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 
set_slot_off(struct controller * ctrl)31 static 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  */
board_added(struct controller * ctrl)59 static 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 
99 err_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  */
remove_board(struct controller * ctrl,bool safe_removal)109 static 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 
132 static int pciehp_enable_slot(struct controller *ctrl);
133 static int pciehp_disable_slot(struct controller *ctrl, bool safe_removal);
134 
pciehp_request(struct controller * ctrl,int action)135 void 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 
pciehp_queue_pushbutton_work(struct work_struct * work)142 void 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 
pciehp_handle_button_press(struct controller * ctrl)161 void 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): Button press: will power off in 5 sec\n",
170 				  slot_name(ctrl));
171 		} else {
172 			ctrl->state = BLINKINGON_STATE;
173 			ctrl_info(ctrl, "Slot(%s): Button press: will power on in 5 sec\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 		cancel_delayed_work(&ctrl->button_work);
189 		if (ctrl->state == BLINKINGOFF_STATE) {
190 			ctrl->state = ON_STATE;
191 			pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_ON,
192 					      PCI_EXP_SLTCTL_ATTN_IND_OFF);
193 			ctrl_info(ctrl, "Slot(%s): Button press: canceling request to power off\n",
194 				  slot_name(ctrl));
195 		} else {
196 			ctrl->state = OFF_STATE;
197 			pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
198 					      PCI_EXP_SLTCTL_ATTN_IND_OFF);
199 			ctrl_info(ctrl, "Slot(%s): Button press: canceling request to power on\n",
200 				  slot_name(ctrl));
201 		}
202 		break;
203 	default:
204 		ctrl_err(ctrl, "Slot(%s): Button press: ignoring invalid state %#x\n",
205 			 slot_name(ctrl), ctrl->state);
206 		break;
207 	}
208 	mutex_unlock(&ctrl->state_lock);
209 }
210 
pciehp_handle_disable_request(struct controller * ctrl)211 void pciehp_handle_disable_request(struct controller *ctrl)
212 {
213 	mutex_lock(&ctrl->state_lock);
214 	switch (ctrl->state) {
215 	case BLINKINGON_STATE:
216 	case BLINKINGOFF_STATE:
217 		cancel_delayed_work(&ctrl->button_work);
218 		break;
219 	}
220 	ctrl->state = POWEROFF_STATE;
221 	mutex_unlock(&ctrl->state_lock);
222 
223 	ctrl->request_result = pciehp_disable_slot(ctrl, SAFE_REMOVAL);
224 }
225 
pciehp_handle_presence_or_link_change(struct controller * ctrl,u32 events)226 void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
227 {
228 	int present, link_active;
229 
230 	/*
231 	 * If the slot is on and presence or link has changed, turn it off.
232 	 * Even if it's occupied again, we cannot assume the card is the same.
233 	 */
234 	mutex_lock(&ctrl->state_lock);
235 	switch (ctrl->state) {
236 	case BLINKINGOFF_STATE:
237 		cancel_delayed_work(&ctrl->button_work);
238 		fallthrough;
239 	case ON_STATE:
240 		ctrl->state = POWEROFF_STATE;
241 		mutex_unlock(&ctrl->state_lock);
242 		if (events & PCI_EXP_SLTSTA_DLLSC)
243 			ctrl_info(ctrl, "Slot(%s): Link Down\n",
244 				  slot_name(ctrl));
245 		if (events & PCI_EXP_SLTSTA_PDC)
246 			ctrl_info(ctrl, "Slot(%s): Card not present\n",
247 				  slot_name(ctrl));
248 		pciehp_disable_slot(ctrl, SURPRISE_REMOVAL);
249 		break;
250 	default:
251 		mutex_unlock(&ctrl->state_lock);
252 		break;
253 	}
254 
255 	/* Turn the slot on if it's occupied or link is up */
256 	mutex_lock(&ctrl->state_lock);
257 	present = pciehp_card_present(ctrl);
258 	link_active = pciehp_check_link_active(ctrl);
259 	if (present <= 0 && link_active <= 0) {
260 		if (ctrl->state == BLINKINGON_STATE) {
261 			ctrl->state = OFF_STATE;
262 			cancel_delayed_work(&ctrl->button_work);
263 			pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
264 					      INDICATOR_NOOP);
265 			ctrl_info(ctrl, "Slot(%s): Card not present\n",
266 				  slot_name(ctrl));
267 		}
268 		mutex_unlock(&ctrl->state_lock);
269 		return;
270 	}
271 
272 	switch (ctrl->state) {
273 	case BLINKINGON_STATE:
274 		cancel_delayed_work(&ctrl->button_work);
275 		fallthrough;
276 	case OFF_STATE:
277 		ctrl->state = POWERON_STATE;
278 		mutex_unlock(&ctrl->state_lock);
279 		if (present)
280 			ctrl_info(ctrl, "Slot(%s): Card present\n",
281 				  slot_name(ctrl));
282 		if (link_active)
283 			ctrl_info(ctrl, "Slot(%s): Link Up\n",
284 				  slot_name(ctrl));
285 		ctrl->request_result = pciehp_enable_slot(ctrl);
286 		break;
287 	default:
288 		mutex_unlock(&ctrl->state_lock);
289 		break;
290 	}
291 }
292 
__pciehp_enable_slot(struct controller * ctrl)293 static int __pciehp_enable_slot(struct controller *ctrl)
294 {
295 	u8 getstatus = 0;
296 
297 	if (MRL_SENS(ctrl)) {
298 		pciehp_get_latch_status(ctrl, &getstatus);
299 		if (getstatus) {
300 			ctrl_info(ctrl, "Slot(%s): Latch open\n",
301 				  slot_name(ctrl));
302 			return -ENODEV;
303 		}
304 	}
305 
306 	if (POWER_CTRL(ctrl)) {
307 		pciehp_get_power_status(ctrl, &getstatus);
308 		if (getstatus) {
309 			ctrl_info(ctrl, "Slot(%s): Already enabled\n",
310 				  slot_name(ctrl));
311 			return 0;
312 		}
313 	}
314 
315 	return board_added(ctrl);
316 }
317 
pciehp_enable_slot(struct controller * ctrl)318 static int pciehp_enable_slot(struct controller *ctrl)
319 {
320 	int ret;
321 
322 	pm_runtime_get_sync(&ctrl->pcie->port->dev);
323 	ret = __pciehp_enable_slot(ctrl);
324 	if (ret && ATTN_BUTTN(ctrl))
325 		/* may be blinking */
326 		pciehp_set_indicators(ctrl, PCI_EXP_SLTCTL_PWR_IND_OFF,
327 				      INDICATOR_NOOP);
328 	pm_runtime_put(&ctrl->pcie->port->dev);
329 
330 	mutex_lock(&ctrl->state_lock);
331 	ctrl->state = ret ? OFF_STATE : ON_STATE;
332 	mutex_unlock(&ctrl->state_lock);
333 
334 	return ret;
335 }
336 
__pciehp_disable_slot(struct controller * ctrl,bool safe_removal)337 static int __pciehp_disable_slot(struct controller *ctrl, bool safe_removal)
338 {
339 	u8 getstatus = 0;
340 
341 	if (POWER_CTRL(ctrl)) {
342 		pciehp_get_power_status(ctrl, &getstatus);
343 		if (!getstatus) {
344 			ctrl_info(ctrl, "Slot(%s): Already disabled\n",
345 				  slot_name(ctrl));
346 			return -EINVAL;
347 		}
348 	}
349 
350 	remove_board(ctrl, safe_removal);
351 	return 0;
352 }
353 
pciehp_disable_slot(struct controller * ctrl,bool safe_removal)354 static int pciehp_disable_slot(struct controller *ctrl, bool safe_removal)
355 {
356 	int ret;
357 
358 	pm_runtime_get_sync(&ctrl->pcie->port->dev);
359 	ret = __pciehp_disable_slot(ctrl, safe_removal);
360 	pm_runtime_put(&ctrl->pcie->port->dev);
361 
362 	mutex_lock(&ctrl->state_lock);
363 	ctrl->state = OFF_STATE;
364 	mutex_unlock(&ctrl->state_lock);
365 
366 	return ret;
367 }
368 
pciehp_sysfs_enable_slot(struct hotplug_slot * hotplug_slot)369 int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot)
370 {
371 	struct controller *ctrl = to_ctrl(hotplug_slot);
372 
373 	mutex_lock(&ctrl->state_lock);
374 	switch (ctrl->state) {
375 	case BLINKINGON_STATE:
376 	case OFF_STATE:
377 		mutex_unlock(&ctrl->state_lock);
378 		/*
379 		 * The IRQ thread becomes a no-op if the user pulls out the
380 		 * card before the thread wakes up, so initialize to -ENODEV.
381 		 */
382 		ctrl->request_result = -ENODEV;
383 		pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
384 		wait_event(ctrl->requester,
385 			   !atomic_read(&ctrl->pending_events) &&
386 			   !ctrl->ist_running);
387 		return ctrl->request_result;
388 	case POWERON_STATE:
389 		ctrl_info(ctrl, "Slot(%s): Already in powering on state\n",
390 			  slot_name(ctrl));
391 		break;
392 	case BLINKINGOFF_STATE:
393 	case ON_STATE:
394 	case POWEROFF_STATE:
395 		ctrl_info(ctrl, "Slot(%s): Already enabled\n",
396 			  slot_name(ctrl));
397 		break;
398 	default:
399 		ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
400 			 slot_name(ctrl), ctrl->state);
401 		break;
402 	}
403 	mutex_unlock(&ctrl->state_lock);
404 
405 	return -ENODEV;
406 }
407 
pciehp_sysfs_disable_slot(struct hotplug_slot * hotplug_slot)408 int pciehp_sysfs_disable_slot(struct hotplug_slot *hotplug_slot)
409 {
410 	struct controller *ctrl = to_ctrl(hotplug_slot);
411 
412 	mutex_lock(&ctrl->state_lock);
413 	switch (ctrl->state) {
414 	case BLINKINGOFF_STATE:
415 	case ON_STATE:
416 		mutex_unlock(&ctrl->state_lock);
417 		pciehp_request(ctrl, DISABLE_SLOT);
418 		wait_event(ctrl->requester,
419 			   !atomic_read(&ctrl->pending_events) &&
420 			   !ctrl->ist_running);
421 		return ctrl->request_result;
422 	case POWEROFF_STATE:
423 		ctrl_info(ctrl, "Slot(%s): Already in powering off state\n",
424 			  slot_name(ctrl));
425 		break;
426 	case BLINKINGON_STATE:
427 	case OFF_STATE:
428 	case POWERON_STATE:
429 		ctrl_info(ctrl, "Slot(%s): Already disabled\n",
430 			  slot_name(ctrl));
431 		break;
432 	default:
433 		ctrl_err(ctrl, "Slot(%s): Invalid state %#x\n",
434 			 slot_name(ctrl), ctrl->state);
435 		break;
436 	}
437 	mutex_unlock(&ctrl->state_lock);
438 
439 	return -ENODEV;
440 }
441