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
11static 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
21int 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(base, base + size, &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}
39EXPORT_SYMBOL_GPL(iomap_create_wc);
40
41void iomap_free(resource_size_t base, unsigned long size)
42{
43	memtype_free_io(base, base + size);
44}
45EXPORT_SYMBOL_GPL(iomap_free);
46
47void __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(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}
65EXPORT_SYMBOL_GPL(__iomap_local_pfn_prot);
66