1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * CompactPCI Hot Plug Driver
4 *
5 * Copyright (C) 2002,2005 SOMA Networks, Inc.
6 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
7 * Copyright (C) 2001 IBM Corp.
8 *
9 * All rights reserved.
10 *
11 * Send feedback to <scottm@somanetworks.com>
12 */
13
14#include <linux/module.h>
15#include <linux/kernel.h>
16#include <linux/sched/signal.h>
17#include <linux/slab.h>
18#include <linux/pci.h>
19#include <linux/pci_hotplug.h>
20#include <linux/init.h>
21#include <linux/interrupt.h>
22#include <linux/atomic.h>
23#include <linux/delay.h>
24#include <linux/kthread.h>
25#include "cpci_hotplug.h"
26
27#define DRIVER_AUTHOR "Scott Murray <scottm@somanetworks.com>"
28#define DRIVER_DESC "CompactPCI Hot Plug Core"
29
30#define MY_NAME "cpci_hotplug"
31
32#define dbg(format, arg...) \
33 do { \
34 if (cpci_debug) \
35 printk(KERN_DEBUG "%s: " format "\n", \
36 MY_NAME, ## arg); \
37 } while (0)
38#define err(format, arg...) printk(KERN_ERR "%s: " format "\n", MY_NAME, ## arg)
39#define info(format, arg...) printk(KERN_INFO "%s: " format "\n", MY_NAME, ## arg)
40#define warn(format, arg...) printk(KERN_WARNING "%s: " format "\n", MY_NAME, ## arg)
41
42/* local variables */
43static DECLARE_RWSEM(list_rwsem);
44static LIST_HEAD(slot_list);
45static int slots;
46static atomic_t extracting;
47int cpci_debug;
48static struct cpci_hp_controller *controller;
49static struct task_struct *cpci_thread;
50static int thread_finished;
51
52static int enable_slot(struct hotplug_slot *slot);
53static int disable_slot(struct hotplug_slot *slot);
54static int set_attention_status(struct hotplug_slot *slot, u8 value);
55static int get_power_status(struct hotplug_slot *slot, u8 *value);
56static int get_attention_status(struct hotplug_slot *slot, u8 *value);
57static int get_adapter_status(struct hotplug_slot *slot, u8 *value);
58static int get_latch_status(struct hotplug_slot *slot, u8 *value);
59
60static const struct hotplug_slot_ops cpci_hotplug_slot_ops = {
61 .enable_slot = enable_slot,
62 .disable_slot = disable_slot,
63 .set_attention_status = set_attention_status,
64 .get_power_status = get_power_status,
65 .get_attention_status = get_attention_status,
66 .get_adapter_status = get_adapter_status,
67 .get_latch_status = get_latch_status,
68};
69
70static int
71enable_slot(struct hotplug_slot *hotplug_slot)
72{
73 struct slot *slot = to_slot(hotplug_slot);
74 int retval = 0;
75
76 dbg("%s - physical_slot = %s", __func__, slot_name(slot));
77
78 if (controller->ops->set_power)
79 retval = controller->ops->set_power(slot, 1);
80 return retval;
81}
82
83static int
84disable_slot(struct hotplug_slot *hotplug_slot)
85{
86 struct slot *slot = to_slot(hotplug_slot);
87 int retval = 0;
88
89 dbg("%s - physical_slot = %s", __func__, slot_name(slot));
90
91 down_write(sem: &list_rwsem);
92
93 /* Unconfigure device */
94 dbg("%s - unconfiguring slot %s", __func__, slot_name(slot));
95 retval = cpci_unconfigure_slot(slot);
96 if (retval) {
97 err("%s - could not unconfigure slot %s",
98 __func__, slot_name(slot));
99 goto disable_error;
100 }
101 dbg("%s - finished unconfiguring slot %s", __func__, slot_name(slot));
102
103 /* Clear EXT (by setting it) */
104 if (cpci_clear_ext(slot)) {
105 err("%s - could not clear EXT for slot %s",
106 __func__, slot_name(slot));
107 retval = -ENODEV;
108 goto disable_error;
109 }
110 cpci_led_on(slot);
111
112 if (controller->ops->set_power) {
113 retval = controller->ops->set_power(slot, 0);
114 if (retval)
115 goto disable_error;
116 }
117
118 slot->adapter_status = 0;
119
120 if (slot->extracting) {
121 slot->extracting = 0;
122 atomic_dec(v: &extracting);
123 }
124disable_error:
125 up_write(sem: &list_rwsem);
126 return retval;
127}
128
129static u8
130cpci_get_power_status(struct slot *slot)
131{
132 u8 power = 1;
133
134 if (controller->ops->get_power)
135 power = controller->ops->get_power(slot);
136 return power;
137}
138
139static int
140get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
141{
142 struct slot *slot = to_slot(hotplug_slot);
143
144 *value = cpci_get_power_status(slot);
145 return 0;
146}
147
148static int
149get_attention_status(struct hotplug_slot *hotplug_slot, u8 *value)
150{
151 struct slot *slot = to_slot(hotplug_slot);
152
153 *value = cpci_get_attention_status(slot);
154 return 0;
155}
156
157static int
158set_attention_status(struct hotplug_slot *hotplug_slot, u8 status)
159{
160 return cpci_set_attention_status(slot: to_slot(hotplug_slot), status);
161}
162
163static int
164get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
165{
166 struct slot *slot = to_slot(hotplug_slot);
167
168 *value = slot->adapter_status;
169 return 0;
170}
171
172static int
173get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
174{
175 struct slot *slot = to_slot(hotplug_slot);
176
177 *value = slot->latch_status;
178 return 0;
179}
180
181static void release_slot(struct slot *slot)
182{
183 pci_dev_put(dev: slot->dev);
184 kfree(objp: slot);
185}
186
187#define SLOT_NAME_SIZE 6
188
189int
190cpci_hp_register_bus(struct pci_bus *bus, u8 first, u8 last)
191{
192 struct slot *slot;
193 char name[SLOT_NAME_SIZE];
194 int status;
195 int i;
196
197 if (!(controller && bus))
198 return -ENODEV;
199
200 /*
201 * Create a structure for each slot, and register that slot
202 * with the pci_hotplug subsystem.
203 */
204 for (i = first; i <= last; ++i) {
205 slot = kzalloc(size: sizeof(struct slot), GFP_KERNEL);
206 if (!slot) {
207 status = -ENOMEM;
208 goto error;
209 }
210
211 slot->bus = bus;
212 slot->number = i;
213 slot->devfn = PCI_DEVFN(i, 0);
214
215 snprintf(buf: name, SLOT_NAME_SIZE, fmt: "%02x:%02x", bus->number, i);
216
217 slot->hotplug_slot.ops = &cpci_hotplug_slot_ops;
218
219 dbg("registering slot %s", name);
220 status = pci_hp_register(&slot->hotplug_slot, bus, i, name);
221 if (status) {
222 err("pci_hp_register failed with error %d", status);
223 goto error_slot;
224 }
225 dbg("slot registered with name: %s", slot_name(slot));
226
227 /* Add slot to our internal list */
228 down_write(sem: &list_rwsem);
229 list_add(new: &slot->slot_list, head: &slot_list);
230 slots++;
231 up_write(sem: &list_rwsem);
232 }
233 return 0;
234error_slot:
235 kfree(objp: slot);
236error:
237 return status;
238}
239EXPORT_SYMBOL_GPL(cpci_hp_register_bus);
240
241int
242cpci_hp_unregister_bus(struct pci_bus *bus)
243{
244 struct slot *slot;
245 struct slot *tmp;
246 int status = 0;
247
248 down_write(sem: &list_rwsem);
249 if (!slots) {
250 up_write(sem: &list_rwsem);
251 return -1;
252 }
253 list_for_each_entry_safe(slot, tmp, &slot_list, slot_list) {
254 if (slot->bus == bus) {
255 list_del(entry: &slot->slot_list);
256 slots--;
257
258 dbg("deregistering slot %s", slot_name(slot));
259 pci_hp_deregister(slot: &slot->hotplug_slot);
260 release_slot(slot);
261 }
262 }
263 up_write(sem: &list_rwsem);
264 return status;
265}
266EXPORT_SYMBOL_GPL(cpci_hp_unregister_bus);
267
268/* This is the interrupt mode interrupt handler */
269static irqreturn_t
270cpci_hp_intr(int irq, void *data)
271{
272 dbg("entered cpci_hp_intr");
273
274 /* Check to see if it was our interrupt */
275 if ((controller->irq_flags & IRQF_SHARED) &&
276 !controller->ops->check_irq(controller->dev_id)) {
277 dbg("exited cpci_hp_intr, not our interrupt");
278 return IRQ_NONE;
279 }
280
281 /* Disable ENUM interrupt */
282 controller->ops->disable_irq();
283
284 /* Trigger processing by the event thread */
285 wake_up_process(tsk: cpci_thread);
286 return IRQ_HANDLED;
287}
288
289/*
290 * According to PICMG 2.1 R2.0, section 6.3.2, upon
291 * initialization, the system driver shall clear the
292 * INS bits of the cold-inserted devices.
293 */
294static int
295init_slots(int clear_ins)
296{
297 struct slot *slot;
298 struct pci_dev *dev;
299
300 dbg("%s - enter", __func__);
301 down_read(sem: &list_rwsem);
302 if (!slots) {
303 up_read(sem: &list_rwsem);
304 return -1;
305 }
306 list_for_each_entry(slot, &slot_list, slot_list) {
307 dbg("%s - looking at slot %s", __func__, slot_name(slot));
308 if (clear_ins && cpci_check_and_clear_ins(slot))
309 dbg("%s - cleared INS for slot %s",
310 __func__, slot_name(slot));
311 dev = pci_get_slot(bus: slot->bus, PCI_DEVFN(slot->number, 0));
312 if (dev) {
313 slot->adapter_status = 1;
314 slot->latch_status = 1;
315 slot->dev = dev;
316 }
317 }
318 up_read(sem: &list_rwsem);
319 dbg("%s - exit", __func__);
320 return 0;
321}
322
323static int
324check_slots(void)
325{
326 struct slot *slot;
327 int extracted;
328 int inserted;
329 u16 hs_csr;
330
331 down_read(sem: &list_rwsem);
332 if (!slots) {
333 up_read(sem: &list_rwsem);
334 err("no slots registered, shutting down");
335 return -1;
336 }
337 extracted = inserted = 0;
338 list_for_each_entry(slot, &slot_list, slot_list) {
339 dbg("%s - looking at slot %s", __func__, slot_name(slot));
340 if (cpci_check_and_clear_ins(slot)) {
341 /*
342 * Some broken hardware (e.g. PLX 9054AB) asserts
343 * ENUM# twice...
344 */
345 if (slot->dev) {
346 warn("slot %s already inserted",
347 slot_name(slot));
348 inserted++;
349 continue;
350 }
351
352 /* Process insertion */
353 dbg("%s - slot %s inserted", __func__, slot_name(slot));
354
355 /* GSM, debug */
356 hs_csr = cpci_get_hs_csr(slot);
357 dbg("%s - slot %s HS_CSR (1) = %04x",
358 __func__, slot_name(slot), hs_csr);
359
360 /* Configure device */
361 dbg("%s - configuring slot %s",
362 __func__, slot_name(slot));
363 if (cpci_configure_slot(slot)) {
364 err("%s - could not configure slot %s",
365 __func__, slot_name(slot));
366 continue;
367 }
368 dbg("%s - finished configuring slot %s",
369 __func__, slot_name(slot));
370
371 /* GSM, debug */
372 hs_csr = cpci_get_hs_csr(slot);
373 dbg("%s - slot %s HS_CSR (2) = %04x",
374 __func__, slot_name(slot), hs_csr);
375
376 slot->latch_status = 1;
377 slot->adapter_status = 1;
378
379 cpci_led_off(slot);
380
381 /* GSM, debug */
382 hs_csr = cpci_get_hs_csr(slot);
383 dbg("%s - slot %s HS_CSR (3) = %04x",
384 __func__, slot_name(slot), hs_csr);
385
386 inserted++;
387 } else if (cpci_check_ext(slot)) {
388 /* Process extraction request */
389 dbg("%s - slot %s extracted",
390 __func__, slot_name(slot));
391
392 /* GSM, debug */
393 hs_csr = cpci_get_hs_csr(slot);
394 dbg("%s - slot %s HS_CSR = %04x",
395 __func__, slot_name(slot), hs_csr);
396
397 if (!slot->extracting) {
398 slot->latch_status = 0;
399 slot->extracting = 1;
400 atomic_inc(v: &extracting);
401 }
402 extracted++;
403 } else if (slot->extracting) {
404 hs_csr = cpci_get_hs_csr(slot);
405 if (hs_csr == 0xffff) {
406 /*
407 * Hmmm, we're likely hosed at this point, should we
408 * bother trying to tell the driver or not?
409 */
410 err("card in slot %s was improperly removed",
411 slot_name(slot));
412 slot->adapter_status = 0;
413 slot->extracting = 0;
414 atomic_dec(v: &extracting);
415 }
416 }
417 }
418 up_read(sem: &list_rwsem);
419 dbg("inserted=%d, extracted=%d, extracting=%d",
420 inserted, extracted, atomic_read(&extracting));
421 if (inserted || extracted)
422 return extracted;
423 else if (!atomic_read(v: &extracting)) {
424 err("cannot find ENUM# source, shutting down");
425 return -1;
426 }
427 return 0;
428}
429
430/* This is the interrupt mode worker thread body */
431static int
432event_thread(void *data)
433{
434 int rc;
435
436 dbg("%s - event thread started", __func__);
437 while (1) {
438 dbg("event thread sleeping");
439 set_current_state(TASK_INTERRUPTIBLE);
440 schedule();
441 if (kthread_should_stop())
442 break;
443 do {
444 rc = check_slots();
445 if (rc > 0) {
446 /* Give userspace a chance to handle extraction */
447 msleep(msecs: 500);
448 } else if (rc < 0) {
449 dbg("%s - error checking slots", __func__);
450 thread_finished = 1;
451 goto out;
452 }
453 } while (atomic_read(v: &extracting) && !kthread_should_stop());
454 if (kthread_should_stop())
455 break;
456
457 /* Re-enable ENUM# interrupt */
458 dbg("%s - re-enabling irq", __func__);
459 controller->ops->enable_irq();
460 }
461 out:
462 return 0;
463}
464
465/* This is the polling mode worker thread body */
466static int
467poll_thread(void *data)
468{
469 int rc;
470
471 while (1) {
472 if (kthread_should_stop() || signal_pending(current))
473 break;
474 if (controller->ops->query_enum()) {
475 do {
476 rc = check_slots();
477 if (rc > 0) {
478 /* Give userspace a chance to handle extraction */
479 msleep(msecs: 500);
480 } else if (rc < 0) {
481 dbg("%s - error checking slots", __func__);
482 thread_finished = 1;
483 goto out;
484 }
485 } while (atomic_read(v: &extracting) && !kthread_should_stop());
486 }
487 msleep(msecs: 100);
488 }
489 out:
490 return 0;
491}
492
493static int
494cpci_start_thread(void)
495{
496 if (controller->irq)
497 cpci_thread = kthread_run(event_thread, NULL, "cpci_hp_eventd");
498 else
499 cpci_thread = kthread_run(poll_thread, NULL, "cpci_hp_polld");
500 if (IS_ERR(ptr: cpci_thread)) {
501 err("Can't start up our thread");
502 return PTR_ERR(ptr: cpci_thread);
503 }
504 thread_finished = 0;
505 return 0;
506}
507
508static void
509cpci_stop_thread(void)
510{
511 kthread_stop(k: cpci_thread);
512 thread_finished = 1;
513}
514
515int
516cpci_hp_register_controller(struct cpci_hp_controller *new_controller)
517{
518 int status = 0;
519
520 if (controller)
521 return -1;
522 if (!(new_controller && new_controller->ops))
523 return -EINVAL;
524 if (new_controller->irq) {
525 if (!(new_controller->ops->enable_irq &&
526 new_controller->ops->disable_irq))
527 status = -EINVAL;
528 if (request_irq(irq: new_controller->irq,
529 handler: cpci_hp_intr,
530 flags: new_controller->irq_flags,
531 MY_NAME,
532 dev: new_controller->dev_id)) {
533 err("Can't get irq %d for the hotplug cPCI controller",
534 new_controller->irq);
535 status = -ENODEV;
536 }
537 dbg("%s - acquired controller irq %d",
538 __func__, new_controller->irq);
539 }
540 if (!status)
541 controller = new_controller;
542 return status;
543}
544EXPORT_SYMBOL_GPL(cpci_hp_register_controller);
545
546static void
547cleanup_slots(void)
548{
549 struct slot *slot;
550 struct slot *tmp;
551
552 /*
553 * Unregister all of our slots with the pci_hotplug subsystem,
554 * and free up all memory that we had allocated.
555 */
556 down_write(sem: &list_rwsem);
557 if (!slots)
558 goto cleanup_null;
559 list_for_each_entry_safe(slot, tmp, &slot_list, slot_list) {
560 list_del(entry: &slot->slot_list);
561 pci_hp_deregister(slot: &slot->hotplug_slot);
562 release_slot(slot);
563 }
564cleanup_null:
565 up_write(sem: &list_rwsem);
566}
567
568int
569cpci_hp_unregister_controller(struct cpci_hp_controller *old_controller)
570{
571 int status = 0;
572
573 if (controller) {
574 if (!thread_finished)
575 cpci_stop_thread();
576 if (controller->irq)
577 free_irq(controller->irq, controller->dev_id);
578 controller = NULL;
579 cleanup_slots();
580 } else
581 status = -ENODEV;
582 return status;
583}
584EXPORT_SYMBOL_GPL(cpci_hp_unregister_controller);
585
586int
587cpci_hp_start(void)
588{
589 static int first = 1;
590 int status;
591
592 dbg("%s - enter", __func__);
593 if (!controller)
594 return -ENODEV;
595
596 down_read(sem: &list_rwsem);
597 if (list_empty(head: &slot_list)) {
598 up_read(sem: &list_rwsem);
599 return -ENODEV;
600 }
601 up_read(sem: &list_rwsem);
602
603 status = init_slots(clear_ins: first);
604 if (first)
605 first = 0;
606 if (status)
607 return status;
608
609 status = cpci_start_thread();
610 if (status)
611 return status;
612 dbg("%s - thread started", __func__);
613
614 if (controller->irq) {
615 /* Start enum interrupt processing */
616 dbg("%s - enabling irq", __func__);
617 controller->ops->enable_irq();
618 }
619 dbg("%s - exit", __func__);
620 return 0;
621}
622EXPORT_SYMBOL_GPL(cpci_hp_start);
623
624int
625cpci_hp_stop(void)
626{
627 if (!controller)
628 return -ENODEV;
629 if (controller->irq) {
630 /* Stop enum interrupt processing */
631 dbg("%s - disabling irq", __func__);
632 controller->ops->disable_irq();
633 }
634 cpci_stop_thread();
635 return 0;
636}
637EXPORT_SYMBOL_GPL(cpci_hp_stop);
638
639int __init
640cpci_hotplug_init(int debug)
641{
642 cpci_debug = debug;
643 return 0;
644}
645

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