1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * processor_driver.c - ACPI Processor Driver
4  *
5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7  *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
8  *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
9  *  			- Added processor hotplug support
10  *  Copyright (C) 2013, Intel Corporation
11  *                      Rafael J. Wysocki <rafael.j.wysocki@intel.com>
12  */
13 
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/cpufreq.h>
18 #include <linux/cpu.h>
19 #include <linux/cpuidle.h>
20 #include <linux/slab.h>
21 #include <linux/acpi.h>
22 
23 #include <acpi/processor.h>
24 
25 #include "internal.h"
26 
27 #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
28 #define ACPI_PROCESSOR_NOTIFY_POWER	0x81
29 #define ACPI_PROCESSOR_NOTIFY_THROTTLING	0x82
30 
31 MODULE_AUTHOR("Paul Diefenbaugh");
32 MODULE_DESCRIPTION("ACPI Processor Driver");
33 MODULE_LICENSE("GPL");
34 
35 static int acpi_processor_start(struct device *dev);
36 static int acpi_processor_stop(struct device *dev);
37 
38 static const struct acpi_device_id processor_device_ids[] = {
39 	{ACPI_PROCESSOR_OBJECT_HID, 0},
40 	{ACPI_PROCESSOR_DEVICE_HID, 0},
41 	{"", 0},
42 };
43 MODULE_DEVICE_TABLE(acpi, processor_device_ids);
44 
45 static struct device_driver acpi_processor_driver = {
46 	.name = "processor",
47 	.bus = &cpu_subsys,
48 	.acpi_match_table = processor_device_ids,
49 	.probe = acpi_processor_start,
50 	.remove = acpi_processor_stop,
51 };
52 
53 static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
54 {
55 	struct acpi_device *device = data;
56 	struct acpi_processor *pr;
57 	int saved;
58 
59 	if (device->handle != handle)
60 		return;
61 
62 	pr = acpi_driver_data(device);
63 	if (!pr)
64 		return;
65 
66 	switch (event) {
67 	case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
68 		saved = pr->performance_platform_limit;
69 		acpi_processor_ppc_has_changed(pr, 1);
70 		if (saved == pr->performance_platform_limit)
71 			break;
72 		acpi_bus_generate_netlink_event(device->pnp.device_class,
73 						  dev_name(&device->dev), event,
74 						  pr->performance_platform_limit);
75 		break;
76 	case ACPI_PROCESSOR_NOTIFY_POWER:
77 		acpi_processor_power_state_has_changed(pr);
78 		acpi_bus_generate_netlink_event(device->pnp.device_class,
79 						  dev_name(&device->dev), event, 0);
80 		break;
81 	case ACPI_PROCESSOR_NOTIFY_THROTTLING:
82 		acpi_processor_tstate_has_changed(pr);
83 		acpi_bus_generate_netlink_event(device->pnp.device_class,
84 						  dev_name(&device->dev), event, 0);
85 		break;
86 	default:
87 		acpi_handle_debug(handle, "Unsupported event [0x%x]\n", event);
88 		break;
89 	}
90 
91 	return;
92 }
93 
94 static int __acpi_processor_start(struct acpi_device *device);
95 
96 static int acpi_soft_cpu_online(unsigned int cpu)
97 {
98 	struct acpi_processor *pr = per_cpu(processors, cpu);
99 	struct acpi_device *device;
100 
101 	if (!pr)
102 		return 0;
103 
104 	device = acpi_fetch_acpi_dev(pr->handle);
105 	if (!device)
106 		return 0;
107 
108 	/*
109 	 * CPU got physically hotplugged and onlined for the first time:
110 	 * Initialize missing things.
111 	 */
112 	if (pr->flags.need_hotplug_init) {
113 		int ret;
114 
115 		pr_info("Will online and init hotplugged CPU: %d\n",
116 			pr->id);
117 		pr->flags.need_hotplug_init = 0;
118 		ret = __acpi_processor_start(device);
119 		WARN(ret, "Failed to start CPU: %d\n", pr->id);
120 	} else {
121 		/* Normal CPU soft online event. */
122 		acpi_processor_ppc_has_changed(pr, 0);
123 		acpi_processor_hotplug(pr);
124 		acpi_processor_reevaluate_tstate(pr, false);
125 		acpi_processor_tstate_has_changed(pr);
126 	}
127 	return 0;
128 }
129 
130 static int acpi_soft_cpu_dead(unsigned int cpu)
131 {
132 	struct acpi_processor *pr = per_cpu(processors, cpu);
133 
134 	if (!pr || !acpi_fetch_acpi_dev(pr->handle))
135 		return 0;
136 
137 	acpi_processor_reevaluate_tstate(pr, true);
138 	return 0;
139 }
140 
141 #ifdef CONFIG_ACPI_CPU_FREQ_PSS
142 static void acpi_pss_perf_init(struct acpi_processor *pr)
143 {
144 	acpi_processor_ppc_has_changed(pr, 0);
145 
146 	acpi_processor_get_throttling_info(pr);
147 
148 	if (pr->flags.throttling)
149 		pr->flags.limit = 1;
150 }
151 #else
152 static inline void acpi_pss_perf_init(struct acpi_processor *pr) {}
153 #endif /* CONFIG_ACPI_CPU_FREQ_PSS */
154 
155 static int __acpi_processor_start(struct acpi_device *device)
156 {
157 	struct acpi_processor *pr = acpi_driver_data(device);
158 	acpi_status status;
159 	int result = 0;
160 
161 	if (!pr)
162 		return -ENODEV;
163 
164 	if (pr->flags.need_hotplug_init)
165 		return 0;
166 
167 	result = acpi_cppc_processor_probe(pr);
168 	if (result && !IS_ENABLED(CONFIG_ACPI_CPU_FREQ_PSS))
169 		dev_dbg(&device->dev, "CPPC data invalid or not present\n");
170 
171 	if (!cpuidle_get_driver() || cpuidle_get_driver() == &acpi_idle_driver)
172 		acpi_processor_power_init(pr);
173 
174 	acpi_pss_perf_init(pr);
175 
176 	result = acpi_processor_thermal_init(pr, device);
177 	if (result)
178 		goto err_power_exit;
179 
180 	status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
181 					     acpi_processor_notify, device);
182 	if (ACPI_SUCCESS(status))
183 		return 0;
184 
185 	result = -ENODEV;
186 	acpi_processor_thermal_exit(pr, device);
187 
188 err_power_exit:
189 	acpi_processor_power_exit(pr);
190 	return result;
191 }
192 
193 static int acpi_processor_start(struct device *dev)
194 {
195 	struct acpi_device *device = ACPI_COMPANION(dev);
196 	int ret;
197 
198 	if (!device)
199 		return -ENODEV;
200 
201 	/* Protect against concurrent CPU hotplug operations */
202 	cpu_hotplug_disable();
203 	ret = __acpi_processor_start(device);
204 	cpu_hotplug_enable();
205 	return ret;
206 }
207 
208 static int acpi_processor_stop(struct device *dev)
209 {
210 	struct acpi_device *device = ACPI_COMPANION(dev);
211 	struct acpi_processor *pr;
212 
213 	if (!device)
214 		return 0;
215 
216 	acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
217 				   acpi_processor_notify);
218 
219 	pr = acpi_driver_data(device);
220 	if (!pr)
221 		return 0;
222 	acpi_processor_power_exit(pr);
223 
224 	acpi_cppc_processor_exit(pr);
225 
226 	acpi_processor_thermal_exit(pr, device);
227 
228 	return 0;
229 }
230 
231 bool acpi_processor_cpufreq_init;
232 
233 static int acpi_processor_notifier(struct notifier_block *nb,
234 				   unsigned long event, void *data)
235 {
236 	struct cpufreq_policy *policy = data;
237 
238 	if (event == CPUFREQ_CREATE_POLICY) {
239 		acpi_thermal_cpufreq_init(policy);
240 		acpi_processor_ppc_init(policy);
241 	} else if (event == CPUFREQ_REMOVE_POLICY) {
242 		acpi_processor_ppc_exit(policy);
243 		acpi_thermal_cpufreq_exit(policy);
244 	}
245 
246 	return 0;
247 }
248 
249 static struct notifier_block acpi_processor_notifier_block = {
250 	.notifier_call = acpi_processor_notifier,
251 };
252 
253 /*
254  * We keep the driver loaded even when ACPI is not running.
255  * This is needed for the powernow-k8 driver, that works even without
256  * ACPI, but needs symbols from this driver
257  */
258 static enum cpuhp_state hp_online;
259 static int __init acpi_processor_driver_init(void)
260 {
261 	int result = 0;
262 
263 	if (acpi_disabled)
264 		return 0;
265 
266 	if (!cpufreq_register_notifier(&acpi_processor_notifier_block,
267 				       CPUFREQ_POLICY_NOTIFIER)) {
268 		acpi_processor_cpufreq_init = true;
269 		acpi_processor_ignore_ppc_init();
270 	}
271 
272 	result = driver_register(&acpi_processor_driver);
273 	if (result < 0)
274 		return result;
275 
276 	result = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
277 					   "acpi/cpu-drv:online",
278 					   acpi_soft_cpu_online, NULL);
279 	if (result < 0)
280 		goto err;
281 	hp_online = result;
282 	cpuhp_setup_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD, "acpi/cpu-drv:dead",
283 				  NULL, acpi_soft_cpu_dead);
284 
285 	acpi_processor_throttling_init();
286 	return 0;
287 err:
288 	driver_unregister(&acpi_processor_driver);
289 	return result;
290 }
291 
292 static void __exit acpi_processor_driver_exit(void)
293 {
294 	if (acpi_disabled)
295 		return;
296 
297 	if (acpi_processor_cpufreq_init) {
298 		cpufreq_unregister_notifier(&acpi_processor_notifier_block,
299 					    CPUFREQ_POLICY_NOTIFIER);
300 		acpi_processor_cpufreq_init = false;
301 	}
302 
303 	cpuhp_remove_state_nocalls(hp_online);
304 	cpuhp_remove_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD);
305 	driver_unregister(&acpi_processor_driver);
306 }
307 
308 module_init(acpi_processor_driver_init);
309 module_exit(acpi_processor_driver_exit);
310 
311 MODULE_ALIAS("processor");
312