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