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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /kernel/iomem.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | kernel/iomem.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/kernel/iomem.c b/kernel/iomem.c new file mode 100644 index 000000000..62c92e43a --- /dev/null +++ b/kernel/iomem.c @@ -0,0 +1,167 @@ +/* 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); |