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
31MODULE_AUTHOR("Paul Diefenbaugh");
32MODULE_DESCRIPTION("ACPI Processor Driver");
33MODULE_LICENSE("GPL");
34
35static int acpi_processor_start(struct device *dev);
36static int acpi_processor_stop(struct device *dev);
37
38static const struct acpi_device_id processor_device_ids[] = {
39	{ACPI_PROCESSOR_OBJECT_HID, 0},
40	{ACPI_PROCESSOR_DEVICE_HID, 0},
41	{"", 0},
42};
43MODULE_DEVICE_TABLE(acpi, processor_device_ids);
44
45static 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
53static 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
94static int __acpi_processor_start(struct acpi_device *device);
95
96static 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
130static 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
142static 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
152static inline void acpi_pss_perf_init(struct acpi_processor *pr) {}
153#endif /* CONFIG_ACPI_CPU_FREQ_PSS */
154
155static 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
188err_power_exit:
189	acpi_processor_power_exit(pr);
190	return result;
191}
192
193static 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
208static 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
231bool acpi_processor_cpufreq_init;
232
233static 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
249static 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 */
258static enum cpuhp_state hp_online;
259static 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;
287err:
288	driver_unregister(&acpi_processor_driver);
289	return result;
290}
291
292static 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
308module_init(acpi_processor_driver_init);
309module_exit(acpi_processor_driver_exit);
310
311MODULE_ALIAS("processor");
312