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
40ACPI_MODULE_NAME("acpi_memhotplug");
41
42static 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
54static int acpi_memory_device_add(struct acpi_device *device,
55				  const struct acpi_device_id *not_used);
56static void acpi_memory_device_remove(struct acpi_device *device);
57
58static 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
67struct 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
76struct 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
82static acpi_status
83acpi_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
119static void
120acpi_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
129static int
130acpi_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
147static 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
168static unsigned long acpi_meminfo_start_pfn(struct acpi_memory_info *info)
169{
170	return PFN_DOWN(info->start_addr);
171}
172
173static unsigned long acpi_meminfo_end_pfn(struct acpi_memory_info *info)
174{
175	return PFN_UP(info->start_addr + info->length-1);
176}
177
178static int acpi_bind_memblk(struct memory_block *mem, void *arg)
179{
180	return acpi_bind_one(&mem->dev, arg);
181}
182
183static 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
191static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
192{
193	acpi_unbind_one(&mem->dev);
194	return 0;
195}
196
197static 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
203static 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
271static 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
291static 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
301static 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
348static 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
360static bool __initdata acpi_no_memhotplug;
361
362void __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
372static 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
381static struct acpi_scan_handler memory_device_handler = {
382	.ids = memory_device_ids,
383};
384
385void __init acpi_memory_hotplug_init(void)
386{
387	acpi_scan_add_handler(&memory_device_handler);
388}
389
390#endif /* CONFIG_ACPI_HOTPLUG_MEMORY */
391