/*-
 * Copyright 2003 Eric Anholt
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * ERIC ANHOLT BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * $FreeBSD: head/sys/dev/drm2/drm_vm.c 235783 2012-05-22 11:07:44Z kib $"
 */

/** @file drm_vm.c
 * Support code for mmaping of DRM maps.
 */

#include <drm/drmP.h>
#include <linux/export.h>
#include <linux/seq_file.h>
#if defined(__ia64__)
#include <linux/efi.h>
#include <linux/slab.h>
#endif
#include <linux/mem_encrypt.h>
#include <asm/pgtable.h>
#include "drm_internal.h"
#include "drm_legacy.h"

#include <sys/mutex2.h>

int
drm_mmap(struct dev_mmap_args *ap)
{
        struct file *filp = ap->a_fp;
        struct drm_file *priv;
        struct cdev *kdev = ap->a_head.a_dev;
        vm_offset_t offset = ap->a_offset;
        struct drm_device *dev = drm_get_device_from_kdev(kdev);
        struct drm_local_map *map = NULL;
        struct drm_hash_item *hash;
        enum drm_map_type type;
        vm_paddr_t phys;

        /*
         * NOTE: If ddev->drm_ttm_bdev is not setup properly, this path
         *       may be hit with a NULL filp and panic.
         */
        priv = filp->private_data;
        if (!priv->authenticated)
                return -EACCES;

        DRM_DEBUG("called with offset %016jx\n", (uintmax_t)offset);
        if (dev->dma && offset < ptoa(dev->dma->page_count)) {
                struct drm_device_dma *dma = dev->dma;

                if (dma->pagelist != NULL) {
                        unsigned long page = offset >> PAGE_SHIFT;
                        unsigned long phys = dma->pagelist[page];

                        // XXX *paddr = phys;
                        ap->a_result = phys;
                        return 0;
                } else {
                        return -1;
                }
        }

        /* A sequential search of a linked list is
           fine here because: 1) there will only be
           about 5-10 entries in the list and, 2) a
           DRI client only has to do this mapping
           once, so it doesn't have to be optimized
           for performance, even if the list was a
           bit longer.
        */
        DRM_LOCK(dev);

        if (drm_ht_find_item(&dev->map_hash, offset, &hash)) {
                DRM_ERROR("Could not find map\n");
                DRM_UNLOCK(dev);
                return -EINVAL;
        }

        map = drm_hash_entry(hash, struct drm_map_list, hash)->map;
        if (map == NULL) {
                DRM_DEBUG("Can't find map, request offset = %016jx\n",
                    (uintmax_t)offset);
                DRM_UNLOCK(dev);
                return -1;
        }
        if (((map->flags & _DRM_RESTRICTED) && !capable(CAP_SYS_ADMIN))) {
                DRM_UNLOCK(dev);
                DRM_DEBUG("restricted map\n");
                return -1;
        }

        type = map->type;
        DRM_UNLOCK(dev);

        switch (type) {
        case _DRM_FRAME_BUFFER:
        case _DRM_AGP:
#if 0   /* XXX */
                *memattr = VM_MEMATTR_WRITE_COMBINING;
#endif
                /* FALLTHROUGH */
        case _DRM_REGISTERS:
                phys = map->offset + offset;
                break;
        case _DRM_SCATTER_GATHER:
#if 0   /* XXX */
                *memattr = VM_MEMATTR_WRITE_COMBINING;
#endif
                /* FALLTHROUGH */
        case _DRM_CONSISTENT:
        case _DRM_SHM:
                phys = vtophys((char *)map->handle + offset);
                break;
        default:
                DRM_ERROR("bad map type %d\n", type);
                return -1;      /* This should never happen. */
        }

        ap->a_result = atop(phys);
        return 0;
}

/* XXX The following is just temporary hack to replace the
 * vm_phys_fictitious functions available on FreeBSD
 */
#define VM_PHYS_FICTITIOUS_NSEGS        8
static struct vm_phys_fictitious_seg {
        vm_paddr_t      start;
        vm_paddr_t      end;
        vm_page_t       first_page;
} vm_phys_fictitious_segs[VM_PHYS_FICTITIOUS_NSEGS];
static struct mtx vm_phys_fictitious_reg_mtx = MTX_INITIALIZER("vmphy");

vm_page_t
vm_phys_fictitious_to_vm_page(vm_paddr_t pa)
{
        struct vm_phys_fictitious_seg *seg;
        vm_page_t m;
        int segind;

        m = NULL;
        for (segind = 0; segind < VM_PHYS_FICTITIOUS_NSEGS; segind++) {
                seg = &vm_phys_fictitious_segs[segind];
                if (pa >= seg->start && pa < seg->end) {
                        m = &seg->first_page[atop(pa - seg->start)];
                        KASSERT((m->flags & PG_FICTITIOUS) != 0,
                            ("%p not fictitious", m));
                        break;
                }
        }
        return (m);
}

int
vm_phys_fictitious_reg_range(vm_paddr_t start, vm_paddr_t end,
                             vm_memattr_t memattr)
{
        struct vm_phys_fictitious_seg *seg;
        vm_page_t fp;
        long i, page_count;
        int segind;

        page_count = (end - start) / PAGE_SIZE;

        fp = kmalloc(page_count * sizeof(struct vm_page), M_DRM,
                    M_WAITOK | M_ZERO);

        for (i = 0; i < page_count; i++) {
                vm_page_initfake(&fp[i], start + PAGE_SIZE * i, memattr);
                atomic_clear_int(&fp[i].busy_count, PBUSY_LOCKED);
        }
        mtx_lock(&vm_phys_fictitious_reg_mtx);
        for (segind = 0; segind < VM_PHYS_FICTITIOUS_NSEGS; segind++) {
                seg = &vm_phys_fictitious_segs[segind];
                if (seg->start == 0 && seg->end == 0) {
                        seg->start = start;
                        seg->end = end;
                        seg->first_page = fp;
                        mtx_unlock(&vm_phys_fictitious_reg_mtx);
                        return (0);
                }
        }
        mtx_unlock(&vm_phys_fictitious_reg_mtx);
        kfree(fp);
        return (EBUSY);
}

void
vm_phys_fictitious_unreg_range(vm_paddr_t start, vm_paddr_t end)
{
        struct vm_phys_fictitious_seg *seg;
        vm_page_t fp;
        int segind;

        mtx_lock(&vm_phys_fictitious_reg_mtx);
        for (segind = 0; segind < VM_PHYS_FICTITIOUS_NSEGS; segind++) {
                seg = &vm_phys_fictitious_segs[segind];
                if (seg->start == start && seg->end == end) {
                        seg->start = seg->end = 0;
                        fp = seg->first_page;
                        seg->first_page = NULL;
                        mtx_unlock(&vm_phys_fictitious_reg_mtx);
                        kfree(fp);
                        return;
                }
        }
        mtx_unlock(&vm_phys_fictitious_reg_mtx);
        KASSERT(0, ("Unregistering not registered fictitious range"));
}