1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2004, 2013 Intel Corporation
4  * Author: Naveen B S <naveen.b.s@intel.com>
5  * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
6  *
7  * All rights reserved.
8  *
9  * ACPI based HotPlug driver that supports Memory Hotplug
10  * This driver fields notifications from firmware for memory add
11  * and remove operations and alerts the VM of the affected memory
12  * ranges.
13  */
14 
15 #include <linux/acpi.h>
16 #include <linux/memory.h>
17 #include <linux/memory_hotplug.h>
18 
19 #include "internal.h"
20 
21 #define ACPI_MEMORY_DEVICE_CLASS		"memory"
22 #define ACPI_MEMORY_DEVICE_HID			"PNP0C80"
23 #define ACPI_MEMORY_DEVICE_NAME			"Hotplug Mem Device"
24 
25 #define _COMPONENT		ACPI_MEMORY_DEVICE_COMPONENT
26 
27 #undef PREFIX
28 #define 	PREFIX		"ACPI:memory_hp:"
29 
30 ACPI_MODULE_NAME("acpi_memhotplug");
31 
32 static const struct acpi_device_id memory_device_ids[] = {
33 	{ACPI_MEMORY_DEVICE_HID, 0},
34 	{"", 0},
35 };
36 
37 #ifdef CONFIG_ACPI_HOTPLUG_MEMORY
38 
39 /* Memory Device States */
40 #define MEMORY_INVALID_STATE	0
41 #define MEMORY_POWER_ON_STATE	1
42 #define MEMORY_POWER_OFF_STATE	2
43 
44 static int acpi_memory_device_add(struct acpi_device *device,
45 				  const struct acpi_device_id *not_used);
46 static void acpi_memory_device_remove(struct acpi_device *device);
47 
48 static struct acpi_scan_handler memory_device_handler = {
49 	.ids = memory_device_ids,
50 	.attach = acpi_memory_device_add,
51 	.detach = acpi_memory_device_remove,
52 	.hotplug = {
53 		.enabled = true,
54 	},
55 };
56 
57 struct acpi_memory_info {
58 	struct list_head list;
59 	u64 start_addr;		/* Memory Range start physical addr */
60 	u64 length;		/* Memory Range length */
61 	unsigned short caching;	/* memory cache attribute */
62 	unsigned short write_protect;	/* memory read/write attribute */
63 	unsigned int enabled:1;
64 };
65 
66 struct acpi_memory_device {
67 	struct acpi_device * device;
68 	unsigned int state;	/* State of the memory device */
69 	struct list_head res_list;
70 };
71 
72 static acpi_status
73 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
74 {
75 	struct acpi_memory_device *mem_device = context;
76 	struct acpi_resource_address64 address64;
77 	struct acpi_memory_info *info, *new;
78 	acpi_status status;
79 
80 	status = acpi_resource_to_address64(resource, &address64);
81 	if (ACPI_FAILURE(status) ||
82 	    (address64.resource_type != ACPI_MEMORY_RANGE))
83 		return AE_OK;
84 
85 	list_for_each_entry(info, &mem_device->res_list, list) {
86 		/* Can we combine the resource range information? */
87 		if ((info->caching == address64.info.mem.caching) &&
88 		    (info->write_protect == address64.info.mem.write_protect) &&
89 		    (info->start_addr + info->length == address64.address.minimum)) {
90 			info->length += address64.address.address_length;
91 			return AE_OK;
92 		}
93 	}
94 
95 	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
96 	if (!new)
97 		return AE_ERROR;
98 
99 	INIT_LIST_HEAD(&new->list);
100 	new->caching = address64.info.mem.caching;
101 	new->write_protect = address64.info.mem.write_protect;
102 	new->start_addr = address64.address.minimum;
103 	new->length = address64.address.address_length;
104 	list_add_tail(&new->list, &mem_device->res_list);
105 
106 	return AE_OK;
107 }
108 
109 static void
110 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
111 {
112 	struct acpi_memory_info *info, *n;
113 
114 	list_for_each_entry_safe(info, n, &mem_device->res_list, list)
115 		kfree(info);
116 	INIT_LIST_HEAD(&mem_device->res_list);
117 }
118 
119 static int
120 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
121 {
122 	acpi_status status;
123 
124 	if (!list_empty(&mem_device->res_list))
125 		return 0;
126 
127 	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
128 				     acpi_memory_get_resource, mem_device);
129 	if (ACPI_FAILURE(status)) {
130 		acpi_memory_free_device_resources(mem_device);
131 		return -EINVAL;
132 	}
133 
134 	return 0;
135 }
136 
137 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
138 {
139 	unsigned long long current_status;
140 
141 	/* Get device present/absent information from the _STA */
142 	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
143 					       METHOD_NAME__STA, NULL,
144 					       &current_status)))
145 		return -ENODEV;
146 	/*
147 	 * Check for device status. Device should be
148 	 * present/enabled/functioning.
149 	 */
150 	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
151 	      && (current_status & ACPI_STA_DEVICE_ENABLED)
152 	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
153 		return -ENODEV;
154 
155 	return 0;
156 }
157 
158 static int acpi_bind_memblk(struct memory_block *mem, void *arg)
159 {
160 	return acpi_bind_one(&mem->dev, arg);
161 }
162 
163 static int acpi_bind_memory_blocks(struct acpi_memory_info *info,
164 				   struct acpi_device *adev)
165 {
166 	return walk_memory_blocks(info->start_addr, info->length, adev,
167 				  acpi_bind_memblk);
168 }
169 
170 static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
171 {
172 	acpi_unbind_one(&mem->dev);
173 	return 0;
174 }
175 
176 static void acpi_unbind_memory_blocks(struct acpi_memory_info *info)
177 {
178 	walk_memory_blocks(info->start_addr, info->length, NULL,
179 			   acpi_unbind_memblk);
180 }
181 
182 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
183 {
184 	acpi_handle handle = mem_device->device->handle;
185 	int result, num_enabled = 0;
186 	struct acpi_memory_info *info;
187 	int node;
188 
189 	node = acpi_get_node(handle);
190 	/*
191 	 * Tell the VM there is more memory here...
192 	 * Note: Assume that this function returns zero on success
193 	 * We don't have memory-hot-add rollback function,now.
194 	 * (i.e. memory-hot-remove function)
195 	 */
196 	list_for_each_entry(info, &mem_device->res_list, list) {
197 		if (info->enabled) { /* just sanity check...*/
198 			num_enabled++;
199 			continue;
200 		}
201 		/*
202 		 * If the memory block size is zero, please ignore it.
203 		 * Don't try to do the following memory hotplug flowchart.
204 		 */
205 		if (!info->length)
206 			continue;
207 		if (node < 0)
208 			node = memory_add_physaddr_to_nid(info->start_addr);
209 
210 		result = __add_memory(node, info->start_addr, info->length);
211 
212 		/*
213 		 * If the memory block has been used by the kernel, add_memory()
214 		 * returns -EEXIST. If add_memory() returns the other error, it
215 		 * means that this memory block is not used by the kernel.
216 		 */
217 		if (result && result != -EEXIST)
218 			continue;
219 
220 		result = acpi_bind_memory_blocks(info, mem_device->device);
221 		if (result) {
222 			acpi_unbind_memory_blocks(info);
223 			return -ENODEV;
224 		}
225 
226 		info->enabled = 1;
227 
228 		/*
229 		 * Add num_enable even if add_memory() returns -EEXIST, so the
230 		 * device is bound to this driver.
231 		 */
232 		num_enabled++;
233 	}
234 	if (!num_enabled) {
235 		dev_err(&mem_device->device->dev, "add_memory failed\n");
236 		mem_device->state = MEMORY_INVALID_STATE;
237 		return -EINVAL;
238 	}
239 	/*
240 	 * Sometimes the memory device will contain several memory blocks.
241 	 * When one memory block is hot-added to the system memory, it will
242 	 * be regarded as a success.
243 	 * Otherwise if the last memory block can't be hot-added to the system
244 	 * memory, it will be failure and the memory device can't be bound with
245 	 * driver.
246 	 */
247 	return 0;
248 }
249 
250 static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
251 {
252 	acpi_handle handle = mem_device->device->handle;
253 	struct acpi_memory_info *info, *n;
254 	int nid = acpi_get_node(handle);
255 
256 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
257 		if (!info->enabled)
258 			continue;
259 
260 		if (nid == NUMA_NO_NODE)
261 			nid = memory_add_physaddr_to_nid(info->start_addr);
262 
263 		acpi_unbind_memory_blocks(info);
264 		__remove_memory(nid, info->start_addr, info->length);
265 		list_del(&info->list);
266 		kfree(info);
267 	}
268 }
269 
270 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
271 {
272 	if (!mem_device)
273 		return;
274 
275 	acpi_memory_free_device_resources(mem_device);
276 	mem_device->device->driver_data = NULL;
277 	kfree(mem_device);
278 }
279 
280 static int acpi_memory_device_add(struct acpi_device *device,
281 				  const struct acpi_device_id *not_used)
282 {
283 	struct acpi_memory_device *mem_device;
284 	int result;
285 
286 	if (!device)
287 		return -EINVAL;
288 
289 	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
290 	if (!mem_device)
291 		return -ENOMEM;
292 
293 	INIT_LIST_HEAD(&mem_device->res_list);
294 	mem_device->device = device;
295 	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
296 	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
297 	device->driver_data = mem_device;
298 
299 	/* Get the range from the _CRS */
300 	result = acpi_memory_get_device_resources(mem_device);
301 	if (result) {
302 		device->driver_data = NULL;
303 		kfree(mem_device);
304 		return result;
305 	}
306 
307 	/* Set the device state */
308 	mem_device->state = MEMORY_POWER_ON_STATE;
309 
310 	result = acpi_memory_check_device(mem_device);
311 	if (result) {
312 		acpi_memory_device_free(mem_device);
313 		return 0;
314 	}
315 
316 	result = acpi_memory_enable_device(mem_device);
317 	if (result) {
318 		dev_err(&device->dev, "acpi_memory_enable_device() error\n");
319 		acpi_memory_device_free(mem_device);
320 		return result;
321 	}
322 
323 	dev_dbg(&device->dev, "Memory device configured by ACPI\n");
324 	return 1;
325 }
326 
327 static void acpi_memory_device_remove(struct acpi_device *device)
328 {
329 	struct acpi_memory_device *mem_device;
330 
331 	if (!device || !acpi_driver_data(device))
332 		return;
333 
334 	mem_device = acpi_driver_data(device);
335 	acpi_memory_remove_memory(mem_device);
336 	acpi_memory_device_free(mem_device);
337 }
338 
339 static bool __initdata acpi_no_memhotplug;
340 
341 void __init acpi_memory_hotplug_init(void)
342 {
343 	if (acpi_no_memhotplug) {
344 		memory_device_handler.attach = NULL;
345 		acpi_scan_add_handler(&memory_device_handler);
346 		return;
347 	}
348 	acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
349 }
350 
351 static int __init disable_acpi_memory_hotplug(char *str)
352 {
353 	acpi_no_memhotplug = true;
354 	return 1;
355 }
356 __setup("acpi_no_memhotplug", disable_acpi_memory_hotplug);
357 
358 #else
359 
360 static struct acpi_scan_handler memory_device_handler = {
361 	.ids = memory_device_ids,
362 };
363 
364 void __init acpi_memory_hotplug_init(void)
365 {
366 	acpi_scan_add_handler(&memory_device_handler);
367 }
368 
369 #endif /* CONFIG_ACPI_HOTPLUG_MEMORY */
370