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- /* SPDX-License-Identifier: GPL-2.0 */
- #include <linux/device.h>
- #include <linux/types.h>
- #include <linux/io.h>
- #include <linux/mm.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
- #ifndef arch_memremap_can_ram_remap
- static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
- unsigned long flags)
- {
- return true;
- }
- #endif
- static void *try_ram_remap(resource_size_t offset, size_t size,
- unsigned long flags)
- {
- 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)) &&
- arch_memremap_can_ram_remap(offset, size, flags))
- 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, MEMREMAP_WC,
- * MEMREMAP_ENC, MEMREMAP_DEC
- *
- * 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.
- * Moreover, 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 satisfied
- * 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, flags);
- 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_ioremap_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);
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