// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright © 2008 Ingo Molnar
 */

#include <asm/iomap.h>
#include <asm/memtype.h>
#include <linux/export.h>
#include <linux/highmem.h>

static int is_io_mapping_possible(resource_size_t base, unsigned long size)
{
#if !defined(CONFIG_X86_PAE) && defined(CONFIG_PHYS_ADDR_T_64BIT)
        /* There is no way to map greater than 1 << 32 address without PAE */
        if (base + size > 0x100000000ULL)
                return 0;
#endif
        return 1;
}

int iomap_create_wc(resource_size_t base, unsigned long size, pgprot_t *prot)
{
        enum page_cache_mode pcm = _PAGE_CACHE_MODE_WC;
        int ret;

        if (!is_io_mapping_possible(base, size))
                return -EINVAL;

        ret = memtype_reserve_io(base, base + size, &pcm);
        if (ret)
                return ret;

        *prot = __pgprot(__PAGE_KERNEL | cachemode2protval(pcm));
        /* Filter out unsupported __PAGE_KERNEL* bits: */
        pgprot_val(*prot) &= __default_kernel_pte_mask;

        return 0;
}
EXPORT_SYMBOL_GPL(iomap_create_wc);

void iomap_free(resource_size_t base, unsigned long size)
{
        memtype_free_io(base, base + size);
}
EXPORT_SYMBOL_GPL(iomap_free);

void __iomem *__iomap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
{
        /*
         * For non-PAT systems, translate non-WB request to UC- just in
         * case the caller set the PWT bit to prot directly without using
         * pgprot_writecombine(). UC- translates to uncached if the MTRR
         * is UC or WC. UC- gets the real intention, of the user, which is
         * "WC if the MTRR is WC, UC if you can't do that."
         */
        if (!pat_enabled() && pgprot2cachemode(prot) != _PAGE_CACHE_MODE_WB)
                prot = __pgprot(__PAGE_KERNEL |
                                cachemode2protval(_PAGE_CACHE_MODE_UC_MINUS));

        /* Filter out unsupported __PAGE_KERNEL* bits: */
        pgprot_val(prot) &= __default_kernel_pte_mask;

        return (void __force __iomem *)__kmap_local_pfn_prot(pfn, prot);
}
EXPORT_SYMBOL_GPL(__iomap_local_pfn_prot);