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