blob: 9d6b55587eaa59a25c38776e43aeff51ba682c40 [file] [log] [blame]
* Copyright(c) 2015 Intel Corporation. All rights reserved.
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* General Public License for more details.
#include <linux/device.h>
#include <linux/types.h>
#include <linux/io.h>
#include <linux/mm.h>
#include <linux/memory_hotplug.h>
#ifndef ioremap_cache
/* temporary while we convert existing ioremap_cache users to memremap */
__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
return ioremap(offset, size);
static void *try_ram_remap(resource_size_t offset, size_t size)
struct page *page = pfn_to_page(offset >> PAGE_SHIFT);
/* In the simple case just return the existing linear address */
if (!PageHighMem(page))
return __va(offset);
return NULL; /* fallback to ioremap_cache */
* memremap() - remap an iomem_resource as cacheable memory
* @offset: iomem resource start address
* @size: size of remap
* @flags: either MEMREMAP_WB or MEMREMAP_WT
* memremap() is "ioremap" for cases where it is known that the resource
* being mapped does not have i/o side effects and the __iomem
* annotation is not applicable.
* MEMREMAP_WB - matches the default mapping for "System RAM" on
* the architecture. This is usually a read-allocate write-back cache.
* Morever, if MEMREMAP_WB is specified and the requested remap region is RAM
* memremap() will bypass establishing a new mapping and instead return
* a pointer into the direct map.
* MEMREMAP_WT - establish a mapping whereby writes either bypass the
* cache or are written through to memory and never exist in a
* cache-dirty state with respect to program visibility. Attempts to
* map "System RAM" with this mapping type will fail.
void *memremap(resource_size_t offset, size_t size, unsigned long flags)
int is_ram = region_intersects(offset, size, "System RAM");
void *addr = NULL;
if (is_ram == REGION_MIXED) {
WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
&offset, (unsigned long) size);
return NULL;
/* Try all mapping types requested until one returns non-NULL */
if (flags & MEMREMAP_WB) {
flags &= ~MEMREMAP_WB;
* MEMREMAP_WB is special in that it can be satisifed
* from the direct map. Some archs depend on the
* capability of memremap() to autodetect cases where
* the requested range is potentially in "System RAM"
if (is_ram == REGION_INTERSECTS)
addr = try_ram_remap(offset, size);
if (!addr)
addr = ioremap_cache(offset, size);
* If we don't have a mapping yet and more request flags are
* pending then we will be attempting to establish a new virtual
* address mapping. Enforce that this mapping is not aliasing
* "System RAM"
if (!addr && is_ram == REGION_INTERSECTS && flags) {
WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
&offset, (unsigned long) size);
return NULL;
if (!addr && (flags & MEMREMAP_WT)) {
flags &= ~MEMREMAP_WT;
addr = ioremap_wt(offset, size);
return addr;
void memunmap(void *addr)
if (is_vmalloc_addr(addr))
iounmap((void __iomem *) addr);
static void devm_memremap_release(struct device *dev, void *res)
static int devm_memremap_match(struct device *dev, void *res, void *match_data)
return *(void **)res == match_data;
void *devm_memremap(struct device *dev, resource_size_t offset,
size_t size, unsigned long flags)
void **ptr, *addr;
ptr = devres_alloc(devm_memremap_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return NULL;
addr = memremap(offset, size, flags);
if (addr) {
*ptr = addr;
devres_add(dev, ptr);
} else
return addr;
void devm_memunmap(struct device *dev, void *addr)
WARN_ON(devres_destroy(dev, devm_memremap_release, devm_memremap_match,
struct page_map {
struct resource res;
static void devm_memremap_pages_release(struct device *dev, void *res)
struct page_map *page_map = res;
/* pages are dead and unused, undo the arch mapping */
arch_remove_memory(page_map->res.start, resource_size(&page_map->res));
void *devm_memremap_pages(struct device *dev, struct resource *res)
int is_ram = region_intersects(res->start, resource_size(res),
"System RAM");
struct page_map *page_map;
int error, nid;
if (is_ram == REGION_MIXED) {
WARN_ONCE(1, "%s attempted on mixed region %pr\n",
__func__, res);
return ERR_PTR(-ENXIO);
if (is_ram == REGION_INTERSECTS)
return __va(res->start);
page_map = devres_alloc(devm_memremap_pages_release,
sizeof(*page_map), GFP_KERNEL);
if (!page_map)
return ERR_PTR(-ENOMEM);
memcpy(&page_map->res, res, sizeof(*res));
nid = dev_to_node(dev);
if (nid < 0)
nid = 0;
error = arch_add_memory(nid, res->start, resource_size(res), true);
if (error) {
return ERR_PTR(error);
devres_add(dev, page_map);
return __va(res->start);