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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166/* SPDX-License-Identifier: GPL-2.0 */#include <linux/device.h>#include <linux/types.h>#include <linux/io.h>#include <linux/mm.h>#include <linux/ioremap.h>
#ifndef arch_memremap_wbstatic void *arch_memremap_wb(resource_size_t offset, unsigned long size, unsigned long flags){#ifdef ioremap_cache return (__force void *)ioremap_cache(offset, size);#else return (__force void *)ioremap(offset, size);#endif}#endif
#ifndef arch_memremap_can_ram_remapstatic 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, flags); }
/* * 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);