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/completion.h>
31 #include <linux/transport_class.h>
33 #include <scsi/scsi_device.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_transport.h>
37 #include "scsi_priv.h"
38 #include "scsi_logging.h"
41 static int scsi_host_next_hn; /* host_no for next new host */
44 static void scsi_host_cls_release(struct class_device *class_dev)
46 put_device(&class_to_shost(class_dev)->shost_gendev);
49 static struct class shost_class = {
51 .release = scsi_host_cls_release,
55 * scsi_host_cancel - cancel outstanding IO to this host
56 * @shost: pointer to struct Scsi_Host
57 * recovery: recovery requested to run.
59 void scsi_host_cancel(struct Scsi_Host *shost, int recovery)
61 struct scsi_device *sdev;
63 set_bit(SHOST_CANCEL, &shost->shost_state);
64 shost_for_each_device(sdev, shost) {
65 scsi_device_cancel(sdev, recovery);
67 wait_event(shost->host_wait, (!test_bit(SHOST_RECOVERY,
68 &shost->shost_state)));
72 * scsi_remove_host - remove a scsi host
73 * @shost: a pointer to a scsi host to remove
75 void scsi_remove_host(struct Scsi_Host *shost)
77 scsi_forget_host(shost);
78 scsi_host_cancel(shost, 0);
79 scsi_proc_host_rm(shost);
81 set_bit(SHOST_DEL, &shost->shost_state);
83 transport_unregister_device(&shost->shost_gendev);
84 class_device_unregister(&shost->shost_classdev);
85 device_del(&shost->shost_gendev);
87 EXPORT_SYMBOL(scsi_remove_host);
90 * scsi_add_host - add a scsi host
91 * @shost: scsi host pointer to add
92 * @dev: a struct device of type scsi class
95 * 0 on success / != 0 for error
97 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
99 struct scsi_host_template *sht = shost->hostt;
102 printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
103 sht->info ? sht->info(shost) : sht->name);
105 if (!shost->can_queue) {
106 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
111 if (!shost->shost_gendev.parent)
112 shost->shost_gendev.parent = dev ? dev : &platform_bus;
114 error = device_add(&shost->shost_gendev);
118 set_bit(SHOST_ADD, &shost->shost_state);
119 get_device(shost->shost_gendev.parent);
121 error = class_device_add(&shost->shost_classdev);
125 get_device(&shost->shost_gendev);
127 if (shost->transportt->host_size &&
128 (shost->shost_data = kmalloc(shost->transportt->host_size,
129 GFP_KERNEL)) == NULL)
130 goto out_del_classdev;
132 error = scsi_sysfs_add_host(shost);
134 goto out_destroy_host;
136 scsi_proc_host_add(shost);
141 class_device_del(&shost->shost_classdev);
143 device_del(&shost->shost_gendev);
147 EXPORT_SYMBOL(scsi_add_host);
149 static void scsi_host_dev_release(struct device *dev)
151 struct Scsi_Host *shost = dev_to_shost(dev);
152 struct device *parent = dev->parent;
154 if (shost->ehandler) {
155 DECLARE_COMPLETION(sem);
156 shost->eh_notify = &sem;
159 wait_for_completion(&sem);
160 shost->eh_notify = NULL;
163 scsi_proc_hostdir_rm(shost->hostt);
164 scsi_destroy_command_freelist(shost);
165 kfree(shost->shost_data);
168 * Some drivers (eg aha1542) do scsi_register()/scsi_unregister()
169 * during probing without performing a scsi_set_device() in between.
170 * In this case dev->parent is NULL.
178 * scsi_host_alloc - register a scsi host adapter instance.
179 * @sht: pointer to scsi host template
180 * @privsize: extra bytes to allocate for driver
183 * Allocate a new Scsi_Host and perform basic initialization.
184 * The host is not published to the scsi midlayer until scsi_add_host
188 * Pointer to a new Scsi_Host
190 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
192 struct Scsi_Host *shost;
193 int gfp_mask = GFP_KERNEL, rval;
194 DECLARE_COMPLETION(complete);
196 if (sht->unchecked_isa_dma && privsize)
197 gfp_mask |= __GFP_DMA;
199 /* Check to see if this host has any error handling facilities */
200 if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
201 !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
202 !sht->eh_host_reset_handler) {
203 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
204 "ERROR: This is not a safe way to run your "
206 "ERROR: The error handling must be added to "
207 "this driver\n", sht->proc_name);
211 shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
214 memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
216 spin_lock_init(&shost->default_lock);
217 scsi_assign_lock(shost, &shost->default_lock);
218 INIT_LIST_HEAD(&shost->__devices);
219 INIT_LIST_HEAD(&shost->eh_cmd_q);
220 INIT_LIST_HEAD(&shost->starved_list);
221 init_waitqueue_head(&shost->host_wait);
223 init_MUTEX(&shost->scan_mutex);
225 shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
226 shost->dma_channel = 0xff;
228 /* These three are default values which can be overridden */
229 shost->max_channel = 0;
233 /* Give each shost a default transportt */
234 shost->transportt = &blank_transport_template;
237 * All drivers right now should be able to handle 12 byte
238 * commands. Every so often there are requests for 16 byte
239 * commands, but individual low-level drivers need to certify that
240 * they actually do something sensible with such commands.
242 shost->max_cmd_len = 12;
244 shost->this_id = sht->this_id;
245 shost->can_queue = sht->can_queue;
246 shost->sg_tablesize = sht->sg_tablesize;
247 shost->cmd_per_lun = sht->cmd_per_lun;
248 shost->unchecked_isa_dma = sht->unchecked_isa_dma;
249 shost->use_clustering = sht->use_clustering;
251 if (sht->max_host_blocked)
252 shost->max_host_blocked = sht->max_host_blocked;
254 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
257 * If the driver imposes no hard sector transfer limit, start at
258 * machine infinity initially.
260 if (sht->max_sectors)
261 shost->max_sectors = sht->max_sectors;
263 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
266 * assume a 4GB boundary, if not set
268 if (sht->dma_boundary)
269 shost->dma_boundary = sht->dma_boundary;
271 shost->dma_boundary = 0xffffffff;
273 rval = scsi_setup_command_freelist(shost);
277 device_initialize(&shost->shost_gendev);
278 snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
280 shost->shost_gendev.release = scsi_host_dev_release;
282 class_device_initialize(&shost->shost_classdev);
283 shost->shost_classdev.dev = &shost->shost_gendev;
284 shost->shost_classdev.class = &shost_class;
285 snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
288 shost->eh_notify = &complete;
289 rval = kernel_thread(scsi_error_handler, shost, 0);
291 goto fail_destroy_freelist;
292 wait_for_completion(&complete);
293 shost->eh_notify = NULL;
295 scsi_proc_hostdir_add(shost->hostt);
298 fail_destroy_freelist:
299 scsi_destroy_command_freelist(shost);
304 EXPORT_SYMBOL(scsi_host_alloc);
306 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
308 struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
311 printk(KERN_WARNING "scsi_register() called on new-style "
312 "template for driver %s\n", sht->name);
317 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
320 EXPORT_SYMBOL(scsi_register);
322 void scsi_unregister(struct Scsi_Host *shost)
324 list_del(&shost->sht_legacy_list);
325 scsi_host_put(shost);
327 EXPORT_SYMBOL(scsi_unregister);
330 * scsi_host_lookup - get a reference to a Scsi_Host by host no
332 * @hostnum: host number to locate
335 * A pointer to located Scsi_Host or NULL.
337 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
339 struct class *class = &shost_class;
340 struct class_device *cdev;
341 struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
343 down_read(&class->subsys.rwsem);
344 list_for_each_entry(cdev, &class->children, node) {
345 p = class_to_shost(cdev);
346 if (p->host_no == hostnum) {
347 shost = scsi_host_get(p);
351 up_read(&class->subsys.rwsem);
355 EXPORT_SYMBOL(scsi_host_lookup);
358 * scsi_host_get - inc a Scsi_Host ref count
359 * @shost: Pointer to Scsi_Host to inc.
361 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
363 if (test_bit(SHOST_DEL, &shost->shost_state) ||
364 !get_device(&shost->shost_gendev))
368 EXPORT_SYMBOL(scsi_host_get);
371 * scsi_host_put - dec a Scsi_Host ref count
372 * @shost: Pointer to Scsi_Host to dec.
374 void scsi_host_put(struct Scsi_Host *shost)
376 put_device(&shost->shost_gendev);
378 EXPORT_SYMBOL(scsi_host_put);
380 int scsi_init_hosts(void)
382 return class_register(&shost_class);
385 void scsi_exit_hosts(void)
387 class_unregister(&shost_class);
390 int scsi_is_host_device(const struct device *dev)
392 return dev->release == scsi_host_dev_release;
394 EXPORT_SYMBOL(scsi_is_host_device);