| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
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| 2 | /* |
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| 3 | * Copyright © 2008 Ingo Molnar |
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| 4 | */ |
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| 5 | |
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| 6 | #include <asm/iomap.h> |
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| 7 | #include <asm/memtype.h> |
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| 8 | #include <linux/export.h> |
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| 9 | #include <linux/highmem.h> |
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| 10 | |
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| 11 | static int is_io_mapping_possible(resource_size_t base, unsigned long size) |
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| 12 | { |
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| 13 | #if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT) |
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| 14 | /* There is no way to map greater than 1 << 32 address without PAE */ |
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| 15 | if (base + size > 0x100000000ULL) |
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| 16 | return 0; |
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| 17 | #endif |
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| 18 | return 1; |
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| 19 | } |
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| 20 | |
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| 21 | int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot) |
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| 22 | { |
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| 23 | enum page_cache_mode pcm = _PAGE_CACHE_MODE_WC; |
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| 24 | int ret; |
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| 25 | |
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| 26 | if (!is_io_mapping_possible(base, size)) |
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| 27 | return -EINVAL; |
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| 28 | |
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| 29 | ret = memtype_reserve_io(start: base, end: base + size, pcm: &pcm); |
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| 30 | if (ret) |
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| 31 | return ret; |
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| 32 | |
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| 33 | *prot = __pgprot(__PAGE_KERNEL | cachemode2protval(pcm)); |
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| 34 | /* Filter out unsupported __PAGE_KERNEL* bits: */ |
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| 35 | pgprot_val(*prot) &= __default_kernel_pte_mask; |
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| 36 | |
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| 37 | return 0; |
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| 38 | } |
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| 39 | EXPORT_SYMBOL_GPL(iomap_create_wc); |
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| 40 | |
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| 41 | void iomap_free(resource_size_t base, unsigned long size) |
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| 42 | { |
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| 43 | memtype_free_io(start: base, end: base + size); |
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| 44 | } |
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| 45 | EXPORT_SYMBOL_GPL(iomap_free); |
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| 46 | |
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| 47 | void __iomem *__iomap_local_pfn_prot(unsigned long pfn, pgprot_t prot) |
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| 48 | { |
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| 49 | /* |
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| 50 | * For non-PAT systems, translate non-WB request to UC- just in |
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| 51 | * case the caller set the PWT bit to prot directly without using |
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| 52 | * pgprot_writecombine(). UC- translates to uncached if the MTRR |
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| 53 | * is UC or WC. UC- gets the real intention, of the user, which is |
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| 54 | * "WC if the MTRR is WC, UC if you can't do that." |
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| 55 | */ |
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| 56 | if (!pat_enabled() && pgprot2cachemode(pgprot: prot) != _PAGE_CACHE_MODE_WB) |
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| 57 | prot = __pgprot(__PAGE_KERNEL | |
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| 58 | cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS)); |
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| 59 | |
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| 60 | /* Filter out unsupported __PAGE_KERNEL* bits: */ |
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| 61 | pgprot_val(prot) &= __default_kernel_pte_mask; |
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| 62 | |
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| 63 | return (void __force __iomem *)__kmap_local_pfn_prot(pfn, prot); |
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| 64 | } |
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| 65 | EXPORT_SYMBOL_GPL(__iomap_local_pfn_prot); |
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| 66 | |
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