linux/drivers/acpi/nvs.c
Rafael J. Wysocki 64f9111dd6 Merge branches 'acpi-ec', 'acpi-apei', 'acpi-soc' and 'acpi-misc'
* acpi-ec:
  ACPI: EC: trust DSDT GPE for certain HP laptop
  ACPI: EC: Make more Asus laptops use ECDT _GPE

* acpi-apei:
  ACPI: APEI: fix synchronous external aborts in user-mode
  ACPI: APEI: Don't warn if ACPI is disabled

* acpi-soc:
  ACPI: LPSS: Use kstrtol() instead of simple_strtol()

* acpi-misc:
  ACPI: NVS: fix doc warnings in nvs.c
  ACPI: NUMA: fix typo in a comment
  ACPI: OSL: Use DEFINE_RES_IO_NAMED() to simplify code
  ACPI: bus: Call kobject_put() in acpi_init() error path
  ACPI: bus: Remove unneeded assignment
  ACPI: configfs: Replace ACPI_INFO() with pr_debug()
  ACPI: ipmi: Remove address space handler in error path
  ACPI: event: Remove redundant initialization of local variable
  ACPI: sbshc: Fix fall-through warning for Clang
2021-06-29 15:51:25 +02:00

214 lines
4.6 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* nvs.c - Routines for saving and restoring ACPI NVS memory region
*
* Copyright (C) 2008-2011 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
*/
#define pr_fmt(fmt) "ACPI: PM: " fmt
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include "internal.h"
/* ACPI NVS regions, APEI may use it */
struct nvs_region {
__u64 phys_start;
__u64 size;
struct list_head node;
};
static LIST_HEAD(nvs_region_list);
#ifdef CONFIG_ACPI_SLEEP
static int suspend_nvs_register(unsigned long start, unsigned long size);
#else
static inline int suspend_nvs_register(unsigned long a, unsigned long b)
{
return 0;
}
#endif
int acpi_nvs_register(__u64 start, __u64 size)
{
struct nvs_region *region;
region = kmalloc(sizeof(*region), GFP_KERNEL);
if (!region)
return -ENOMEM;
region->phys_start = start;
region->size = size;
list_add_tail(&region->node, &nvs_region_list);
return suspend_nvs_register(start, size);
}
int acpi_nvs_for_each_region(int (*func)(__u64 start, __u64 size, void *data),
void *data)
{
int rc;
struct nvs_region *region;
list_for_each_entry(region, &nvs_region_list, node) {
rc = func(region->phys_start, region->size, data);
if (rc)
return rc;
}
return 0;
}
#ifdef CONFIG_ACPI_SLEEP
/*
* Platforms, like ACPI, may want us to save some memory used by them during
* suspend 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;
bool unmap;
struct list_head node;
};
static LIST_HEAD(nvs_list);
/**
* suspend_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.
*/
static int suspend_nvs_register(unsigned long start, unsigned long size)
{
struct nvs_page *entry, *next;
pr_info("Registering ACPI NVS region [mem %#010lx-%#010lx] (%ld bytes)\n",
start, start + size - 1, size);
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;
}
/**
* suspend_nvs_free - free data pages allocated for saving NVS regions
*/
void suspend_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) {
if (entry->unmap) {
iounmap(entry->kaddr);
entry->unmap = false;
} else {
acpi_os_unmap_iomem(entry->kaddr,
entry->size);
}
entry->kaddr = NULL;
}
}
}
/**
* suspend_nvs_alloc - allocate memory necessary for saving NVS regions
*/
int suspend_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) {
suspend_nvs_free();
return -ENOMEM;
}
}
return 0;
}
/**
* suspend_nvs_save - save NVS memory regions
*/
int suspend_nvs_save(void)
{
struct nvs_page *entry;
pr_info("Saving platform NVS memory\n");
list_for_each_entry(entry, &nvs_list, node)
if (entry->data) {
unsigned long phys = entry->phys_start;
unsigned int size = entry->size;
entry->kaddr = acpi_os_get_iomem(phys, size);
if (!entry->kaddr) {
entry->kaddr = acpi_os_ioremap(phys, size);
entry->unmap = !!entry->kaddr;
}
if (!entry->kaddr) {
suspend_nvs_free();
return -ENOMEM;
}
memcpy(entry->data, entry->kaddr, entry->size);
}
return 0;
}
/**
* suspend_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 suspend_nvs_restore(void)
{
struct nvs_page *entry;
pr_info("Restoring platform NVS memory\n");
list_for_each_entry(entry, &nvs_list, node)
if (entry->data)
memcpy(entry->kaddr, entry->data, entry->size);
}
#endif