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	{"", 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};
58
59static acpi_status
60acpi_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
96static void
97acpi_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
106static int
107acpi_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
124static 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
145static int acpi_bind_memblk(struct memory_block *mem, void *arg)
146{
147	return acpi_bind_one(&mem->dev, arg);
148}
149
150static 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
157static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
158{
159	acpi_unbind_one(&mem->dev);
160	return 0;
161}
162
163static 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
169static 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	int node;
175
176	node = acpi_get_node(handle);
177	/*
178	 * Tell the VM there is more memory here...
179	 * Note: Assume that this function returns zero on success
180	 * We don't have memory-hot-add rollback function,now.
181	 * (i.e. memory-hot-remove function)
182	 */
183	list_for_each_entry(info, &mem_device->res_list, list) {
184		if (info->enabled) { /* just sanity check...*/
185			num_enabled++;
186			continue;
187		}
188		/*
189		 * If the memory block size is zero, please ignore it.
190		 * Don't try to do the following memory hotplug flowchart.
191		 */
192		if (!info->length)
193			continue;
194		if (node < 0)
195			node = memory_add_physaddr_to_nid(info->start_addr);
196
197		result = __add_memory(node, info->start_addr, info->length,
198				      MHP_NONE);
199
200		/*
201		 * If the memory block has been used by the kernel, add_memory()
202		 * returns -EEXIST. If add_memory() returns the other error, it
203		 * means that this memory block is not used by the kernel.
204		 */
205		if (result && result != -EEXIST)
206			continue;
207
208		result = acpi_bind_memory_blocks(info, mem_device->device);
209		if (result) {
210			acpi_unbind_memory_blocks(info);
211			return -ENODEV;
212		}
213
214		info->enabled = 1;
215
216		/*
217		 * Add num_enable even if add_memory() returns -EEXIST, so the
218		 * device is bound to this driver.
219		 */
220		num_enabled++;
221	}
222	if (!num_enabled) {
223		dev_err(&mem_device->device->dev, "add_memory failed\n");
224		return -EINVAL;
225	}
226	/*
227	 * Sometimes the memory device will contain several memory blocks.
228	 * When one memory block is hot-added to the system memory, it will
229	 * be regarded as a success.
230	 * Otherwise if the last memory block can't be hot-added to the system
231	 * memory, it will be failure and the memory device can't be bound with
232	 * driver.
233	 */
234	return 0;
235}
236
237static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
238{
239	acpi_handle handle = mem_device->device->handle;
240	struct acpi_memory_info *info, *n;
241	int nid = acpi_get_node(handle);
242
243	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
244		if (!info->enabled)
245			continue;
246
247		if (nid == NUMA_NO_NODE)
248			nid = memory_add_physaddr_to_nid(info->start_addr);
249
250		acpi_unbind_memory_blocks(info);
251		__remove_memory(nid, info->start_addr, info->length);
252		list_del(&info->list);
253		kfree(info);
254	}
255}
256
257static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
258{
259	if (!mem_device)
260		return;
261
262	acpi_memory_free_device_resources(mem_device);
263	mem_device->device->driver_data = NULL;
264	kfree(mem_device);
265}
266
267static int acpi_memory_device_add(struct acpi_device *device,
268				  const struct acpi_device_id *not_used)
269{
270	struct acpi_memory_device *mem_device;
271	int result;
272
273	if (!device)
274		return -EINVAL;
275
276	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
277	if (!mem_device)
278		return -ENOMEM;
279
280	INIT_LIST_HEAD(&mem_device->res_list);
281	mem_device->device = device;
282	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
283	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
284	device->driver_data = mem_device;
285
286	/* Get the range from the _CRS */
287	result = acpi_memory_get_device_resources(mem_device);
288	if (result) {
289		device->driver_data = NULL;
290		kfree(mem_device);
291		return result;
292	}
293
294	result = acpi_memory_check_device(mem_device);
295	if (result) {
296		acpi_memory_device_free(mem_device);
297		return 0;
298	}
299
300	result = acpi_memory_enable_device(mem_device);
301	if (result) {
302		dev_err(&device->dev, "acpi_memory_enable_device() error\n");
303		acpi_memory_device_free(mem_device);
304		return result;
305	}
306
307	dev_dbg(&device->dev, "Memory device configured by ACPI\n");
308	return 1;
309}
310
311static void acpi_memory_device_remove(struct acpi_device *device)
312{
313	struct acpi_memory_device *mem_device;
314
315	if (!device || !acpi_driver_data(device))
316		return;
317
318	mem_device = acpi_driver_data(device);
319	acpi_memory_remove_memory(mem_device);
320	acpi_memory_device_free(mem_device);
321}
322
323static bool __initdata acpi_no_memhotplug;
324
325void __init acpi_memory_hotplug_init(void)
326{
327	if (acpi_no_memhotplug) {
328		memory_device_handler.attach = NULL;
329		acpi_scan_add_handler(&memory_device_handler);
330		return;
331	}
332	acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
333}
334
335static int __init disable_acpi_memory_hotplug(char *str)
336{
337	acpi_no_memhotplug = true;
338	return 1;
339}
340__setup("acpi_no_memhotplug", disable_acpi_memory_hotplug);
341
342#else
343
344static struct acpi_scan_handler memory_device_handler = {
345	.ids = memory_device_ids,
346};
347
348void __init acpi_memory_hotplug_init(void)
349{
350	acpi_scan_add_handler(&memory_device_handler);
351}
352
353#endif /* CONFIG_ACPI_HOTPLUG_MEMORY */
354