/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2010 Isilon Systems, Inc.
 * Copyright (c) 2016 Matthew Macy (mmacy@mattmacy.io)
 * Copyright (c) 2017 Mellanox Technologies, Ltd.
 * Copyright (c) 2021 Vladimir Kondratyev <wulf@FreeBSD.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef _LINUXKPI_LINUX_HIGHMEM_H_
#define _LINUXKPI_LINUX_HIGHMEM_H_

#include <sys/types.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/sf_buf.h>

#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/pmap.h>

#include <linux/mm.h>
#include <linux/page.h>
#include <linux/hardirq.h>

#define PageHighMem(p)          (0)

static inline struct page *
kmap_to_page(void *addr)
{

        return (virt_to_page(addr));
}

static inline void *
kmap(struct page *page)
{
        struct sf_buf *sf;

        if (PMAP_HAS_DMAP) {
                return ((void *)PHYS_TO_DMAP(page_to_phys(page)));
        } else {
                sched_pin();
                sf = sf_buf_alloc(page, SFB_NOWAIT | SFB_CPUPRIVATE);
                if (sf == NULL) {
                        sched_unpin();
                        return (NULL);
                }
                return ((void *)sf_buf_kva(sf));
        }
}

static inline void *
kmap_atomic_prot(struct page *page, pgprot_t prot)
{
        vm_memattr_t attr = pgprot2cachemode(prot);

        if (attr != VM_MEMATTR_DEFAULT) {
                page->flags |= PG_FICTITIOUS;
                pmap_page_set_memattr(page, attr);
        }
        return (kmap(page));
}

static inline void *
kmap_atomic(struct page *page)
{

        return (kmap_atomic_prot(page, VM_PROT_ALL));
}

static inline void *
kmap_local_page(struct page *page)
{
        return (kmap(page));
}

static inline void *
kmap_local_page_prot(struct page *page, pgprot_t prot)
{

        return (kmap_atomic_prot(page, prot));
}

static inline void
kunmap(struct page *page)
{
        struct sf_buf *sf;

        if (!PMAP_HAS_DMAP) {
                /* lookup SF buffer in list */
                sf = sf_buf_alloc(page, SFB_NOWAIT | SFB_CPUPRIVATE);

                /* double-free */
                sf_buf_free(sf);
                sf_buf_free(sf);

                sched_unpin();
        }
}

static inline void
kunmap_atomic(void *vaddr)
{

        if (!PMAP_HAS_DMAP)
                kunmap(virt_to_page(vaddr));
}

static inline void
kunmap_local(void *addr)
{

        kunmap_atomic(addr);
}

static inline void
memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
{
        char *from;

        KASSERT(offset + len <= PAGE_SIZE,
            ("%s: memcpy from page %p to address %p: "
             "offset+len (%zu+%zu) would go beyond page end",
             __func__, page, to, offset, len));

        from = kmap_local_page(page);
        memcpy(to, from + offset, len);
        kunmap_local(from);
}

static inline void
memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len)
{
        char *to;

        KASSERT(offset + len <= PAGE_SIZE,
            ("%s: memcpy from address %p to page %p: "
             "offset+len (%zu+%zu) would go beyond page end",
             __func__, from, page, offset, len));

        to = kmap_local_page(page);
        memcpy(to + offset, from, len);
        kunmap_local(to);
}

#endif  /* _LINUXKPI_LINUX_HIGHMEM_H_ */