/*
 * Copyright (c) 2015-2020 François Tigeot <ftigeot@wolfpond.org>
 * All rights reserved.
 *
 * 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 unmodified, 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 ``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 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 _LINUX_IOMAPPING_H_
#define _LINUX_IOMAPPING_H_

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/bug.h>
#include <linux/io.h>
#include <asm/page.h>

#include <asm/iomap.h>

struct io_mapping {
        resource_size_t base;
        unsigned long size;
        unsigned long prot;
        void *vaddr;
};

static inline struct io_mapping *
io_mapping_create_wc(resource_size_t base, unsigned long size)
{
        struct io_mapping *map;

        map = kmalloc(sizeof(struct io_mapping), M_DRM, M_WAITOK);
        map->base = base;
        map->size = size;
        map->prot = VM_MEMATTR_WRITE_COMBINING;

        map->vaddr = pmap_mapdev_attr(base, size,
                                        VM_MEMATTR_WRITE_COMBINING);
        if (map->vaddr == NULL)
                return NULL;

        return map;
}

static inline void io_mapping_free(struct io_mapping *mapping)
{
        /* Default memory attribute is write-back */
        pmap_mapdev_attr(mapping->base, mapping->size, VM_MEMATTR_WRITE_BACK);
        kfree(mapping);
}

static inline void *
io_mapping_map_wc(struct io_mapping *mapping,
                  unsigned long offset,
                  unsigned long size)
{
        BUG_ON(offset >= mapping->size);

        return ioremap_wc(mapping->base + offset, size);
}

static inline void *
io_mapping_map_atomic_wc(struct io_mapping *mapping, unsigned long offset)
{
        return ioremap_wc(mapping->base + offset, PAGE_SIZE);
}

static inline void
io_mapping_unmap(void *vaddr)
{
        iounmap(vaddr);
}

static inline void
io_mapping_unmap_atomic(void *vaddr)
{
        iounmap(vaddr);
}

static inline struct io_mapping *
io_mapping_init_wc(struct io_mapping *iomap,
                   resource_size_t base,
                   unsigned long size)
{
        iomap->base = base;
        iomap->size = size;
        iomap->vaddr = ioremap_wc(base, size);
        iomap->prot = pgprot_writecombine(PAGE_KERNEL_IO);

        return iomap;
}

static inline void
io_mapping_fini(struct io_mapping *mapping)
{
        iounmap(mapping->vaddr);
}

#endif  /* _LINUX_IOMAPPING_H_ */