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