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