xref: /linux/drivers/pci/hotplug/pciehp_core.c (revision a4eb44a6435d6d8f9e642407a4a06f65eb90ca04)
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  * Authors:
15  *   Dan Zink <dan.zink@compaq.com>
16  *   Greg Kroah-Hartman <greg@kroah.com>
17  *   Dely Sy <dely.l.sy@intel.com>"
18  */
19 
20 #define pr_fmt(fmt) "pciehp: " fmt
21 #define dev_fmt pr_fmt
22 
23 #include <linux/moduleparam.h>
24 #include <linux/kernel.h>
25 #include <linux/slab.h>
26 #include <linux/types.h>
27 #include <linux/pci.h>
28 #include "pciehp.h"
29 
30 #include "../pci.h"
31 
32 /* Global variables */
33 bool pciehp_poll_mode;
34 int pciehp_poll_time;
35 
36 /*
37  * not really modular, but the easiest way to keep compat with existing
38  * bootargs behaviour is to continue using module_param here.
39  */
40 module_param(pciehp_poll_mode, bool, 0644);
41 module_param(pciehp_poll_time, int, 0644);
42 MODULE_PARM_DESC(pciehp_poll_mode, "Using polling mechanism for hot-plug events or not");
43 MODULE_PARM_DESC(pciehp_poll_time, "Polling mechanism frequency, in seconds");
44 
45 static int set_attention_status(struct hotplug_slot *slot, u8 value);
46 static int get_power_status(struct hotplug_slot *slot, u8 *value);
47 static int get_latch_status(struct hotplug_slot *slot, u8 *value);
48 static int get_adapter_status(struct hotplug_slot *slot, u8 *value);
49 
50 static int init_slot(struct controller *ctrl)
51 {
52 	struct hotplug_slot_ops *ops;
53 	char name[SLOT_NAME_SIZE];
54 	int retval;
55 
56 	/* Setup hotplug slot ops */
57 	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
58 	if (!ops)
59 		return -ENOMEM;
60 
61 	ops->enable_slot = pciehp_sysfs_enable_slot;
62 	ops->disable_slot = pciehp_sysfs_disable_slot;
63 	ops->get_power_status = get_power_status;
64 	ops->get_adapter_status = get_adapter_status;
65 	ops->reset_slot = pciehp_reset_slot;
66 	if (MRL_SENS(ctrl))
67 		ops->get_latch_status = get_latch_status;
68 	if (ATTN_LED(ctrl)) {
69 		ops->get_attention_status = pciehp_get_attention_status;
70 		ops->set_attention_status = set_attention_status;
71 	} else if (ctrl->pcie->port->hotplug_user_indicators) {
72 		ops->get_attention_status = pciehp_get_raw_indicator_status;
73 		ops->set_attention_status = pciehp_set_raw_indicator_status;
74 	}
75 
76 	/* register this slot with the hotplug pci core */
77 	ctrl->hotplug_slot.ops = ops;
78 	snprintf(name, SLOT_NAME_SIZE, "%u", PSN(ctrl));
79 
80 	retval = pci_hp_initialize(&ctrl->hotplug_slot,
81 				   ctrl->pcie->port->subordinate, 0, name);
82 	if (retval) {
83 		ctrl_err(ctrl, "pci_hp_initialize failed: error %d\n", retval);
84 		kfree(ops);
85 	}
86 	return retval;
87 }
88 
89 static void cleanup_slot(struct controller *ctrl)
90 {
91 	struct hotplug_slot *hotplug_slot = &ctrl->hotplug_slot;
92 
93 	pci_hp_destroy(hotplug_slot);
94 	kfree(hotplug_slot->ops);
95 }
96 
97 /*
98  * set_attention_status - Turns the Attention Indicator on, off or blinking
99  */
100 static int set_attention_status(struct hotplug_slot *hotplug_slot, u8 status)
101 {
102 	struct controller *ctrl = to_ctrl(hotplug_slot);
103 	struct pci_dev *pdev = ctrl->pcie->port;
104 
105 	if (status)
106 		status <<= PCI_EXP_SLTCTL_ATTN_IND_SHIFT;
107 	else
108 		status = PCI_EXP_SLTCTL_ATTN_IND_OFF;
109 
110 	pci_config_pm_runtime_get(pdev);
111 	pciehp_set_indicators(ctrl, INDICATOR_NOOP, status);
112 	pci_config_pm_runtime_put(pdev);
113 	return 0;
114 }
115 
116 static int get_power_status(struct hotplug_slot *hotplug_slot, u8 *value)
117 {
118 	struct controller *ctrl = to_ctrl(hotplug_slot);
119 	struct pci_dev *pdev = ctrl->pcie->port;
120 
121 	pci_config_pm_runtime_get(pdev);
122 	pciehp_get_power_status(ctrl, value);
123 	pci_config_pm_runtime_put(pdev);
124 	return 0;
125 }
126 
127 static int get_latch_status(struct hotplug_slot *hotplug_slot, u8 *value)
128 {
129 	struct controller *ctrl = to_ctrl(hotplug_slot);
130 	struct pci_dev *pdev = ctrl->pcie->port;
131 
132 	pci_config_pm_runtime_get(pdev);
133 	pciehp_get_latch_status(ctrl, value);
134 	pci_config_pm_runtime_put(pdev);
135 	return 0;
136 }
137 
138 static int get_adapter_status(struct hotplug_slot *hotplug_slot, u8 *value)
139 {
140 	struct controller *ctrl = to_ctrl(hotplug_slot);
141 	struct pci_dev *pdev = ctrl->pcie->port;
142 	int ret;
143 
144 	pci_config_pm_runtime_get(pdev);
145 	ret = pciehp_card_present_or_link_active(ctrl);
146 	pci_config_pm_runtime_put(pdev);
147 	if (ret < 0)
148 		return ret;
149 
150 	*value = ret;
151 	return 0;
152 }
153 
154 /**
155  * pciehp_check_presence() - synthesize event if presence has changed
156  * @ctrl: controller to check
157  *
158  * On probe and resume, an explicit presence check is necessary to bring up an
159  * occupied slot or bring down an unoccupied slot.  This can't be triggered by
160  * events in the Slot Status register, they may be stale and are therefore
161  * cleared.  Secondly, sending an interrupt for "events that occur while
162  * interrupt generation is disabled [when] interrupt generation is subsequently
163  * enabled" is optional per PCIe r4.0, sec 6.7.3.4.
164  */
165 static void pciehp_check_presence(struct controller *ctrl)
166 {
167 	int occupied;
168 
169 	down_read_nested(&ctrl->reset_lock, ctrl->depth);
170 	mutex_lock(&ctrl->state_lock);
171 
172 	occupied = pciehp_card_present_or_link_active(ctrl);
173 	if ((occupied > 0 && (ctrl->state == OFF_STATE ||
174 			  ctrl->state == BLINKINGON_STATE)) ||
175 	    (!occupied && (ctrl->state == ON_STATE ||
176 			   ctrl->state == BLINKINGOFF_STATE)))
177 		pciehp_request(ctrl, PCI_EXP_SLTSTA_PDC);
178 
179 	mutex_unlock(&ctrl->state_lock);
180 	up_read(&ctrl->reset_lock);
181 }
182 
183 static int pciehp_probe(struct pcie_device *dev)
184 {
185 	int rc;
186 	struct controller *ctrl;
187 
188 	/* If this is not a "hotplug" service, we have no business here. */
189 	if (dev->service != PCIE_PORT_SERVICE_HP)
190 		return -ENODEV;
191 
192 	if (!dev->port->subordinate) {
193 		/* Can happen if we run out of bus numbers during probe */
194 		pci_err(dev->port,
195 			"Hotplug bridge without secondary bus, ignoring\n");
196 		return -ENODEV;
197 	}
198 
199 	ctrl = pcie_init(dev);
200 	if (!ctrl) {
201 		pci_err(dev->port, "Controller initialization failed\n");
202 		return -ENODEV;
203 	}
204 	set_service_data(dev, ctrl);
205 
206 	/* Setup the slot information structures */
207 	rc = init_slot(ctrl);
208 	if (rc) {
209 		if (rc == -EBUSY)
210 			ctrl_warn(ctrl, "Slot already registered by another hotplug driver\n");
211 		else
212 			ctrl_err(ctrl, "Slot initialization failed (%d)\n", rc);
213 		goto err_out_release_ctlr;
214 	}
215 
216 	/* Enable events after we have setup the data structures */
217 	rc = pcie_init_notification(ctrl);
218 	if (rc) {
219 		ctrl_err(ctrl, "Notification initialization failed (%d)\n", rc);
220 		goto err_out_free_ctrl_slot;
221 	}
222 
223 	/* Publish to user space */
224 	rc = pci_hp_add(&ctrl->hotplug_slot);
225 	if (rc) {
226 		ctrl_err(ctrl, "Publication to user space failed (%d)\n", rc);
227 		goto err_out_shutdown_notification;
228 	}
229 
230 	pciehp_check_presence(ctrl);
231 
232 	return 0;
233 
234 err_out_shutdown_notification:
235 	pcie_shutdown_notification(ctrl);
236 err_out_free_ctrl_slot:
237 	cleanup_slot(ctrl);
238 err_out_release_ctlr:
239 	pciehp_release_ctrl(ctrl);
240 	return -ENODEV;
241 }
242 
243 static void pciehp_remove(struct pcie_device *dev)
244 {
245 	struct controller *ctrl = get_service_data(dev);
246 
247 	pci_hp_del(&ctrl->hotplug_slot);
248 	pcie_shutdown_notification(ctrl);
249 	cleanup_slot(ctrl);
250 	pciehp_release_ctrl(ctrl);
251 }
252 
253 #ifdef CONFIG_PM
254 static bool pme_is_native(struct pcie_device *dev)
255 {
256 	const struct pci_host_bridge *host;
257 
258 	host = pci_find_host_bridge(dev->port->bus);
259 	return pcie_ports_native || host->native_pme;
260 }
261 
262 static void pciehp_disable_interrupt(struct pcie_device *dev)
263 {
264 	/*
265 	 * Disable hotplug interrupt so that it does not trigger
266 	 * immediately when the downstream link goes down.
267 	 */
268 	if (pme_is_native(dev))
269 		pcie_disable_interrupt(get_service_data(dev));
270 }
271 
272 #ifdef CONFIG_PM_SLEEP
273 static int pciehp_suspend(struct pcie_device *dev)
274 {
275 	/*
276 	 * If the port is already runtime suspended we can keep it that
277 	 * way.
278 	 */
279 	if (dev_pm_skip_suspend(&dev->port->dev))
280 		return 0;
281 
282 	pciehp_disable_interrupt(dev);
283 	return 0;
284 }
285 
286 static int pciehp_resume_noirq(struct pcie_device *dev)
287 {
288 	struct controller *ctrl = get_service_data(dev);
289 
290 	/* pci_restore_state() just wrote to the Slot Control register */
291 	ctrl->cmd_started = jiffies;
292 	ctrl->cmd_busy = true;
293 
294 	/* clear spurious events from rediscovery of inserted card */
295 	if (ctrl->state == ON_STATE || ctrl->state == BLINKINGOFF_STATE)
296 		pcie_clear_hotplug_events(ctrl);
297 
298 	return 0;
299 }
300 #endif
301 
302 static int pciehp_resume(struct pcie_device *dev)
303 {
304 	struct controller *ctrl = get_service_data(dev);
305 
306 	if (pme_is_native(dev))
307 		pcie_enable_interrupt(ctrl);
308 
309 	pciehp_check_presence(ctrl);
310 
311 	return 0;
312 }
313 
314 static int pciehp_runtime_suspend(struct pcie_device *dev)
315 {
316 	pciehp_disable_interrupt(dev);
317 	return 0;
318 }
319 
320 static int pciehp_runtime_resume(struct pcie_device *dev)
321 {
322 	struct controller *ctrl = get_service_data(dev);
323 
324 	/* pci_restore_state() just wrote to the Slot Control register */
325 	ctrl->cmd_started = jiffies;
326 	ctrl->cmd_busy = true;
327 
328 	/* clear spurious events from rediscovery of inserted card */
329 	if ((ctrl->state == ON_STATE || ctrl->state == BLINKINGOFF_STATE) &&
330 	     pme_is_native(dev))
331 		pcie_clear_hotplug_events(ctrl);
332 
333 	return pciehp_resume(dev);
334 }
335 #endif /* PM */
336 
337 static struct pcie_port_service_driver hpdriver_portdrv = {
338 	.name		= "pciehp",
339 	.port_type	= PCIE_ANY_PORT,
340 	.service	= PCIE_PORT_SERVICE_HP,
341 
342 	.probe		= pciehp_probe,
343 	.remove		= pciehp_remove,
344 
345 #ifdef	CONFIG_PM
346 #ifdef	CONFIG_PM_SLEEP
347 	.suspend	= pciehp_suspend,
348 	.resume_noirq	= pciehp_resume_noirq,
349 	.resume		= pciehp_resume,
350 #endif
351 	.runtime_suspend = pciehp_runtime_suspend,
352 	.runtime_resume	= pciehp_runtime_resume,
353 #endif	/* PM */
354 
355 	.slot_reset	= pciehp_slot_reset,
356 };
357 
358 int __init pcie_hp_init(void)
359 {
360 	int retval = 0;
361 
362 	retval = pcie_port_service_register(&hpdriver_portdrv);
363 	pr_debug("pcie_port_service_register = %d\n", retval);
364 	if (retval)
365 		pr_debug("Failure to register service\n");
366 
367 	return retval;
368 }
369