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 static const struct acpi_device_id memory_device_ids[] = {
26 	{ACPI_MEMORY_DEVICE_HID, 0},
27 	{"", 0},
28 };
29 
30 #ifdef CONFIG_ACPI_HOTPLUG_MEMORY
31 
32 static int acpi_memory_device_add(struct acpi_device *device,
33 				  const struct acpi_device_id *not_used);
34 static void acpi_memory_device_remove(struct acpi_device *device);
35 
36 static struct acpi_scan_handler memory_device_handler = {
37 	.ids = memory_device_ids,
38 	.attach = acpi_memory_device_add,
39 	.detach = acpi_memory_device_remove,
40 	.hotplug = {
41 		.enabled = true,
42 	},
43 };
44 
45 struct acpi_memory_info {
46 	struct list_head list;
47 	u64 start_addr;		/* Memory Range start physical addr */
48 	u64 length;		/* Memory Range length */
49 	unsigned short caching;	/* memory cache attribute */
50 	unsigned short write_protect;	/* memory read/write attribute */
51 	unsigned int enabled:1;
52 };
53 
54 struct acpi_memory_device {
55 	struct acpi_device *device;
56 	struct list_head res_list;
57 	int mgid;
58 };
59 
60 static acpi_status
61 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
62 {
63 	struct acpi_memory_device *mem_device = context;
64 	struct acpi_resource_address64 address64;
65 	struct acpi_memory_info *info, *new;
66 	acpi_status status;
67 
68 	status = acpi_resource_to_address64(resource, &address64);
69 	if (ACPI_FAILURE(status) ||
70 	    (address64.resource_type != ACPI_MEMORY_RANGE))
71 		return AE_OK;
72 
73 	list_for_each_entry(info, &mem_device->res_list, list) {
74 		/* Can we combine the resource range information? */
75 		if ((info->caching == address64.info.mem.caching) &&
76 		    (info->write_protect == address64.info.mem.write_protect) &&
77 		    (info->start_addr + info->length == address64.address.minimum)) {
78 			info->length += address64.address.address_length;
79 			return AE_OK;
80 		}
81 	}
82 
83 	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
84 	if (!new)
85 		return AE_ERROR;
86 
87 	INIT_LIST_HEAD(&new->list);
88 	new->caching = address64.info.mem.caching;
89 	new->write_protect = address64.info.mem.write_protect;
90 	new->start_addr = address64.address.minimum;
91 	new->length = address64.address.address_length;
92 	list_add_tail(&new->list, &mem_device->res_list);
93 
94 	return AE_OK;
95 }
96 
97 static void
98 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
99 {
100 	struct acpi_memory_info *info, *n;
101 
102 	list_for_each_entry_safe(info, n, &mem_device->res_list, list)
103 		kfree(info);
104 	INIT_LIST_HEAD(&mem_device->res_list);
105 }
106 
107 static int
108 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
109 {
110 	acpi_status status;
111 
112 	if (!list_empty(&mem_device->res_list))
113 		return 0;
114 
115 	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
116 				     acpi_memory_get_resource, mem_device);
117 	if (ACPI_FAILURE(status)) {
118 		acpi_memory_free_device_resources(mem_device);
119 		return -EINVAL;
120 	}
121 
122 	return 0;
123 }
124 
125 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
126 {
127 	unsigned long long current_status;
128 
129 	/* Get device present/absent information from the _STA */
130 	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
131 					       METHOD_NAME__STA, NULL,
132 					       &current_status)))
133 		return -ENODEV;
134 	/*
135 	 * Check for device status. Device should be
136 	 * present/enabled/functioning.
137 	 */
138 	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
139 	      && (current_status & ACPI_STA_DEVICE_ENABLED)
140 	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
141 		return -ENODEV;
142 
143 	return 0;
144 }
145 
146 static int acpi_bind_memblk(struct memory_block *mem, void *arg)
147 {
148 	return acpi_bind_one(&mem->dev, arg);
149 }
150 
151 static int acpi_bind_memory_blocks(struct acpi_memory_info *info,
152 				   struct acpi_device *adev)
153 {
154 	return walk_memory_blocks(info->start_addr, info->length, adev,
155 				  acpi_bind_memblk);
156 }
157 
158 static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
159 {
160 	acpi_unbind_one(&mem->dev);
161 	return 0;
162 }
163 
164 static void acpi_unbind_memory_blocks(struct acpi_memory_info *info)
165 {
166 	walk_memory_blocks(info->start_addr, info->length, NULL,
167 			   acpi_unbind_memblk);
168 }
169 
170 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
171 {
172 	acpi_handle handle = mem_device->device->handle;
173 	mhp_t mhp_flags = MHP_NID_IS_MGID;
174 	int result, num_enabled = 0;
175 	struct acpi_memory_info *info;
176 	u64 total_length = 0;
177 	int node, mgid;
178 
179 	node = acpi_get_node(handle);
180 
181 	list_for_each_entry(info, &mem_device->res_list, list) {
182 		if (!info->length)
183 			continue;
184 		/* We want a single node for the whole memory group */
185 		if (node < 0)
186 			node = memory_add_physaddr_to_nid(info->start_addr);
187 		total_length += info->length;
188 	}
189 
190 	if (!total_length) {
191 		dev_err(&mem_device->device->dev, "device is empty\n");
192 		return -EINVAL;
193 	}
194 
195 	mgid = memory_group_register_static(node, PFN_UP(total_length));
196 	if (mgid < 0)
197 		return mgid;
198 	mem_device->mgid = mgid;
199 
200 	/*
201 	 * Tell the VM there is more memory here...
202 	 * Note: Assume that this function returns zero on success
203 	 * We don't have memory-hot-add rollback function,now.
204 	 * (i.e. memory-hot-remove function)
205 	 */
206 	list_for_each_entry(info, &mem_device->res_list, list) {
207 		/*
208 		 * If the memory block size is zero, please ignore it.
209 		 * Don't try to do the following memory hotplug flowchart.
210 		 */
211 		if (!info->length)
212 			continue;
213 
214 		if (mhp_supports_memmap_on_memory(info->length))
215 			mhp_flags |= MHP_MEMMAP_ON_MEMORY;
216 		result = __add_memory(mgid, info->start_addr, info->length,
217 				      mhp_flags);
218 
219 		/*
220 		 * If the memory block has been used by the kernel, add_memory()
221 		 * returns -EEXIST. If add_memory() returns the other error, it
222 		 * means that this memory block is not used by the kernel.
223 		 */
224 		if (result && result != -EEXIST)
225 			continue;
226 
227 		result = acpi_bind_memory_blocks(info, mem_device->device);
228 		if (result) {
229 			acpi_unbind_memory_blocks(info);
230 			return -ENODEV;
231 		}
232 
233 		info->enabled = 1;
234 
235 		/*
236 		 * Add num_enable even if add_memory() returns -EEXIST, so the
237 		 * device is bound to this driver.
238 		 */
239 		num_enabled++;
240 	}
241 	if (!num_enabled) {
242 		dev_err(&mem_device->device->dev, "add_memory failed\n");
243 		return -EINVAL;
244 	}
245 	/*
246 	 * Sometimes the memory device will contain several memory blocks.
247 	 * When one memory block is hot-added to the system memory, it will
248 	 * be regarded as a success.
249 	 * Otherwise if the last memory block can't be hot-added to the system
250 	 * memory, it will be failure and the memory device can't be bound with
251 	 * driver.
252 	 */
253 	return 0;
254 }
255 
256 static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
257 {
258 	struct acpi_memory_info *info, *n;
259 
260 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
261 		if (!info->enabled)
262 			continue;
263 
264 		acpi_unbind_memory_blocks(info);
265 		__remove_memory(info->start_addr, info->length);
266 		list_del(&info->list);
267 		kfree(info);
268 	}
269 }
270 
271 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
272 {
273 	if (!mem_device)
274 		return;
275 
276 	/* In case we succeeded adding *some* memory, unregistering fails. */
277 	if (mem_device->mgid >= 0)
278 		memory_group_unregister(mem_device->mgid);
279 
280 	acpi_memory_free_device_resources(mem_device);
281 	mem_device->device->driver_data = NULL;
282 	kfree(mem_device);
283 }
284 
285 static int acpi_memory_device_add(struct acpi_device *device,
286 				  const struct acpi_device_id *not_used)
287 {
288 	struct acpi_memory_device *mem_device;
289 	int result;
290 
291 	if (!device)
292 		return -EINVAL;
293 
294 	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
295 	if (!mem_device)
296 		return -ENOMEM;
297 
298 	INIT_LIST_HEAD(&mem_device->res_list);
299 	mem_device->device = device;
300 	mem_device->mgid = -1;
301 	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
302 	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
303 	device->driver_data = mem_device;
304 
305 	/* Get the range from the _CRS */
306 	result = acpi_memory_get_device_resources(mem_device);
307 	if (result) {
308 		device->driver_data = NULL;
309 		kfree(mem_device);
310 		return result;
311 	}
312 
313 	result = acpi_memory_check_device(mem_device);
314 	if (result) {
315 		acpi_memory_device_free(mem_device);
316 		return 0;
317 	}
318 
319 	result = acpi_memory_enable_device(mem_device);
320 	if (result) {
321 		dev_err(&device->dev, "acpi_memory_enable_device() error\n");
322 		acpi_memory_device_free(mem_device);
323 		return result;
324 	}
325 
326 	dev_dbg(&device->dev, "Memory device configured by ACPI\n");
327 	return 1;
328 }
329 
330 static void acpi_memory_device_remove(struct acpi_device *device)
331 {
332 	struct acpi_memory_device *mem_device;
333 
334 	if (!device || !acpi_driver_data(device))
335 		return;
336 
337 	mem_device = acpi_driver_data(device);
338 	acpi_memory_remove_memory(mem_device);
339 	acpi_memory_device_free(mem_device);
340 }
341 
342 static bool __initdata acpi_no_memhotplug;
343 
344 void __init acpi_memory_hotplug_init(void)
345 {
346 	if (acpi_no_memhotplug) {
347 		memory_device_handler.attach = NULL;
348 		acpi_scan_add_handler(&memory_device_handler);
349 		return;
350 	}
351 	acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
352 }
353 
354 static int __init disable_acpi_memory_hotplug(char *str)
355 {
356 	acpi_no_memhotplug = true;
357 	return 1;
358 }
359 __setup("acpi_no_memhotplug", disable_acpi_memory_hotplug);
360 
361 #else
362 
363 static struct acpi_scan_handler memory_device_handler = {
364 	.ids = memory_device_ids,
365 };
366 
367 void __init acpi_memory_hotplug_init(void)
368 {
369 	acpi_scan_add_handler(&memory_device_handler);
370 }
371 
372 #endif /* CONFIG_ACPI_HOTPLUG_MEMORY */
373