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
45ACPI_MODULE_NAME("acpi_memhotplug");
46
47static 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
59static int acpi_memory_device_add(struct acpi_device *device,
60				  const struct acpi_device_id *not_used);
61static void acpi_memory_device_remove(struct acpi_device *device);
62
63static 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
72struct 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
81struct 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
87static acpi_status
88acpi_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.minimum)) {
105			info->length += address64.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.minimum;
118	new->length = address64.address_length;
119	list_add_tail(&new->list, &mem_device->res_list);
120
121	return AE_OK;
122}
123
124static void
125acpi_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
134static int
135acpi_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
152static 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
173static unsigned long acpi_meminfo_start_pfn(struct acpi_memory_info *info)
174{
175	return PFN_DOWN(info->start_addr);
176}
177
178static unsigned long acpi_meminfo_end_pfn(struct acpi_memory_info *info)
179{
180	return PFN_UP(info->start_addr + info->length-1);
181}
182
183static int acpi_bind_memblk(struct memory_block *mem, void *arg)
184{
185	return acpi_bind_one(&mem->dev, arg);
186}
187
188static 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
196static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
197{
198	acpi_unbind_one(&mem->dev);
199	return 0;
200}
201
202static 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
208static 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
276static 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
296static 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
306static 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
353static 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
365static bool __initdata acpi_no_memhotplug;
366
367void __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
377static 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
386static struct acpi_scan_handler memory_device_handler = {
387	.ids = memory_device_ids,
388};
389
390void __init acpi_memory_hotplug_init(void)
391{
392	acpi_scan_add_handler(&memory_device_handler);
393}
394
395#endif /* CONFIG_ACPI_HOTPLUG_MEMORY */
396