15981690dSDan Williams /* SPDX-License-Identifier: GPL-2.0 */
25981690dSDan Williams #include <linux/device.h>
35981690dSDan Williams #include <linux/types.h>
45981690dSDan Williams #include <linux/io.h>
55981690dSDan Williams #include <linux/mm.h>
6016fec91SBaoquan He #include <linux/ioremap.h>
75981690dSDan Williams
85981690dSDan Williams #ifndef arch_memremap_wb
arch_memremap_wb(resource_size_t offset,unsigned long size)95981690dSDan Williams static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
105981690dSDan Williams {
11*68af0514SArnd Bergmann #ifdef ioremap_cache
125981690dSDan Williams return (__force void *)ioremap_cache(offset, size);
13*68af0514SArnd Bergmann #else
14*68af0514SArnd Bergmann return (__force void *)ioremap(offset, size);
15*68af0514SArnd Bergmann #endif
165981690dSDan Williams }
175981690dSDan Williams #endif
185981690dSDan Williams
195981690dSDan Williams #ifndef arch_memremap_can_ram_remap
arch_memremap_can_ram_remap(resource_size_t offset,size_t size,unsigned long flags)205981690dSDan Williams static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size,
215981690dSDan Williams unsigned long flags)
225981690dSDan Williams {
235981690dSDan Williams return true;
245981690dSDan Williams }
255981690dSDan Williams #endif
265981690dSDan Williams
try_ram_remap(resource_size_t offset,size_t size,unsigned long flags)275981690dSDan Williams static void *try_ram_remap(resource_size_t offset, size_t size,
285981690dSDan Williams unsigned long flags)
295981690dSDan Williams {
305981690dSDan Williams unsigned long pfn = PHYS_PFN(offset);
315981690dSDan Williams
325981690dSDan Williams /* In the simple case just return the existing linear address */
335981690dSDan Williams if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) &&
345981690dSDan Williams arch_memremap_can_ram_remap(offset, size, flags))
355981690dSDan Williams return __va(offset);
365981690dSDan Williams
375981690dSDan Williams return NULL; /* fallback to arch_memremap_wb */
385981690dSDan Williams }
395981690dSDan Williams
405981690dSDan Williams /**
415981690dSDan Williams * memremap() - remap an iomem_resource as cacheable memory
425981690dSDan Williams * @offset: iomem resource start address
435981690dSDan Williams * @size: size of remap
445981690dSDan Williams * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,
455981690dSDan Williams * MEMREMAP_ENC, MEMREMAP_DEC
465981690dSDan Williams *
475981690dSDan Williams * memremap() is "ioremap" for cases where it is known that the resource
485981690dSDan Williams * being mapped does not have i/o side effects and the __iomem
495981690dSDan Williams * annotation is not applicable. In the case of multiple flags, the different
505981690dSDan Williams * mapping types will be attempted in the order listed below until one of
515981690dSDan Williams * them succeeds.
525981690dSDan Williams *
535981690dSDan Williams * MEMREMAP_WB - matches the default mapping for System RAM on
545981690dSDan Williams * the architecture. This is usually a read-allocate write-back cache.
55f6c6010aSWei Yang * Moreover, if MEMREMAP_WB is specified and the requested remap region is RAM
565981690dSDan Williams * memremap() will bypass establishing a new mapping and instead return
575981690dSDan Williams * a pointer into the direct map.
585981690dSDan Williams *
595981690dSDan Williams * MEMREMAP_WT - establish a mapping whereby writes either bypass the
605981690dSDan Williams * cache or are written through to memory and never exist in a
615981690dSDan Williams * cache-dirty state with respect to program visibility. Attempts to
625981690dSDan Williams * map System RAM with this mapping type will fail.
635981690dSDan Williams *
645981690dSDan Williams * MEMREMAP_WC - establish a writecombine mapping, whereby writes may
655981690dSDan Williams * be coalesced together (e.g. in the CPU's write buffers), but is otherwise
665981690dSDan Williams * uncached. Attempts to map System RAM with this mapping type will fail.
675981690dSDan Williams */
memremap(resource_size_t offset,size_t size,unsigned long flags)685981690dSDan Williams void *memremap(resource_size_t offset, size_t size, unsigned long flags)
695981690dSDan Williams {
705981690dSDan Williams int is_ram = region_intersects(offset, size,
715981690dSDan Williams IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE);
725981690dSDan Williams void *addr = NULL;
735981690dSDan Williams
745981690dSDan Williams if (!flags)
755981690dSDan Williams return NULL;
765981690dSDan Williams
775981690dSDan Williams if (is_ram == REGION_MIXED) {
785981690dSDan Williams WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n",
795981690dSDan Williams &offset, (unsigned long) size);
805981690dSDan Williams return NULL;
815981690dSDan Williams }
825981690dSDan Williams
835981690dSDan Williams /* Try all mapping types requested until one returns non-NULL */
845981690dSDan Williams if (flags & MEMREMAP_WB) {
855981690dSDan Williams /*
86f6c6010aSWei Yang * MEMREMAP_WB is special in that it can be satisfied
875981690dSDan Williams * from the direct map. Some archs depend on the
885981690dSDan Williams * capability of memremap() to autodetect cases where
895981690dSDan Williams * the requested range is potentially in System RAM.
905981690dSDan Williams */
915981690dSDan Williams if (is_ram == REGION_INTERSECTS)
925981690dSDan Williams addr = try_ram_remap(offset, size, flags);
935981690dSDan Williams if (!addr)
945981690dSDan Williams addr = arch_memremap_wb(offset, size);
955981690dSDan Williams }
965981690dSDan Williams
975981690dSDan Williams /*
985981690dSDan Williams * If we don't have a mapping yet and other request flags are
995981690dSDan Williams * present then we will be attempting to establish a new virtual
1005981690dSDan Williams * address mapping. Enforce that this mapping is not aliasing
1015981690dSDan Williams * System RAM.
1025981690dSDan Williams */
1035981690dSDan Williams if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) {
1045981690dSDan Williams WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n",
1055981690dSDan Williams &offset, (unsigned long) size);
1065981690dSDan Williams return NULL;
1075981690dSDan Williams }
1085981690dSDan Williams
1095981690dSDan Williams if (!addr && (flags & MEMREMAP_WT))
1105981690dSDan Williams addr = ioremap_wt(offset, size);
1115981690dSDan Williams
1125981690dSDan Williams if (!addr && (flags & MEMREMAP_WC))
1135981690dSDan Williams addr = ioremap_wc(offset, size);
1145981690dSDan Williams
1155981690dSDan Williams return addr;
1165981690dSDan Williams }
1175981690dSDan Williams EXPORT_SYMBOL(memremap);
1185981690dSDan Williams
memunmap(void * addr)1195981690dSDan Williams void memunmap(void *addr)
1205981690dSDan Williams {
1219bd3bb67SAneesh Kumar K.V if (is_ioremap_addr(addr))
1225981690dSDan Williams iounmap((void __iomem *) addr);
1235981690dSDan Williams }
1245981690dSDan Williams EXPORT_SYMBOL(memunmap);
1255981690dSDan Williams
devm_memremap_release(struct device * dev,void * res)1265981690dSDan Williams static void devm_memremap_release(struct device *dev, void *res)
1275981690dSDan Williams {
1285981690dSDan Williams memunmap(*(void **)res);
1295981690dSDan Williams }
1305981690dSDan Williams
devm_memremap_match(struct device * dev,void * res,void * match_data)1315981690dSDan Williams static int devm_memremap_match(struct device *dev, void *res, void *match_data)
1325981690dSDan Williams {
1335981690dSDan Williams return *(void **)res == match_data;
1345981690dSDan Williams }
1355981690dSDan Williams
devm_memremap(struct device * dev,resource_size_t offset,size_t size,unsigned long flags)1365981690dSDan Williams void *devm_memremap(struct device *dev, resource_size_t offset,
1375981690dSDan Williams size_t size, unsigned long flags)
1385981690dSDan Williams {
1395981690dSDan Williams void **ptr, *addr;
1405981690dSDan Williams
1415981690dSDan Williams ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL,
1425981690dSDan Williams dev_to_node(dev));
1435981690dSDan Williams if (!ptr)
1445981690dSDan Williams return ERR_PTR(-ENOMEM);
1455981690dSDan Williams
1465981690dSDan Williams addr = memremap(offset, size, flags);
1475981690dSDan Williams if (addr) {
1485981690dSDan Williams *ptr = addr;
1495981690dSDan Williams devres_add(dev, ptr);
1505981690dSDan Williams } else {
1515981690dSDan Williams devres_free(ptr);
1525981690dSDan Williams return ERR_PTR(-ENXIO);
1535981690dSDan Williams }
1545981690dSDan Williams
1555981690dSDan Williams return addr;
1565981690dSDan Williams }
1575981690dSDan Williams EXPORT_SYMBOL(devm_memremap);
1585981690dSDan Williams
devm_memunmap(struct device * dev,void * addr)1595981690dSDan Williams void devm_memunmap(struct device *dev, void *addr)
1605981690dSDan Williams {
1615981690dSDan Williams WARN_ON(devres_release(dev, devm_memremap_release,
1625981690dSDan Williams devm_memremap_match, addr));
1635981690dSDan Williams }
1645981690dSDan Williams EXPORT_SYMBOL(devm_memunmap);
165