/*
 * Copyright (C) 2013 Red Hat
 * Author: Rob Clark <robdclark@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

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

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

static void msm_gem_vunmap_locked(struct drm_gem_object *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;
}

/* 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);

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

                msm_obj->sgt = drm_prime_pages_to_sg(p, npages);
                if (IS_ERR(msm_obj->sgt)) {
                        dev_err(dev->dev, "failed to allocate sgt\n");
                        return ERR_CAST(msm_obj->sgt);
                }

                msm_obj->pages = p;

                /* 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))
                        dma_map_sg(dev->dev, msm_obj->sgt->sgl,
                                        msm_obj->sgt->nents, DMA_BIDIRECTIONAL);
        }

        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) {
                /* 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))
                        dma_unmap_sg(obj->dev->dev, msm_obj->sgt->sgl,
                                        msm_obj->sgt->nents, DMA_BIDIRECTIONAL);
                sg_free_table(msm_obj->sgt);
                kfree(msm_obj->sgt);

                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;

        mutex_lock(&msm_obj->lock);

        if (WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED)) {
                mutex_unlock(&msm_obj->lock);
                return ERR_PTR(-EBUSY);
        }

        p = get_pages(obj);
        mutex_unlock(&msm_obj->lock);
        return p;
}

void msm_gem_put_pages(struct drm_gem_object *obj)
{
        /* when we start tracking the pin count, then do something here */
}

int msm_gem_mmap_obj(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;

        if (msm_obj->flags & MSM_BO_WC) {
                vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
        } else if (msm_obj->flags & MSM_BO_UNCACHED) {
                vma->vm_page_prot = pgprot_noncached(vm_get_page_prot(vma->vm_flags));
        } else {
                /*
                 * Shunt off cached objs to shmem file so they have their own
                 * address_space (so unmap_mapping_range does what we want,
                 * in particular in the case of mmap'd dmabufs)
                 */
                fput(vma->vm_file);
                get_file(obj->filp);
                vma->vm_pgoff = 0;
                vma->vm_file  = obj->filp;

                vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
        }

        return 0;
}

int msm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
{
        int ret;

        ret = drm_gem_mmap(filp, vma);
        if (ret) {
                DBG("mmap failed: %d", ret);
                return ret;
        }

        return msm_gem_mmap_obj(vma->vm_private_data, vma);
}

int 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 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.
         */
        ret = mutex_lock_interruptible(&msm_obj->lock);
        if (ret)
                goto out;

        if (WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED)) {
                mutex_unlock(&msm_obj->lock);
                return VM_FAULT_SIGBUS;
        }

        /* make sure we have pages attached now */
        pages = get_pages(obj);
        if (IS_ERR(pages)) {
                ret = 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 = vm_insert_mixed(vma, vmf->address, __pfn_to_pfn_t(pfn, PFN_DEV));

out_unlock:
        mutex_unlock(&msm_obj->lock);
out:
        switch (ret) {
        case -EAGAIN:
        case 0:
        case -ERESTARTSYS:
        case -EINTR:
        case -EBUSY:
                /*
                 * EBUSY is ok: this just means that another thread
                 * already did the job.
                 */
                return VM_FAULT_NOPAGE;
        case -ENOMEM:
                return VM_FAULT_OOM;
        default:
                return VM_FAULT_SIGBUS;
        }
}

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

        WARN_ON(!mutex_is_locked(&msm_obj->lock));

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

        if (ret) {
                dev_err(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;
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        mutex_lock(&msm_obj->lock);
        offset = mmap_offset(obj);
        mutex_unlock(&msm_obj->lock);
        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;

        WARN_ON(!mutex_is_locked(&msm_obj->lock));

        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;

        WARN_ON(!mutex_is_locked(&msm_obj->lock));

        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);
}

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

        WARN_ON(!mutex_is_locked(&msm_obj->lock));

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

/* get iova, taking a reference.  Should have a matching put */
int msm_gem_get_iova(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace, uint64_t *iova)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct msm_gem_vma *vma;
        int ret = 0;

        mutex_lock(&msm_obj->lock);

        if (WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED)) {
                mutex_unlock(&msm_obj->lock);
                return -EBUSY;
        }

        vma = lookup_vma(obj, aspace);

        if (!vma) {
                struct page **pages;

                vma = add_vma(obj, aspace);
                if (IS_ERR(vma)) {
                        ret = PTR_ERR(vma);
                        goto unlock;
                }

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

                ret = msm_gem_map_vma(aspace, vma, msm_obj->sgt,
                                obj->size >> PAGE_SHIFT);
                if (ret)
                        goto fail;
        }

        *iova = vma->iova;

        mutex_unlock(&msm_obj->lock);
        return 0;

fail:
        del_vma(vma);
unlock:
        mutex_unlock(&msm_obj->lock);
        return ret;
}

/* get iova without taking a reference, used in places where you have
 * already done a 'msm_gem_get_iova()'.
 */
uint64_t msm_gem_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;

        mutex_lock(&msm_obj->lock);
        vma = lookup_vma(obj, aspace);
        mutex_unlock(&msm_obj->lock);
        WARN_ON(!vma);

        return vma ? vma->iova : 0;
}

void msm_gem_put_iova(struct drm_gem_object *obj,
                struct msm_gem_address_space *aspace)
{
        // XXX TODO ..
        // NOTE: probably don't need a _locked() version.. we wouldn't
        // normally unmap here, but instead just mark that it could be
        // unmapped (if the iova refcnt drops to zero), but then later
        // if another _get_iova_locked() fails we can start unmapping
        // things that are no longer needed..
}

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);
}

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_unreference_unlocked(obj);

fail:
        return ret;
}

void *msm_gem_get_vaddr(struct drm_gem_object *obj)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        int ret = 0;

        mutex_lock(&msm_obj->lock);

        if (WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED)) {
                mutex_unlock(&msm_obj->lock);
                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, pgprot_writecombine(PAGE_KERNEL));
                if (msm_obj->vaddr == NULL) {
                        ret = -ENOMEM;
                        goto fail;
                }
        }

        mutex_unlock(&msm_obj->lock);
        return msm_obj->vaddr;

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

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

        mutex_lock(&msm_obj->lock);
        WARN_ON(msm_obj->vmap_count < 1);
        msm_obj->vmap_count--;
        mutex_unlock(&msm_obj->lock);
}

/* 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);

        mutex_lock(&msm_obj->lock);

        WARN_ON(!mutex_is_locked(&obj->dev->struct_mutex));

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

        madv = msm_obj->madv;

        mutex_unlock(&msm_obj->lock);

        return (madv != __MSM_MADV_PURGED);
}

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

        WARN_ON(!mutex_is_locked(&dev->struct_mutex));
        WARN_ON(!is_purgeable(msm_obj));
        WARN_ON(obj->import_attach);

        mutex_lock_nested(&msm_obj->lock, subclass);

        put_iova(obj);

        msm_gem_vunmap_locked(obj);

        put_pages(obj);

        msm_obj->madv = __MSM_MADV_PURGED;

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

        mutex_unlock(&msm_obj->lock);
}

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

        WARN_ON(!mutex_is_locked(&msm_obj->lock));

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

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

void msm_gem_vunmap(struct drm_gem_object *obj, enum msm_gem_lock subclass)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);

        mutex_lock_nested(&msm_obj->lock, subclass);
        msm_gem_vunmap_locked(obj);
        mutex_unlock(&msm_obj->lock);
}

/* must be called before _move_to_active().. */
int msm_gem_sync_object(struct drm_gem_object *obj,
                struct msm_fence_context *fctx, bool exclusive)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        struct reservation_object_list *fobj;
        struct dma_fence *fence;
        int i, ret;

        fobj = reservation_object_get_list(msm_obj->resv);
        if (!fobj || (fobj->shared_count == 0)) {
                fence = reservation_object_get_excl(msm_obj->resv);
                /* don't need to wait on our own fences, since ring is fifo */
                if (fence && (fence->context != fctx->context)) {
                        ret = dma_fence_wait(fence, true);
                        if (ret)
                                return ret;
                }
        }

        if (!exclusive || !fobj)
                return 0;

        for (i = 0; i < fobj->shared_count; i++) {
                fence = rcu_dereference_protected(fobj->shared[i],
                                                reservation_object_held(msm_obj->resv));
                if (fence->context != fctx->context) {
                        ret = dma_fence_wait(fence, true);
                        if (ret)
                                return ret;
                }
        }

        return 0;
}

void msm_gem_move_to_active(struct drm_gem_object *obj,
                struct msm_gpu *gpu, bool exclusive, struct dma_fence *fence)
{
        struct msm_gem_object *msm_obj = to_msm_bo(obj);
        WARN_ON(msm_obj->madv != MSM_MADV_WILLNEED);
        msm_obj->gpu = gpu;
        if (exclusive)
                reservation_object_add_excl_fence(msm_obj->resv, fence);
        else
                reservation_object_add_shared_fence(msm_obj->resv, fence);
        list_del_init(&msm_obj->mm_list);
        list_add_tail(&msm_obj->mm_list, &gpu->active_list);
}

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

        WARN_ON(!mutex_is_locked(&dev->struct_mutex));

        msm_obj->gpu = NULL;
        list_del_init(&msm_obj->mm_list);
        list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
}

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

        ret = reservation_object_wait_timeout_rcu(msm_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 %u\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_object *msm_obj = to_msm_bo(obj);
        struct reservation_object *robj = msm_obj->resv;
        struct reservation_object_list *fobj;
        struct dma_fence *fence;
        struct msm_gem_vma *vma;
        uint64_t off = drm_vma_node_start(&obj->vma_node);
        const char *madv;

        mutex_lock(&msm_obj->lock);

        switch (msm_obj->madv) {
        case __MSM_MADV_PURGED:
                madv = " purged";
                break;
        case MSM_MADV_DONTNEED:
                madv = " purgeable";
                break;
        case MSM_MADV_WILLNEED:
        default:
                madv = "";
                break;
        }

        seq_printf(m, "%08x: %c %2d (%2d) %08llx %p\t",
                        msm_obj->flags, is_active(msm_obj) ? 'A' : 'I',
                        obj->name, kref_read(&obj->refcount),
                        off, msm_obj->vaddr);

        /* FIXME: we need to print the address space here too */
        list_for_each_entry(vma, &msm_obj->vmas, list)
                seq_printf(m, " %08llx", vma->iova);

        seq_printf(m, " %zu%s\n", obj->size, madv);

        rcu_read_lock();
        fobj = rcu_dereference(robj->fence);
        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 = rcu_dereference(robj->fence_excl);
        if (fence)
                describe_fence(fence, "Exclusive", m);
        rcu_read_unlock();

        mutex_unlock(&msm_obj->lock);
}

void msm_gem_describe_objects(struct list_head *list, struct seq_file *m)
{
        struct msm_gem_object *msm_obj;
        int count = 0;
        size_t size = 0;

        list_for_each_entry(msm_obj, list, mm_list) {
                struct drm_gem_object *obj = &msm_obj->base;
                seq_printf(m, "   ");
                msm_gem_describe(obj, m);
                count++;
                size += obj->size;
        }

        seq_printf(m, "Total %d objects, %zu bytes\n", count, size);
}
#endif

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

        WARN_ON(!mutex_is_locked(&dev->struct_mutex));

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

        list_del(&msm_obj->mm_list);

        mutex_lock(&msm_obj->lock);

        put_iova(obj);

        if (obj->import_attach) {
                if (msm_obj->vaddr)
                        dma_buf_vunmap(obj->import_attach->dmabuf, msm_obj->vaddr);

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

                drm_prime_gem_destroy(obj, msm_obj->sgt);
        } else {
                msm_gem_vunmap_locked(obj);
                put_pages(obj);
        }

        if (msm_obj->resv == &msm_obj->_resv)
                reservation_object_fini(msm_obj->resv);

        drm_gem_object_release(obj);

        mutex_unlock(&msm_obj->lock);
        kfree(msm_obj);
}

/* 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)
{
        struct drm_gem_object *obj;
        int ret;

        obj = msm_gem_new(dev, size, flags);

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

        ret = drm_gem_handle_create(file, obj, handle);

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

        return ret;
}

static int msm_gem_new_impl(struct drm_device *dev,
                uint32_t size, uint32_t flags,
                struct reservation_object *resv,
                struct drm_gem_object **obj,
                bool struct_mutex_locked)
{
        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;
        default:
                dev_err(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;

        mutex_init(&msm_obj->lock);

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

        if (resv) {
                msm_obj->resv = resv;
        } else {
                msm_obj->resv = &msm_obj->_resv;
                reservation_object_init(msm_obj->resv);
        }

        INIT_LIST_HEAD(&msm_obj->submit_entry);
        INIT_LIST_HEAD(&msm_obj->vmas);

        if (struct_mutex_locked) {
                WARN_ON(!mutex_is_locked(&dev->struct_mutex));
                list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
        } else {
                mutex_lock(&dev->struct_mutex);
                list_add_tail(&msm_obj->mm_list, &priv->inactive_list);
                mutex_unlock(&dev->struct_mutex);
        }

        *obj = &msm_obj->base;

        return 0;
}

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

        size = PAGE_ALIGN(size);

        if (!iommu_present(&platform_bus_type))
                use_vram = true;
        else if ((flags & MSM_BO_STOLEN) && priv->vram.size)
                use_vram = true;

        if (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, NULL, &obj, struct_mutex_locked);
        if (ret)
                goto fail;

        if (use_vram) {
                struct msm_gem_vma *vma;
                struct page **pages;
                struct msm_gem_object *msm_obj = to_msm_bo(obj);

                mutex_lock(&msm_obj->lock);

                vma = add_vma(obj, NULL);
                mutex_unlock(&msm_obj->lock);
                if (IS_ERR(vma)) {
                        ret = PTR_ERR(vma);
                        goto fail;
                }

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

                drm_gem_private_object_init(dev, obj, size);

                pages = get_pages(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;
        }

        return obj;

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

struct drm_gem_object *msm_gem_new_locked(struct drm_device *dev,
                uint32_t size, uint32_t flags)
{
        return _msm_gem_new(dev, size, flags, true);
}

struct drm_gem_object *msm_gem_new(struct drm_device *dev,
                uint32_t size, uint32_t flags)
{
        return _msm_gem_new(dev, size, flags, false);
}

struct drm_gem_object *msm_gem_import(struct drm_device *dev,
                struct dma_buf *dmabuf, struct sg_table *sgt)
{
        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 (!iommu_present(&platform_bus_type)) {
                dev_err(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, dmabuf->resv, &obj, false);
        if (ret)
                goto fail;

        drm_gem_private_object_init(dev, obj, size);

        npages = size / PAGE_SIZE;

        msm_obj = to_msm_bo(obj);
        mutex_lock(&msm_obj->lock);
        msm_obj->sgt = sgt;
        msm_obj->pages = kvmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
        if (!msm_obj->pages) {
                mutex_unlock(&msm_obj->lock);
                ret = -ENOMEM;
                goto fail;

        }

        ret = drm_prime_sg_to_page_addr_arrays(sgt, msm_obj->pages, NULL, npages);
        if (ret) {
                mutex_unlock(&msm_obj->lock);
                goto fail;
        }

        mutex_unlock(&msm_obj->lock);
        return obj;

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

static 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, bool locked)
{
        void *vaddr;
        struct drm_gem_object *obj = _msm_gem_new(dev, size, flags, locked);
        int ret;

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

        if (iova) {
                ret = msm_gem_get_iova(obj, aspace, iova);
                if (ret) {
                        drm_gem_object_unreference(obj);
                        return ERR_PTR(ret);
                }
        }

        vaddr = msm_gem_get_vaddr(obj);
        if (IS_ERR(vaddr)) {
                msm_gem_put_iova(obj, aspace);
                drm_gem_object_unreference(obj);
                return ERR_CAST(vaddr);
        }

        if (bo)
                *bo = obj;

        return vaddr;
}

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)
{
        return _msm_gem_kernel_new(dev, size, flags, aspace, bo, iova, false);
}

void *msm_gem_kernel_new_locked(struct drm_device *dev, uint32_t size,
                uint32_t flags, struct msm_gem_address_space *aspace,
                struct drm_gem_object **bo, uint64_t *iova)
{
        return _msm_gem_kernel_new(dev, size, flags, aspace, bo, iova, true);
}