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