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65 lines
1.8 KiB
65 lines
1.8 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright © 2008 Ingo Molnar |
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*/ |
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#include <asm/iomap.h> |
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#include <asm/memtype.h> |
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#include <linux/export.h> |
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#include <linux/highmem.h> |
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static int is_io_mapping_possible(resource_size_t base, unsigned long size) |
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{ |
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#if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT) |
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/* There is no way to map greater than 1 << 32 address without PAE */ |
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if (base + size > 0x100000000ULL) |
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return 0; |
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#endif |
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return 1; |
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} |
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int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot) |
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{ |
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enum page_cache_mode pcm = _PAGE_CACHE_MODE_WC; |
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int ret; |
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if (!is_io_mapping_possible(base, size)) |
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return -EINVAL; |
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ret = memtype_reserve_io(base, base + size, &pcm); |
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if (ret) |
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return ret; |
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*prot = __pgprot(__PAGE_KERNEL | cachemode2protval(pcm)); |
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/* Filter out unsupported __PAGE_KERNEL* bits: */ |
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pgprot_val(*prot) &= __default_kernel_pte_mask; |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(iomap_create_wc); |
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void iomap_free(resource_size_t base, unsigned long size) |
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{ |
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memtype_free_io(base, base + size); |
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} |
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EXPORT_SYMBOL_GPL(iomap_free); |
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void __iomem *__iomap_local_pfn_prot(unsigned long pfn, pgprot_t prot) |
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{ |
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/* |
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* For non-PAT systems, translate non-WB request to UC- just in |
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* case the caller set the PWT bit to prot directly without using |
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* pgprot_writecombine(). UC- translates to uncached if the MTRR |
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* is UC or WC. UC- gets the real intention, of the user, which is |
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* "WC if the MTRR is WC, UC if you can't do that." |
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*/ |
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if (!pat_enabled() && pgprot2cachemode(prot) != _PAGE_CACHE_MODE_WB) |
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prot = __pgprot(__PAGE_KERNEL | |
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cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS)); |
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/* Filter out unsupported __PAGE_KERNEL* bits: */ |
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pgprot_val(prot) &= __default_kernel_pte_mask; |
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return (void __force __iomem *)__kmap_local_pfn_prot(pfn, prot); |
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} |
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EXPORT_SYMBOL_GPL(__iomap_local_pfn_prot);
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