// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2013 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 */

#include <linux/dma-map-ops.h>
#include <linux/spinlock.h>
#include <linux/shmem_fs.h>
#include <linux/dma-buf.h>
#include <linux/pfn_t.h>

#include <drm/drm_prime.h>

#include "msm_drv.h"
#include "msm_fence.h"
#include "msm_gem.h"
#include "msm_gpu.h"
#include "msm_mmu.h"

static void update_inactive(struct msm_gem_object *msm_obj);

static dma_addr_t physaddr(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_drm_private *priv = obj->dev->dev_private;
        return (((dma_addr_t)msm_obj->vram_node->start) << PAGE_SHIFT) +
                        priv->vram.paddr;
}

static bool use_pages(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        return !msm_obj->vram_node;
}

/*
 * Cache sync.. this is a bit over-complicated, to fit dma-mapping
 * API.  Really GPU cache is out of scope here (handled on cmdstream)
 * and all we need to do is invalidate newly allocated pages before
 * mapping to CPU as uncached/writecombine.
 *
 * On top of this, we have the added headache, that depending on
 * display generation, the display's iommu may be wired up to either
 * the toplevel drm device (mdss), or to the mdp sub-node, meaning
 * that here we either have dma-direct or iommu ops.
 *
 * Let this be a cautionary tail of abstraction gone wrong.
 */

static void sync_for_device(struct msm_gem_object *msm_obj)
{
        struct device *dev = msm_obj->base.dev->dev;

        dma_map_sgtable(dev, msm_obj->sgt, DMA_BIDIRECTIONAL, 0);
}

static void sync_for_cpu(struct msm_gem_object *msm_obj)
{
        struct device *dev = msm_obj->base.dev->dev;

        dma_unmap_sgtable(dev, msm_obj->sgt, DMA_BIDIRECTIONAL, 0);
}

/* allocate pages from VRAM carveout, used when no IOMMU: */
static struct page **get_pages_vram(struct drm_gem_object *obj, int npages)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_drm_private *priv = obj->dev->dev_private;
        dma_addr_t paddr;
        struct page **p;
        int ret, i;

        p = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
        if (!p)
                return ERR_PTR(-ENOMEM);

        spin_lock(&priv->vram.lock);
        ret = drm_mm_insert_node(&priv->vram.mm, msm_obj->vram_node, npages);
        spin_unlock(&priv->vram.lock);
        if (ret) {
                kvfree(p);
                return ERR_PTR(ret);
        }

        paddr = physaddr(obj);
        for (i = 0; i < npages; i++) {
                p[i] = phys_to_page(paddr);
                paddr += PAGE_SIZE;
        }

        return p;
}

static struct page **get_pages(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        if (!msm_obj->pages) {
                struct drm_device *dev = obj->dev;
                struct page **p;
                int npages = obj->size >> PAGE_SHIFT;

                if (use_pages(obj))
                        p = drm_gem_get_pages(obj);
                else
                        p = get_pages_vram(obj, npages);

                if (IS_ERR(p)) {
                        DRM_DEV_ERROR(dev->dev, "could not get pages: %ld\n",
                                        PTR_ERR(p));
                        return p;
                }

                msm_obj->pages = p;

                msm_obj->sgt = drm_prime_pages_to_sg(obj->dev, p, npages);
                if (IS_ERR(msm_obj->sgt)) {
                        void *ptr = ERR_CAST(msm_obj->sgt);

                        DRM_DEV_ERROR(dev->dev, "failed to allocate sgt\n");
                        msm_obj->sgt = NULL;
                        return ptr;
                }

                /* For non-cached buffers, ensure the new pages are clean
                 * because display controller, GPU, etc. are not coherent:
                 */
                if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED))
                        sync_for_device(msm_obj);

                update_inactive(msm_obj);
        }

        return msm_obj->pages;
}

static void put_pages_vram(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_drm_private *priv = obj->dev->dev_private;

        spin_lock(&priv->vram.lock);
        drm_mm_remove_node(msm_obj->vram_node);
        spin_unlock(&priv->vram.lock);

        kvfree(msm_obj->pages);
}

static void put_pages(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        if (msm_obj->pages) {
                if (msm_obj->sgt) {
                        /* For non-cached buffers, ensure the new
                         * pages are clean because display controller,
                         * GPU, etc. are not coherent:
                         */
                        if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED))
                                sync_for_cpu(msm_obj);

                        sg_free_table(msm_obj->sgt);
                        kfree(msm_obj->sgt);
                        msm_obj->sgt = NULL;
                }

                if (use_pages(obj))
                        drm_gem_put_pages(obj, msm_obj->pages, true, false);
                else
                        put_pages_vram(obj);

                msm_obj->pages = NULL;
        }
}

struct page **msm_gem_get_pages(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct page **p;

        msm_gem_lock(obj);

        if (GEM_WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED)) {
                msm_gem_unlock(obj);
                return ERR_PTR(-EBUSY);
        }

        p = get_pages(obj);

        if (!IS_ERR(p)) {
                msm_obj->pin_count++;
                update_inactive(msm_obj);
        }

        msm_gem_unlock(obj);
        return p;
}

void msm_gem_put_pages(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        msm_gem_lock(obj);
        msm_obj->pin_count--;
        GEM_WARN_ON(msm_obj->pin_count < 0);
        update_inactive(msm_obj);
        msm_gem_unlock(obj);
}

static pgprot_t msm_gem_pgprot(struct msm_gem_object *msm_obj, pgprot_t prot)
{
        if (msm_obj->flags & (MSM_BO_WC|MSM_BO_UNCACHED))
                return pgprot_writecombine(prot);
        return prot;
}

static vm_fault_t msm_gem_fault(struct vm_fault *vmf)
{
        struct vm_area_struct *vma = vmf->vma;
        struct drm_gem_object *obj = vma->vm_private_data;
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct page **pages;
        unsigned long pfn;
        pgoff_t pgoff;
        int err;
        vm_fault_t ret;

        /*
         * vm_ops.open/drm_gem_mmap_obj and close get and put
         * a reference on obj. So, we dont need to hold one here.
         */
        err = msm_gem_lock_interruptible(obj);
        if (err) {
                ret = VM_FAULT_NOPAGE;
                goto out;
        }

        if (GEM_WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED)) {
                msm_gem_unlock(obj);
                return VM_FAULT_SIGBUS;
        }

        /* make sure we have pages attached now */
        pages = get_pages(obj);
        if (IS_ERR(pages)) {
                ret = vmf_error(PTR_ERR(pages));
                goto out_unlock;
        }

        /* We don't use vmf->pgoff since that has the fake offset: */
        pgoff = (vmf->address - vma->vm_start) >> PAGE_SHIFT;

        pfn = page_to_pfn(pages[pgoff]);

        VERB("Inserting %p pfn %lx, pa %lx", (void *)vmf->address,
                        pfn, pfn << PAGE_SHIFT);

        ret = vmf_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV));
out_unlock:
        msm_gem_unlock(obj);
out:
        return ret;
}

/** get mmap offset */
static uint64_t mmap_offset(struct drm_gem_object *obj)
{
        struct drm_device *dev = obj->dev;
        int ret;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        /* Make it mmapable */
        ret = drm_gem_create_mmap_offset(obj);

        if (ret) {
                DRM_DEV_ERROR(dev->dev, "could not allocate mmap offset\n");
                return 0;
        }

        return drm_vma_node_offset_addr(&obj->vma_node);
}

uint64_t msm_gem_mmap_offset(struct drm_gem_object *obj)
{
        uint64_t offset;

        msm_gem_lock(obj);
        offset = mmap_offset(obj);
        msm_gem_unlock(obj);
        return offset;
}

static struct msm_gem_vma *add_vma(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_gem_vma *vma;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        vma = kzalloc(sizeof(*vma), GFP_KERNEL);
        if (!vma)
                return ERR_PTR(-ENOMEM);

        vma->aspace = aspace;

        list_add_tail(&vma->list, &msm_obj->vmas);

        return vma;
}

static struct msm_gem_vma *lookup_vma(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_gem_vma *vma;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        list_for_each_entry(vma, &msm_obj->vmas, list) {
                if (vma->aspace == aspace)
                        return vma;
        }

        return NULL;
}

static void del_vma(struct msm_gem_vma *vma)
{
        if (!vma)
                return;

        list_del(&vma->list);
        kfree(vma);
}

/*
 * If close is true, this also closes the VMA (releasing the allocated
 * iova range) in addition to removing the iommu mapping.  In the eviction
 * case (!close), we keep the iova allocated, but only remove the iommu
 * mapping.
 */
static void
put_iova_spaces(struct drm_gem_object *obj, bool close)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_gem_vma *vma;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        list_for_each_entry(vma, &msm_obj->vmas, list) {
                if (vma->aspace) {
                        msm_gem_purge_vma(vma->aspace, vma);
                        if (close)
                                msm_gem_close_vma(vma->aspace, vma);
                }
        }
}

/* Called with msm_obj locked */
static void
put_iova_vmas(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_gem_vma *vma, *tmp;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        list_for_each_entry_safe(vma, tmp, &msm_obj->vmas, list) {
                del_vma(vma);
        }
}

static int get_iova_locked(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace, uint64_t *iova,
                u64 range_start, u64 range_end)
{
        struct msm_gem_vma *vma;
        int ret = 0;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        vma = lookup_vma(obj, aspace);

        if (!vma) {
                vma = add_vma(obj, aspace);
                if (IS_ERR(vma))
                        return PTR_ERR(vma);

                ret = msm_gem_init_vma(aspace, vma, obj->size >> PAGE_SHIFT,
                        range_start, range_end);
                if (ret) {
                        del_vma(vma);
                        return ret;
                }
        }

        *iova = vma->iova;
        return 0;
}

static int msm_gem_pin_iova(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_gem_vma *vma;
        struct page **pages;
        int ret, prot = IOMMU_READ;

        if (!(msm_obj->flags & MSM_BO_GPU_READONLY))
                prot |= IOMMU_WRITE;

        if (msm_obj->flags & MSM_BO_MAP_PRIV)
                prot |= IOMMU_PRIV;

        if (msm_obj->flags & MSM_BO_CACHED_COHERENT)
                prot |= IOMMU_CACHE;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        if (GEM_WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED))
                return -EBUSY;

        vma = lookup_vma(obj, aspace);
        if (GEM_WARN_ON(!vma))
                return -EINVAL;

        pages = get_pages(obj);
        if (IS_ERR(pages))
                return PTR_ERR(pages);

        ret = msm_gem_map_vma(aspace, vma, prot,
                        msm_obj->sgt, obj->size >> PAGE_SHIFT);

        if (!ret)
                msm_obj->pin_count++;

        return ret;
}

static int get_and_pin_iova_range_locked(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace, uint64_t *iova,
                u64 range_start, u64 range_end)
{
        u64 local;
        int ret;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        ret = get_iova_locked(obj, aspace, &local,
                range_start, range_end);

        if (!ret)
                ret = msm_gem_pin_iova(obj, aspace);

        if (!ret)
                *iova = local;

        return ret;
}

/*
 * get iova and pin it. Should have a matching put
 * limits iova to specified range (in pages)
 */
int msm_gem_get_and_pin_iova_range(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace, uint64_t *iova,
                u64 range_start, u64 range_end)
{
        int ret;

        msm_gem_lock(obj);
        ret = get_and_pin_iova_range_locked(obj, aspace, iova, range_start, range_end);
        msm_gem_unlock(obj);

        return ret;
}

int msm_gem_get_and_pin_iova_locked(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace, uint64_t *iova)
{
        return get_and_pin_iova_range_locked(obj, aspace, iova, 0, U64_MAX);
}

/* get iova and pin it. Should have a matching put */
int msm_gem_get_and_pin_iova(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace, uint64_t *iova)
{
        return msm_gem_get_and_pin_iova_range(obj, aspace, iova, 0, U64_MAX);
}

/*
 * Get an iova but don't pin it. Doesn't need a put because iovas are currently
 * valid for the life of the object
 */
int msm_gem_get_iova(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace, uint64_t *iova)
{
        int ret;

        msm_gem_lock(obj);
        ret = get_iova_locked(obj, aspace, iova, 0, U64_MAX);
        msm_gem_unlock(obj);

        return ret;
}

/* get iova without taking a reference, used in places where you have
 * already done a 'msm_gem_get_and_pin_iova' or 'msm_gem_get_iova'
 */
uint64_t msm_gem_iova(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace)
{
        struct msm_gem_vma *vma;

        msm_gem_lock(obj);
        vma = lookup_vma(obj, aspace);
        msm_gem_unlock(obj);
        GEM_WARN_ON(!vma);

        return vma ? vma->iova : 0;
}

/*
 * Locked variant of msm_gem_unpin_iova()
 */
void msm_gem_unpin_iova_locked(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_gem_vma *vma;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        vma = lookup_vma(obj, aspace);

        if (!GEM_WARN_ON(!vma)) {
                msm_gem_unmap_vma(aspace, vma);

                msm_obj->pin_count--;
                GEM_WARN_ON(msm_obj->pin_count < 0);

                update_inactive(msm_obj);
        }
}

/*
 * Unpin a iova by updating the reference counts. The memory isn't actually
 * purged until something else (shrinker, mm_notifier, destroy, etc) decides
 * to get rid of it
 */
void msm_gem_unpin_iova(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace)
{
        msm_gem_lock(obj);
        msm_gem_unpin_iova_locked(obj, aspace);
        msm_gem_unlock(obj);
}

int msm_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
                struct drm_mode_create_dumb *args)
{
        args->pitch = align_pitch(args->width, args->bpp);
        args->size  = PAGE_ALIGN(args->pitch * args->height);
        return msm_gem_new_handle(dev, file, args->size,
                        MSM_BO_SCANOUT | MSM_BO_WC, &args->handle, "dumb");
}

int msm_gem_dumb_map_offset(struct drm_file *file, struct drm_device *dev,
                uint32_t handle, uint64_t *offset)
{
        struct drm_gem_object *obj;
        int ret = 0;

        /* GEM does all our handle to object mapping */
        obj = drm_gem_object_lookup(file, handle);
        if (obj == NULL) {
                ret = -ENOENT;
                goto fail;
        }

        *offset = msm_gem_mmap_offset(obj);

        drm_gem_object_put(obj);

fail:
        return ret;
}

static void *get_vaddr(struct drm_gem_object *obj, unsigned madv)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        int ret = 0;

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        if (obj->import_attach)
                return ERR_PTR(-ENODEV);

        if (GEM_WARN_ON(msm_obj->madv > madv)) {
                DRM_DEV_ERROR(obj->dev->dev, "Invalid madv state: %u vs %u\n",
                        msm_obj->madv, madv);
                return ERR_PTR(-EBUSY);
        }

        /* increment vmap_count *before* vmap() call, so shrinker can
         * check vmap_count (is_vunmapable()) outside of msm_obj lock.
         * This guarantees that we won't try to msm_gem_vunmap() this
         * same object from within the vmap() call (while we already
         * hold msm_obj lock)
         */
        msm_obj->vmap_count++;

        if (!msm_obj->vaddr) {
                struct page **pages = get_pages(obj);
                if (IS_ERR(pages)) {
                        ret = PTR_ERR(pages);
                        goto fail;
                }
                msm_obj->vaddr = vmap(pages, obj->size >> PAGE_SHIFT,
                                VM_MAP, msm_gem_pgprot(msm_obj, PAGE_KERNEL));
                if (msm_obj->vaddr == NULL) {
                        ret = -ENOMEM;
                        goto fail;
                }

                update_inactive(msm_obj);
        }

        return msm_obj->vaddr;

fail:
        msm_obj->vmap_count--;
        return ERR_PTR(ret);
}

void *msm_gem_get_vaddr_locked(struct drm_gem_object *obj)
{
        return get_vaddr(obj, MSM_MADV_WILLNEED);
}

void *msm_gem_get_vaddr(struct drm_gem_object *obj)
{
        void *ret;

        msm_gem_lock(obj);
        ret = msm_gem_get_vaddr_locked(obj);
        msm_gem_unlock(obj);

        return ret;
}

/*
 * Don't use this!  It is for the very special case of dumping
 * submits from GPU hangs or faults, were the bo may already
 * be MSM_MADV_DONTNEED, but we know the buffer is still on the
 * active list.
 */
void *msm_gem_get_vaddr_active(struct drm_gem_object *obj)
{
        return get_vaddr(obj, __MSM_MADV_PURGED);
}

void msm_gem_put_vaddr_locked(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        GEM_WARN_ON(!msm_gem_is_locked(obj));
        GEM_WARN_ON(msm_obj->vmap_count < 1);

        msm_obj->vmap_count--;
}

void msm_gem_put_vaddr(struct drm_gem_object *obj)
{
        msm_gem_lock(obj);
        msm_gem_put_vaddr_locked(obj);
        msm_gem_unlock(obj);
}

/* Update madvise status, returns true if not purged, else
 * false or -errno.
 */
int msm_gem_madvise(struct drm_gem_object *obj, unsigned madv)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        msm_gem_lock(obj);

        if (msm_obj->madv != __MSM_MADV_PURGED)
                msm_obj->madv = madv;

        madv = msm_obj->madv;

        /* If the obj is inactive, we might need to move it
         * between inactive lists
         */
        if (msm_obj->active_count == 0)
                update_inactive(msm_obj);

        msm_gem_unlock(obj);

        return (madv != __MSM_MADV_PURGED);
}

void msm_gem_purge(struct drm_gem_object *obj)
{
        struct drm_device *dev = obj->dev;
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        GEM_WARN_ON(!msm_gem_is_locked(obj));
        GEM_WARN_ON(!is_purgeable(msm_obj));

        /* Get rid of any iommu mapping(s): */
        put_iova_spaces(obj, true);

        msm_gem_vunmap(obj);

        drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);

        put_pages(obj);

        put_iova_vmas(obj);

        msm_obj->madv = __MSM_MADV_PURGED;
        update_inactive(msm_obj);

        drm_gem_free_mmap_offset(obj);

        /* Our goal here is to return as much of the memory as
         * is possible back to the system as we are called from OOM.
         * To do this we must instruct the shmfs to drop all of its
         * backing pages, *now*.
         */
        shmem_truncate_range(file_inode(obj->filp), 0, (loff_t)-1);

        invalidate_mapping_pages(file_inode(obj->filp)->i_mapping,
                        0, (loff_t)-1);
}

/*
 * Unpin the backing pages and make them available to be swapped out.
 */
void msm_gem_evict(struct drm_gem_object *obj)
{
        struct drm_device *dev = obj->dev;
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        GEM_WARN_ON(!msm_gem_is_locked(obj));
        GEM_WARN_ON(is_unevictable(msm_obj));
        GEM_WARN_ON(!msm_obj->evictable);
        GEM_WARN_ON(msm_obj->active_count);

        /* Get rid of any iommu mapping(s): */
        put_iova_spaces(obj, false);

        drm_vma_node_unmap(&obj->vma_node, dev->anon_inode->i_mapping);

        put_pages(obj);

        update_inactive(msm_obj);
}

void msm_gem_vunmap(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        GEM_WARN_ON(!msm_gem_is_locked(obj));

        if (!msm_obj->vaddr || GEM_WARN_ON(!is_vunmapable(msm_obj)))
                return;

        vunmap(msm_obj->vaddr);
        msm_obj->vaddr = NULL;
}

void msm_gem_active_get(struct drm_gem_object *obj, struct msm_gpu *gpu)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_drm_private *priv = obj->dev->dev_private;

        might_sleep();
        GEM_WARN_ON(!msm_gem_is_locked(obj));
        GEM_WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED);
        GEM_WARN_ON(msm_obj->dontneed);

        if (msm_obj->active_count++ == 0) {
                mutex_lock(&priv->mm_lock);
                if (msm_obj->evictable)
                        mark_unevictable(msm_obj);
                list_move_tail(&msm_obj->mm_list, &gpu->active_list);
                mutex_unlock(&priv->mm_lock);
        }
}

void msm_gem_active_put(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        might_sleep();
        GEM_WARN_ON(!msm_gem_is_locked(obj));

        if (--msm_obj->active_count == 0) {
                update_inactive(msm_obj);
        }
}

static void update_inactive(struct msm_gem_object *msm_obj)
{
        struct msm_drm_private *priv = msm_obj->base.dev->dev_private;

        GEM_WARN_ON(!msm_gem_is_locked(&msm_obj->base));

        if (msm_obj->active_count != 0)
                return;

        mutex_lock(&priv->mm_lock);

        if (msm_obj->dontneed)
                mark_unpurgeable(msm_obj);
        if (msm_obj->evictable)
                mark_unevictable(msm_obj);

        list_del(&msm_obj->mm_list);
        if ((msm_obj->madv == MSM_MADV_WILLNEED) && msm_obj->sgt) {
                list_add_tail(&msm_obj->mm_list, &priv->inactive_willneed);
                mark_evictable(msm_obj);
        } else if (msm_obj->madv == MSM_MADV_DONTNEED) {
                list_add_tail(&msm_obj->mm_list, &priv->inactive_dontneed);
                mark_purgeable(msm_obj);
        } else {
                GEM_WARN_ON((msm_obj->madv != __MSM_MADV_PURGED) && msm_obj->sgt);
                list_add_tail(&msm_obj->mm_list, &priv->inactive_unpinned);
        }

        mutex_unlock(&priv->mm_lock);
}

int msm_gem_cpu_prep(struct drm_gem_object *obj, uint32_t op, ktime_t *timeout)
{
        bool write = !!(op & MSM_PREP_WRITE);
        unsigned long remain =
                op & MSM_PREP_NOSYNC ? 0 : timeout_to_jiffies(timeout);
        long ret;

        ret = dma_resv_wait_timeout(obj->resv, write, true,  remain);
        if (ret == 0)
                return remain == 0 ? -EBUSY : -ETIMEDOUT;
        else if (ret < 0)
                return ret;

        /* TODO cache maintenance */

        return 0;
}

int msm_gem_cpu_fini(struct drm_gem_object *obj)
{
        /* TODO cache maintenance */
        return 0;
}

#ifdef CONFIG_DEBUG_FS
static void describe_fence(struct dma_fence *fence, const char *type,
                struct seq_file *m)
{
        if (!dma_fence_is_signaled(fence))
                seq_printf(m, "\t%9s: %s %s seq %llu\n", type,
                                fence->ops->get_driver_name(fence),
                                fence->ops->get_timeline_name(fence),
                                fence->seqno);
}

void msm_gem_describe(struct drm_gem_object *obj, struct seq_file *m,
                struct msm_gem_stats *stats)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct dma_resv *robj = obj->resv;
        struct dma_resv_list *fobj;
        struct dma_fence *fence;
        struct msm_gem_vma *vma;
        uint64_t off = drm_vma_node_start(&obj->vma_node);
        const char *madv;

        msm_gem_lock(obj);

        stats->all.count++;
        stats->all.size += obj->size;

        if (is_active(msm_obj)) {
                stats->active.count++;
                stats->active.size += obj->size;
        }

        if (msm_obj->pages) {
                stats->resident.count++;
                stats->resident.size += obj->size;
        }

        switch (msm_obj->madv) {
        case __MSM_MADV_PURGED:
                stats->purged.count++;
                stats->purged.size += obj->size;
                madv = " purged";
                break;
        case MSM_MADV_DONTNEED:
                stats->purgeable.count++;
                stats->purgeable.size += obj->size;
                madv = " purgeable";
                break;
        case MSM_MADV_WILLNEED:
        default:
                madv = "";
                break;
        }

        seq_printf(m, "%08x: %c %2d (%2d) %08llx %p",
                        msm_obj->flags, is_active(msm_obj) ? 'A' : 'I',
                        obj->name, kref_read(&obj->refcount),
                        off, msm_obj->vaddr);

        seq_printf(m, " %08zu %9s %-32s\n", obj->size, madv, msm_obj->name);

        if (!list_empty(&msm_obj->vmas)) {

                seq_puts(m, "      vmas:");

                list_for_each_entry(vma, &msm_obj->vmas, list) {
                        const char *name, *comm;
                        if (vma->aspace) {
                                struct msm_gem_address_space *aspace = vma->aspace;
                                struct task_struct *task =
                                        get_pid_task(aspace->pid, PIDTYPE_PID);
                                if (task) {
                                        comm = kstrdup(task->comm, GFP_KERNEL);
                                } else {
                                        comm = NULL;
                                }
                                name = aspace->name;
                        } else {
                                name = comm = NULL;
                        }
                        seq_printf(m, " [%s%s%s: aspace=%p, %08llx,%s,inuse=%d]",
                                name, comm ? ":" : "", comm ? comm : "",
                                vma->aspace, vma->iova,
                                vma->mapped ? "mapped" : "unmapped",
                                vma->inuse);
                        kfree(comm);
                }

                seq_puts(m, "\n");
        }

        rcu_read_lock();
        fobj = dma_resv_shared_list(robj);
        if (fobj) {
                unsigned int i, shared_count = fobj->shared_count;

                for (i = 0; i < shared_count; i++) {
                        fence = rcu_dereference(fobj->shared[i]);
                        describe_fence(fence, "Shared", m);
                }
        }

        fence = dma_resv_excl_fence(robj);
        if (fence)
                describe_fence(fence, "Exclusive", m);
        rcu_read_unlock();

        msm_gem_unlock(obj);
}

void msm_gem_describe_objects(struct list_head *list, struct seq_file *m)
{
        struct msm_gem_stats stats = {};
        struct msm_gem_object *msm_obj;

        seq_puts(m, "   flags       id ref  offset   kaddr            size     madv      name\n");
        list_for_each_entry(msm_obj, list, node) {
                struct drm_gem_object *obj = &msm_obj->base;
                seq_puts(m, "   ");
                msm_gem_describe(obj, m, &stats);
        }

        seq_printf(m, "Total:     %4d objects, %9zu bytes\n",
                        stats.all.count, stats.all.size);
        seq_printf(m, "Active:    %4d objects, %9zu bytes\n",
                        stats.active.count, stats.active.size);
        seq_printf(m, "Resident:  %4d objects, %9zu bytes\n",
                        stats.resident.count, stats.resident.size);
        seq_printf(m, "Purgeable: %4d objects, %9zu bytes\n",
                        stats.purgeable.count, stats.purgeable.size);
        seq_printf(m, "Purged:    %4d objects, %9zu bytes\n",
                        stats.purged.count, stats.purged.size);
}
#endif

/* don't call directly!  Use drm_gem_object_put() */
void msm_gem_free_object(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct drm_device *dev = obj->dev;
        struct msm_drm_private *priv = dev->dev_private;

        mutex_lock(&priv->obj_lock);
        list_del(&msm_obj->node);
        mutex_unlock(&priv->obj_lock);

        mutex_lock(&priv->mm_lock);
        if (msm_obj->dontneed)
                mark_unpurgeable(msm_obj);
        list_del(&msm_obj->mm_list);
        mutex_unlock(&priv->mm_lock);

        msm_gem_lock(obj);

        /* object should not be on active list: */
        GEM_WARN_ON(is_active(msm_obj));

        put_iova_spaces(obj, true);

        if (obj->import_attach) {
                GEM_WARN_ON(msm_obj->vaddr);

                /* Don't drop the pages for imported dmabuf, as they are not
                 * ours, just free the array we allocated:
                 */
                kvfree(msm_obj->pages);

                put_iova_vmas(obj);

                /* dma_buf_detach() grabs resv lock, so we need to unlock
                 * prior to drm_prime_gem_destroy
                 */
                msm_gem_unlock(obj);

                drm_prime_gem_destroy(obj, msm_obj->sgt);
        } else {
                msm_gem_vunmap(obj);
                put_pages(obj);
                put_iova_vmas(obj);
                msm_gem_unlock(obj);
        }

        drm_gem_object_release(obj);

        kfree(msm_obj);
}

static int msm_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        vma->vm_flags &= ~VM_PFNMAP;
        vma->vm_flags |= VM_MIXEDMAP | VM_DONTEXPAND;
        vma->vm_page_prot = msm_gem_pgprot(msm_obj, vm_get_page_prot(vma->vm_flags));

        return 0;
}

/* convenience method to construct a GEM buffer object, and userspace handle */
int msm_gem_new_handle(struct drm_device *dev, struct drm_file *file,
                uint32_t size, uint32_t flags, uint32_t *handle,
                char *name)
{
        struct drm_gem_object *obj;
        int ret;

        obj = msm_gem_new(dev, size, flags);

        if (IS_ERR(obj))
                return PTR_ERR(obj);

        if (name)
                msm_gem_object_set_name(obj, "%s", name);

        ret = drm_gem_handle_create(file, obj, handle);

        /* drop reference from allocate - handle holds it now */
        drm_gem_object_put(obj);

        return ret;
}

static const struct vm_operations_struct vm_ops = {
        .fault = msm_gem_fault,
        .open = drm_gem_vm_open,
        .close = drm_gem_vm_close,
};

static const struct drm_gem_object_funcs msm_gem_object_funcs = {
        .free = msm_gem_free_object,
        .pin = msm_gem_prime_pin,
        .unpin = msm_gem_prime_unpin,
        .get_sg_table = msm_gem_prime_get_sg_table,
        .vmap = msm_gem_prime_vmap,
        .vunmap = msm_gem_prime_vunmap,
        .mmap = msm_gem_object_mmap,
        .vm_ops = &vm_ops,
};

static int msm_gem_new_impl(struct drm_device *dev,
                uint32_t size, uint32_t flags,
                struct drm_gem_object **obj)
{
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_gem_object *msm_obj;

        switch (flags & MSM_BO_CACHE_MASK) {
        case MSM_BO_UNCACHED:
        case MSM_BO_CACHED:
        case MSM_BO_WC:
                break;
        case MSM_BO_CACHED_COHERENT:
                if (priv->has_cached_coherent)
                        break;
                fallthrough;
        default:
                DRM_DEV_ERROR(dev->dev, "invalid cache flag: %x\n",
                                (flags & MSM_BO_CACHE_MASK));
                return -EINVAL;
        }

        msm_obj = kzalloc(sizeof(*msm_obj), GFP_KERNEL);
        if (!msm_obj)
                return -ENOMEM;

        msm_obj->flags = flags;
        msm_obj->madv = MSM_MADV_WILLNEED;

        INIT_LIST_HEAD(&msm_obj->vmas);

        *obj = &msm_obj->base;
        (*obj)->funcs = &msm_gem_object_funcs;

        return 0;
}

struct drm_gem_object *msm_gem_new(struct drm_device *dev, uint32_t size, uint32_t flags)
{
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_gem_object *msm_obj;
        struct drm_gem_object *obj = NULL;
        bool use_vram = false;
        int ret;

        size = PAGE_ALIGN(size);

        if (!msm_use_mmu(dev))
                use_vram = true;
        else if ((flags & (MSM_BO_STOLEN | MSM_BO_SCANOUT)) && priv->vram.size)
                use_vram = true;

        if (GEM_WARN_ON(use_vram && !priv->vram.size))
                return ERR_PTR(-EINVAL);

        /* Disallow zero sized objects as they make the underlying
         * infrastructure grumpy
         */
        if (size == 0)
                return ERR_PTR(-EINVAL);

        ret = msm_gem_new_impl(dev, size, flags, &obj);
        if (ret)
                goto fail;

        msm_obj = to_msm_bo(obj);

        if (use_vram) {
                struct msm_gem_vma *vma;
                struct page **pages;

                drm_gem_private_object_init(dev, obj, size);

                msm_gem_lock(obj);

                vma = add_vma(obj, NULL);
                msm_gem_unlock(obj);
                if (IS_ERR(vma)) {
                        ret = PTR_ERR(vma);
                        goto fail;
                }

                to_msm_bo(obj)->vram_node = &vma->node;

                /* Call chain get_pages() -> update_inactive() tries to
                 * access msm_obj->mm_list, but it is not initialized yet.
                 * To avoid NULL pointer dereference error, initialize
                 * mm_list to be empty.
                 */
                INIT_LIST_HEAD(&msm_obj->mm_list);

                msm_gem_lock(obj);
                pages = get_pages(obj);
                msm_gem_unlock(obj);
                if (IS_ERR(pages)) {
                        ret = PTR_ERR(pages);
                        goto fail;
                }

                vma->iova = physaddr(obj);
        } else {
                ret = drm_gem_object_init(dev, obj, size);
                if (ret)
                        goto fail;
                /*
                 * Our buffers are kept pinned, so allocating them from the
                 * MOVABLE zone is a really bad idea, and conflicts with CMA.
                 * See comments above new_inode() why this is required _and_
                 * expected if you're going to pin these pages.
                 */
                mapping_set_gfp_mask(obj->filp->f_mapping, GFP_HIGHUSER);
        }

        mutex_lock(&priv->mm_lock);
        list_add_tail(&msm_obj->mm_list, &priv->inactive_unpinned);
        mutex_unlock(&priv->mm_lock);

        mutex_lock(&priv->obj_lock);
        list_add_tail(&msm_obj->node, &priv->objects);
        mutex_unlock(&priv->obj_lock);

        return obj;

fail:
        drm_gem_object_put(obj);
        return ERR_PTR(ret);
}

struct drm_gem_object *msm_gem_import(struct drm_device *dev,
                struct dma_buf *dmabuf, struct sg_table *sgt)
{
        struct msm_drm_private *priv = dev->dev_private;
        struct msm_gem_object *msm_obj;
        struct drm_gem_object *obj;
        uint32_t size;
        int ret, npages;

        /* if we don't have IOMMU, don't bother pretending we can import: */
        if (!msm_use_mmu(dev)) {
                DRM_DEV_ERROR(dev->dev, "cannot import without IOMMU\n");
                return ERR_PTR(-EINVAL);
        }

        size = PAGE_ALIGN(dmabuf->size);

        ret = msm_gem_new_impl(dev, size, MSM_BO_WC, &obj);
        if (ret)
                goto fail;

        drm_gem_private_object_init(dev, obj, size);

        npages = size / PAGE_SIZE;

        msm_obj = to_msm_bo(obj);
        msm_gem_lock(obj);
        msm_obj->sgt = sgt;
        msm_obj->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
        if (!msm_obj->pages) {
                msm_gem_unlock(obj);
                ret = -ENOMEM;
                goto fail;
        }

        ret = drm_prime_sg_to_page_array(sgt, msm_obj->pages, npages);
        if (ret) {
                msm_gem_unlock(obj);
                goto fail;
        }

        msm_gem_unlock(obj);

        mutex_lock(&priv->mm_lock);
        list_add_tail(&msm_obj->mm_list, &priv->inactive_unpinned);
        mutex_unlock(&priv->mm_lock);

        mutex_lock(&priv->obj_lock);
        list_add_tail(&msm_obj->node, &priv->objects);
        mutex_unlock(&priv->obj_lock);

        return obj;

fail:
        drm_gem_object_put(obj);
        return ERR_PTR(ret);
}

void *msm_gem_kernel_new(struct drm_device *dev, uint32_t size,
                uint32_t flags, struct msm_gem_address_space *aspace,
                struct drm_gem_object **bo, uint64_t *iova)
{
        void *vaddr;
        struct drm_gem_object *obj = msm_gem_new(dev, size, flags);
        int ret;

        if (IS_ERR(obj))
                return ERR_CAST(obj);

        if (iova) {
                ret = msm_gem_get_and_pin_iova(obj, aspace, iova);
                if (ret)
                        goto err;
        }

        vaddr = msm_gem_get_vaddr(obj);
        if (IS_ERR(vaddr)) {
                msm_gem_unpin_iova(obj, aspace);
                ret = PTR_ERR(vaddr);
                goto err;
        }

        if (bo)
                *bo = obj;

        return vaddr;
err:
        drm_gem_object_put(obj);

        return ERR_PTR(ret);

}

void msm_gem_kernel_put(struct drm_gem_object *bo,
                struct msm_gem_address_space *aspace)
{
        if (IS_ERR_OR_NULL(bo))
                return;

        msm_gem_put_vaddr(bo);
        msm_gem_unpin_iova(bo, aspace);
        drm_gem_object_put(bo);
}

void msm_gem_object_set_name(struct drm_gem_object *bo, const char *fmt, ...)
{
        struct msm_gem_object *msm_obj = to_msm_bo(bo);
        va_list ap;

        if (!fmt)
                return;

        va_start(ap, fmt);
        vsnprintf(msm_obj->name, sizeof(msm_obj->name), fmt, ap);
        va_end(ap);
}