x86: arch/x86/mm/init_32.c cleanup
[wrt350n-kernel.git] / drivers / firewire / fw-device.c
blob56681b3b297baa43ed5b756151933b9a57f05f2c
1 /*
2 * Device probing and sysfs code.
4 * Copyright (C) 2005-2006 Kristian Hoegsberg <krh@bitplanet.net>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software Foundation,
18 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21 #include <linux/module.h>
22 #include <linux/wait.h>
23 #include <linux/errno.h>
24 #include <linux/kthread.h>
25 #include <linux/device.h>
26 #include <linux/delay.h>
27 #include <linux/idr.h>
28 #include <linux/rwsem.h>
29 #include <asm/semaphore.h>
30 #include <linux/ctype.h>
31 #include "fw-transaction.h"
32 #include "fw-topology.h"
33 #include "fw-device.h"
35 void fw_csr_iterator_init(struct fw_csr_iterator *ci, u32 * p)
37 ci->p = p + 1;
38 ci->end = ci->p + (p[0] >> 16);
40 EXPORT_SYMBOL(fw_csr_iterator_init);
42 int fw_csr_iterator_next(struct fw_csr_iterator *ci, int *key, int *value)
44 *key = *ci->p >> 24;
45 *value = *ci->p & 0xffffff;
47 return ci->p++ < ci->end;
49 EXPORT_SYMBOL(fw_csr_iterator_next);
51 static int is_fw_unit(struct device *dev);
53 static int match_unit_directory(u32 * directory, const struct fw_device_id *id)
55 struct fw_csr_iterator ci;
56 int key, value, match;
58 match = 0;
59 fw_csr_iterator_init(&ci, directory);
60 while (fw_csr_iterator_next(&ci, &key, &value)) {
61 if (key == CSR_VENDOR && value == id->vendor)
62 match |= FW_MATCH_VENDOR;
63 if (key == CSR_MODEL && value == id->model)
64 match |= FW_MATCH_MODEL;
65 if (key == CSR_SPECIFIER_ID && value == id->specifier_id)
66 match |= FW_MATCH_SPECIFIER_ID;
67 if (key == CSR_VERSION && value == id->version)
68 match |= FW_MATCH_VERSION;
71 return (match & id->match_flags) == id->match_flags;
74 static int fw_unit_match(struct device *dev, struct device_driver *drv)
76 struct fw_unit *unit = fw_unit(dev);
77 struct fw_driver *driver = fw_driver(drv);
78 int i;
80 /* We only allow binding to fw_units. */
81 if (!is_fw_unit(dev))
82 return 0;
84 for (i = 0; driver->id_table[i].match_flags != 0; i++) {
85 if (match_unit_directory(unit->directory, &driver->id_table[i]))
86 return 1;
89 return 0;
92 static int get_modalias(struct fw_unit *unit, char *buffer, size_t buffer_size)
94 struct fw_device *device = fw_device(unit->device.parent);
95 struct fw_csr_iterator ci;
97 int key, value;
98 int vendor = 0;
99 int model = 0;
100 int specifier_id = 0;
101 int version = 0;
103 fw_csr_iterator_init(&ci, &device->config_rom[5]);
104 while (fw_csr_iterator_next(&ci, &key, &value)) {
105 switch (key) {
106 case CSR_VENDOR:
107 vendor = value;
108 break;
109 case CSR_MODEL:
110 model = value;
111 break;
115 fw_csr_iterator_init(&ci, unit->directory);
116 while (fw_csr_iterator_next(&ci, &key, &value)) {
117 switch (key) {
118 case CSR_SPECIFIER_ID:
119 specifier_id = value;
120 break;
121 case CSR_VERSION:
122 version = value;
123 break;
127 return snprintf(buffer, buffer_size,
128 "ieee1394:ven%08Xmo%08Xsp%08Xver%08X",
129 vendor, model, specifier_id, version);
132 static int
133 fw_unit_uevent(struct device *dev, struct kobj_uevent_env *env)
135 struct fw_unit *unit = fw_unit(dev);
136 char modalias[64];
138 get_modalias(unit, modalias, sizeof(modalias));
140 if (add_uevent_var(env, "MODALIAS=%s", modalias))
141 return -ENOMEM;
143 return 0;
146 struct bus_type fw_bus_type = {
147 .name = "firewire",
148 .match = fw_unit_match,
150 EXPORT_SYMBOL(fw_bus_type);
152 struct fw_device *fw_device_get(struct fw_device *device)
154 get_device(&device->device);
156 return device;
159 void fw_device_put(struct fw_device *device)
161 put_device(&device->device);
164 static void fw_device_release(struct device *dev)
166 struct fw_device *device = fw_device(dev);
167 unsigned long flags;
170 * Take the card lock so we don't set this to NULL while a
171 * FW_NODE_UPDATED callback is being handled.
173 spin_lock_irqsave(&device->card->lock, flags);
174 device->node->data = NULL;
175 spin_unlock_irqrestore(&device->card->lock, flags);
177 fw_node_put(device->node);
178 fw_card_put(device->card);
179 kfree(device->config_rom);
180 kfree(device);
183 int fw_device_enable_phys_dma(struct fw_device *device)
185 return device->card->driver->enable_phys_dma(device->card,
186 device->node_id,
187 device->generation);
189 EXPORT_SYMBOL(fw_device_enable_phys_dma);
191 struct config_rom_attribute {
192 struct device_attribute attr;
193 u32 key;
196 static ssize_t
197 show_immediate(struct device *dev, struct device_attribute *dattr, char *buf)
199 struct config_rom_attribute *attr =
200 container_of(dattr, struct config_rom_attribute, attr);
201 struct fw_csr_iterator ci;
202 u32 *dir;
203 int key, value;
205 if (is_fw_unit(dev))
206 dir = fw_unit(dev)->directory;
207 else
208 dir = fw_device(dev)->config_rom + 5;
210 fw_csr_iterator_init(&ci, dir);
211 while (fw_csr_iterator_next(&ci, &key, &value))
212 if (attr->key == key)
213 return snprintf(buf, buf ? PAGE_SIZE : 0,
214 "0x%06x\n", value);
216 return -ENOENT;
219 #define IMMEDIATE_ATTR(name, key) \
220 { __ATTR(name, S_IRUGO, show_immediate, NULL), key }
222 static ssize_t
223 show_text_leaf(struct device *dev, struct device_attribute *dattr, char *buf)
225 struct config_rom_attribute *attr =
226 container_of(dattr, struct config_rom_attribute, attr);
227 struct fw_csr_iterator ci;
228 u32 *dir, *block = NULL, *p, *end;
229 int length, key, value, last_key = 0;
230 char *b;
232 if (is_fw_unit(dev))
233 dir = fw_unit(dev)->directory;
234 else
235 dir = fw_device(dev)->config_rom + 5;
237 fw_csr_iterator_init(&ci, dir);
238 while (fw_csr_iterator_next(&ci, &key, &value)) {
239 if (attr->key == last_key &&
240 key == (CSR_DESCRIPTOR | CSR_LEAF))
241 block = ci.p - 1 + value;
242 last_key = key;
245 if (block == NULL)
246 return -ENOENT;
248 length = min(block[0] >> 16, 256U);
249 if (length < 3)
250 return -ENOENT;
252 if (block[1] != 0 || block[2] != 0)
253 /* Unknown encoding. */
254 return -ENOENT;
256 if (buf == NULL)
257 return length * 4;
259 b = buf;
260 end = &block[length + 1];
261 for (p = &block[3]; p < end; p++, b += 4)
262 * (u32 *) b = (__force u32) __cpu_to_be32(*p);
264 /* Strip trailing whitespace and add newline. */
265 while (b--, (isspace(*b) || *b == '\0') && b > buf);
266 strcpy(b + 1, "\n");
268 return b + 2 - buf;
271 #define TEXT_LEAF_ATTR(name, key) \
272 { __ATTR(name, S_IRUGO, show_text_leaf, NULL), key }
274 static struct config_rom_attribute config_rom_attributes[] = {
275 IMMEDIATE_ATTR(vendor, CSR_VENDOR),
276 IMMEDIATE_ATTR(hardware_version, CSR_HARDWARE_VERSION),
277 IMMEDIATE_ATTR(specifier_id, CSR_SPECIFIER_ID),
278 IMMEDIATE_ATTR(version, CSR_VERSION),
279 IMMEDIATE_ATTR(model, CSR_MODEL),
280 TEXT_LEAF_ATTR(vendor_name, CSR_VENDOR),
281 TEXT_LEAF_ATTR(model_name, CSR_MODEL),
282 TEXT_LEAF_ATTR(hardware_version_name, CSR_HARDWARE_VERSION),
285 static void
286 init_fw_attribute_group(struct device *dev,
287 struct device_attribute *attrs,
288 struct fw_attribute_group *group)
290 struct device_attribute *attr;
291 int i, j;
293 for (j = 0; attrs[j].attr.name != NULL; j++)
294 group->attrs[j] = &attrs[j].attr;
296 for (i = 0; i < ARRAY_SIZE(config_rom_attributes); i++) {
297 attr = &config_rom_attributes[i].attr;
298 if (attr->show(dev, attr, NULL) < 0)
299 continue;
300 group->attrs[j++] = &attr->attr;
303 BUG_ON(j >= ARRAY_SIZE(group->attrs));
304 group->attrs[j++] = NULL;
305 group->groups[0] = &group->group;
306 group->groups[1] = NULL;
307 group->group.attrs = group->attrs;
308 dev->groups = group->groups;
311 static ssize_t
312 modalias_show(struct device *dev,
313 struct device_attribute *attr, char *buf)
315 struct fw_unit *unit = fw_unit(dev);
316 int length;
318 length = get_modalias(unit, buf, PAGE_SIZE);
319 strcpy(buf + length, "\n");
321 return length + 1;
324 static ssize_t
325 rom_index_show(struct device *dev,
326 struct device_attribute *attr, char *buf)
328 struct fw_device *device = fw_device(dev->parent);
329 struct fw_unit *unit = fw_unit(dev);
331 return snprintf(buf, PAGE_SIZE, "%d\n",
332 (int)(unit->directory - device->config_rom));
335 static struct device_attribute fw_unit_attributes[] = {
336 __ATTR_RO(modalias),
337 __ATTR_RO(rom_index),
338 __ATTR_NULL,
341 static ssize_t
342 config_rom_show(struct device *dev, struct device_attribute *attr, char *buf)
344 struct fw_device *device = fw_device(dev);
346 memcpy(buf, device->config_rom, device->config_rom_length * 4);
348 return device->config_rom_length * 4;
351 static ssize_t
352 guid_show(struct device *dev, struct device_attribute *attr, char *buf)
354 struct fw_device *device = fw_device(dev);
355 u64 guid;
357 guid = ((u64)device->config_rom[3] << 32) | device->config_rom[4];
359 return snprintf(buf, PAGE_SIZE, "0x%016llx\n",
360 (unsigned long long)guid);
363 static struct device_attribute fw_device_attributes[] = {
364 __ATTR_RO(config_rom),
365 __ATTR_RO(guid),
366 __ATTR_NULL,
369 struct read_quadlet_callback_data {
370 struct completion done;
371 int rcode;
372 u32 data;
375 static void
376 complete_transaction(struct fw_card *card, int rcode,
377 void *payload, size_t length, void *data)
379 struct read_quadlet_callback_data *callback_data = data;
381 if (rcode == RCODE_COMPLETE)
382 callback_data->data = be32_to_cpu(*(__be32 *)payload);
383 callback_data->rcode = rcode;
384 complete(&callback_data->done);
387 static int read_rom(struct fw_device *device, int index, u32 * data)
389 struct read_quadlet_callback_data callback_data;
390 struct fw_transaction t;
391 u64 offset;
393 init_completion(&callback_data.done);
395 offset = 0xfffff0000400ULL + index * 4;
396 fw_send_request(device->card, &t, TCODE_READ_QUADLET_REQUEST,
397 device->node_id, device->generation, device->max_speed,
398 offset, NULL, 4, complete_transaction, &callback_data);
400 wait_for_completion(&callback_data.done);
402 *data = callback_data.data;
404 return callback_data.rcode;
407 static int read_bus_info_block(struct fw_device *device)
409 static u32 rom[256];
410 u32 stack[16], sp, key;
411 int i, end, length;
413 device->max_speed = SCODE_100;
415 /* First read the bus info block. */
416 for (i = 0; i < 5; i++) {
417 if (read_rom(device, i, &rom[i]) != RCODE_COMPLETE)
418 return -1;
420 * As per IEEE1212 7.2, during power-up, devices can
421 * reply with a 0 for the first quadlet of the config
422 * rom to indicate that they are booting (for example,
423 * if the firmware is on the disk of a external
424 * harddisk). In that case we just fail, and the
425 * retry mechanism will try again later.
427 if (i == 0 && rom[i] == 0)
428 return -1;
431 device->max_speed = device->node->max_speed;
434 * Determine the speed of
435 * - devices with link speed less than PHY speed,
436 * - devices with 1394b PHY (unless only connected to 1394a PHYs),
437 * - all devices if there are 1394b repeaters.
438 * Note, we cannot use the bus info block's link_spd as starting point
439 * because some buggy firmwares set it lower than necessary and because
440 * 1394-1995 nodes do not have the field.
442 if ((rom[2] & 0x7) < device->max_speed ||
443 device->max_speed == SCODE_BETA ||
444 device->card->beta_repeaters_present) {
445 u32 dummy;
447 /* for S1600 and S3200 */
448 if (device->max_speed == SCODE_BETA)
449 device->max_speed = device->card->link_speed;
451 while (device->max_speed > SCODE_100) {
452 if (read_rom(device, 0, &dummy) == RCODE_COMPLETE)
453 break;
454 device->max_speed--;
459 * Now parse the config rom. The config rom is a recursive
460 * directory structure so we parse it using a stack of
461 * references to the blocks that make up the structure. We
462 * push a reference to the root directory on the stack to
463 * start things off.
465 length = i;
466 sp = 0;
467 stack[sp++] = 0xc0000005;
468 while (sp > 0) {
470 * Pop the next block reference of the stack. The
471 * lower 24 bits is the offset into the config rom,
472 * the upper 8 bits are the type of the reference the
473 * block.
475 key = stack[--sp];
476 i = key & 0xffffff;
477 if (i >= ARRAY_SIZE(rom))
479 * The reference points outside the standard
480 * config rom area, something's fishy.
482 return -1;
484 /* Read header quadlet for the block to get the length. */
485 if (read_rom(device, i, &rom[i]) != RCODE_COMPLETE)
486 return -1;
487 end = i + (rom[i] >> 16) + 1;
488 i++;
489 if (end > ARRAY_SIZE(rom))
491 * This block extends outside standard config
492 * area (and the array we're reading it
493 * into). That's broken, so ignore this
494 * device.
496 return -1;
499 * Now read in the block. If this is a directory
500 * block, check the entries as we read them to see if
501 * it references another block, and push it in that case.
503 while (i < end) {
504 if (read_rom(device, i, &rom[i]) != RCODE_COMPLETE)
505 return -1;
506 if ((key >> 30) == 3 && (rom[i] >> 30) > 1 &&
507 sp < ARRAY_SIZE(stack))
508 stack[sp++] = i + rom[i];
509 i++;
511 if (length < i)
512 length = i;
515 device->config_rom = kmalloc(length * 4, GFP_KERNEL);
516 if (device->config_rom == NULL)
517 return -1;
518 memcpy(device->config_rom, rom, length * 4);
519 device->config_rom_length = length;
521 return 0;
524 static void fw_unit_release(struct device *dev)
526 struct fw_unit *unit = fw_unit(dev);
528 kfree(unit);
531 static struct device_type fw_unit_type = {
532 .uevent = fw_unit_uevent,
533 .release = fw_unit_release,
536 static int is_fw_unit(struct device *dev)
538 return dev->type == &fw_unit_type;
541 static void create_units(struct fw_device *device)
543 struct fw_csr_iterator ci;
544 struct fw_unit *unit;
545 int key, value, i;
547 i = 0;
548 fw_csr_iterator_init(&ci, &device->config_rom[5]);
549 while (fw_csr_iterator_next(&ci, &key, &value)) {
550 if (key != (CSR_UNIT | CSR_DIRECTORY))
551 continue;
554 * Get the address of the unit directory and try to
555 * match the drivers id_tables against it.
557 unit = kzalloc(sizeof(*unit), GFP_KERNEL);
558 if (unit == NULL) {
559 fw_error("failed to allocate memory for unit\n");
560 continue;
563 unit->directory = ci.p + value - 1;
564 unit->device.bus = &fw_bus_type;
565 unit->device.type = &fw_unit_type;
566 unit->device.parent = &device->device;
567 snprintf(unit->device.bus_id, sizeof(unit->device.bus_id),
568 "%s.%d", device->device.bus_id, i++);
570 init_fw_attribute_group(&unit->device,
571 fw_unit_attributes,
572 &unit->attribute_group);
573 if (device_register(&unit->device) < 0)
574 goto skip_unit;
576 continue;
578 skip_unit:
579 kfree(unit);
583 static int shutdown_unit(struct device *device, void *data)
585 device_unregister(device);
587 return 0;
590 static DECLARE_RWSEM(idr_rwsem);
591 static DEFINE_IDR(fw_device_idr);
592 int fw_cdev_major;
594 struct fw_device *fw_device_from_devt(dev_t devt)
596 struct fw_device *device;
598 down_read(&idr_rwsem);
599 device = idr_find(&fw_device_idr, MINOR(devt));
600 up_read(&idr_rwsem);
602 return device;
605 static void fw_device_shutdown(struct work_struct *work)
607 struct fw_device *device =
608 container_of(work, struct fw_device, work.work);
609 int minor = MINOR(device->device.devt);
611 down_write(&idr_rwsem);
612 idr_remove(&fw_device_idr, minor);
613 up_write(&idr_rwsem);
615 fw_device_cdev_remove(device);
616 device_for_each_child(&device->device, NULL, shutdown_unit);
617 device_unregister(&device->device);
620 static struct device_type fw_device_type = {
621 .release = fw_device_release,
625 * These defines control the retry behavior for reading the config
626 * rom. It shouldn't be necessary to tweak these; if the device
627 * doesn't respond to a config rom read within 10 seconds, it's not
628 * going to respond at all. As for the initial delay, a lot of
629 * devices will be able to respond within half a second after bus
630 * reset. On the other hand, it's not really worth being more
631 * aggressive than that, since it scales pretty well; if 10 devices
632 * are plugged in, they're all getting read within one second.
635 #define MAX_RETRIES 10
636 #define RETRY_DELAY (3 * HZ)
637 #define INITIAL_DELAY (HZ / 2)
639 static void fw_device_init(struct work_struct *work)
641 struct fw_device *device =
642 container_of(work, struct fw_device, work.work);
643 int minor, err;
646 * All failure paths here set node->data to NULL, so that we
647 * don't try to do device_for_each_child() on a kfree()'d
648 * device.
651 if (read_bus_info_block(device) < 0) {
652 if (device->config_rom_retries < MAX_RETRIES) {
653 device->config_rom_retries++;
654 schedule_delayed_work(&device->work, RETRY_DELAY);
655 } else {
656 fw_notify("giving up on config rom for node id %x\n",
657 device->node_id);
658 if (device->node == device->card->root_node)
659 schedule_delayed_work(&device->card->work, 0);
660 fw_device_release(&device->device);
662 return;
665 err = -ENOMEM;
666 down_write(&idr_rwsem);
667 if (idr_pre_get(&fw_device_idr, GFP_KERNEL))
668 err = idr_get_new(&fw_device_idr, device, &minor);
669 up_write(&idr_rwsem);
670 if (err < 0)
671 goto error;
673 device->device.bus = &fw_bus_type;
674 device->device.type = &fw_device_type;
675 device->device.parent = device->card->device;
676 device->device.devt = MKDEV(fw_cdev_major, minor);
677 snprintf(device->device.bus_id, sizeof(device->device.bus_id),
678 "fw%d", minor);
680 init_fw_attribute_group(&device->device,
681 fw_device_attributes,
682 &device->attribute_group);
683 if (device_add(&device->device)) {
684 fw_error("Failed to add device.\n");
685 goto error_with_cdev;
688 create_units(device);
691 * Transition the device to running state. If it got pulled
692 * out from under us while we did the intialization work, we
693 * have to shut down the device again here. Normally, though,
694 * fw_node_event will be responsible for shutting it down when
695 * necessary. We have to use the atomic cmpxchg here to avoid
696 * racing with the FW_NODE_DESTROYED case in
697 * fw_node_event().
699 if (atomic_cmpxchg(&device->state,
700 FW_DEVICE_INITIALIZING,
701 FW_DEVICE_RUNNING) == FW_DEVICE_SHUTDOWN)
702 fw_device_shutdown(&device->work.work);
703 else
704 fw_notify("created new fw device %s "
705 "(%d config rom retries, S%d00)\n",
706 device->device.bus_id, device->config_rom_retries,
707 1 << device->max_speed);
710 * Reschedule the IRM work if we just finished reading the
711 * root node config rom. If this races with a bus reset we
712 * just end up running the IRM work a couple of extra times -
713 * pretty harmless.
715 if (device->node == device->card->root_node)
716 schedule_delayed_work(&device->card->work, 0);
718 return;
720 error_with_cdev:
721 down_write(&idr_rwsem);
722 idr_remove(&fw_device_idr, minor);
723 up_write(&idr_rwsem);
724 error:
725 put_device(&device->device);
728 static int update_unit(struct device *dev, void *data)
730 struct fw_unit *unit = fw_unit(dev);
731 struct fw_driver *driver = (struct fw_driver *)dev->driver;
733 if (is_fw_unit(dev) && driver != NULL && driver->update != NULL) {
734 down(&dev->sem);
735 driver->update(unit);
736 up(&dev->sem);
739 return 0;
742 static void fw_device_update(struct work_struct *work)
744 struct fw_device *device =
745 container_of(work, struct fw_device, work.work);
747 fw_device_cdev_update(device);
748 device_for_each_child(&device->device, NULL, update_unit);
751 void fw_node_event(struct fw_card *card, struct fw_node *node, int event)
753 struct fw_device *device;
755 switch (event) {
756 case FW_NODE_CREATED:
757 case FW_NODE_LINK_ON:
758 if (!node->link_on)
759 break;
761 device = kzalloc(sizeof(*device), GFP_ATOMIC);
762 if (device == NULL)
763 break;
766 * Do minimal intialization of the device here, the
767 * rest will happen in fw_device_init(). We need the
768 * card and node so we can read the config rom and we
769 * need to do device_initialize() now so
770 * device_for_each_child() in FW_NODE_UPDATED is
771 * doesn't freak out.
773 device_initialize(&device->device);
774 atomic_set(&device->state, FW_DEVICE_INITIALIZING);
775 device->card = fw_card_get(card);
776 device->node = fw_node_get(node);
777 device->node_id = node->node_id;
778 device->generation = card->generation;
779 INIT_LIST_HEAD(&device->client_list);
782 * Set the node data to point back to this device so
783 * FW_NODE_UPDATED callbacks can update the node_id
784 * and generation for the device.
786 node->data = device;
789 * Many devices are slow to respond after bus resets,
790 * especially if they are bus powered and go through
791 * power-up after getting plugged in. We schedule the
792 * first config rom scan half a second after bus reset.
794 INIT_DELAYED_WORK(&device->work, fw_device_init);
795 schedule_delayed_work(&device->work, INITIAL_DELAY);
796 break;
798 case FW_NODE_UPDATED:
799 if (!node->link_on || node->data == NULL)
800 break;
802 device = node->data;
803 device->node_id = node->node_id;
804 device->generation = card->generation;
805 if (atomic_read(&device->state) == FW_DEVICE_RUNNING) {
806 PREPARE_DELAYED_WORK(&device->work, fw_device_update);
807 schedule_delayed_work(&device->work, 0);
809 break;
811 case FW_NODE_DESTROYED:
812 case FW_NODE_LINK_OFF:
813 if (!node->data)
814 break;
817 * Destroy the device associated with the node. There
818 * are two cases here: either the device is fully
819 * initialized (FW_DEVICE_RUNNING) or we're in the
820 * process of reading its config rom
821 * (FW_DEVICE_INITIALIZING). If it is fully
822 * initialized we can reuse device->work to schedule a
823 * full fw_device_shutdown(). If not, there's work
824 * scheduled to read it's config rom, and we just put
825 * the device in shutdown state to have that code fail
826 * to create the device.
828 device = node->data;
829 if (atomic_xchg(&device->state,
830 FW_DEVICE_SHUTDOWN) == FW_DEVICE_RUNNING) {
831 PREPARE_DELAYED_WORK(&device->work, fw_device_shutdown);
832 schedule_delayed_work(&device->work, 0);
834 break;