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
25static const struct acpi_device_id memory_device_ids[] = {
26 {ACPI_MEMORY_DEVICE_HID, 0},
27 {.id: "", .driver_data: 0},
28};
29
30#ifdef CONFIG_ACPI_HOTPLUG_MEMORY
31
32static int acpi_memory_device_add(struct acpi_device *device,
33 const struct acpi_device_id *not_used);
34static void acpi_memory_device_remove(struct acpi_device *device);
35
36static 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
45struct 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
54struct acpi_memory_device {
55 struct acpi_device *device;
56 struct list_head res_list;
57 int mgid;
58};
59
60static acpi_status
61acpi_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
97static void
98acpi_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
107static int
108acpi_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
125static 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
146static int acpi_bind_memblk(struct memory_block *mem, void *arg)
147{
148 return acpi_bind_one(&mem->dev, arg);
149}
150
151static 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
158static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
159{
160 acpi_unbind_one(&mem->dev);
161 return 0;
162}
163
164static 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
170static 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
255static 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
270static 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
284static 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
329static 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
341static bool __initdata acpi_no_memhotplug;
342
343void __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
353static 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
362static struct acpi_scan_handler memory_device_handler = {
363 .ids = memory_device_ids,
364};
365
366void __init acpi_memory_hotplug_init(void)
367{
368 acpi_scan_add_handler(handler: &memory_device_handler);
369}
370
371#endif /* CONFIG_ACPI_HOTPLUG_MEMORY */
372