1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * PCI Express Hot Plug Controller Driver
4 *
5 * Copyright (C) 1995,2001 Compaq Computer Corporation
6 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
7 * Copyright (C) 2001 IBM Corp.
8 * Copyright (C) 2003-2004 Intel Corporation
9 *
10 * All rights reserved.
11 *
12 * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
13 *
14 */
15
16#define dev_fmt(fmt) "pciehp: " fmt
17
18#include <linux/kernel.h>
19#include <linux/types.h>
20#include <linux/pm_runtime.h>
21#include <linux/pci.h>
22#include "pciehp.h"
23
24/* The following routines constitute the bulk of the
25   hotplug controller logic
26 */
27
28#define SAFE_REMOVAL	 true
29#define SURPRISE_REMOVAL false
30
31static void set_slot_off(struct controller *ctrl)
32{
33	/*
34	 * Turn off slot, turn on attention indicator, turn off power
35	 * indicator
36	 */
37	if (POWER_CTRL(ctrl)) {
38		pciehp_power_off_slot(ctrl);
39
40		/*
41		 * After turning power off, we must wait for at least 1 second
42		 * before taking any action that relies on power having been
43		 * removed from the slot/adapter.
44		 */
45		msleep(1000);
46	}
47
48	pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
49			      PCI_EXP_SLTCTL_ATTN_IND_ON);
50}
51
52/**
53 * board_added - Called after a board has been added to the system.
54 * @ctrl: PCIe hotplug controller where board is added
55 *
56 * Turns power on for the board.
57 * Configures board.
58 */
59static int board_added(struct controller *ctrl)
60{
61	int retval = 0;
62	struct pci_bus *parent = ctrl->pcie->port->subordinate;
63
64	if (POWER_CTRL(ctrl)) {
65		/* Power on slot */
66		retval = pciehp_power_on_slot(ctrl);
67		if (retval)
68			return retval;
69	}
70
71	pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_BLINK,
72			      INDICATOR_NOOP);
73
74	/* Check link training status */
75	retval = pciehp_check_link_status(ctrl);
76	if (retval)
77		goto err_exit;
78
79	/* Check for a power fault */
80	if (ctrl->power_fault_detected || pciehp_query_power_fault(ctrl)) {
81		ctrl_err(ctrl, "Slot(%s): Power fault\n", slot_name(ctrl));
82		retval = -EIO;
83		goto err_exit;
84	}
85
86	retval = pciehp_configure_device(ctrl);
87	if (retval) {
88		if (retval != -EEXIST) {
89			ctrl_err(ctrl, "Cannot add device at %04x:%02x:00\n",
90				 pci_domain_nr(parent), parent->number);
91			goto err_exit;
92		}
93	}
94
95	pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_ON,
96			      PCI_EXP_SLTCTL_ATTN_IND_OFF);
97	return 0;
98
99err_exit:
100	set_slot_off(ctrl);
101	return retval;
102}
103
104/**
105 * remove_board - Turn off slot and Power Indicator
106 * @ctrl: PCIe hotplug controller where board is being removed
107 * @safe_removal: whether the board is safely removed (versus surprise removed)
108 */
109static void remove_board(struct controller *ctrl, bool safe_removal)
110{
111	pciehp_unconfigure_device(ctrl, safe_removal);
112
113	if (POWER_CTRL(ctrl)) {
114		pciehp_power_off_slot(ctrl);
115
116		/*
117		 * After turning power off, we must wait for at least 1 second
118		 * before taking any action that relies on power having been
119		 * removed from the slot/adapter.
120		 */
121		msleep(1000);
122
123		/* Ignore link or presence changes caused by power off */
124		atomic_and(~(PCI_EXP_SLTSTA_DLLSC | PCI_EXP_SLTSTA_PDC),
125			   &ctrl->pending_events);
126	}
127
128	pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
129			      INDICATOR_NOOP);
130}
131
132static int pciehp_enable_slot(struct controller *ctrl);
133static int pciehp_disable_slot(struct controller *ctrl, bool safe_removal);
134
135void pciehp_request(struct controller *ctrl, int action)
136{
137	atomic_or(action, &ctrl->pending_events);
138	if (!pciehp_poll_mode)
139		irq_wake_thread(ctrl->pcie->irq, ctrl);
140}
141
142void pciehp_queue_pushbutton_work(struct work_struct *work)
143{
144	struct controller *ctrl = container_of(work, struct controller,
145					       button_work.work);
146
147	mutex_lock(&ctrl->state_lock);
148	switch (ctrl->state) {
149	case BLINKINGOFF_STATE:
150		pciehp_request(ctrl, DISABLE_SLOT);
151		break;
152	case BLINKINGON_STATE:
153		pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
154		break;
155	default:
156		break;
157	}
158	mutex_unlock(&ctrl->state_lock);
159}
160
161void pciehp_handle_button_press(struct controller *ctrl)
162{
163	mutex_lock(&ctrl->state_lock);
164	switch (ctrl->state) {
165	case OFF_STATE:
166	case ON_STATE:
167		if (ctrl->state == ON_STATE) {
168			ctrl->state = BLINKINGOFF_STATE;
169			ctrl_info(ctrl, "Slot(%s): Powering off due to button press\n",
170				  slot_name(ctrl));
171		} else {
172			ctrl->state = BLINKINGON_STATE;
173			ctrl_info(ctrl, "Slot(%s) Powering on due to button press\n",
174				  slot_name(ctrl));
175		}
176		/* blink power indicator and turn off attention */
177		pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_BLINK,
178				      PCI_EXP_SLTCTL_ATTN_IND_OFF);
179		schedule_delayed_work(&ctrl->button_work, 5 * HZ);
180		break;
181	case BLINKINGOFF_STATE:
182	case BLINKINGON_STATE:
183		/*
184		 * Cancel if we are still blinking; this means that we
185		 * press the attention again before the 5 sec. limit
186		 * expires to cancel hot-add or hot-remove
187		 */
188		ctrl_info(ctrl, "Slot(%s): Button cancel\n", slot_name(ctrl));
189		cancel_delayed_work(&ctrl->button_work);
190		if (ctrl->state == BLINKINGOFF_STATE) {
191			ctrl->state = ON_STATE;
192			pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_ON,
193					      PCI_EXP_SLTCTL_ATTN_IND_OFF);
194		} else {
195			ctrl->state = OFF_STATE;
196			pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
197					      PCI_EXP_SLTCTL_ATTN_IND_OFF);
198		}
199		ctrl_info(ctrl, "Slot(%s): Action canceled due to button press\n",
200			  slot_name(ctrl));
201		break;
202	default:
203		ctrl_err(ctrl, "Slot(%s): Ignoring invalid state %#x\n",
204			 slot_name(ctrl), ctrl->state);
205		break;
206	}
207	mutex_unlock(&ctrl->state_lock);
208}
209
210void pciehp_handle_disable_request(struct controller *ctrl)
211{
212	mutex_lock(&ctrl->state_lock);
213	switch (ctrl->state) {
214	case BLINKINGON_STATE:
215	case BLINKINGOFF_STATE:
216		cancel_delayed_work(&ctrl->button_work);
217		break;
218	}
219	ctrl->state = POWEROFF_STATE;
220	mutex_unlock(&ctrl->state_lock);
221
222	ctrl->request_result = pciehp_disable_slot(ctrl, SAFE_REMOVAL);
223}
224
225void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
226{
227	int present, link_active;
228
229	/*
230	 * If the slot is on and presence or link has changed, turn it off.
231	 * Even if it's occupied again, we cannot assume the card is the same.
232	 */
233	mutex_lock(&ctrl->state_lock);
234	switch (ctrl->state) {
235	case BLINKINGOFF_STATE:
236		cancel_delayed_work(&ctrl->button_work);
237		fallthrough;
238	case ON_STATE:
239		ctrl->state = POWEROFF_STATE;
240		mutex_unlock(&ctrl->state_lock);
241		if (events & PCI_EXP_SLTSTA_DLLSC)
242			ctrl_info(ctrl, "Slot(%s): Link Down\n",
243				  slot_name(ctrl));
244		if (events & PCI_EXP_SLTSTA_PDC)
245			ctrl_info(ctrl, "Slot(%s): Card not present\n",
246				  slot_name(ctrl));
247		pciehp_disable_slot(ctrl, SURPRISE_REMOVAL);
248		break;
249	default:
250		mutex_unlock(&ctrl->state_lock);
251		break;
252	}
253
254	/* Turn the slot on if it's occupied or link is up */
255	mutex_lock(&ctrl->state_lock);
256	present = pciehp_card_present(ctrl);
257	link_active = pciehp_check_link_active(ctrl);
258	if (present <= 0 && link_active <= 0) {
259		if (ctrl->state == BLINKINGON_STATE) {
260			ctrl->state = OFF_STATE;
261			cancel_delayed_work(&ctrl->button_work);
262			pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
263					      INDICATOR_NOOP);
264			ctrl_info(ctrl, "Slot(%s): Card not present\n",
265				  slot_name(ctrl));
266		}
267		mutex_unlock(&ctrl->state_lock);
268		return;
269	}
270
271	switch (ctrl->state) {
272	case BLINKINGON_STATE:
273		cancel_delayed_work(&ctrl->button_work);
274		fallthrough;
275	case OFF_STATE:
276		ctrl->state = POWERON_STATE;
277		mutex_unlock(&ctrl->state_lock);
278		if (present)
279			ctrl_info(ctrl, "Slot(%s): Card present\n",
280				  slot_name(ctrl));
281		if (link_active)
282			ctrl_info(ctrl, "Slot(%s): Link Up\n",
283				  slot_name(ctrl));
284		ctrl->request_result = pciehp_enable_slot(ctrl);
285		break;
286	default:
287		mutex_unlock(&ctrl->state_lock);
288		break;
289	}
290}
291
292static int __pciehp_enable_slot(struct controller *ctrl)
293{
294	u8 getstatus = 0;
295
296	if (MRL_SENS(ctrl)) {
297		pciehp_get_latch_status(ctrl, &getstatus);
298		if (getstatus) {
299			ctrl_info(ctrl, "Slot(%s): Latch open\n",
300				  slot_name(ctrl));
301			return -ENODEV;
302		}
303	}
304
305	if (POWER_CTRL(ctrl)) {
306		pciehp_get_power_status(ctrl, &getstatus);
307		if (getstatus) {
308			ctrl_info(ctrl, "Slot(%s): Already enabled\n",
309				  slot_name(ctrl));
310			return 0;
311		}
312	}
313
314	return board_added(ctrl);
315}
316
317static int pciehp_enable_slot(struct controller *ctrl)
318{
319	int ret;
320
321	pm_runtime_get_sync(&ctrl->pcie->port->dev);
322	ret = __pciehp_enable_slot(ctrl);
323	if (ret && ATTN_BUTTN(ctrl))
324		/* may be blinking */
325		pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
326				      INDICATOR_NOOP);
327	pm_runtime_put(&ctrl->pcie->port->dev);
328
329	mutex_lock(&ctrl->state_lock);
330	ctrl->state = ret ? OFF_STATE : ON_STATE;
331	mutex_unlock(&ctrl->state_lock);
332
333	return ret;
334}
335
336static int __pciehp_disable_slot(struct controller *ctrl, bool safe_removal)
337{
338	u8 getstatus = 0;
339
340	if (POWER_CTRL(ctrl)) {
341		pciehp_get_power_status(ctrl, &getstatus);
342		if (!getstatus) {
343			ctrl_info(ctrl, "Slot(%s): Already disabled\n",
344				  slot_name(ctrl));
345			return -EINVAL;
346		}
347	}
348
349	remove_board(ctrl, safe_removal);
350	return 0;
351}
352
353static int pciehp_disable_slot(struct controller *ctrl, bool safe_removal)
354{
355	int ret;
356
357	pm_runtime_get_sync(&ctrl->pcie->port->dev);
358	ret = __pciehp_disable_slot(ctrl, safe_removal);
359	pm_runtime_put(&ctrl->pcie->port->dev);
360
361	mutex_lock(&ctrl->state_lock);
362	ctrl->state = OFF_STATE;
363	mutex_unlock(&ctrl->state_lock);
364
365	return ret;
366}
367
368int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot)
369{
370	struct controller *ctrl = to_ctrl(hotplug_slot);
371
372	mutex_lock(&ctrl->state_lock);
373	switch (ctrl->state) {
374	case BLINKINGON_STATE:
375	case OFF_STATE:
376		mutex_unlock(&ctrl->state_lock);
377		/*
378		 * The IRQ thread becomes a no-op if the user pulls out the
379		 * card before the thread wakes up, so initialize to -ENODEV.
380		 */
381		ctrl->request_result = -ENODEV;
382		pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
383		wait_event(ctrl->requester,
384			   !atomic_read(&ctrl->pending_events) &&
385			   !ctrl->ist_running);
386		return ctrl->request_result;
387	case POWERON_STATE:
388		ctrl_info(ctrl, "Slot(%s): Already in powering on state\n",
389			  slot_name(ctrl));
390		break;
391	case BLINKINGOFF_STATE:
392	case ON_STATE:
393	case POWEROFF_STATE:
394		ctrl_info(ctrl, "Slot(%s): Already enabled\n",
395			  slot_name(ctrl));
396		break;
397	default:
398		ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
399			 slot_name(ctrl), ctrl->state);
400		break;
401	}
402	mutex_unlock(&ctrl->state_lock);
403
404	return -ENODEV;
405}
406
407int pciehp_sysfs_disable_slot(struct hotplug_slot *hotplug_slot)
408{
409	struct controller *ctrl = to_ctrl(hotplug_slot);
410
411	mutex_lock(&ctrl->state_lock);
412	switch (ctrl->state) {
413	case BLINKINGOFF_STATE:
414	case ON_STATE:
415		mutex_unlock(&ctrl->state_lock);
416		pciehp_request(ctrl, DISABLE_SLOT);
417		wait_event(ctrl->requester,
418			   !atomic_read(&ctrl->pending_events) &&
419			   !ctrl->ist_running);
420		return ctrl->request_result;
421	case POWEROFF_STATE:
422		ctrl_info(ctrl, "Slot(%s): Already in powering off state\n",
423			  slot_name(ctrl));
424		break;
425	case BLINKINGON_STATE:
426	case OFF_STATE:
427	case POWERON_STATE:
428		ctrl_info(ctrl, "Slot(%s): Already disabled\n",
429			  slot_name(ctrl));
430		break;
431	default:
432		ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
433			 slot_name(ctrl), ctrl->state);
434		break;
435	}
436	mutex_unlock(&ctrl->state_lock);
437
438	return -ENODEV;
439}
440