/* * linux/kernel/power/hibernate_nvs.c - Routines for handling NVS memory * * Copyright (C) 2008,2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc. * * This file is released under the GPLv2. */ #include <linux/io.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/mm.h> #include <linux/suspend.h> /* * Platforms, like ACPI, may want us to save some memory used by them during * hibernation and to restore the contents of this memory during the subsequent * resume. The code below implements a mechanism allowing us to do that. */ struct nvs_page { unsigned long phys_start; unsigned int size; void *kaddr; void *data; struct list_head node; }; static LIST_HEAD(nvs_list); /** * hibernate_nvs_register - register platform NVS memory region to save * @start - physical address of the region * @size - size of the region * * The NVS region need not be page-aligned (both ends) and we arrange * things so that the data from page-aligned addresses in this region will * be copied into separate RAM pages. */ int hibernate_nvs_register(unsigned long start, unsigned long size) { struct nvs_page *entry, *next; while (size > 0) { unsigned int nr_bytes; entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL); if (!entry) goto Error; list_add_tail(&entry->node, &nvs_list); entry->phys_start = start; nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK); entry->size = (size < nr_bytes) ? size : nr_bytes; start += entry->size; size -= entry->size; } return 0; Error: list_for_each_entry_safe(entry, next, &nvs_list, node) { list_del(&entry->node); kfree(entry); } return -ENOMEM; } /** * hibernate_nvs_free - free data pages allocated for saving NVS regions */ void hibernate_nvs_free(void) { struct nvs_page *entry; list_for_each_entry(entry, &nvs_list, node) if (entry->data) { free_page((unsigned long)entry->data); entry->data = NULL; if (entry->kaddr) { iounmap(entry->kaddr); entry->kaddr = NULL; } } } /** * hibernate_nvs_alloc - allocate memory necessary for saving NVS regions */ int hibernate_nvs_alloc(void) { struct nvs_page *entry; list_for_each_entry(entry, &nvs_list, node) { entry->data = (void *)__get_free_page(GFP_KERNEL); if (!entry->data) { hibernate_nvs_free(); return -ENOMEM; } } return 0; } /** * hibernate_nvs_save - save NVS memory regions */ void hibernate_nvs_save(void) { struct nvs_page *entry; printk(KERN_INFO "PM: Saving platform NVS memory\n"); list_for_each_entry(entry, &nvs_list, node) if (entry->data) { entry->kaddr = ioremap(entry->phys_start, entry->size); memcpy(entry->data, entry->kaddr, entry->size); } } /** * hibernate_nvs_restore - restore NVS memory regions * * This function is going to be called with interrupts disabled, so it * cannot iounmap the virtual addresses used to access the NVS region. */ void hibernate_nvs_restore(void) { struct nvs_page *entry; printk(KERN_INFO "PM: Restoring platform NVS memory\n"); list_for_each_entry(entry, &nvs_list, node) if (entry->data) memcpy(entry->kaddr, entry->data, entry->size); }