// SPDX-License-Identifier: GPL-2.0-only
/*
 * arch/sh/mm/kmap.c
 *
 * Copyright (C) 1999, 2000, 2002  Niibe Yutaka
 * Copyright (C) 2002 - 2009  Paul Mundt
 */
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/highmem.h>
#include <linux/module.h>
#include <asm/mmu_context.h>
#include <asm/cacheflush.h>

static pte_t *kmap_coherent_pte;

void __init kmap_coherent_init(void)
{
        unsigned long vaddr;

        /* cache the first coherent kmap pte */
        vaddr = __fix_to_virt(FIX_CMAP_BEGIN);
        kmap_coherent_pte = virt_to_kpte(vaddr);
}

void *kmap_coherent(struct page *page, unsigned long addr)
{
        struct folio *folio = page_folio(page);
        enum fixed_addresses idx;
        unsigned long vaddr;

        BUG_ON(!test_bit(PG_dcache_clean, &folio->flags.f));

        preempt_disable();
        pagefault_disable();

        idx = FIX_CMAP_END -
                (((addr >> PAGE_SHIFT) & (FIX_N_COLOURS - 1)) +
                 (FIX_N_COLOURS * smp_processor_id()));

        vaddr = __fix_to_virt(idx);

        BUG_ON(!pte_none(*(kmap_coherent_pte - idx)));
        set_pte(kmap_coherent_pte - idx, mk_pte(page, PAGE_KERNEL));

        return (void *)vaddr;
}

void kunmap_coherent(void *kvaddr)
{
        if (kvaddr >= (void *)FIXADDR_START) {
                unsigned long vaddr = (unsigned long)kvaddr & PAGE_MASK;
                enum fixed_addresses idx = __virt_to_fix(vaddr);

                /* XXX.. Kill this later, here for sanity at the moment.. */
                __flush_purge_region((void *)vaddr, PAGE_SIZE);

                pte_clear(&init_mm, vaddr, kmap_coherent_pte - idx);
                local_flush_tlb_one(get_asid(), vaddr);
        }

        pagefault_enable();
        preempt_enable();
}