cpci_hotplug_core.c

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