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167 lines
4.7 KiB
167 lines
4.7 KiB
/* SPDX-License-Identifier: GPL-2.0 */ |
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#include <linux/device.h> |
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#include <linux/types.h> |
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#include <linux/io.h> |
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#include <linux/mm.h> |
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#ifndef ioremap_cache |
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/* temporary while we convert existing ioremap_cache users to memremap */ |
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__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size) |
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{ |
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return ioremap(offset, size); |
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} |
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#endif |
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#ifndef arch_memremap_wb |
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static void *arch_memremap_wb(resource_size_t offset, unsigned long size) |
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{ |
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return (__force void *)ioremap_cache(offset, size); |
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} |
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#endif |
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#ifndef arch_memremap_can_ram_remap |
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static bool arch_memremap_can_ram_remap(resource_size_t offset, size_t size, |
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unsigned long flags) |
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{ |
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return true; |
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} |
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#endif |
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static void *try_ram_remap(resource_size_t offset, size_t size, |
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unsigned long flags) |
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{ |
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unsigned long pfn = PHYS_PFN(offset); |
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/* In the simple case just return the existing linear address */ |
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if (pfn_valid(pfn) && !PageHighMem(pfn_to_page(pfn)) && |
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arch_memremap_can_ram_remap(offset, size, flags)) |
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return __va(offset); |
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return NULL; /* fallback to arch_memremap_wb */ |
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} |
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/** |
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* memremap() - remap an iomem_resource as cacheable memory |
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* @offset: iomem resource start address |
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* @size: size of remap |
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* @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC, |
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* MEMREMAP_ENC, MEMREMAP_DEC |
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* |
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* memremap() is "ioremap" for cases where it is known that the resource |
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* being mapped does not have i/o side effects and the __iomem |
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* annotation is not applicable. In the case of multiple flags, the different |
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* mapping types will be attempted in the order listed below until one of |
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* them succeeds. |
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* |
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* MEMREMAP_WB - matches the default mapping for System RAM on |
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* the architecture. This is usually a read-allocate write-back cache. |
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* Moreover, if MEMREMAP_WB is specified and the requested remap region is RAM |
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* memremap() will bypass establishing a new mapping and instead return |
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* a pointer into the direct map. |
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* |
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* MEMREMAP_WT - establish a mapping whereby writes either bypass the |
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* cache or are written through to memory and never exist in a |
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* cache-dirty state with respect to program visibility. Attempts to |
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* map System RAM with this mapping type will fail. |
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* |
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* MEMREMAP_WC - establish a writecombine mapping, whereby writes may |
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* be coalesced together (e.g. in the CPU's write buffers), but is otherwise |
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* uncached. Attempts to map System RAM with this mapping type will fail. |
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*/ |
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void *memremap(resource_size_t offset, size_t size, unsigned long flags) |
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{ |
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int is_ram = region_intersects(offset, size, |
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IORESOURCE_SYSTEM_RAM, IORES_DESC_NONE); |
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void *addr = NULL; |
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if (!flags) |
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return NULL; |
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if (is_ram == REGION_MIXED) { |
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WARN_ONCE(1, "memremap attempted on mixed range %pa size: %#lx\n", |
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&offset, (unsigned long) size); |
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return NULL; |
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} |
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/* Try all mapping types requested until one returns non-NULL */ |
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if (flags & MEMREMAP_WB) { |
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/* |
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* MEMREMAP_WB is special in that it can be satisfied |
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* from the direct map. Some archs depend on the |
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* capability of memremap() to autodetect cases where |
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* the requested range is potentially in System RAM. |
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*/ |
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if (is_ram == REGION_INTERSECTS) |
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addr = try_ram_remap(offset, size, flags); |
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if (!addr) |
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addr = arch_memremap_wb(offset, size); |
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} |
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/* |
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* If we don't have a mapping yet and other request flags are |
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* present then we will be attempting to establish a new virtual |
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* address mapping. Enforce that this mapping is not aliasing |
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* System RAM. |
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*/ |
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if (!addr && is_ram == REGION_INTERSECTS && flags != MEMREMAP_WB) { |
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WARN_ONCE(1, "memremap attempted on ram %pa size: %#lx\n", |
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&offset, (unsigned long) size); |
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return NULL; |
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} |
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if (!addr && (flags & MEMREMAP_WT)) |
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addr = ioremap_wt(offset, size); |
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if (!addr && (flags & MEMREMAP_WC)) |
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addr = ioremap_wc(offset, size); |
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return addr; |
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} |
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EXPORT_SYMBOL(memremap); |
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void memunmap(void *addr) |
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{ |
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if (is_ioremap_addr(addr)) |
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iounmap((void __iomem *) addr); |
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} |
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EXPORT_SYMBOL(memunmap); |
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static void devm_memremap_release(struct device *dev, void *res) |
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{ |
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memunmap(*(void **)res); |
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} |
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static int devm_memremap_match(struct device *dev, void *res, void *match_data) |
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{ |
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return *(void **)res == match_data; |
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} |
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void *devm_memremap(struct device *dev, resource_size_t offset, |
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size_t size, unsigned long flags) |
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{ |
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void **ptr, *addr; |
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ptr = devres_alloc_node(devm_memremap_release, sizeof(*ptr), GFP_KERNEL, |
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dev_to_node(dev)); |
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if (!ptr) |
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return ERR_PTR(-ENOMEM); |
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addr = memremap(offset, size, flags); |
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if (addr) { |
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*ptr = addr; |
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devres_add(dev, ptr); |
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} else { |
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devres_free(ptr); |
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return ERR_PTR(-ENXIO); |
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} |
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return addr; |
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} |
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EXPORT_SYMBOL(devm_memremap); |
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void devm_memunmap(struct device *dev, void *addr) |
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{ |
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WARN_ON(devres_release(dev, devm_memremap_release, |
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devm_memremap_match, addr)); |
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} |
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EXPORT_SYMBOL(devm_memunmap);
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