shpchp_ctrl.c revision 9f593e30b318719b0e3889c730cc3a2d0729a707
1/*
2 * Standard Hot Plug Controller Driver
3 *
4 * Copyright (C) 1995,2001 Compaq Computer Corporation
5 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
6 * Copyright (C) 2001 IBM Corp.
7 * Copyright (C) 2003-2004 Intel Corporation
8 *
9 * All rights reserved.
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or (at
14 * your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful, but
17 * WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
19 * NON INFRINGEMENT.  See the GNU General Public License for more
20 * details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 *
26 * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
27 *
28 */
29
30#include <linux/module.h>
31#include <linux/kernel.h>
32#include <linux/types.h>
33#include <linux/smp_lock.h>
34#include <linux/pci.h>
35#include <linux/workqueue.h>
36#include "../pci.h"
37#include "shpchp.h"
38
39static void interrupt_event_handler(struct work_struct *work);
40static int shpchp_enable_slot(struct slot *p_slot);
41static int shpchp_disable_slot(struct slot *p_slot);
42
43static int queue_interrupt_event(struct slot *p_slot, u32 event_type)
44{
45	struct event_info *info;
46
47	info = kmalloc(sizeof(*info), GFP_ATOMIC);
48	if (!info)
49		return -ENOMEM;
50
51	info->event_type = event_type;
52	info->p_slot = p_slot;
53	INIT_WORK(&info->work, interrupt_event_handler);
54
55	schedule_work(&info->work);
56
57	return 0;
58}
59
60u8 shpchp_handle_attention_button(u8 hp_slot, struct controller *ctrl)
61{
62	struct slot *p_slot;
63	u32 event_type;
64
65	/* Attention Button Change */
66	dbg("shpchp:  Attention button interrupt received.\n");
67
68	p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
69	p_slot->hpc_ops->get_adapter_status(p_slot, &(p_slot->presence_save));
70
71	/*
72	 *  Button pressed - See if need to TAKE ACTION!!!
73	 */
74	info("Button pressed on Slot(%s)\n", p_slot->name);
75	event_type = INT_BUTTON_PRESS;
76
77	queue_interrupt_event(p_slot, event_type);
78
79	return 0;
80
81}
82
83u8 shpchp_handle_switch_change(u8 hp_slot, struct controller *ctrl)
84{
85	struct slot *p_slot;
86	u8 getstatus;
87	u32 event_type;
88
89	/* Switch Change */
90	dbg("shpchp:  Switch interrupt received.\n");
91
92	p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
93	p_slot->hpc_ops->get_adapter_status(p_slot, &(p_slot->presence_save));
94	p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
95	dbg("%s: Card present %x Power status %x\n", __FUNCTION__,
96		p_slot->presence_save, p_slot->pwr_save);
97
98	if (getstatus) {
99		/*
100		 * Switch opened
101		 */
102		info("Latch open on Slot(%s)\n", p_slot->name);
103		event_type = INT_SWITCH_OPEN;
104		if (p_slot->pwr_save && p_slot->presence_save) {
105			event_type = INT_POWER_FAULT;
106			err("Surprise Removal of card\n");
107		}
108	} else {
109		/*
110		 *  Switch closed
111		 */
112		info("Latch close on Slot(%s)\n", p_slot->name);
113		event_type = INT_SWITCH_CLOSE;
114	}
115
116	queue_interrupt_event(p_slot, event_type);
117
118	return 1;
119}
120
121u8 shpchp_handle_presence_change(u8 hp_slot, struct controller *ctrl)
122{
123	struct slot *p_slot;
124	u32 event_type;
125
126	/* Presence Change */
127	dbg("shpchp:  Presence/Notify input change.\n");
128
129	p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
130
131	/*
132	 * Save the presence state
133	 */
134	p_slot->hpc_ops->get_adapter_status(p_slot, &(p_slot->presence_save));
135	if (p_slot->presence_save) {
136		/*
137		 * Card Present
138		 */
139		info("Card present on Slot(%s)\n", p_slot->name);
140		event_type = INT_PRESENCE_ON;
141	} else {
142		/*
143		 * Not Present
144		 */
145		info("Card not present on Slot(%s)\n", p_slot->name);
146		event_type = INT_PRESENCE_OFF;
147	}
148
149	queue_interrupt_event(p_slot, event_type);
150
151	return 1;
152}
153
154u8 shpchp_handle_power_fault(u8 hp_slot, struct controller *ctrl)
155{
156	struct slot *p_slot;
157	u32 event_type;
158
159	/* Power fault */
160	dbg("shpchp:  Power fault interrupt received.\n");
161
162	p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
163
164	if ( !(p_slot->hpc_ops->query_power_fault(p_slot))) {
165		/*
166		 * Power fault Cleared
167		 */
168		info("Power fault cleared on Slot(%s)\n", p_slot->name);
169		p_slot->status = 0x00;
170		event_type = INT_POWER_FAULT_CLEAR;
171	} else {
172		/*
173		 *   Power fault
174		 */
175		info("Power fault on Slot(%s)\n", p_slot->name);
176		event_type = INT_POWER_FAULT;
177		/* set power fault status for this board */
178		p_slot->status = 0xFF;
179		info("power fault bit %x set\n", hp_slot);
180	}
181
182	queue_interrupt_event(p_slot, event_type);
183
184	return 1;
185}
186
187/* The following routines constitute the bulk of the
188   hotplug controller logic
189 */
190static int change_bus_speed(struct controller *ctrl, struct slot *p_slot,
191		enum pci_bus_speed speed)
192{
193	int rc = 0;
194
195	dbg("%s: change to speed %d\n", __FUNCTION__, speed);
196	if ((rc = p_slot->hpc_ops->set_bus_speed_mode(p_slot, speed))) {
197		err("%s: Issue of set bus speed mode command failed\n",
198		    __FUNCTION__);
199		return WRONG_BUS_FREQUENCY;
200	}
201	return rc;
202}
203
204static int fix_bus_speed(struct controller *ctrl, struct slot *pslot,
205		u8 flag, enum pci_bus_speed asp, enum pci_bus_speed bsp,
206		enum pci_bus_speed msp)
207{
208	int rc = 0;
209
210	/*
211	 * If other slots on the same bus are occupied, we cannot
212	 * change the bus speed.
213	 */
214	if (flag) {
215		if (asp < bsp) {
216			err("%s: speed of bus %x and adapter %x mismatch\n",
217			    __FUNCTION__, bsp, asp);
218			rc = WRONG_BUS_FREQUENCY;
219		}
220		return rc;
221	}
222
223	if (asp < msp) {
224		if (bsp != asp)
225			rc = change_bus_speed(ctrl, pslot, asp);
226	} else {
227		if (bsp != msp)
228			rc = change_bus_speed(ctrl, pslot, msp);
229	}
230	return rc;
231}
232
233/**
234 * board_added - Called after a board has been added to the system.
235 *
236 * Turns power on for the board
237 * Configures board
238 *
239 */
240static int board_added(struct slot *p_slot)
241{
242	u8 hp_slot;
243	u8 slots_not_empty = 0;
244	int rc = 0;
245	enum pci_bus_speed asp, bsp, msp;
246	struct controller *ctrl = p_slot->ctrl;
247
248	hp_slot = p_slot->device - ctrl->slot_device_offset;
249
250	dbg("%s: p_slot->device, slot_offset, hp_slot = %d, %d ,%d\n",
251			__FUNCTION__, p_slot->device,
252			ctrl->slot_device_offset, hp_slot);
253
254	/* Power on slot without connecting to bus */
255	rc = p_slot->hpc_ops->power_on_slot(p_slot);
256	if (rc) {
257		err("%s: Failed to power on slot\n", __FUNCTION__);
258		return -1;
259	}
260
261	if ((ctrl->pci_dev->vendor == 0x8086) && (ctrl->pci_dev->device == 0x0332)) {
262		if (slots_not_empty)
263			return WRONG_BUS_FREQUENCY;
264
265		if ((rc = p_slot->hpc_ops->set_bus_speed_mode(p_slot, PCI_SPEED_33MHz))) {
266			err("%s: Issue of set bus speed mode command failed\n", __FUNCTION__);
267			return WRONG_BUS_FREQUENCY;
268		}
269
270		/* turn on board, blink green LED, turn off Amber LED */
271		if ((rc = p_slot->hpc_ops->slot_enable(p_slot))) {
272			err("%s: Issue of Slot Enable command failed\n", __FUNCTION__);
273			return rc;
274		}
275	}
276
277	rc = p_slot->hpc_ops->get_adapter_speed(p_slot, &asp);
278	if (rc) {
279		err("%s: Can't get adapter speed or bus mode mismatch\n",
280		    __FUNCTION__);
281		return WRONG_BUS_FREQUENCY;
282	}
283
284	rc = p_slot->hpc_ops->get_cur_bus_speed(p_slot, &bsp);
285	if (rc) {
286		err("%s: Can't get bus operation speed\n", __FUNCTION__);
287		return WRONG_BUS_FREQUENCY;
288	}
289
290	rc = p_slot->hpc_ops->get_max_bus_speed(p_slot, &msp);
291	if (rc) {
292		err("%s: Can't get max bus operation speed\n", __FUNCTION__);
293		msp = bsp;
294	}
295
296	/* Check if there are other slots or devices on the same bus */
297	if (!list_empty(&ctrl->pci_dev->subordinate->devices))
298		slots_not_empty = 1;
299
300	dbg("%s: slots_not_empty %d, adapter_speed %d, bus_speed %d, "
301	    "max_bus_speed %d\n", __FUNCTION__, slots_not_empty, asp,
302	    bsp, msp);
303
304	rc = fix_bus_speed(ctrl, p_slot, slots_not_empty, asp, bsp, msp);
305	if (rc)
306		return rc;
307
308	/* turn on board, blink green LED, turn off Amber LED */
309	if ((rc = p_slot->hpc_ops->slot_enable(p_slot))) {
310		err("%s: Issue of Slot Enable command failed\n", __FUNCTION__);
311		return rc;
312	}
313
314	/* Wait for ~1 second */
315	msleep(1000);
316
317	dbg("%s: slot status = %x\n", __FUNCTION__, p_slot->status);
318	/* Check for a power fault */
319	if (p_slot->status == 0xFF) {
320		/* power fault occurred, but it was benign */
321		dbg("%s: power fault\n", __FUNCTION__);
322		rc = POWER_FAILURE;
323		p_slot->status = 0;
324		goto err_exit;
325	}
326
327	if (shpchp_configure_device(p_slot)) {
328		err("Cannot add device at 0x%x:0x%x\n", p_slot->bus,
329				p_slot->device);
330		goto err_exit;
331	}
332
333	p_slot->status = 0;
334	p_slot->is_a_board = 0x01;
335	p_slot->pwr_save = 1;
336
337	p_slot->hpc_ops->green_led_on(p_slot);
338
339	return 0;
340
341err_exit:
342	/* turn off slot, turn on Amber LED, turn off Green LED */
343	rc = p_slot->hpc_ops->slot_disable(p_slot);
344	if (rc) {
345		err("%s: Issue of Slot Disable command failed\n", __FUNCTION__);
346		return rc;
347	}
348
349	return(rc);
350}
351
352
353/**
354 * remove_board - Turns off slot and LED's
355 *
356 */
357static int remove_board(struct slot *p_slot)
358{
359	struct controller *ctrl = p_slot->ctrl;
360	u8 hp_slot;
361	int rc;
362
363	if (shpchp_unconfigure_device(p_slot))
364		return(1);
365
366	hp_slot = p_slot->device - ctrl->slot_device_offset;
367	p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
368
369	dbg("In %s, hp_slot = %d\n", __FUNCTION__, hp_slot);
370
371	/* Change status to shutdown */
372	if (p_slot->is_a_board)
373		p_slot->status = 0x01;
374
375	/* turn off slot, turn on Amber LED, turn off Green LED */
376	rc = p_slot->hpc_ops->slot_disable(p_slot);
377	if (rc) {
378		err("%s: Issue of Slot Disable command failed\n", __FUNCTION__);
379		return rc;
380	}
381
382	rc = p_slot->hpc_ops->set_attention_status(p_slot, 0);
383	if (rc) {
384		err("%s: Issue of Set Attention command failed\n", __FUNCTION__);
385		return rc;
386	}
387
388	p_slot->pwr_save = 0;
389	p_slot->is_a_board = 0;
390
391	return 0;
392}
393
394
395struct pushbutton_work_info {
396	struct slot *p_slot;
397	struct work_struct work;
398};
399
400/**
401 * shpchp_pushbutton_thread
402 *
403 * Scheduled procedure to handle blocking stuff for the pushbuttons
404 * Handles all pending events and exits.
405 *
406 */
407static void shpchp_pushbutton_thread(struct work_struct *work)
408{
409	struct pushbutton_work_info *info =
410		container_of(work, struct pushbutton_work_info, work);
411	struct slot *p_slot = info->p_slot;
412
413	mutex_lock(&p_slot->lock);
414	switch (p_slot->state) {
415	case POWEROFF_STATE:
416		mutex_unlock(&p_slot->lock);
417		shpchp_disable_slot(p_slot);
418		mutex_lock(&p_slot->lock);
419		p_slot->state = STATIC_STATE;
420		break;
421	case POWERON_STATE:
422		mutex_unlock(&p_slot->lock);
423		if (shpchp_enable_slot(p_slot))
424			p_slot->hpc_ops->green_led_off(p_slot);
425		mutex_lock(&p_slot->lock);
426		p_slot->state = STATIC_STATE;
427		break;
428	default:
429		break;
430	}
431	mutex_unlock(&p_slot->lock);
432
433	kfree(info);
434}
435
436void queue_pushbutton_work(struct work_struct *work)
437{
438	struct slot *p_slot = container_of(work, struct slot, work.work);
439	struct pushbutton_work_info *info;
440
441	info = kmalloc(sizeof(*info), GFP_KERNEL);
442	if (!info) {
443		err("%s: Cannot allocate memory\n", __FUNCTION__);
444		return;
445	}
446	info->p_slot = p_slot;
447	INIT_WORK(&info->work, shpchp_pushbutton_thread);
448
449	mutex_lock(&p_slot->lock);
450	switch (p_slot->state) {
451	case BLINKINGOFF_STATE:
452		p_slot->state = POWEROFF_STATE;
453		break;
454	case BLINKINGON_STATE:
455		p_slot->state = POWERON_STATE;
456		break;
457	default:
458		goto out;
459	}
460	queue_work(shpchp_wq, &info->work);
461 out:
462	mutex_unlock(&p_slot->lock);
463}
464
465static int update_slot_info (struct slot *slot)
466{
467	struct hotplug_slot_info *info;
468	int result;
469
470	info = kmalloc(sizeof(*info), GFP_KERNEL);
471	if (!info)
472		return -ENOMEM;
473
474	slot->hpc_ops->get_power_status(slot, &(info->power_status));
475	slot->hpc_ops->get_attention_status(slot, &(info->attention_status));
476	slot->hpc_ops->get_latch_status(slot, &(info->latch_status));
477	slot->hpc_ops->get_adapter_status(slot, &(info->adapter_status));
478
479	result = pci_hp_change_slot_info(slot->hotplug_slot, info);
480	kfree (info);
481	return result;
482}
483
484/*
485 * Note: This function must be called with slot->lock held
486 */
487static void handle_button_press_event(struct slot *p_slot)
488{
489	u8 getstatus;
490
491	switch (p_slot->state) {
492	case STATIC_STATE:
493		p_slot->hpc_ops->get_power_status(p_slot, &getstatus);
494		if (getstatus) {
495			p_slot->state = BLINKINGOFF_STATE;
496			info("PCI slot #%s - powering off due to button "
497			     "press.\n", p_slot->name);
498		} else {
499			p_slot->state = BLINKINGON_STATE;
500			info("PCI slot #%s - powering on due to button "
501			     "press.\n", p_slot->name);
502		}
503		/* blink green LED and turn off amber */
504		p_slot->hpc_ops->green_led_blink(p_slot);
505		p_slot->hpc_ops->set_attention_status(p_slot, 0);
506
507		schedule_delayed_work(&p_slot->work, 5*HZ);
508		break;
509	case BLINKINGOFF_STATE:
510	case BLINKINGON_STATE:
511		/*
512		 * Cancel if we are still blinking; this means that we
513		 * press the attention again before the 5 sec. limit
514		 * expires to cancel hot-add or hot-remove
515		 */
516		info("Button cancel on Slot(%s)\n", p_slot->name);
517		dbg("%s: button cancel\n", __FUNCTION__);
518		cancel_delayed_work(&p_slot->work);
519		if (p_slot->state == BLINKINGOFF_STATE)
520			p_slot->hpc_ops->green_led_on(p_slot);
521		else
522			p_slot->hpc_ops->green_led_off(p_slot);
523		p_slot->hpc_ops->set_attention_status(p_slot, 0);
524		info("PCI slot #%s - action canceled due to button press\n",
525		     p_slot->name);
526		p_slot->state = STATIC_STATE;
527		break;
528	case POWEROFF_STATE:
529	case POWERON_STATE:
530		/*
531		 * Ignore if the slot is on power-on or power-off state;
532		 * this means that the previous attention button action
533		 * to hot-add or hot-remove is undergoing
534		 */
535		info("Button ignore on Slot(%s)\n", p_slot->name);
536		update_slot_info(p_slot);
537		break;
538	default:
539		warn("Not a valid state\n");
540		break;
541	}
542}
543
544static void interrupt_event_handler(struct work_struct *work)
545{
546	struct event_info *info = container_of(work, struct event_info, work);
547	struct slot *p_slot = info->p_slot;
548
549	mutex_lock(&p_slot->lock);
550	switch (info->event_type) {
551	case INT_BUTTON_PRESS:
552		handle_button_press_event(p_slot);
553		break;
554	case INT_POWER_FAULT:
555		dbg("%s: power fault\n", __FUNCTION__);
556		p_slot->hpc_ops->set_attention_status(p_slot, 1);
557		p_slot->hpc_ops->green_led_off(p_slot);
558		break;
559	default:
560		update_slot_info(p_slot);
561		break;
562	}
563	mutex_unlock(&p_slot->lock);
564
565	kfree(info);
566}
567
568
569static int shpchp_enable_slot (struct slot *p_slot)
570{
571	u8 getstatus = 0;
572	int rc, retval = -ENODEV;
573
574	/* Check to see if (latch closed, card present, power off) */
575	mutex_lock(&p_slot->ctrl->crit_sect);
576	rc = p_slot->hpc_ops->get_adapter_status(p_slot, &getstatus);
577	if (rc || !getstatus) {
578		info("No adapter on slot(%s)\n", p_slot->name);
579		goto out;
580	}
581	rc = p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
582	if (rc || getstatus) {
583		info("Latch open on slot(%s)\n", p_slot->name);
584		goto out;
585	}
586	rc = p_slot->hpc_ops->get_power_status(p_slot, &getstatus);
587	if (rc || getstatus) {
588		info("Already enabled on slot(%s)\n", p_slot->name);
589		goto out;
590	}
591
592	p_slot->is_a_board = 1;
593
594	/* We have to save the presence info for these slots */
595	p_slot->hpc_ops->get_adapter_status(p_slot, &(p_slot->presence_save));
596	p_slot->hpc_ops->get_power_status(p_slot, &(p_slot->pwr_save));
597	dbg("%s: p_slot->pwr_save %x\n", __FUNCTION__, p_slot->pwr_save);
598	p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
599
600	if(((p_slot->ctrl->pci_dev->vendor == PCI_VENDOR_ID_AMD) ||
601	    (p_slot->ctrl->pci_dev->device == PCI_DEVICE_ID_AMD_POGO_7458))
602	     && p_slot->ctrl->num_slots == 1) {
603		/* handle amd pogo errata; this must be done before enable  */
604		amd_pogo_errata_save_misc_reg(p_slot);
605		retval = board_added(p_slot);
606		/* handle amd pogo errata; this must be done after enable  */
607		amd_pogo_errata_restore_misc_reg(p_slot);
608	} else
609		retval = board_added(p_slot);
610
611	if (retval) {
612		p_slot->hpc_ops->get_adapter_status(p_slot,
613				&(p_slot->presence_save));
614		p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
615	}
616
617	update_slot_info(p_slot);
618 out:
619	mutex_unlock(&p_slot->ctrl->crit_sect);
620	return retval;
621}
622
623
624static int shpchp_disable_slot (struct slot *p_slot)
625{
626	u8 getstatus = 0;
627	int rc, retval = -ENODEV;
628
629	if (!p_slot->ctrl)
630		return -ENODEV;
631
632	/* Check to see if (latch closed, card present, power on) */
633	mutex_lock(&p_slot->ctrl->crit_sect);
634
635	rc = p_slot->hpc_ops->get_adapter_status(p_slot, &getstatus);
636	if (rc || !getstatus) {
637		info("No adapter on slot(%s)\n", p_slot->name);
638		goto out;
639	}
640	rc = p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
641	if (rc || getstatus) {
642		info("Latch open on slot(%s)\n", p_slot->name);
643		goto out;
644	}
645	rc = p_slot->hpc_ops->get_power_status(p_slot, &getstatus);
646	if (rc || !getstatus) {
647		info("Already disabled slot(%s)\n", p_slot->name);
648		goto out;
649	}
650
651	retval = remove_board(p_slot);
652	update_slot_info(p_slot);
653 out:
654	mutex_unlock(&p_slot->ctrl->crit_sect);
655	return retval;
656}
657
658int shpchp_sysfs_enable_slot(struct slot *p_slot)
659{
660	int retval = -ENODEV;
661
662	mutex_lock(&p_slot->lock);
663	switch (p_slot->state) {
664	case BLINKINGON_STATE:
665		cancel_delayed_work(&p_slot->work);
666	case STATIC_STATE:
667		p_slot->state = POWERON_STATE;
668		mutex_unlock(&p_slot->lock);
669		retval = shpchp_enable_slot(p_slot);
670		mutex_lock(&p_slot->lock);
671		p_slot->state = STATIC_STATE;
672		break;
673	case POWERON_STATE:
674		info("Slot %s is already in powering on state\n",
675		     p_slot->name);
676		break;
677	case BLINKINGOFF_STATE:
678	case POWEROFF_STATE:
679		info("Already enabled on slot %s\n", p_slot->name);
680		break;
681	default:
682		err("Not a valid state on slot %s\n", p_slot->name);
683		break;
684	}
685	mutex_unlock(&p_slot->lock);
686
687	return retval;
688}
689
690int shpchp_sysfs_disable_slot(struct slot *p_slot)
691{
692	int retval = -ENODEV;
693
694	mutex_lock(&p_slot->lock);
695	switch (p_slot->state) {
696	case BLINKINGOFF_STATE:
697		cancel_delayed_work(&p_slot->work);
698	case STATIC_STATE:
699		p_slot->state = POWEROFF_STATE;
700		mutex_unlock(&p_slot->lock);
701		retval = shpchp_disable_slot(p_slot);
702		mutex_lock(&p_slot->lock);
703		p_slot->state = STATIC_STATE;
704		break;
705	case POWEROFF_STATE:
706		info("Slot %s is already in powering off state\n",
707		     p_slot->name);
708		break;
709	case BLINKINGON_STATE:
710	case POWERON_STATE:
711		info("Already disabled on slot %s\n", p_slot->name);
712		break;
713	default:
714		err("Not a valid state on slot %s\n", p_slot->name);
715		break;
716	}
717	mutex_unlock(&p_slot->lock);
718
719	return retval;
720}
721