and associated functions.
21 * September 04, 2002 Mike Anderson (andmike@us.ibm.com)
24 #include <linux/module.h>
25 #include <linux/blkdev.h>
26 #include <linux/kernel.h>
27 #include <linux/string.h>
29 #include <linux/init.h>
30 #include <linux/list.h>
31 #include <linux/completion.h>
32 #include <linux/unistd.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_transport.h>
38 #include "scsi_priv.h"
39 #include "scsi_logging.h"
42 static int scsi_host_next_hn; /* host_no for next new host */
45 static void scsi_host_cls_release(struct class_device *class_dev)
47 put_device(&class_to_shost(class_dev)->shost_gendev);
50 static struct class shost_class = {
52 .release = scsi_host_cls_release,
55 static int scsi_device_cancel_cb(struct device *dev, void *data)
57 return scsi_device_cancel(to_scsi_device(dev), *(int *)data);
61 * scsi_host_cancel - cancel outstanding IO to this host
62 * @shost: pointer to struct Scsi_Host
63 * recovery: recovery requested to run.
65 void scsi_host_cancel(struct Scsi_Host *shost, int recovery)
67 set_bit(SHOST_CANCEL, &shost->shost_state);
68 device_for_each_child(&shost->shost_gendev, &recovery,
69 scsi_device_cancel_cb);
70 wait_event(shost->host_wait, (!test_bit(SHOST_RECOVERY,
71 &shost->shost_state)));
75 * scsi_remove_host - remove a scsi host
76 * @shost: a pointer to a scsi host to remove
78 void scsi_remove_host(struct Scsi_Host *shost)
80 scsi_host_cancel(shost, 0);
81 scsi_proc_host_rm(shost);
82 scsi_forget_host(shost);
84 set_bit(SHOST_DEL, &shost->shost_state);
86 class_device_unregister(&shost->shost_classdev);
87 device_del(&shost->shost_gendev);
91 * scsi_add_host - add a scsi host
92 * @shost: scsi host pointer to add
93 * @dev: a struct device of type scsi class
96 * 0 on success / != 0 for error
98 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
100 struct scsi_host_template *sht = shost->hostt;
103 printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
104 sht->info ? sht->info(shost) : sht->name);
106 if (!shost->can_queue) {
107 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
112 if (!shost->shost_gendev.parent)
113 shost->shost_gendev.parent = dev ? dev : &platform_bus;
115 error = device_add(&shost->shost_gendev);
119 set_bit(SHOST_ADD, &shost->shost_state);
120 get_device(shost->shost_gendev.parent);
122 error = class_device_add(&shost->shost_classdev);
126 get_device(&shost->shost_gendev);
128 error = scsi_sysfs_add_host(shost);
130 goto out_del_classdev;
132 scsi_proc_host_add(shost);
136 class_device_del(&shost->shost_classdev);
138 device_del(&shost->shost_gendev);
143 static void scsi_host_dev_release(struct device *dev)
145 struct Scsi_Host *shost = dev_to_shost(dev);
146 struct device *parent = dev->parent;
148 if (shost->ehandler) {
149 DECLARE_COMPLETION(sem);
150 shost->eh_notify = &sem;
153 wait_for_completion(&sem);
154 shost->eh_notify = NULL;
157 scsi_proc_hostdir_rm(shost->hostt);
158 scsi_destroy_command_freelist(shost);
161 * Some drivers (eg aha1542) do scsi_register()/scsi_unregister()
162 * during probing without performing a scsi_set_device() in between.
163 * In this case dev->parent is NULL.
171 * scsi_host_alloc - register a scsi host adapter instance.
172 * @sht: pointer to scsi host template
173 * @privsize: extra bytes to allocate for driver
176 * Allocate a new Scsi_Host and perform basic initialization.
177 * The host is not published to the scsi midlayer until scsi_add_host
181 * Pointer to a new Scsi_Host
183 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
185 struct Scsi_Host *shost;
186 int gfp_mask = GFP_KERNEL, rval;
187 DECLARE_COMPLETION(complete);
189 if (sht->unchecked_isa_dma && privsize)
190 gfp_mask |= __GFP_DMA;
192 /* Check to see if this host has any error handling facilities */
193 if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
194 !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
195 !sht->eh_host_reset_handler) {
196 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
197 "ERROR: This is not a safe way to run your "
199 "ERROR: The error handling must be added to "
200 "this driver\n", sht->proc_name);
204 shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
207 memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
209 spin_lock_init(&shost->default_lock);
210 scsi_assign_lock(shost, &shost->default_lock);
211 INIT_LIST_HEAD(&shost->__devices);
212 INIT_LIST_HEAD(&shost->eh_cmd_q);
213 INIT_LIST_HEAD(&shost->starved_list);
214 init_waitqueue_head(&shost->host_wait);
216 init_MUTEX(&shost->scan_mutex);
218 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
219 shost->dma_channel = 0xff;
221 /* These three are default values which can be overridden */
222 shost->max_channel = 0;
226 /* Give each shost a default transportt if the driver
227 * doesn't yet support Transport Attributes */
228 if (!shost->transportt)
229 shost->transportt = &blank_transport_template;
232 * All drivers right now should be able to handle 12 byte
233 * commands. Every so often there are requests for 16 byte
234 * commands, but individual low-level drivers need to certify that
235 * they actually do something sensible with such commands.
237 shost->max_cmd_len = 12;
239 shost->this_id = sht->this_id;
240 shost->can_queue = sht->can_queue;
241 shost->sg_tablesize = sht->sg_tablesize;
242 shost->cmd_per_lun = sht->cmd_per_lun;
243 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
244 shost->use_clustering = sht->use_clustering;
246 if (sht->max_host_blocked)
247 shost->max_host_blocked = sht->max_host_blocked;
249 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
252 * If the driver imposes no hard sector transfer limit, start at
253 * machine infinity initially.
255 if (sht->max_sectors)
256 shost->max_sectors = sht->max_sectors;
258 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
261 * assume a 4GB boundary, if not set
263 if (sht->dma_boundary)
264 shost->dma_boundary = sht->dma_boundary;
266 shost->dma_boundary = 0xffffffff;
268 rval = scsi_setup_command_freelist(shost);
272 device_initialize(&shost->shost_gendev);
273 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
275 shost->shost_gendev.release = scsi_host_dev_release;
277 class_device_initialize(&shost->shost_classdev);
278 shost->shost_classdev.dev = &shost->shost_gendev;
279 shost->shost_classdev.class = &shost_class;
280 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
283 shost->eh_notify = &complete;
284 rval = kernel_thread(scsi_error_handler, shost, 0);
286 goto fail_destroy_freelist;
287 wait_for_completion(&complete);
288 shost->eh_notify = NULL;
289 scsi_proc_hostdir_add(shost->hostt);
292 fail_destroy_freelist:
293 scsi_destroy_command_freelist(shost);
299 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
301 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
304 printk(KERN_WARNING "scsi_register() called on new-style "
305 "template for driver %s\n", sht->name);
310 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
314 void scsi_unregister(struct Scsi_Host *shost)
316 list_del(&shost->sht_legacy_list);
317 scsi_host_put(shost);
321 * scsi_host_lookup - get a reference to a Scsi_Host by host no
323 * @hostnum: host number to locate
326 * A pointer to located Scsi_Host or NULL.
328 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
330 struct class *class = &shost_class;
331 struct class_device *cdev;
332 struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
334 down_read(&class->subsys.rwsem);
335 list_for_each_entry(cdev, &class->children, node) {
336 p = class_to_shost(cdev);
337 if (p->host_no == hostnum) {
338 shost = scsi_host_get(p);
342 up_read(&class->subsys.rwsem);
348 * scsi_host_get - inc a Scsi_Host ref count
349 * @shost: Pointer to Scsi_Host to inc.
351 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
353 if (test_bit(SHOST_DEL, &shost->shost_state) ||
354 !get_device(&shost->shost_gendev))
360 * scsi_host_put - dec a Scsi_Host ref count
361 * @shost: Pointer to Scsi_Host to dec.
363 void scsi_host_put(struct Scsi_Host *shost)
365 put_device(&shost->shost_gendev);
368 int scsi_init_hosts(void)
370 return class_register(&shost_class);
373 void scsi_exit_hosts(void)
375 class_unregister(&shost_class);