1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * PCI HotPlug Controller Core
4 *
5 * Copyright (C) 2001-2002 Greg Kroah-Hartman (greg@kroah.com)
6 * Copyright (C) 2001-2002 IBM Corp.
7 *
8 * All rights reserved.
9 *
10 * Send feedback to <kristen.c.accardi@intel.com>
11 *
12 * Authors:
13 * Greg Kroah-Hartman <greg@kroah.com>
14 * Scott Murray <scottm@somanetworks.com>
15 */
16
17#include <linux/module.h> /* try_module_get & module_put */
18#include <linux/moduleparam.h>
19#include <linux/kernel.h>
20#include <linux/types.h>
21#include <linux/list.h>
22#include <linux/kobject.h>
23#include <linux/sysfs.h>
24#include <linux/pagemap.h>
25#include <linux/init.h>
26#include <linux/mount.h>
27#include <linux/namei.h>
28#include <linux/mutex.h>
29#include <linux/pci.h>
30#include <linux/pci_hotplug.h>
31#include <linux/uaccess.h>
32#include "../pci.h"
33#include "cpci_hotplug.h"
34
35#define MY_NAME "pci_hotplug"
36
37#define dbg(fmt, arg...) do { if (debug) printk(KERN_DEBUG "%s: %s: " fmt, MY_NAME, __func__, ## arg); } while (0)
38#define err(format, arg...) printk(KERN_ERR "%s: " format, MY_NAME, ## arg)
39#define info(format, arg...) printk(KERN_INFO "%s: " format, MY_NAME, ## arg)
40#define warn(format, arg...) printk(KERN_WARNING "%s: " format, MY_NAME, ## arg)
41
42/* local variables */
43static bool debug;
44
45static LIST_HEAD(pci_hotplug_slot_list);
46static DEFINE_MUTEX(pci_hp_mutex);
47
48/* Weee, fun with macros... */
49#define GET_STATUS(name, type) \
50static int get_##name(struct hotplug_slot *slot, type *value) \
51{ \
52 const struct hotplug_slot_ops *ops = slot->ops; \
53 int retval = 0; \
54 if (!try_module_get(slot->owner)) \
55 return -ENODEV; \
56 if (ops->get_##name) \
57 retval = ops->get_##name(slot, value); \
58 module_put(slot->owner); \
59 return retval; \
60}
61
62GET_STATUS(power_status, u8)
63GET_STATUS(attention_status, u8)
64GET_STATUS(latch_status, u8)
65GET_STATUS(adapter_status, u8)
66
67static ssize_t power_read_file(struct pci_slot *pci_slot, char *buf)
68{
69 int retval;
70 u8 value;
71
72 retval = get_power_status(slot: pci_slot->hotplug, value: &value);
73 if (retval)
74 return retval;
75
76 return sysfs_emit(buf, fmt: "%d\n", value);
77}
78
79static ssize_t power_write_file(struct pci_slot *pci_slot, const char *buf,
80 size_t count)
81{
82 struct hotplug_slot *slot = pci_slot->hotplug;
83 unsigned long lpower;
84 u8 power;
85 int retval = 0;
86
87 lpower = simple_strtoul(buf, NULL, 10);
88 power = (u8)(lpower & 0xff);
89 dbg("power = %d\n", power);
90
91 if (!try_module_get(module: slot->owner)) {
92 retval = -ENODEV;
93 goto exit;
94 }
95 switch (power) {
96 case 0:
97 if (slot->ops->disable_slot)
98 retval = slot->ops->disable_slot(slot);
99 break;
100
101 case 1:
102 if (slot->ops->enable_slot)
103 retval = slot->ops->enable_slot(slot);
104 break;
105
106 default:
107 err("Illegal value specified for power\n");
108 retval = -EINVAL;
109 }
110 module_put(module: slot->owner);
111
112exit:
113 if (retval)
114 return retval;
115 return count;
116}
117
118static struct pci_slot_attribute hotplug_slot_attr_power = {
119 .attr = {.name = "power", .mode = S_IFREG | S_IRUGO | S_IWUSR},
120 .show = power_read_file,
121 .store = power_write_file
122};
123
124static ssize_t attention_read_file(struct pci_slot *pci_slot, char *buf)
125{
126 int retval;
127 u8 value;
128
129 retval = get_attention_status(slot: pci_slot->hotplug, value: &value);
130 if (retval)
131 return retval;
132
133 return sysfs_emit(buf, fmt: "%d\n", value);
134}
135
136static ssize_t attention_write_file(struct pci_slot *pci_slot, const char *buf,
137 size_t count)
138{
139 struct hotplug_slot *slot = pci_slot->hotplug;
140 const struct hotplug_slot_ops *ops = slot->ops;
141 unsigned long lattention;
142 u8 attention;
143 int retval = 0;
144
145 lattention = simple_strtoul(buf, NULL, 10);
146 attention = (u8)(lattention & 0xff);
147 dbg(" - attention = %d\n", attention);
148
149 if (!try_module_get(module: slot->owner)) {
150 retval = -ENODEV;
151 goto exit;
152 }
153 if (ops->set_attention_status)
154 retval = ops->set_attention_status(slot, attention);
155 module_put(module: slot->owner);
156
157exit:
158 if (retval)
159 return retval;
160 return count;
161}
162
163static struct pci_slot_attribute hotplug_slot_attr_attention = {
164 .attr = {.name = "attention", .mode = S_IFREG | S_IRUGO | S_IWUSR},
165 .show = attention_read_file,
166 .store = attention_write_file
167};
168
169static ssize_t latch_read_file(struct pci_slot *pci_slot, char *buf)
170{
171 int retval;
172 u8 value;
173
174 retval = get_latch_status(slot: pci_slot->hotplug, value: &value);
175 if (retval)
176 return retval;
177
178 return sysfs_emit(buf, fmt: "%d\n", value);
179}
180
181static struct pci_slot_attribute hotplug_slot_attr_latch = {
182 .attr = {.name = "latch", .mode = S_IFREG | S_IRUGO},
183 .show = latch_read_file,
184};
185
186static ssize_t presence_read_file(struct pci_slot *pci_slot, char *buf)
187{
188 int retval;
189 u8 value;
190
191 retval = get_adapter_status(slot: pci_slot->hotplug, value: &value);
192 if (retval)
193 return retval;
194
195 return sysfs_emit(buf, fmt: "%d\n", value);
196}
197
198static struct pci_slot_attribute hotplug_slot_attr_presence = {
199 .attr = {.name = "adapter", .mode = S_IFREG | S_IRUGO},
200 .show = presence_read_file,
201};
202
203static ssize_t test_write_file(struct pci_slot *pci_slot, const char *buf,
204 size_t count)
205{
206 struct hotplug_slot *slot = pci_slot->hotplug;
207 unsigned long ltest;
208 u32 test;
209 int retval = 0;
210
211 ltest = simple_strtoul(buf, NULL, 10);
212 test = (u32)(ltest & 0xffffffff);
213 dbg("test = %d\n", test);
214
215 if (!try_module_get(module: slot->owner)) {
216 retval = -ENODEV;
217 goto exit;
218 }
219 if (slot->ops->hardware_test)
220 retval = slot->ops->hardware_test(slot, test);
221 module_put(module: slot->owner);
222
223exit:
224 if (retval)
225 return retval;
226 return count;
227}
228
229static struct pci_slot_attribute hotplug_slot_attr_test = {
230 .attr = {.name = "test", .mode = S_IFREG | S_IRUGO | S_IWUSR},
231 .store = test_write_file
232};
233
234static bool has_power_file(struct pci_slot *pci_slot)
235{
236 struct hotplug_slot *slot = pci_slot->hotplug;
237
238 if ((!slot) || (!slot->ops))
239 return false;
240 if ((slot->ops->enable_slot) ||
241 (slot->ops->disable_slot) ||
242 (slot->ops->get_power_status))
243 return true;
244 return false;
245}
246
247static bool has_attention_file(struct pci_slot *pci_slot)
248{
249 struct hotplug_slot *slot = pci_slot->hotplug;
250
251 if ((!slot) || (!slot->ops))
252 return false;
253 if ((slot->ops->set_attention_status) ||
254 (slot->ops->get_attention_status))
255 return true;
256 return false;
257}
258
259static bool has_latch_file(struct pci_slot *pci_slot)
260{
261 struct hotplug_slot *slot = pci_slot->hotplug;
262
263 if ((!slot) || (!slot->ops))
264 return false;
265 if (slot->ops->get_latch_status)
266 return true;
267 return false;
268}
269
270static bool has_adapter_file(struct pci_slot *pci_slot)
271{
272 struct hotplug_slot *slot = pci_slot->hotplug;
273
274 if ((!slot) || (!slot->ops))
275 return false;
276 if (slot->ops->get_adapter_status)
277 return true;
278 return false;
279}
280
281static bool has_test_file(struct pci_slot *pci_slot)
282{
283 struct hotplug_slot *slot = pci_slot->hotplug;
284
285 if ((!slot) || (!slot->ops))
286 return false;
287 if (slot->ops->hardware_test)
288 return true;
289 return false;
290}
291
292static int fs_add_slot(struct pci_slot *pci_slot)
293{
294 int retval = 0;
295
296 /* Create symbolic link to the hotplug driver module */
297 pci_hp_create_module_link(pci_slot);
298
299 if (has_power_file(pci_slot)) {
300 retval = sysfs_create_file(kobj: &pci_slot->kobj,
301 attr: &hotplug_slot_attr_power.attr);
302 if (retval)
303 goto exit_power;
304 }
305
306 if (has_attention_file(pci_slot)) {
307 retval = sysfs_create_file(kobj: &pci_slot->kobj,
308 attr: &hotplug_slot_attr_attention.attr);
309 if (retval)
310 goto exit_attention;
311 }
312
313 if (has_latch_file(pci_slot)) {
314 retval = sysfs_create_file(kobj: &pci_slot->kobj,
315 attr: &hotplug_slot_attr_latch.attr);
316 if (retval)
317 goto exit_latch;
318 }
319
320 if (has_adapter_file(pci_slot)) {
321 retval = sysfs_create_file(kobj: &pci_slot->kobj,
322 attr: &hotplug_slot_attr_presence.attr);
323 if (retval)
324 goto exit_adapter;
325 }
326
327 if (has_test_file(pci_slot)) {
328 retval = sysfs_create_file(kobj: &pci_slot->kobj,
329 attr: &hotplug_slot_attr_test.attr);
330 if (retval)
331 goto exit_test;
332 }
333
334 goto exit;
335
336exit_test:
337 if (has_adapter_file(pci_slot))
338 sysfs_remove_file(kobj: &pci_slot->kobj,
339 attr: &hotplug_slot_attr_presence.attr);
340exit_adapter:
341 if (has_latch_file(pci_slot))
342 sysfs_remove_file(kobj: &pci_slot->kobj, attr: &hotplug_slot_attr_latch.attr);
343exit_latch:
344 if (has_attention_file(pci_slot))
345 sysfs_remove_file(kobj: &pci_slot->kobj,
346 attr: &hotplug_slot_attr_attention.attr);
347exit_attention:
348 if (has_power_file(pci_slot))
349 sysfs_remove_file(kobj: &pci_slot->kobj, attr: &hotplug_slot_attr_power.attr);
350exit_power:
351 pci_hp_remove_module_link(pci_slot);
352exit:
353 return retval;
354}
355
356static void fs_remove_slot(struct pci_slot *pci_slot)
357{
358 if (has_power_file(pci_slot))
359 sysfs_remove_file(kobj: &pci_slot->kobj, attr: &hotplug_slot_attr_power.attr);
360
361 if (has_attention_file(pci_slot))
362 sysfs_remove_file(kobj: &pci_slot->kobj,
363 attr: &hotplug_slot_attr_attention.attr);
364
365 if (has_latch_file(pci_slot))
366 sysfs_remove_file(kobj: &pci_slot->kobj, attr: &hotplug_slot_attr_latch.attr);
367
368 if (has_adapter_file(pci_slot))
369 sysfs_remove_file(kobj: &pci_slot->kobj,
370 attr: &hotplug_slot_attr_presence.attr);
371
372 if (has_test_file(pci_slot))
373 sysfs_remove_file(kobj: &pci_slot->kobj, attr: &hotplug_slot_attr_test.attr);
374
375 pci_hp_remove_module_link(pci_slot);
376}
377
378static struct hotplug_slot *get_slot_from_name(const char *name)
379{
380 struct hotplug_slot *slot;
381
382 list_for_each_entry(slot, &pci_hotplug_slot_list, slot_list) {
383 if (strcmp(hotplug_slot_name(slot), name) == 0)
384 return slot;
385 }
386 return NULL;
387}
388
389/**
390 * __pci_hp_register - register a hotplug_slot with the PCI hotplug subsystem
391 * @bus: bus this slot is on
392 * @slot: pointer to the &struct hotplug_slot to register
393 * @devnr: device number
394 * @name: name registered with kobject core
395 * @owner: caller module owner
396 * @mod_name: caller module name
397 *
398 * Prepares a hotplug slot for in-kernel use and immediately publishes it to
399 * user space in one go. Drivers may alternatively carry out the two steps
400 * separately by invoking pci_hp_initialize() and pci_hp_add().
401 *
402 * Returns 0 if successful, anything else for an error.
403 */
404int __pci_hp_register(struct hotplug_slot *slot, struct pci_bus *bus,
405 int devnr, const char *name,
406 struct module *owner, const char *mod_name)
407{
408 int result;
409
410 result = __pci_hp_initialize(slot, bus, nr: devnr, name, owner, mod_name);
411 if (result)
412 return result;
413
414 result = pci_hp_add(slot);
415 if (result)
416 pci_hp_destroy(slot);
417
418 return result;
419}
420EXPORT_SYMBOL_GPL(__pci_hp_register);
421
422/**
423 * __pci_hp_initialize - prepare hotplug slot for in-kernel use
424 * @slot: pointer to the &struct hotplug_slot to initialize
425 * @bus: bus this slot is on
426 * @devnr: slot number
427 * @name: name registered with kobject core
428 * @owner: caller module owner
429 * @mod_name: caller module name
430 *
431 * Allocate and fill in a PCI slot for use by a hotplug driver. Once this has
432 * been called, the driver may invoke hotplug_slot_name() to get the slot's
433 * unique name. The driver must be prepared to handle a ->reset_slot callback
434 * from this point on.
435 *
436 * Returns 0 on success or a negative int on error.
437 */
438int __pci_hp_initialize(struct hotplug_slot *slot, struct pci_bus *bus,
439 int devnr, const char *name, struct module *owner,
440 const char *mod_name)
441{
442 struct pci_slot *pci_slot;
443
444 if (slot == NULL)
445 return -ENODEV;
446 if (slot->ops == NULL)
447 return -EINVAL;
448
449 slot->owner = owner;
450 slot->mod_name = mod_name;
451
452 /*
453 * No problems if we call this interface from both ACPI_PCI_SLOT
454 * driver and call it here again. If we've already created the
455 * pci_slot, the interface will simply bump the refcount.
456 */
457 pci_slot = pci_create_slot(parent: bus, slot_nr: devnr, name, hotplug: slot);
458 if (IS_ERR(ptr: pci_slot))
459 return PTR_ERR(ptr: pci_slot);
460
461 slot->pci_slot = pci_slot;
462 pci_slot->hotplug = slot;
463 return 0;
464}
465EXPORT_SYMBOL_GPL(__pci_hp_initialize);
466
467/**
468 * pci_hp_add - publish hotplug slot to user space
469 * @slot: pointer to the &struct hotplug_slot to publish
470 *
471 * Make a hotplug slot's sysfs interface available and inform user space of its
472 * addition by sending a uevent. The hotplug driver must be prepared to handle
473 * all &struct hotplug_slot_ops callbacks from this point on.
474 *
475 * Returns 0 on success or a negative int on error.
476 */
477int pci_hp_add(struct hotplug_slot *slot)
478{
479 struct pci_slot *pci_slot = slot->pci_slot;
480 int result;
481
482 result = fs_add_slot(pci_slot);
483 if (result)
484 return result;
485
486 kobject_uevent(kobj: &pci_slot->kobj, action: KOBJ_ADD);
487 mutex_lock(&pci_hp_mutex);
488 list_add(new: &slot->slot_list, head: &pci_hotplug_slot_list);
489 mutex_unlock(lock: &pci_hp_mutex);
490 dbg("Added slot %s to the list\n", hotplug_slot_name(slot));
491 return 0;
492}
493EXPORT_SYMBOL_GPL(pci_hp_add);
494
495/**
496 * pci_hp_deregister - deregister a hotplug_slot with the PCI hotplug subsystem
497 * @slot: pointer to the &struct hotplug_slot to deregister
498 *
499 * The @slot must have been registered with the pci hotplug subsystem
500 * previously with a call to pci_hp_register().
501 *
502 * Returns 0 if successful, anything else for an error.
503 */
504void pci_hp_deregister(struct hotplug_slot *slot)
505{
506 pci_hp_del(slot);
507 pci_hp_destroy(slot);
508}
509EXPORT_SYMBOL_GPL(pci_hp_deregister);
510
511/**
512 * pci_hp_del - unpublish hotplug slot from user space
513 * @slot: pointer to the &struct hotplug_slot to unpublish
514 *
515 * Remove a hotplug slot's sysfs interface.
516 *
517 * Returns 0 on success or a negative int on error.
518 */
519void pci_hp_del(struct hotplug_slot *slot)
520{
521 struct hotplug_slot *temp;
522
523 if (WARN_ON(!slot))
524 return;
525
526 mutex_lock(&pci_hp_mutex);
527 temp = get_slot_from_name(name: hotplug_slot_name(slot));
528 if (WARN_ON(temp != slot)) {
529 mutex_unlock(lock: &pci_hp_mutex);
530 return;
531 }
532
533 list_del(entry: &slot->slot_list);
534 mutex_unlock(lock: &pci_hp_mutex);
535 dbg("Removed slot %s from the list\n", hotplug_slot_name(slot));
536 fs_remove_slot(pci_slot: slot->pci_slot);
537}
538EXPORT_SYMBOL_GPL(pci_hp_del);
539
540/**
541 * pci_hp_destroy - remove hotplug slot from in-kernel use
542 * @slot: pointer to the &struct hotplug_slot to destroy
543 *
544 * Destroy a PCI slot used by a hotplug driver. Once this has been called,
545 * the driver may no longer invoke hotplug_slot_name() to get the slot's
546 * unique name. The driver no longer needs to handle a ->reset_slot callback
547 * from this point on.
548 *
549 * Returns 0 on success or a negative int on error.
550 */
551void pci_hp_destroy(struct hotplug_slot *slot)
552{
553 struct pci_slot *pci_slot = slot->pci_slot;
554
555 slot->pci_slot = NULL;
556 pci_slot->hotplug = NULL;
557 pci_destroy_slot(slot: pci_slot);
558}
559EXPORT_SYMBOL_GPL(pci_hp_destroy);
560
561static int __init pci_hotplug_init(void)
562{
563 int result;
564
565 result = cpci_hotplug_init(debug);
566 if (result) {
567 err("cpci_hotplug_init with error %d\n", result);
568 return result;
569 }
570
571 return result;
572}
573device_initcall(pci_hotplug_init);
574
575/*
576 * not really modular, but the easiest way to keep compat with existing
577 * bootargs behaviour is to continue using module_param here.
578 */
579module_param(debug, bool, 0644);
580MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
581

source code of linux/drivers/pci/hotplug/pci_hotplug_core.c