66 lines
1.8 KiB
C
66 lines
1.8 KiB
C
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// 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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