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/*
* 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
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/radix-tree.h>
#include <linux/memremap.h>
#include <linux/device.h>
#include <linux/types.h>
#include <linux/pfn_t.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);
}
#endif
#ifndef arch_memremap_wb
static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
{
return (__force void *)ioremap_cache(offset, size);
}
#endif
static void *try_ram_remap(resource_size_t offset, size_t size)
{
unsigned long pfn = PHYS_PFN(offset);
/* In the simple case just return the existing linear address */
if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)))
return __va(offset);
return NULL; /* fallback to arch_memremap_wb */
}
/**
* memremap() - remap an iomem_resource as cacheable memory
* @offset: iomem resource start address
* @size: size of remap
* @flags: any of MEMREMAP_WB, MEMREMAP_WT and MEMREMAP_WC
*
* 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. In the case of multiple flags, the different
* mapping types will be attempted in the order listed below until one of
* them succeeds.
*
* 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.
*
* MEMREMAP_WC - establish a writecombine mapping, whereby writes may
* be coalesced together (e.g. in the CPU's write buffers), but is otherwise
* uncached. 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,
IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
void *addr = NULL;
if (!flags)
return 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) {
/*
* 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 = arch_memremap_wb(offset, size);
}
/*
* If we don't have a mapping yet and other request flags are
* present 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 != MEMREMAP_WB) {
WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
&offset, (unsigned long) size);
return NULL;
}
if (!addr && (flags & MEMREMAP_WT))
addr = ioremap_wt(offset, size);
if (!addr && (flags & MEMREMAP_WC))
addr = ioremap_wc(offset, size);
return addr;
}
EXPORT_SYMBOL(memremap);
void memunmap(void *addr)
{
if (is_vmalloc_addr(addr))
iounmap((void __iomem *) addr);
}
EXPORT_SYMBOL(memunmap);
static void devm_memremap_release(struct device *dev, void *res)
{
memunmap(*(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_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
dev_to_node(dev));
if (!ptr)
return ERR_PTR(-ENOMEM);
addr = memremap(offset, size, flags);
if (addr) {
*ptr = addr;
devres_add(dev, ptr);
} else {
devres_free(ptr);
return ERR_PTR(-ENXIO);
}
return addr;
}
EXPORT_SYMBOL(devm_memremap);
void devm_memunmap(struct device *dev, void *addr)
{
WARN_ON(devres_release(dev, devm_memremap_release,
devm_memremap_match, addr));
}
EXPORT_SYMBOL(devm_memunmap);
#ifdef CONFIG_ZONE_DEVICE
static DEFINE_MUTEX(pgmap_lock);
static RADIX_TREE(pgmap_radix, GFP_KERNEL);
#define SECTION_MASK ~((1UL << PA_SECTION_SHIFT) - 1)
#define SECTION_SIZE (1UL << PA_SECTION_SHIFT)
struct page_map {
struct resource res;
struct percpu_ref *ref;
struct dev_pagemap pgmap;
struct vmem_altmap altmap;
};
static void pgmap_radix_release(struct resource *res)
{
resource_size_t key, align_start, align_size, align_end;
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(resource_size(res), SECTION_SIZE);
align_end = align_start + align_size - 1;
mutex_lock(&pgmap_lock);
for (key = res->start; key <= res->end; key += SECTION_SIZE)
radix_tree_delete(&pgmap_radix, key >> PA_SECTION_SHIFT);
mutex_unlock(&pgmap_lock);
}
static unsigned long pfn_first(struct page_map *page_map)
{
struct dev_pagemap *pgmap = &page_map->pgmap;
const struct resource *res = &page_map->res;
struct vmem_altmap *altmap = pgmap->altmap;
unsigned long pfn;
pfn = res->start >> PAGE_SHIFT;
if (altmap)
pfn += vmem_altmap_offset(altmap);
return pfn;
}
static unsigned long pfn_end(struct page_map *page_map)
{
const struct resource *res = &page_map->res;
return (res->start + resource_size(res)) >> PAGE_SHIFT;
}
#define for_each_device_pfn(pfn, map) \
for (pfn = pfn_first(map); pfn < pfn_end(map); pfn++)
static void devm_memremap_pages_release(struct device *dev, void *data)
{
struct page_map *page_map = data;
struct resource *res = &page_map->res;
resource_size_t align_start, align_size;
struct dev_pagemap *pgmap = &page_map->pgmap;
unsigned long pfn;
for_each_device_pfn(pfn, page_map)
put_page(pfn_to_page(pfn));
if (percpu_ref_tryget_live(pgmap->ref)) {
dev_WARN(dev, "%s: page mapping is still live!\n", __func__);
percpu_ref_put(pgmap->ref);
}
/* pages are dead and unused, undo the arch mapping */
align_start = res->start & ~(SECTION_SIZE - 1);
align_size = ALIGN(resource_size(res), SECTION_SIZE);
mem_hotplug_begin();
arch_remove_memory(align_start, align_size);
mem_hotplug_done();
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
pgmap_radix_release(res);
dev_WARN_ONCE(dev, pgmap->altmap && pgmap->altmap->alloc,
"%s: failed to free all reserved pages\n", __func__);
}
/* assumes rcu_read_lock() held at entry */
struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
{
struct page_map *page_map;
WARN_ON_ONCE(!rcu_read_lock_held());
page_map = radix_tree_lookup(&pgmap_radix, phys >> PA_SECTION_SHIFT);
return page_map ? &page_map->pgmap : NULL;
}
/**
* devm_memremap_pages - remap and provide memmap backing for the given resource
* @dev: hosting device for @res
* @res: "host memory" address range
* @ref: a live per-cpu reference count
* @altmap: optional descriptor for allocating the memmap from @res
*
* Notes:
* 1/ @ref must be 'live' on entry and 'dead' before devm_memunmap_pages() time
* (or devm release event). The expected order of events is that @ref has
* been through percpu_ref_kill() before devm_memremap_pages_release(). The
* wait for the completion of all references being dropped and
* percpu_ref_exit() must occur after devm_memremap_pages_release().
*
* 2/ @res is expected to be a host memory range that could feasibly be
* treated as a "System RAM" range, i.e. not a device mmio range, but
* this is not enforced.
*/
void *devm_memremap_pages(struct device *dev
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