Adds a nolock function to the w1 interface to avoid locking the
[linux-2.6/next.git] / drivers / pci / hotplug / shpchp_ctrl.c
blobb00b09bdd38aab2b5f442bd1e6b552a2046a3108
1 /*
2 * Standard Hot Plug Controller Driver
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
9 * All rights reserved.
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.
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.
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.
26 * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
30 #include <linux/module.h>
31 #include <linux/kernel.h>
32 #include <linux/types.h>
33 #include <linux/slab.h>
34 #include <linux/pci.h>
35 #include "../pci.h"
36 #include "shpchp.h"
38 static void interrupt_event_handler(struct work_struct *work);
39 static int shpchp_enable_slot(struct slot *p_slot);
40 static int shpchp_disable_slot(struct slot *p_slot);
42 static int queue_interrupt_event(struct slot *p_slot, u32 event_type)
44 struct event_info *info;
46 info = kmalloc(sizeof(*info), GFP_ATOMIC);
47 if (!info)
48 return -ENOMEM;
50 info->event_type = event_type;
51 info->p_slot = p_slot;
52 INIT_WORK(&info->work, interrupt_event_handler);
54 queue_work(shpchp_wq, &info->work);
56 return 0;
59 u8 shpchp_handle_attention_button(u8 hp_slot, struct controller *ctrl)
61 struct slot *p_slot;
62 u32 event_type;
64 /* Attention Button Change */
65 ctrl_dbg(ctrl, "Attention button interrupt received\n");
67 p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
68 p_slot->hpc_ops->get_adapter_status(p_slot, &(p_slot->presence_save));
71 * Button pressed - See if need to TAKE ACTION!!!
73 ctrl_info(ctrl, "Button pressed on Slot(%s)\n", slot_name(p_slot));
74 event_type = INT_BUTTON_PRESS;
76 queue_interrupt_event(p_slot, event_type);
78 return 0;
82 u8 shpchp_handle_switch_change(u8 hp_slot, struct controller *ctrl)
84 struct slot *p_slot;
85 u8 getstatus;
86 u32 event_type;
88 /* Switch Change */
89 ctrl_dbg(ctrl, "Switch interrupt received\n");
91 p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
92 p_slot->hpc_ops->get_adapter_status(p_slot, &(p_slot->presence_save));
93 p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
94 ctrl_dbg(ctrl, "Card present %x Power status %x\n",
95 p_slot->presence_save, p_slot->pwr_save);
97 if (getstatus) {
99 * Switch opened
101 ctrl_info(ctrl, "Latch open on Slot(%s)\n", slot_name(p_slot));
102 event_type = INT_SWITCH_OPEN;
103 if (p_slot->pwr_save && p_slot->presence_save) {
104 event_type = INT_POWER_FAULT;
105 ctrl_err(ctrl, "Surprise Removal of card\n");
107 } else {
109 * Switch closed
111 ctrl_info(ctrl, "Latch close on Slot(%s)\n", slot_name(p_slot));
112 event_type = INT_SWITCH_CLOSE;
115 queue_interrupt_event(p_slot, event_type);
117 return 1;
120 u8 shpchp_handle_presence_change(u8 hp_slot, struct controller *ctrl)
122 struct slot *p_slot;
123 u32 event_type;
125 /* Presence Change */
126 ctrl_dbg(ctrl, "Presence/Notify input change\n");
128 p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
131 * Save the presence state
133 p_slot->hpc_ops->get_adapter_status(p_slot, &(p_slot->presence_save));
134 if (p_slot->presence_save) {
136 * Card Present
138 ctrl_info(ctrl, "Card present on Slot(%s)\n",
139 slot_name(p_slot));
140 event_type = INT_PRESENCE_ON;
141 } else {
143 * Not Present
145 ctrl_info(ctrl, "Card not present on Slot(%s)\n",
146 slot_name(p_slot));
147 event_type = INT_PRESENCE_OFF;
150 queue_interrupt_event(p_slot, event_type);
152 return 1;
155 u8 shpchp_handle_power_fault(u8 hp_slot, struct controller *ctrl)
157 struct slot *p_slot;
158 u32 event_type;
160 /* Power fault */
161 ctrl_dbg(ctrl, "Power fault interrupt received\n");
163 p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
165 if ( !(p_slot->hpc_ops->query_power_fault(p_slot))) {
167 * Power fault Cleared
169 ctrl_info(ctrl, "Power fault cleared on Slot(%s)\n",
170 slot_name(p_slot));
171 p_slot->status = 0x00;
172 event_type = INT_POWER_FAULT_CLEAR;
173 } else {
175 * Power fault
177 ctrl_info(ctrl, "Power fault on Slot(%s)\n", slot_name(p_slot));
178 event_type = INT_POWER_FAULT;
179 /* set power fault status for this board */
180 p_slot->status = 0xFF;
181 ctrl_info(ctrl, "Power fault bit %x set\n", hp_slot);
184 queue_interrupt_event(p_slot, event_type);
186 return 1;
189 /* The following routines constitute the bulk of the
190 hotplug controller logic
192 static int change_bus_speed(struct controller *ctrl, struct slot *p_slot,
193 enum pci_bus_speed speed)
195 int rc = 0;
197 ctrl_dbg(ctrl, "Change speed to %d\n", speed);
198 if ((rc = p_slot->hpc_ops->set_bus_speed_mode(p_slot, speed))) {
199 ctrl_err(ctrl, "%s: Issue of set bus speed mode command "
200 "failed\n", __func__);
201 return WRONG_BUS_FREQUENCY;
203 return rc;
206 static int fix_bus_speed(struct controller *ctrl, struct slot *pslot,
207 u8 flag, enum pci_bus_speed asp, enum pci_bus_speed bsp,
208 enum pci_bus_speed msp)
210 int rc = 0;
213 * If other slots on the same bus are occupied, we cannot
214 * change the bus speed.
216 if (flag) {
217 if (asp < bsp) {
218 ctrl_err(ctrl, "Speed of bus %x and adapter %x "
219 "mismatch\n", bsp, asp);
220 rc = WRONG_BUS_FREQUENCY;
222 return rc;
225 if (asp < msp) {
226 if (bsp != asp)
227 rc = change_bus_speed(ctrl, pslot, asp);
228 } else {
229 if (bsp != msp)
230 rc = change_bus_speed(ctrl, pslot, msp);
232 return rc;
236 * board_added - Called after a board has been added to the system.
237 * @p_slot: target &slot
239 * Turns power on for the board.
240 * Configures board.
242 static int board_added(struct slot *p_slot)
244 u8 hp_slot;
245 u8 slots_not_empty = 0;
246 int rc = 0;
247 enum pci_bus_speed asp, bsp, msp;
248 struct controller *ctrl = p_slot->ctrl;
249 struct pci_bus *parent = ctrl->pci_dev->subordinate;
251 hp_slot = p_slot->device - ctrl->slot_device_offset;
253 ctrl_dbg(ctrl,
254 "%s: p_slot->device, slot_offset, hp_slot = %d, %d ,%d\n",
255 __func__, p_slot->device, ctrl->slot_device_offset, hp_slot);
257 /* Power on slot without connecting to bus */
258 rc = p_slot->hpc_ops->power_on_slot(p_slot);
259 if (rc) {
260 ctrl_err(ctrl, "Failed to power on slot\n");
261 return -1;
264 if ((ctrl->pci_dev->vendor == 0x8086) && (ctrl->pci_dev->device == 0x0332)) {
265 if (slots_not_empty)
266 return WRONG_BUS_FREQUENCY;
268 if ((rc = p_slot->hpc_ops->set_bus_speed_mode(p_slot, PCI_SPEED_33MHz))) {
269 ctrl_err(ctrl, "%s: Issue of set bus speed mode command"
270 " failed\n", __func__);
271 return WRONG_BUS_FREQUENCY;
274 /* turn on board, blink green LED, turn off Amber LED */
275 if ((rc = p_slot->hpc_ops->slot_enable(p_slot))) {
276 ctrl_err(ctrl, "Issue of Slot Enable command failed\n");
277 return rc;
281 rc = p_slot->hpc_ops->get_adapter_speed(p_slot, &asp);
282 if (rc) {
283 ctrl_err(ctrl, "Can't get adapter speed or "
284 "bus mode mismatch\n");
285 return WRONG_BUS_FREQUENCY;
288 bsp = ctrl->pci_dev->bus->cur_bus_speed;
289 msp = ctrl->pci_dev->bus->max_bus_speed;
291 /* Check if there are other slots or devices on the same bus */
292 if (!list_empty(&ctrl->pci_dev->subordinate->devices))
293 slots_not_empty = 1;
295 ctrl_dbg(ctrl, "%s: slots_not_empty %d, adapter_speed %d, bus_speed %d,"
296 " max_bus_speed %d\n", __func__, slots_not_empty, asp,
297 bsp, msp);
299 rc = fix_bus_speed(ctrl, p_slot, slots_not_empty, asp, bsp, msp);
300 if (rc)
301 return rc;
303 /* turn on board, blink green LED, turn off Amber LED */
304 if ((rc = p_slot->hpc_ops->slot_enable(p_slot))) {
305 ctrl_err(ctrl, "Issue of Slot Enable command failed\n");
306 return rc;
309 /* Wait for ~1 second */
310 msleep(1000);
312 ctrl_dbg(ctrl, "%s: slot status = %x\n", __func__, p_slot->status);
313 /* Check for a power fault */
314 if (p_slot->status == 0xFF) {
315 /* power fault occurred, but it was benign */
316 ctrl_dbg(ctrl, "%s: Power fault\n", __func__);
317 rc = POWER_FAILURE;
318 p_slot->status = 0;
319 goto err_exit;
322 if (shpchp_configure_device(p_slot)) {
323 ctrl_err(ctrl, "Cannot add device at %04x:%02x:%02x\n",
324 pci_domain_nr(parent), p_slot->bus, p_slot->device);
325 goto err_exit;
328 p_slot->status = 0;
329 p_slot->is_a_board = 0x01;
330 p_slot->pwr_save = 1;
332 p_slot->hpc_ops->green_led_on(p_slot);
334 return 0;
336 err_exit:
337 /* turn off slot, turn on Amber LED, turn off Green LED */
338 rc = p_slot->hpc_ops->slot_disable(p_slot);
339 if (rc) {
340 ctrl_err(ctrl, "%s: Issue of Slot Disable command failed\n",
341 __func__);
342 return rc;
345 return(rc);
350 * remove_board - Turns off slot and LEDs
351 * @p_slot: target &slot
353 static int remove_board(struct slot *p_slot)
355 struct controller *ctrl = p_slot->ctrl;
356 u8 hp_slot;
357 int rc;
359 if (shpchp_unconfigure_device(p_slot))
360 return(1);
362 hp_slot = p_slot->device - ctrl->slot_device_offset;
363 p_slot = shpchp_find_slot(ctrl, hp_slot + ctrl->slot_device_offset);
365 ctrl_dbg(ctrl, "%s: hp_slot = %d\n", __func__, hp_slot);
367 /* Change status to shutdown */
368 if (p_slot->is_a_board)
369 p_slot->status = 0x01;
371 /* turn off slot, turn on Amber LED, turn off Green LED */
372 rc = p_slot->hpc_ops->slot_disable(p_slot);
373 if (rc) {
374 ctrl_err(ctrl, "%s: Issue of Slot Disable command failed\n",
375 __func__);
376 return rc;
379 rc = p_slot->hpc_ops->set_attention_status(p_slot, 0);
380 if (rc) {
381 ctrl_err(ctrl, "Issue of Set Attention command failed\n");
382 return rc;
385 p_slot->pwr_save = 0;
386 p_slot->is_a_board = 0;
388 return 0;
392 struct pushbutton_work_info {
393 struct slot *p_slot;
394 struct work_struct work;
398 * shpchp_pushbutton_thread - handle pushbutton events
399 * @work: &struct work_struct to be handled
401 * Scheduled procedure to handle blocking stuff for the pushbuttons.
402 * Handles all pending events and exits.
404 static void shpchp_pushbutton_thread(struct work_struct *work)
406 struct pushbutton_work_info *info =
407 container_of(work, struct pushbutton_work_info, work);
408 struct slot *p_slot = info->p_slot;
410 mutex_lock(&p_slot->lock);
411 switch (p_slot->state) {
412 case POWEROFF_STATE:
413 mutex_unlock(&p_slot->lock);
414 shpchp_disable_slot(p_slot);
415 mutex_lock(&p_slot->lock);
416 p_slot->state = STATIC_STATE;
417 break;
418 case POWERON_STATE:
419 mutex_unlock(&p_slot->lock);
420 if (shpchp_enable_slot(p_slot))
421 p_slot->hpc_ops->green_led_off(p_slot);
422 mutex_lock(&p_slot->lock);
423 p_slot->state = STATIC_STATE;
424 break;
425 default:
426 break;
428 mutex_unlock(&p_slot->lock);
430 kfree(info);
433 void shpchp_queue_pushbutton_work(struct work_struct *work)
435 struct slot *p_slot = container_of(work, struct slot, work.work);
436 struct pushbutton_work_info *info;
438 info = kmalloc(sizeof(*info), GFP_KERNEL);
439 if (!info) {
440 ctrl_err(p_slot->ctrl, "%s: Cannot allocate memory\n",
441 __func__);
442 return;
444 info->p_slot = p_slot;
445 INIT_WORK(&info->work, shpchp_pushbutton_thread);
447 mutex_lock(&p_slot->lock);
448 switch (p_slot->state) {
449 case BLINKINGOFF_STATE:
450 p_slot->state = POWEROFF_STATE;
451 break;
452 case BLINKINGON_STATE:
453 p_slot->state = POWERON_STATE;
454 break;
455 default:
456 kfree(info);
457 goto out;
459 queue_work(shpchp_ordered_wq, &info->work);
460 out:
461 mutex_unlock(&p_slot->lock);
464 static int update_slot_info (struct slot *slot)
466 struct hotplug_slot_info *info;
467 int result;
469 info = kmalloc(sizeof(*info), GFP_KERNEL);
470 if (!info)
471 return -ENOMEM;
473 slot->hpc_ops->get_power_status(slot, &(info->power_status));
474 slot->hpc_ops->get_attention_status(slot, &(info->attention_status));
475 slot->hpc_ops->get_latch_status(slot, &(info->latch_status));
476 slot->hpc_ops->get_adapter_status(slot, &(info->adapter_status));
478 result = pci_hp_change_slot_info(slot->hotplug_slot, info);
479 kfree (info);
480 return result;
484 * Note: This function must be called with slot->lock held
486 static void handle_button_press_event(struct slot *p_slot)
488 u8 getstatus;
489 struct controller *ctrl = p_slot->ctrl;
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 ctrl_info(ctrl, "PCI slot #%s - powering off due to "
497 "button press.\n", slot_name(p_slot));
498 } else {
499 p_slot->state = BLINKINGON_STATE;
500 ctrl_info(ctrl, "PCI slot #%s - powering on due to "
501 "button press.\n", slot_name(p_slot));
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);
507 queue_delayed_work(shpchp_wq, &p_slot->work, 5*HZ);
508 break;
509 case BLINKINGOFF_STATE:
510 case BLINKINGON_STATE:
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
516 ctrl_info(ctrl, "Button cancel on Slot(%s)\n",
517 slot_name(p_slot));
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 ctrl_info(ctrl, "PCI slot #%s - action canceled due to "
525 "button press\n", slot_name(p_slot));
526 p_slot->state = STATIC_STATE;
527 break;
528 case POWEROFF_STATE:
529 case POWERON_STATE:
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
535 ctrl_info(ctrl, "Button ignore on Slot(%s)\n",
536 slot_name(p_slot));
537 update_slot_info(p_slot);
538 break;
539 default:
540 ctrl_warn(ctrl, "Not a valid state\n");
541 break;
545 static void interrupt_event_handler(struct work_struct *work)
547 struct event_info *info = container_of(work, struct event_info, work);
548 struct slot *p_slot = info->p_slot;
550 mutex_lock(&p_slot->lock);
551 switch (info->event_type) {
552 case INT_BUTTON_PRESS:
553 handle_button_press_event(p_slot);
554 break;
555 case INT_POWER_FAULT:
556 ctrl_dbg(p_slot->ctrl, "%s: Power fault\n", __func__);
557 p_slot->hpc_ops->set_attention_status(p_slot, 1);
558 p_slot->hpc_ops->green_led_off(p_slot);
559 break;
560 default:
561 update_slot_info(p_slot);
562 break;
564 mutex_unlock(&p_slot->lock);
566 kfree(info);
570 static int shpchp_enable_slot (struct slot *p_slot)
572 u8 getstatus = 0;
573 int rc, retval = -ENODEV;
574 struct controller *ctrl = p_slot->ctrl;
576 /* Check to see if (latch closed, card present, power off) */
577 mutex_lock(&p_slot->ctrl->crit_sect);
578 rc = p_slot->hpc_ops->get_adapter_status(p_slot, &getstatus);
579 if (rc || !getstatus) {
580 ctrl_info(ctrl, "No adapter on slot(%s)\n", slot_name(p_slot));
581 goto out;
583 rc = p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
584 if (rc || getstatus) {
585 ctrl_info(ctrl, "Latch open on slot(%s)\n", slot_name(p_slot));
586 goto out;
588 rc = p_slot->hpc_ops->get_power_status(p_slot, &getstatus);
589 if (rc || getstatus) {
590 ctrl_info(ctrl, "Already enabled on slot(%s)\n",
591 slot_name(p_slot));
592 goto out;
595 p_slot->is_a_board = 1;
597 /* We have to save the presence info for these slots */
598 p_slot->hpc_ops->get_adapter_status(p_slot, &(p_slot->presence_save));
599 p_slot->hpc_ops->get_power_status(p_slot, &(p_slot->pwr_save));
600 ctrl_dbg(ctrl, "%s: p_slot->pwr_save %x\n", __func__, p_slot->pwr_save);
601 p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
603 if(((p_slot->ctrl->pci_dev->vendor == PCI_VENDOR_ID_AMD) ||
604 (p_slot->ctrl->pci_dev->device == PCI_DEVICE_ID_AMD_POGO_7458))
605 && p_slot->ctrl->num_slots == 1) {
606 /* handle amd pogo errata; this must be done before enable */
607 amd_pogo_errata_save_misc_reg(p_slot);
608 retval = board_added(p_slot);
609 /* handle amd pogo errata; this must be done after enable */
610 amd_pogo_errata_restore_misc_reg(p_slot);
611 } else
612 retval = board_added(p_slot);
614 if (retval) {
615 p_slot->hpc_ops->get_adapter_status(p_slot,
616 &(p_slot->presence_save));
617 p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
620 update_slot_info(p_slot);
621 out:
622 mutex_unlock(&p_slot->ctrl->crit_sect);
623 return retval;
627 static int shpchp_disable_slot (struct slot *p_slot)
629 u8 getstatus = 0;
630 int rc, retval = -ENODEV;
631 struct controller *ctrl = p_slot->ctrl;
633 if (!p_slot->ctrl)
634 return -ENODEV;
636 /* Check to see if (latch closed, card present, power on) */
637 mutex_lock(&p_slot->ctrl->crit_sect);
639 rc = p_slot->hpc_ops->get_adapter_status(p_slot, &getstatus);
640 if (rc || !getstatus) {
641 ctrl_info(ctrl, "No adapter on slot(%s)\n", slot_name(p_slot));
642 goto out;
644 rc = p_slot->hpc_ops->get_latch_status(p_slot, &getstatus);
645 if (rc || getstatus) {
646 ctrl_info(ctrl, "Latch open on slot(%s)\n", slot_name(p_slot));
647 goto out;
649 rc = p_slot->hpc_ops->get_power_status(p_slot, &getstatus);
650 if (rc || !getstatus) {
651 ctrl_info(ctrl, "Already disabled on slot(%s)\n",
652 slot_name(p_slot));
653 goto out;
656 retval = remove_board(p_slot);
657 update_slot_info(p_slot);
658 out:
659 mutex_unlock(&p_slot->ctrl->crit_sect);
660 return retval;
663 int shpchp_sysfs_enable_slot(struct slot *p_slot)
665 int retval = -ENODEV;
666 struct controller *ctrl = p_slot->ctrl;
668 mutex_lock(&p_slot->lock);
669 switch (p_slot->state) {
670 case BLINKINGON_STATE:
671 cancel_delayed_work(&p_slot->work);
672 case STATIC_STATE:
673 p_slot->state = POWERON_STATE;
674 mutex_unlock(&p_slot->lock);
675 retval = shpchp_enable_slot(p_slot);
676 mutex_lock(&p_slot->lock);
677 p_slot->state = STATIC_STATE;
678 break;
679 case POWERON_STATE:
680 ctrl_info(ctrl, "Slot %s is already in powering on state\n",
681 slot_name(p_slot));
682 break;
683 case BLINKINGOFF_STATE:
684 case POWEROFF_STATE:
685 ctrl_info(ctrl, "Already enabled on slot %s\n",
686 slot_name(p_slot));
687 break;
688 default:
689 ctrl_err(ctrl, "Not a valid state on slot %s\n",
690 slot_name(p_slot));
691 break;
693 mutex_unlock(&p_slot->lock);
695 return retval;
698 int shpchp_sysfs_disable_slot(struct slot *p_slot)
700 int retval = -ENODEV;
701 struct controller *ctrl = p_slot->ctrl;
703 mutex_lock(&p_slot->lock);
704 switch (p_slot->state) {
705 case BLINKINGOFF_STATE:
706 cancel_delayed_work(&p_slot->work);
707 case STATIC_STATE:
708 p_slot->state = POWEROFF_STATE;
709 mutex_unlock(&p_slot->lock);
710 retval = shpchp_disable_slot(p_slot);
711 mutex_lock(&p_slot->lock);
712 p_slot->state = STATIC_STATE;
713 break;
714 case POWEROFF_STATE:
715 ctrl_info(ctrl, "Slot %s is already in powering off state\n",
716 slot_name(p_slot));
717 break;
718 case BLINKINGON_STATE:
719 case POWERON_STATE:
720 ctrl_info(ctrl, "Already disabled on slot %s\n",
721 slot_name(p_slot));
722 break;
723 default:
724 ctrl_err(ctrl, "Not a valid state on slot %s\n",
725 slot_name(p_slot));
726 break;
728 mutex_unlock(&p_slot->lock);
730 return retval;