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 		mhp_flags |= MHP_MEMMAP_ON_MEMORY;
215 		result = __add_memory(mgid, info->start_addr, info->length,
216 				      mhp_flags);
217 
218 		/*
219 		 * If the memory block has been used by the kernel, add_memory()
220 		 * returns -EEXIST. If add_memory() returns the other error, it
221 		 * means that this memory block is not used by the kernel.
222 		 */
223 		if (result && result != -EEXIST)
224 			continue;
225 
226 		result = acpi_bind_memory_blocks(info, mem_device->device);
227 		if (result) {
228 			acpi_unbind_memory_blocks(info);
229 			return -ENODEV;
230 		}
231 
232 		info->enabled = 1;
233 
234 		/*
235 		 * Add num_enable even if add_memory() returns -EEXIST, so the
236 		 * device is bound to this driver.
237 		 */
238 		num_enabled++;
239 	}
240 	if (!num_enabled) {
241 		dev_err(&mem_device->device->dev, "add_memory failed\n");
242 		return -EINVAL;
243 	}
244 	/*
245 	 * Sometimes the memory device will contain several memory blocks.
246 	 * When one memory block is hot-added to the system memory, it will
247 	 * be regarded as a success.
248 	 * Otherwise if the last memory block can't be hot-added to the system
249 	 * memory, it will be failure and the memory device can't be bound with
250 	 * driver.
251 	 */
252 	return 0;
253 }
254 
255 static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
256 {
257 	struct acpi_memory_info *info, *n;
258 
259 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
260 		if (!info->enabled)
261 			continue;
262 
263 		acpi_unbind_memory_blocks(info);
264 		__remove_memory(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 	/* In case we succeeded adding *some* memory, unregistering fails. */
276 	if (mem_device->mgid >= 0)
277 		memory_group_unregister(mem_device->mgid);
278 
279 	acpi_memory_free_device_resources(mem_device);
280 	mem_device->device->driver_data = NULL;
281 	kfree(mem_device);
282 }
283 
284 static int acpi_memory_device_add(struct acpi_device *device,
285 				  const struct acpi_device_id *not_used)
286 {
287 	struct acpi_memory_device *mem_device;
288 	int result;
289 
290 	if (!device)
291 		return -EINVAL;
292 
293 	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
294 	if (!mem_device)
295 		return -ENOMEM;
296 
297 	INIT_LIST_HEAD(&mem_device->res_list);
298 	mem_device->device = device;
299 	mem_device->mgid = -1;
300 	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
301 	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
302 	device->driver_data = mem_device;
303 
304 	/* Get the range from the _CRS */
305 	result = acpi_memory_get_device_resources(mem_device);
306 	if (result) {
307 		device->driver_data = NULL;
308 		kfree(mem_device);
309 		return result;
310 	}
311 
312 	result = acpi_memory_check_device(mem_device);
313 	if (result) {
314 		acpi_memory_device_free(mem_device);
315 		return 0;
316 	}
317 
318 	result = acpi_memory_enable_device(mem_device);
319 	if (result) {
320 		dev_err(&device->dev, "acpi_memory_enable_device() error\n");
321 		acpi_memory_device_free(mem_device);
322 		return result;
323 	}
324 
325 	dev_dbg(&device->dev, "Memory device configured by ACPI\n");
326 	return 1;
327 }
328 
329 static void acpi_memory_device_remove(struct acpi_device *device)
330 {
331 	struct acpi_memory_device *mem_device;
332 
333 	if (!device || !acpi_driver_data(device))
334 		return;
335 
336 	mem_device = acpi_driver_data(device);
337 	acpi_memory_remove_memory(mem_device);
338 	acpi_memory_device_free(mem_device);
339 }
340 
341 static bool __initdata acpi_no_memhotplug;
342 
343 void __init acpi_memory_hotplug_init(void)
344 {
345 	if (acpi_no_memhotplug) {
346 		memory_device_handler.attach = NULL;
347 		acpi_scan_add_handler(&memory_device_handler);
348 		return;
349 	}
350 	acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
351 }
352 
353 static int __init disable_acpi_memory_hotplug(char *str)
354 {
355 	acpi_no_memhotplug = true;
356 	return 1;
357 }
358 __setup("acpi_no_memhotplug", disable_acpi_memory_hotplug);
359 
360 #else
361 
362 static struct acpi_scan_handler memory_device_handler = {
363 	.ids = memory_device_ids,
364 };
365 
366 void __init acpi_memory_hotplug_init(void)
367 {
368 	acpi_scan_add_handler(&memory_device_handler);
369 }
370 
371 #endif /* CONFIG_ACPI_HOTPLUG_MEMORY */
372