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 static const struct acpi_device_id memory_device_ids[] = {
48 	{ACPI_MEMORY_DEVICE_HID, 0},
49 	{"", 0},
50 };
51 
52 #ifdef CONFIG_ACPI_HOTPLUG_MEMORY
53 
54 /* Memory Device States */
55 #define MEMORY_INVALID_STATE	0
56 #define MEMORY_POWER_ON_STATE	1
57 #define MEMORY_POWER_OFF_STATE	2
58 
59 static int acpi_memory_device_add(struct acpi_device *device,
60 				  const struct acpi_device_id *not_used);
61 static void acpi_memory_device_remove(struct acpi_device *device);
62 
63 static struct acpi_scan_handler memory_device_handler = {
64 	.ids = memory_device_ids,
65 	.attach = acpi_memory_device_add,
66 	.detach = acpi_memory_device_remove,
67 	.hotplug = {
68 		.enabled = true,
69 	},
70 };
71 
72 struct acpi_memory_info {
73 	struct list_head list;
74 	u64 start_addr;		/* Memory Range start physical addr */
75 	u64 length;		/* Memory Range length */
76 	unsigned short caching;	/* memory cache attribute */
77 	unsigned short write_protect;	/* memory read/write attribute */
78 	unsigned int enabled:1;
79 };
80 
81 struct acpi_memory_device {
82 	struct acpi_device * device;
83 	unsigned int state;	/* State of the memory device */
84 	struct list_head res_list;
85 };
86 
87 static acpi_status
88 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
89 {
90 	struct acpi_memory_device *mem_device = context;
91 	struct acpi_resource_address64 address64;
92 	struct acpi_memory_info *info, *new;
93 	acpi_status status;
94 
95 	status = acpi_resource_to_address64(resource, &address64);
96 	if (ACPI_FAILURE(status) ||
97 	    (address64.resource_type != ACPI_MEMORY_RANGE))
98 		return AE_OK;
99 
100 	list_for_each_entry(info, &mem_device->res_list, list) {
101 		/* Can we combine the resource range information? */
102 		if ((info->caching == address64.info.mem.caching) &&
103 		    (info->write_protect == address64.info.mem.write_protect) &&
104 		    (info->start_addr + info->length == address64.address.minimum)) {
105 			info->length += address64.address.address_length;
106 			return AE_OK;
107 		}
108 	}
109 
110 	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
111 	if (!new)
112 		return AE_ERROR;
113 
114 	INIT_LIST_HEAD(&new->list);
115 	new->caching = address64.info.mem.caching;
116 	new->write_protect = address64.info.mem.write_protect;
117 	new->start_addr = address64.address.minimum;
118 	new->length = address64.address.address_length;
119 	list_add_tail(&new->list, &mem_device->res_list);
120 
121 	return AE_OK;
122 }
123 
124 static void
125 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
126 {
127 	struct acpi_memory_info *info, *n;
128 
129 	list_for_each_entry_safe(info, n, &mem_device->res_list, list)
130 		kfree(info);
131 	INIT_LIST_HEAD(&mem_device->res_list);
132 }
133 
134 static int
135 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
136 {
137 	acpi_status status;
138 
139 	if (!list_empty(&mem_device->res_list))
140 		return 0;
141 
142 	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
143 				     acpi_memory_get_resource, mem_device);
144 	if (ACPI_FAILURE(status)) {
145 		acpi_memory_free_device_resources(mem_device);
146 		return -EINVAL;
147 	}
148 
149 	return 0;
150 }
151 
152 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
153 {
154 	unsigned long long current_status;
155 
156 	/* Get device present/absent information from the _STA */
157 	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
158 					       METHOD_NAME__STA, NULL,
159 					       &current_status)))
160 		return -ENODEV;
161 	/*
162 	 * Check for device status. Device should be
163 	 * present/enabled/functioning.
164 	 */
165 	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
166 	      && (current_status & ACPI_STA_DEVICE_ENABLED)
167 	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
168 		return -ENODEV;
169 
170 	return 0;
171 }
172 
173 static unsigned long acpi_meminfo_start_pfn(struct acpi_memory_info *info)
174 {
175 	return PFN_DOWN(info->start_addr);
176 }
177 
178 static unsigned long acpi_meminfo_end_pfn(struct acpi_memory_info *info)
179 {
180 	return PFN_UP(info->start_addr + info->length-1);
181 }
182 
183 static int acpi_bind_memblk(struct memory_block *mem, void *arg)
184 {
185 	return acpi_bind_one(&mem->dev, arg);
186 }
187 
188 static int acpi_bind_memory_blocks(struct acpi_memory_info *info,
189 				   struct acpi_device *adev)
190 {
191 	return walk_memory_range(acpi_meminfo_start_pfn(info),
192 				 acpi_meminfo_end_pfn(info), adev,
193 				 acpi_bind_memblk);
194 }
195 
196 static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
197 {
198 	acpi_unbind_one(&mem->dev);
199 	return 0;
200 }
201 
202 static void acpi_unbind_memory_blocks(struct acpi_memory_info *info)
203 {
204 	walk_memory_range(acpi_meminfo_start_pfn(info),
205 			  acpi_meminfo_end_pfn(info), NULL, acpi_unbind_memblk);
206 }
207 
208 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
209 {
210 	acpi_handle handle = mem_device->device->handle;
211 	int result, num_enabled = 0;
212 	struct acpi_memory_info *info;
213 	int node;
214 
215 	node = acpi_get_node(handle);
216 	/*
217 	 * Tell the VM there is more memory here...
218 	 * Note: Assume that this function returns zero on success
219 	 * We don't have memory-hot-add rollback function,now.
220 	 * (i.e. memory-hot-remove function)
221 	 */
222 	list_for_each_entry(info, &mem_device->res_list, list) {
223 		if (info->enabled) { /* just sanity check...*/
224 			num_enabled++;
225 			continue;
226 		}
227 		/*
228 		 * If the memory block size is zero, please ignore it.
229 		 * Don't try to do the following memory hotplug flowchart.
230 		 */
231 		if (!info->length)
232 			continue;
233 		if (node < 0)
234 			node = memory_add_physaddr_to_nid(info->start_addr);
235 
236 		result = add_memory(node, info->start_addr, info->length);
237 
238 		/*
239 		 * If the memory block has been used by the kernel, add_memory()
240 		 * returns -EEXIST. If add_memory() returns the other error, it
241 		 * means that this memory block is not used by the kernel.
242 		 */
243 		if (result && result != -EEXIST)
244 			continue;
245 
246 		result = acpi_bind_memory_blocks(info, mem_device->device);
247 		if (result) {
248 			acpi_unbind_memory_blocks(info);
249 			return -ENODEV;
250 		}
251 
252 		info->enabled = 1;
253 
254 		/*
255 		 * Add num_enable even if add_memory() returns -EEXIST, so the
256 		 * device is bound to this driver.
257 		 */
258 		num_enabled++;
259 	}
260 	if (!num_enabled) {
261 		dev_err(&mem_device->device->dev, "add_memory failed\n");
262 		mem_device->state = MEMORY_INVALID_STATE;
263 		return -EINVAL;
264 	}
265 	/*
266 	 * Sometimes the memory device will contain several memory blocks.
267 	 * When one memory block is hot-added to the system memory, it will
268 	 * be regarded as a success.
269 	 * Otherwise if the last memory block can't be hot-added to the system
270 	 * memory, it will be failure and the memory device can't be bound with
271 	 * driver.
272 	 */
273 	return 0;
274 }
275 
276 static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
277 {
278 	acpi_handle handle = mem_device->device->handle;
279 	struct acpi_memory_info *info, *n;
280 	int nid = acpi_get_node(handle);
281 
282 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
283 		if (!info->enabled)
284 			continue;
285 
286 		if (nid == NUMA_NO_NODE)
287 			nid = memory_add_physaddr_to_nid(info->start_addr);
288 
289 		acpi_unbind_memory_blocks(info);
290 		remove_memory(nid, info->start_addr, info->length);
291 		list_del(&info->list);
292 		kfree(info);
293 	}
294 }
295 
296 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
297 {
298 	if (!mem_device)
299 		return;
300 
301 	acpi_memory_free_device_resources(mem_device);
302 	mem_device->device->driver_data = NULL;
303 	kfree(mem_device);
304 }
305 
306 static int acpi_memory_device_add(struct acpi_device *device,
307 				  const struct acpi_device_id *not_used)
308 {
309 	struct acpi_memory_device *mem_device;
310 	int result;
311 
312 	if (!device)
313 		return -EINVAL;
314 
315 	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
316 	if (!mem_device)
317 		return -ENOMEM;
318 
319 	INIT_LIST_HEAD(&mem_device->res_list);
320 	mem_device->device = device;
321 	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
322 	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
323 	device->driver_data = mem_device;
324 
325 	/* Get the range from the _CRS */
326 	result = acpi_memory_get_device_resources(mem_device);
327 	if (result) {
328 		device->driver_data = NULL;
329 		kfree(mem_device);
330 		return result;
331 	}
332 
333 	/* Set the device state */
334 	mem_device->state = MEMORY_POWER_ON_STATE;
335 
336 	result = acpi_memory_check_device(mem_device);
337 	if (result) {
338 		acpi_memory_device_free(mem_device);
339 		return 0;
340 	}
341 
342 	result = acpi_memory_enable_device(mem_device);
343 	if (result) {
344 		dev_err(&device->dev, "acpi_memory_enable_device() error\n");
345 		acpi_memory_device_free(mem_device);
346 		return result;
347 	}
348 
349 	dev_dbg(&device->dev, "Memory device configured by ACPI\n");
350 	return 1;
351 }
352 
353 static void acpi_memory_device_remove(struct acpi_device *device)
354 {
355 	struct acpi_memory_device *mem_device;
356 
357 	if (!device || !acpi_driver_data(device))
358 		return;
359 
360 	mem_device = acpi_driver_data(device);
361 	acpi_memory_remove_memory(mem_device);
362 	acpi_memory_device_free(mem_device);
363 }
364 
365 static bool __initdata acpi_no_memhotplug;
366 
367 void __init acpi_memory_hotplug_init(void)
368 {
369 	if (acpi_no_memhotplug) {
370 		memory_device_handler.attach = NULL;
371 		acpi_scan_add_handler(&memory_device_handler);
372 		return;
373 	}
374 	acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
375 }
376 
377 static int __init disable_acpi_memory_hotplug(char *str)
378 {
379 	acpi_no_memhotplug = true;
380 	return 1;
381 }
382 __setup("acpi_no_memhotplug", disable_acpi_memory_hotplug);
383 
384 #else
385 
386 static struct acpi_scan_handler memory_device_handler = {
387 	.ids = memory_device_ids,
388 };
389 
390 void __init acpi_memory_hotplug_init(void)
391 {
392 	acpi_scan_add_handler(&memory_device_handler);
393 }
394 
395 #endif /* CONFIG_ACPI_HOTPLUG_MEMORY */
396