1/*
2 * nvs.c - Routines for saving and restoring ACPI NVS memory region
3 *
4 * Copyright (C) 2008-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
5 *
6 * This file is released under the GPLv2.
7 */
8
9#include <linux/io.h>
10#include <linux/kernel.h>
11#include <linux/list.h>
12#include <linux/mm.h>
13#include <linux/slab.h>
14#include <linux/acpi.h>
15
16#include "internal.h"
17
18/* ACPI NVS regions, APEI may use it */
19
20struct nvs_region {
21	__u64 phys_start;
22	__u64 size;
23	struct list_head node;
24};
25
26static LIST_HEAD(nvs_region_list);
27
28#ifdef CONFIG_ACPI_SLEEP
29static int suspend_nvs_register(unsigned long start, unsigned long size);
30#else
31static inline int suspend_nvs_register(unsigned long a, unsigned long b)
32{
33	return 0;
34}
35#endif
36
37int acpi_nvs_register(__u64 start, __u64 size)
38{
39	struct nvs_region *region;
40
41	region = kmalloc(sizeof(*region), GFP_KERNEL);
42	if (!region)
43		return -ENOMEM;
44	region->phys_start = start;
45	region->size = size;
46	list_add_tail(&region->node, &nvs_region_list);
47
48	return suspend_nvs_register(start, size);
49}
50
51int acpi_nvs_for_each_region(int (*func)(__u64 start, __u64 size, void *data),
52			     void *data)
53{
54	int rc;
55	struct nvs_region *region;
56
57	list_for_each_entry(region, &nvs_region_list, node) {
58		rc = func(region->phys_start, region->size, data);
59		if (rc)
60			return rc;
61	}
62
63	return 0;
64}
65
66
67#ifdef CONFIG_ACPI_SLEEP
68/*
69 * Platforms, like ACPI, may want us to save some memory used by them during
70 * suspend and to restore the contents of this memory during the subsequent
71 * resume.  The code below implements a mechanism allowing us to do that.
72 */
73
74struct nvs_page {
75	unsigned long phys_start;
76	unsigned int size;
77	void *kaddr;
78	void *data;
79	bool unmap;
80	struct list_head node;
81};
82
83static LIST_HEAD(nvs_list);
84
85/**
86 *	suspend_nvs_register - register platform NVS memory region to save
87 *	@start - physical address of the region
88 *	@size - size of the region
89 *
90 *	The NVS region need not be page-aligned (both ends) and we arrange
91 *	things so that the data from page-aligned addresses in this region will
92 *	be copied into separate RAM pages.
93 */
94static int suspend_nvs_register(unsigned long start, unsigned long size)
95{
96	struct nvs_page *entry, *next;
97
98	pr_info("PM: Registering ACPI NVS region [mem %#010lx-%#010lx] (%ld bytes)\n",
99		start, start + size - 1, size);
100
101	while (size > 0) {
102		unsigned int nr_bytes;
103
104		entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL);
105		if (!entry)
106			goto Error;
107
108		list_add_tail(&entry->node, &nvs_list);
109		entry->phys_start = start;
110		nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK);
111		entry->size = (size < nr_bytes) ? size : nr_bytes;
112
113		start += entry->size;
114		size -= entry->size;
115	}
116	return 0;
117
118 Error:
119	list_for_each_entry_safe(entry, next, &nvs_list, node) {
120		list_del(&entry->node);
121		kfree(entry);
122	}
123	return -ENOMEM;
124}
125
126/**
127 *	suspend_nvs_free - free data pages allocated for saving NVS regions
128 */
129void suspend_nvs_free(void)
130{
131	struct nvs_page *entry;
132
133	list_for_each_entry(entry, &nvs_list, node)
134		if (entry->data) {
135			free_page((unsigned long)entry->data);
136			entry->data = NULL;
137			if (entry->kaddr) {
138				if (entry->unmap) {
139					iounmap(entry->kaddr);
140					entry->unmap = false;
141				} else {
142					acpi_os_unmap_iomem(entry->kaddr,
143							    entry->size);
144				}
145				entry->kaddr = NULL;
146			}
147		}
148}
149
150/**
151 *	suspend_nvs_alloc - allocate memory necessary for saving NVS regions
152 */
153int suspend_nvs_alloc(void)
154{
155	struct nvs_page *entry;
156
157	list_for_each_entry(entry, &nvs_list, node) {
158		entry->data = (void *)__get_free_page(GFP_KERNEL);
159		if (!entry->data) {
160			suspend_nvs_free();
161			return -ENOMEM;
162		}
163	}
164	return 0;
165}
166
167/**
168 *	suspend_nvs_save - save NVS memory regions
169 */
170int suspend_nvs_save(void)
171{
172	struct nvs_page *entry;
173
174	printk(KERN_INFO "PM: Saving platform NVS memory\n");
175
176	list_for_each_entry(entry, &nvs_list, node)
177		if (entry->data) {
178			unsigned long phys = entry->phys_start;
179			unsigned int size = entry->size;
180
181			entry->kaddr = acpi_os_get_iomem(phys, size);
182			if (!entry->kaddr) {
183				entry->kaddr = acpi_os_ioremap(phys, size);
184				entry->unmap = !!entry->kaddr;
185			}
186			if (!entry->kaddr) {
187				suspend_nvs_free();
188				return -ENOMEM;
189			}
190			memcpy(entry->data, entry->kaddr, entry->size);
191		}
192
193	return 0;
194}
195
196/**
197 *	suspend_nvs_restore - restore NVS memory regions
198 *
199 *	This function is going to be called with interrupts disabled, so it
200 *	cannot iounmap the virtual addresses used to access the NVS region.
201 */
202void suspend_nvs_restore(void)
203{
204	struct nvs_page *entry;
205
206	printk(KERN_INFO "PM: Restoring platform NVS memory\n");
207
208	list_for_each_entry(entry, &nvs_list, node)
209		if (entry->data)
210			memcpy(entry->kaddr, entry->data, entry->size);
211}
212#endif
213