1 /*
2  * Copyright (C) 2004, 2013 Intel Corporation
3  * Author: Naveen B S <naveen.b.s@intel.com>
4  * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
5  *
6  * All rights reserved.
7  *
8  * This program is free software; you can redistribute it and/or modify
9  * it under the terms of the GNU General Public License as published by
10  * the Free Software Foundation; either version 2 of the License, or (at
11  * your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful, but
14  * WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
16  * NON INFRINGEMENT.  See the GNU General Public License for more
17  * details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; if not, write to the Free Software
21  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22  *
23  *
24  * ACPI based HotPlug driver that supports Memory Hotplug
25  * This driver fields notifications from firmware for memory add
26  * and remove operations and alerts the VM of the affected memory
27  * ranges.
28  */
29 
30 #include <linux/acpi.h>
31 #include <linux/memory.h>
32 #include <linux/memory_hotplug.h>
33 
34 #include "internal.h"
35 
36 #define ACPI_MEMORY_DEVICE_CLASS		"memory"
37 #define ACPI_MEMORY_DEVICE_HID			"PNP0C80"
38 #define ACPI_MEMORY_DEVICE_NAME			"Hotplug Mem Device"
39 
40 #define _COMPONENT		ACPI_MEMORY_DEVICE_COMPONENT
41 
42 #undef PREFIX
43 #define 	PREFIX		"ACPI:memory_hp:"
44 
45 ACPI_MODULE_NAME("acpi_memhotplug");
46 
47 /* Memory Device States */
48 #define MEMORY_INVALID_STATE	0
49 #define MEMORY_POWER_ON_STATE	1
50 #define MEMORY_POWER_OFF_STATE	2
51 
52 static int acpi_memory_device_add(struct acpi_device *device,
53 				  const struct acpi_device_id *not_used);
54 static void acpi_memory_device_remove(struct acpi_device *device);
55 
56 static const struct acpi_device_id memory_device_ids[] = {
57 	{ACPI_MEMORY_DEVICE_HID, 0},
58 	{"", 0},
59 };
60 
61 static struct acpi_scan_handler memory_device_handler = {
62 	.ids = memory_device_ids,
63 	.attach = acpi_memory_device_add,
64 	.detach = acpi_memory_device_remove,
65 	.hotplug = {
66 		.enabled = true,
67 	},
68 };
69 
70 struct acpi_memory_info {
71 	struct list_head list;
72 	u64 start_addr;		/* Memory Range start physical addr */
73 	u64 length;		/* Memory Range length */
74 	unsigned short caching;	/* memory cache attribute */
75 	unsigned short write_protect;	/* memory read/write attribute */
76 	unsigned int enabled:1;
77 };
78 
79 struct acpi_memory_device {
80 	struct acpi_device * device;
81 	unsigned int state;	/* State of the memory device */
82 	struct list_head res_list;
83 };
84 
85 static acpi_status
86 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
87 {
88 	struct acpi_memory_device *mem_device = context;
89 	struct acpi_resource_address64 address64;
90 	struct acpi_memory_info *info, *new;
91 	acpi_status status;
92 
93 	status = acpi_resource_to_address64(resource, &address64);
94 	if (ACPI_FAILURE(status) ||
95 	    (address64.resource_type != ACPI_MEMORY_RANGE))
96 		return AE_OK;
97 
98 	list_for_each_entry(info, &mem_device->res_list, list) {
99 		/* Can we combine the resource range information? */
100 		if ((info->caching == address64.info.mem.caching) &&
101 		    (info->write_protect == address64.info.mem.write_protect) &&
102 		    (info->start_addr + info->length == address64.minimum)) {
103 			info->length += address64.address_length;
104 			return AE_OK;
105 		}
106 	}
107 
108 	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
109 	if (!new)
110 		return AE_ERROR;
111 
112 	INIT_LIST_HEAD(&new->list);
113 	new->caching = address64.info.mem.caching;
114 	new->write_protect = address64.info.mem.write_protect;
115 	new->start_addr = address64.minimum;
116 	new->length = address64.address_length;
117 	list_add_tail(&new->list, &mem_device->res_list);
118 
119 	return AE_OK;
120 }
121 
122 static void
123 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
124 {
125 	struct acpi_memory_info *info, *n;
126 
127 	list_for_each_entry_safe(info, n, &mem_device->res_list, list)
128 		kfree(info);
129 	INIT_LIST_HEAD(&mem_device->res_list);
130 }
131 
132 static int
133 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
134 {
135 	acpi_status status;
136 
137 	if (!list_empty(&mem_device->res_list))
138 		return 0;
139 
140 	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
141 				     acpi_memory_get_resource, mem_device);
142 	if (ACPI_FAILURE(status)) {
143 		acpi_memory_free_device_resources(mem_device);
144 		return -EINVAL;
145 	}
146 
147 	return 0;
148 }
149 
150 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
151 {
152 	unsigned long long current_status;
153 
154 	/* Get device present/absent information from the _STA */
155 	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
156 					       METHOD_NAME__STA, NULL,
157 					       &current_status)))
158 		return -ENODEV;
159 	/*
160 	 * Check for device status. Device should be
161 	 * present/enabled/functioning.
162 	 */
163 	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
164 	      && (current_status & ACPI_STA_DEVICE_ENABLED)
165 	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
166 		return -ENODEV;
167 
168 	return 0;
169 }
170 
171 static unsigned long acpi_meminfo_start_pfn(struct acpi_memory_info *info)
172 {
173 	return PFN_DOWN(info->start_addr);
174 }
175 
176 static unsigned long acpi_meminfo_end_pfn(struct acpi_memory_info *info)
177 {
178 	return PFN_UP(info->start_addr + info->length-1);
179 }
180 
181 static int acpi_bind_memblk(struct memory_block *mem, void *arg)
182 {
183 	return acpi_bind_one(&mem->dev, (acpi_handle)arg);
184 }
185 
186 static int acpi_bind_memory_blocks(struct acpi_memory_info *info,
187 				   acpi_handle handle)
188 {
189 	return walk_memory_range(acpi_meminfo_start_pfn(info),
190 				 acpi_meminfo_end_pfn(info), (void *)handle,
191 				 acpi_bind_memblk);
192 }
193 
194 static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
195 {
196 	acpi_unbind_one(&mem->dev);
197 	return 0;
198 }
199 
200 static void acpi_unbind_memory_blocks(struct acpi_memory_info *info,
201 				      acpi_handle handle)
202 {
203 	walk_memory_range(acpi_meminfo_start_pfn(info),
204 			  acpi_meminfo_end_pfn(info), NULL, acpi_unbind_memblk);
205 }
206 
207 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
208 {
209 	acpi_handle handle = mem_device->device->handle;
210 	int result, num_enabled = 0;
211 	struct acpi_memory_info *info;
212 	int node;
213 
214 	node = acpi_get_node(handle);
215 	/*
216 	 * Tell the VM there is more memory here...
217 	 * Note: Assume that this function returns zero on success
218 	 * We don't have memory-hot-add rollback function,now.
219 	 * (i.e. memory-hot-remove function)
220 	 */
221 	list_for_each_entry(info, &mem_device->res_list, list) {
222 		if (info->enabled) { /* just sanity check...*/
223 			num_enabled++;
224 			continue;
225 		}
226 		/*
227 		 * If the memory block size is zero, please ignore it.
228 		 * Don't try to do the following memory hotplug flowchart.
229 		 */
230 		if (!info->length)
231 			continue;
232 		if (node < 0)
233 			node = memory_add_physaddr_to_nid(info->start_addr);
234 
235 		result = add_memory(node, info->start_addr, info->length);
236 
237 		/*
238 		 * If the memory block has been used by the kernel, add_memory()
239 		 * returns -EEXIST. If add_memory() returns the other error, it
240 		 * means that this memory block is not used by the kernel.
241 		 */
242 		if (result && result != -EEXIST)
243 			continue;
244 
245 		result = acpi_bind_memory_blocks(info, handle);
246 		if (result) {
247 			acpi_unbind_memory_blocks(info, handle);
248 			return -ENODEV;
249 		}
250 
251 		info->enabled = 1;
252 
253 		/*
254 		 * Add num_enable even if add_memory() returns -EEXIST, so the
255 		 * device is bound to this driver.
256 		 */
257 		num_enabled++;
258 	}
259 	if (!num_enabled) {
260 		dev_err(&mem_device->device->dev, "add_memory failed\n");
261 		mem_device->state = MEMORY_INVALID_STATE;
262 		return -EINVAL;
263 	}
264 	/*
265 	 * Sometimes the memory device will contain several memory blocks.
266 	 * When one memory block is hot-added to the system memory, it will
267 	 * be regarded as a success.
268 	 * Otherwise if the last memory block can't be hot-added to the system
269 	 * memory, it will be failure and the memory device can't be bound with
270 	 * driver.
271 	 */
272 	return 0;
273 }
274 
275 static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
276 {
277 	acpi_handle handle = mem_device->device->handle;
278 	struct acpi_memory_info *info, *n;
279 	int nid = acpi_get_node(handle);
280 
281 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
282 		if (!info->enabled)
283 			continue;
284 
285 		if (nid == NUMA_NO_NODE)
286 			nid = memory_add_physaddr_to_nid(info->start_addr);
287 
288 		acpi_unbind_memory_blocks(info, handle);
289 		remove_memory(nid, info->start_addr, info->length);
290 		list_del(&info->list);
291 		kfree(info);
292 	}
293 }
294 
295 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
296 {
297 	if (!mem_device)
298 		return;
299 
300 	acpi_memory_free_device_resources(mem_device);
301 	mem_device->device->driver_data = NULL;
302 	kfree(mem_device);
303 }
304 
305 static int acpi_memory_device_add(struct acpi_device *device,
306 				  const struct acpi_device_id *not_used)
307 {
308 	struct acpi_memory_device *mem_device;
309 	int result;
310 
311 	if (!device)
312 		return -EINVAL;
313 
314 	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
315 	if (!mem_device)
316 		return -ENOMEM;
317 
318 	INIT_LIST_HEAD(&mem_device->res_list);
319 	mem_device->device = device;
320 	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
321 	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
322 	device->driver_data = mem_device;
323 
324 	/* Get the range from the _CRS */
325 	result = acpi_memory_get_device_resources(mem_device);
326 	if (result) {
327 		device->driver_data = NULL;
328 		kfree(mem_device);
329 		return result;
330 	}
331 
332 	/* Set the device state */
333 	mem_device->state = MEMORY_POWER_ON_STATE;
334 
335 	result = acpi_memory_check_device(mem_device);
336 	if (result) {
337 		acpi_memory_device_free(mem_device);
338 		return 0;
339 	}
340 
341 	result = acpi_memory_enable_device(mem_device);
342 	if (result) {
343 		dev_err(&device->dev, "acpi_memory_enable_device() error\n");
344 		acpi_memory_device_free(mem_device);
345 		return result;
346 	}
347 
348 	dev_dbg(&device->dev, "Memory device configured by ACPI\n");
349 	return 1;
350 }
351 
352 static void acpi_memory_device_remove(struct acpi_device *device)
353 {
354 	struct acpi_memory_device *mem_device;
355 
356 	if (!device || !acpi_driver_data(device))
357 		return;
358 
359 	mem_device = acpi_driver_data(device);
360 	acpi_memory_remove_memory(mem_device);
361 	acpi_memory_device_free(mem_device);
362 }
363 
364 void __init acpi_memory_hotplug_init(void)
365 {
366 	acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
367 }
368