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  * ACPI based HotPlug driver that supports Memory Hotplug
20  * This driver fields notifications from firmware for memory add
21  * and remove operations and alerts the VM of the affected memory
22  * ranges.
23  */
24 
25 #include <linux/acpi.h>
26 #include <linux/memory.h>
27 #include <linux/memory_hotplug.h>
28 
29 #include "internal.h"
30 
31 #define ACPI_MEMORY_DEVICE_CLASS		"memory"
32 #define ACPI_MEMORY_DEVICE_HID			"PNP0C80"
33 #define ACPI_MEMORY_DEVICE_NAME			"Hotplug Mem Device"
34 
35 #define _COMPONENT		ACPI_MEMORY_DEVICE_COMPONENT
36 
37 #undef PREFIX
38 #define 	PREFIX		"ACPI:memory_hp:"
39 
40 ACPI_MODULE_NAME("acpi_memhotplug");
41 
42 static const struct acpi_device_id memory_device_ids[] = {
43 	{ACPI_MEMORY_DEVICE_HID, 0},
44 	{"", 0},
45 };
46 
47 #ifdef CONFIG_ACPI_HOTPLUG_MEMORY
48 
49 /* Memory Device States */
50 #define MEMORY_INVALID_STATE	0
51 #define MEMORY_POWER_ON_STATE	1
52 #define MEMORY_POWER_OFF_STATE	2
53 
54 static int acpi_memory_device_add(struct acpi_device *device,
55 				  const struct acpi_device_id *not_used);
56 static void acpi_memory_device_remove(struct acpi_device *device);
57 
58 static struct acpi_scan_handler memory_device_handler = {
59 	.ids = memory_device_ids,
60 	.attach = acpi_memory_device_add,
61 	.detach = acpi_memory_device_remove,
62 	.hotplug = {
63 		.enabled = true,
64 	},
65 };
66 
67 struct acpi_memory_info {
68 	struct list_head list;
69 	u64 start_addr;		/* Memory Range start physical addr */
70 	u64 length;		/* Memory Range length */
71 	unsigned short caching;	/* memory cache attribute */
72 	unsigned short write_protect;	/* memory read/write attribute */
73 	unsigned int enabled:1;
74 };
75 
76 struct acpi_memory_device {
77 	struct acpi_device * device;
78 	unsigned int state;	/* State of the memory device */
79 	struct list_head res_list;
80 };
81 
82 static acpi_status
83 acpi_memory_get_resource(struct acpi_resource *resource, void *context)
84 {
85 	struct acpi_memory_device *mem_device = context;
86 	struct acpi_resource_address64 address64;
87 	struct acpi_memory_info *info, *new;
88 	acpi_status status;
89 
90 	status = acpi_resource_to_address64(resource, &address64);
91 	if (ACPI_FAILURE(status) ||
92 	    (address64.resource_type != ACPI_MEMORY_RANGE))
93 		return AE_OK;
94 
95 	list_for_each_entry(info, &mem_device->res_list, list) {
96 		/* Can we combine the resource range information? */
97 		if ((info->caching == address64.info.mem.caching) &&
98 		    (info->write_protect == address64.info.mem.write_protect) &&
99 		    (info->start_addr + info->length == address64.address.minimum)) {
100 			info->length += address64.address.address_length;
101 			return AE_OK;
102 		}
103 	}
104 
105 	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
106 	if (!new)
107 		return AE_ERROR;
108 
109 	INIT_LIST_HEAD(&new->list);
110 	new->caching = address64.info.mem.caching;
111 	new->write_protect = address64.info.mem.write_protect;
112 	new->start_addr = address64.address.minimum;
113 	new->length = address64.address.address_length;
114 	list_add_tail(&new->list, &mem_device->res_list);
115 
116 	return AE_OK;
117 }
118 
119 static void
120 acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
121 {
122 	struct acpi_memory_info *info, *n;
123 
124 	list_for_each_entry_safe(info, n, &mem_device->res_list, list)
125 		kfree(info);
126 	INIT_LIST_HEAD(&mem_device->res_list);
127 }
128 
129 static int
130 acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
131 {
132 	acpi_status status;
133 
134 	if (!list_empty(&mem_device->res_list))
135 		return 0;
136 
137 	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
138 				     acpi_memory_get_resource, mem_device);
139 	if (ACPI_FAILURE(status)) {
140 		acpi_memory_free_device_resources(mem_device);
141 		return -EINVAL;
142 	}
143 
144 	return 0;
145 }
146 
147 static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
148 {
149 	unsigned long long current_status;
150 
151 	/* Get device present/absent information from the _STA */
152 	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
153 					       METHOD_NAME__STA, NULL,
154 					       &current_status)))
155 		return -ENODEV;
156 	/*
157 	 * Check for device status. Device should be
158 	 * present/enabled/functioning.
159 	 */
160 	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
161 	      && (current_status & ACPI_STA_DEVICE_ENABLED)
162 	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
163 		return -ENODEV;
164 
165 	return 0;
166 }
167 
168 static unsigned long acpi_meminfo_start_pfn(struct acpi_memory_info *info)
169 {
170 	return PFN_DOWN(info->start_addr);
171 }
172 
173 static unsigned long acpi_meminfo_end_pfn(struct acpi_memory_info *info)
174 {
175 	return PFN_UP(info->start_addr + info->length-1);
176 }
177 
178 static int acpi_bind_memblk(struct memory_block *mem, void *arg)
179 {
180 	return acpi_bind_one(&mem->dev, arg);
181 }
182 
183 static int acpi_bind_memory_blocks(struct acpi_memory_info *info,
184 				   struct acpi_device *adev)
185 {
186 	return walk_memory_range(acpi_meminfo_start_pfn(info),
187 				 acpi_meminfo_end_pfn(info), adev,
188 				 acpi_bind_memblk);
189 }
190 
191 static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
192 {
193 	acpi_unbind_one(&mem->dev);
194 	return 0;
195 }
196 
197 static void acpi_unbind_memory_blocks(struct acpi_memory_info *info)
198 {
199 	walk_memory_range(acpi_meminfo_start_pfn(info),
200 			  acpi_meminfo_end_pfn(info), NULL, acpi_unbind_memblk);
201 }
202 
203 static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
204 {
205 	acpi_handle handle = mem_device->device->handle;
206 	int result, num_enabled = 0;
207 	struct acpi_memory_info *info;
208 	int node;
209 
210 	node = acpi_get_node(handle);
211 	/*
212 	 * Tell the VM there is more memory here...
213 	 * Note: Assume that this function returns zero on success
214 	 * We don't have memory-hot-add rollback function,now.
215 	 * (i.e. memory-hot-remove function)
216 	 */
217 	list_for_each_entry(info, &mem_device->res_list, list) {
218 		if (info->enabled) { /* just sanity check...*/
219 			num_enabled++;
220 			continue;
221 		}
222 		/*
223 		 * If the memory block size is zero, please ignore it.
224 		 * Don't try to do the following memory hotplug flowchart.
225 		 */
226 		if (!info->length)
227 			continue;
228 		if (node < 0)
229 			node = memory_add_physaddr_to_nid(info->start_addr);
230 
231 		result = __add_memory(node, info->start_addr, info->length);
232 
233 		/*
234 		 * If the memory block has been used by the kernel, add_memory()
235 		 * returns -EEXIST. If add_memory() returns the other error, it
236 		 * means that this memory block is not used by the kernel.
237 		 */
238 		if (result && result != -EEXIST)
239 			continue;
240 
241 		result = acpi_bind_memory_blocks(info, mem_device->device);
242 		if (result) {
243 			acpi_unbind_memory_blocks(info);
244 			return -ENODEV;
245 		}
246 
247 		info->enabled = 1;
248 
249 		/*
250 		 * Add num_enable even if add_memory() returns -EEXIST, so the
251 		 * device is bound to this driver.
252 		 */
253 		num_enabled++;
254 	}
255 	if (!num_enabled) {
256 		dev_err(&mem_device->device->dev, "add_memory failed\n");
257 		mem_device->state = MEMORY_INVALID_STATE;
258 		return -EINVAL;
259 	}
260 	/*
261 	 * Sometimes the memory device will contain several memory blocks.
262 	 * When one memory block is hot-added to the system memory, it will
263 	 * be regarded as a success.
264 	 * Otherwise if the last memory block can't be hot-added to the system
265 	 * memory, it will be failure and the memory device can't be bound with
266 	 * driver.
267 	 */
268 	return 0;
269 }
270 
271 static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
272 {
273 	acpi_handle handle = mem_device->device->handle;
274 	struct acpi_memory_info *info, *n;
275 	int nid = acpi_get_node(handle);
276 
277 	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
278 		if (!info->enabled)
279 			continue;
280 
281 		if (nid == NUMA_NO_NODE)
282 			nid = memory_add_physaddr_to_nid(info->start_addr);
283 
284 		acpi_unbind_memory_blocks(info);
285 		__remove_memory(nid, info->start_addr, info->length);
286 		list_del(&info->list);
287 		kfree(info);
288 	}
289 }
290 
291 static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
292 {
293 	if (!mem_device)
294 		return;
295 
296 	acpi_memory_free_device_resources(mem_device);
297 	mem_device->device->driver_data = NULL;
298 	kfree(mem_device);
299 }
300 
301 static int acpi_memory_device_add(struct acpi_device *device,
302 				  const struct acpi_device_id *not_used)
303 {
304 	struct acpi_memory_device *mem_device;
305 	int result;
306 
307 	if (!device)
308 		return -EINVAL;
309 
310 	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
311 	if (!mem_device)
312 		return -ENOMEM;
313 
314 	INIT_LIST_HEAD(&mem_device->res_list);
315 	mem_device->device = device;
316 	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
317 	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
318 	device->driver_data = mem_device;
319 
320 	/* Get the range from the _CRS */
321 	result = acpi_memory_get_device_resources(mem_device);
322 	if (result) {
323 		device->driver_data = NULL;
324 		kfree(mem_device);
325 		return result;
326 	}
327 
328 	/* Set the device state */
329 	mem_device->state = MEMORY_POWER_ON_STATE;
330 
331 	result = acpi_memory_check_device(mem_device);
332 	if (result) {
333 		acpi_memory_device_free(mem_device);
334 		return 0;
335 	}
336 
337 	result = acpi_memory_enable_device(mem_device);
338 	if (result) {
339 		dev_err(&device->dev, "acpi_memory_enable_device() error\n");
340 		acpi_memory_device_free(mem_device);
341 		return result;
342 	}
343 
344 	dev_dbg(&device->dev, "Memory device configured by ACPI\n");
345 	return 1;
346 }
347 
348 static void acpi_memory_device_remove(struct acpi_device *device)
349 {
350 	struct acpi_memory_device *mem_device;
351 
352 	if (!device || !acpi_driver_data(device))
353 		return;
354 
355 	mem_device = acpi_driver_data(device);
356 	acpi_memory_remove_memory(mem_device);
357 	acpi_memory_device_free(mem_device);
358 }
359 
360 static bool __initdata acpi_no_memhotplug;
361 
362 void __init acpi_memory_hotplug_init(void)
363 {
364 	if (acpi_no_memhotplug) {
365 		memory_device_handler.attach = NULL;
366 		acpi_scan_add_handler(&memory_device_handler);
367 		return;
368 	}
369 	acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
370 }
371 
372 static int __init disable_acpi_memory_hotplug(char *str)
373 {
374 	acpi_no_memhotplug = true;
375 	return 1;
376 }
377 __setup("acpi_no_memhotplug", disable_acpi_memory_hotplug);
378 
379 #else
380 
381 static struct acpi_scan_handler memory_device_handler = {
382 	.ids = memory_device_ids,
383 };
384 
385 void __init acpi_memory_hotplug_init(void)
386 {
387 	acpi_scan_add_handler(&memory_device_handler);
388 }
389 
390 #endif /* CONFIG_ACPI_HOTPLUG_MEMORY */
391