drm/gem: Add drm_gem_object_funcs

This adds an optional function table on GEM objects.
The main benefit is for drivers that support more than one type of
memory (shmem,vram,cma) for their buffers depending on the hardware it
runs on. With the callbacks attached to the GEM object itself, it is
easier to have core helpers for the the various buffer types. The driver
only has to make the decision about buffer type on GEM object creation
and all other callbacks can be handled by the chosen helper.

drm_driver->gem_prime_res_obj has not been added since there's a todo to
put a reservation_object into drm_gem_object.

v3: Add todo entry

v2: Drop drm_gem_object_funcs->prime_mmap in favour of
drm_gem_prime_mmap() (Daniel Vetter)

v1:
- drm_gem_object_funcs.map -> .prime_map let it only do PRIME mmap like
  the function it superseeds (Daniel Vetter)
- Flip around the if ladders and make obj->funcs the first choice
  highlighting the fact that this the new default way of doing it
  (Daniel Vetter)

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181110145647.17580-4-noralf@tronnes.org

3 files changed, 121 insertions, 34 deletions

diff --git a/drivers/gpu/drm/drm_client.c b/drivers/gpu/drm/drm_client.c
index fc03d26fcacc..9b2bd28dde0a 100644
--- a/drivers/gpu/drm/drm_client.c
+++ b/drivers/gpu/drm/drm_client.c
@@ -81,8 +81,7 @@ int drm_client_init(struct drm_device *dev, struct drm_client_dev *client,
 {
         int ret;
 
-        if (!drm_core_check_feature(dev, DRIVER_MODESET) ||
-            !dev->driver->dumb_create || !dev->driver->gem_prime_vmap)
+        if (!drm_core_check_feature(dev, DRIVER_MODESET) || !dev->driver->dumb_create)
                 return -EOPNOTSUPP;
 
         if (funcs && !try_module_get(funcs->owner))
@@ -229,8 +228,7 @@ static void drm_client_buffer_delete(struct drm_client_buffer *buffer)
 {
         struct drm_device *dev = buffer->client->dev;
 
-        if (buffer->vaddr && dev->driver->gem_prime_vunmap)
-                dev->driver->gem_prime_vunmap(buffer->gem, buffer->vaddr);
+        drm_gem_vunmap(buffer->gem, buffer->vaddr);
 
         if (buffer->gem)
                 drm_gem_object_put_unlocked(buffer->gem);
@@ -283,9 +281,9 @@ drm_client_buffer_create(struct drm_client_dev *client, u32 width, u32 height, u
          * fd_install step out of the driver backend hooks, to make that
          * final step optional for internal users.
          */
-        vaddr = dev->driver->gem_prime_vmap(obj);
-        if (!vaddr) {
-                ret = -ENOMEM;
+        vaddr = drm_gem_vmap(obj);
+        if (IS_ERR(vaddr)) {
+                ret = PTR_ERR(vaddr);
                 goto err_delete;
         }
 
diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
index 512078ebd97b..8b55ece97967 100644
--- a/drivers/gpu/drm/drm_gem.c
+++ b/drivers/gpu/drm/drm_gem.c
@@ -257,7 +257,9 @@ drm_gem_object_release_handle(int id, void *ptr, void *data)
         struct drm_gem_object *obj = ptr;
         struct drm_device *dev = obj->dev;
 
-        if (dev->driver->gem_close_object)
+        if (obj->funcs && obj->funcs->close)
+                obj->funcs->close(obj, file_priv);
+        else if (dev->driver->gem_close_object)
                 dev->driver->gem_close_object(obj, file_priv);
 
         if (drm_core_check_feature(dev, DRIVER_PRIME))
@@ -410,7 +412,11 @@ drm_gem_handle_create_tail(struct drm_file *file_priv,
         if (ret)
                 goto err_remove;
 
-        if (dev->driver->gem_open_object) {
+        if (obj->funcs && obj->funcs->open) {
+                ret = obj->funcs->open(obj, file_priv);
+                if (ret)
+                        goto err_revoke;
+        } else if (dev->driver->gem_open_object) {
                 ret = dev->driver->gem_open_object(obj, file_priv);
                 if (ret)
                         goto err_revoke;
@@ -835,7 +841,9 @@ drm_gem_object_free(struct kref *kref)
                 container_of(kref, struct drm_gem_object, refcount);
         struct drm_device *dev = obj->dev;
 
-        if (dev->driver->gem_free_object_unlocked) {
+        if (obj->funcs) {
+                obj->funcs->free(obj);
+        } else if (dev->driver->gem_free_object_unlocked) {
                 dev->driver->gem_free_object_unlocked(obj);
         } else if (dev->driver->gem_free_object) {
                 WARN_ON(!mutex_is_locked(&dev->struct_mutex));
@@ -864,13 +872,13 @@ drm_gem_object_put_unlocked(struct drm_gem_object *obj)
 
         dev = obj->dev;
 
-        if (dev->driver->gem_free_object_unlocked) {
-                kref_put(&obj->refcount, drm_gem_object_free);
-        } else {
+        if (dev->driver->gem_free_object) {
                 might_lock(&dev->struct_mutex);
                 if (kref_put_mutex(&obj->refcount, drm_gem_object_free,
                                 &dev->struct_mutex))
                         mutex_unlock(&dev->struct_mutex);
+        } else {
+                kref_put(&obj->refcount, drm_gem_object_free);
         }
 }
 EXPORT_SYMBOL(drm_gem_object_put_unlocked);
@@ -960,11 +968,14 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
         if (obj_size < vma->vm_end - vma->vm_start)
                 return -EINVAL;
 
-        if (!dev->driver->gem_vm_ops)
+        if (obj->funcs && obj->funcs->vm_ops)
+                vma->vm_ops = obj->funcs->vm_ops;
+        else if (dev->driver->gem_vm_ops)
+                vma->vm_ops = dev->driver->gem_vm_ops;
+        else
                 return -EINVAL;
 
         vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
-        vma->vm_ops = dev->driver->gem_vm_ops;
         vma->vm_private_data = obj;
         vma->vm_page_prot = pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
         vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
@@ -1066,6 +1077,86 @@ void drm_gem_print_info(struct drm_printer *p, unsigned int indent,
         drm_printf_indent(p, indent, "imported=%s\n",
                           obj->import_attach ? "yes" : "no");
 
-        if (obj->dev->driver->gem_print_info)
+        if (obj->funcs && obj->funcs->print_info)
+                obj->funcs->print_info(p, indent, obj);
+        else if (obj->dev->driver->gem_print_info)
                 obj->dev->driver->gem_print_info(p, indent, obj);
 }
+
+/**
+ * drm_gem_pin - Pin backing buffer in memory
+ * @obj: GEM object
+ *
+ * Make sure the backing buffer is pinned in memory.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_gem_pin(struct drm_gem_object *obj)
+{
+        if (obj->funcs && obj->funcs->pin)
+                return obj->funcs->pin(obj);
+        else if (obj->dev->driver->gem_prime_pin)
+                return obj->dev->driver->gem_prime_pin(obj);
+        else
+                return 0;
+}
+EXPORT_SYMBOL(drm_gem_pin);
+
+/**
+ * drm_gem_unpin - Unpin backing buffer from memory
+ * @obj: GEM object
+ *
+ * Relax the requirement that the backing buffer is pinned in memory.
+ */
+void drm_gem_unpin(struct drm_gem_object *obj)
+{
+        if (obj->funcs && obj->funcs->unpin)
+                obj->funcs->unpin(obj);
+        else if (obj->dev->driver->gem_prime_unpin)
+                obj->dev->driver->gem_prime_unpin(obj);
+}
+EXPORT_SYMBOL(drm_gem_unpin);
+
+/**
+ * drm_gem_vmap - Map buffer into kernel virtual address space
+ * @obj: GEM object
+ *
+ * Returns:
+ * A virtual pointer to a newly created GEM object or an ERR_PTR-encoded negative
+ * error code on failure.
+ */
+void *drm_gem_vmap(struct drm_gem_object *obj)
+{
+        void *vaddr;
+
+        if (obj->funcs && obj->funcs->vmap)
+                vaddr = obj->funcs->vmap(obj);
+        else if (obj->dev->driver->gem_prime_vmap)
+                vaddr = obj->dev->driver->gem_prime_vmap(obj);
+        else
+                vaddr = ERR_PTR(-EOPNOTSUPP);
+
+        if (!vaddr)
+                vaddr = ERR_PTR(-ENOMEM);
+
+        return vaddr;
+}
+EXPORT_SYMBOL(drm_gem_vmap);
+
+/**
+ * drm_gem_vunmap - Remove buffer mapping from kernel virtual address space
+ * @obj: GEM object
+ * @vaddr: Virtual address (can be NULL)
+ */
+void drm_gem_vunmap(struct drm_gem_object *obj, void *vaddr)
+{
+        if (!vaddr)
+                return;
+
+        if (obj->funcs && obj->funcs->vunmap)
+                obj->funcs->vunmap(obj, vaddr);
+        else if (obj->dev->driver->gem_prime_vunmap)
+                obj->dev->driver->gem_prime_vunmap(obj, vaddr);
+}
+EXPORT_SYMBOL(drm_gem_vunmap);
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 6a4fe0216e27..5737cb8c6f03 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -199,7 +199,6 @@ int drm_gem_map_attach(struct dma_buf *dma_buf,
 {
         struct drm_prime_attachment *prime_attach;
         struct drm_gem_object *obj = dma_buf->priv;
-        struct drm_device *dev = obj->dev;
 
         prime_attach = kzalloc(sizeof(*prime_attach), GFP_KERNEL);
         if (!prime_attach)
@@ -208,10 +207,7 @@ int drm_gem_map_attach(struct dma_buf *dma_buf,
         prime_attach->dir = DMA_NONE;
         attach->priv = prime_attach;
 
-        if (!dev->driver->gem_prime_pin)
-                return 0;
-
-        return dev->driver->gem_prime_pin(obj);
+        return drm_gem_pin(obj);
 }
 EXPORT_SYMBOL(drm_gem_map_attach);
 
@@ -228,7 +224,6 @@ void drm_gem_map_detach(struct dma_buf *dma_buf,
 {
         struct drm_prime_attachment *prime_attach = attach->priv;
         struct drm_gem_object *obj = dma_buf->priv;
-        struct drm_device *dev = obj->dev;
 
         if (prime_attach) {
                 struct sg_table *sgt = prime_attach->sgt;
@@ -247,8 +242,7 @@ void drm_gem_map_detach(struct dma_buf *dma_buf,
                 attach->priv = NULL;
         }
 
-        if (dev->driver->gem_prime_unpin)
-                dev->driver->gem_prime_unpin(obj);
+        drm_gem_unpin(obj);
 }
 EXPORT_SYMBOL(drm_gem_map_detach);
 
@@ -310,7 +304,10 @@ struct sg_table *drm_gem_map_dma_buf(struct dma_buf_attachment *attach,
         if (WARN_ON(prime_attach->dir != DMA_NONE))
                 return ERR_PTR(-EBUSY);
 
-        sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
+        if (obj->funcs)
+                sgt = obj->funcs->get_sg_table(obj);
+        else
+                sgt = obj->dev->driver->gem_prime_get_sg_table(obj);
 
         if (!IS_ERR(sgt)) {
                 if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
@@ -406,12 +403,13 @@ EXPORT_SYMBOL(drm_gem_dmabuf_release);
 void *drm_gem_dmabuf_vmap(struct dma_buf *dma_buf)
 {
         struct drm_gem_object *obj = dma_buf->priv;
-        struct drm_device *dev = obj->dev;
+        void *vaddr;
 
-        if (dev->driver->gem_prime_vmap)
-                return dev->driver->gem_prime_vmap(obj);
-        else
-                return NULL;
+        vaddr = drm_gem_vmap(obj);
+        if (IS_ERR(vaddr))
+                vaddr = NULL;
+
+        return vaddr;
 }
 EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
 
@@ -426,10 +424,8 @@ EXPORT_SYMBOL(drm_gem_dmabuf_vmap);
 void drm_gem_dmabuf_vunmap(struct dma_buf *dma_buf, void *vaddr)
 {
         struct drm_gem_object *obj = dma_buf->priv;
-        struct drm_device *dev = obj->dev;
 
-        if (dev->driver->gem_prime_vunmap)
-                dev->driver->gem_prime_vunmap(obj, vaddr);
+        drm_gem_vunmap(obj, vaddr);
 }
 EXPORT_SYMBOL(drm_gem_dmabuf_vunmap);
 
@@ -529,7 +525,9 @@ static struct dma_buf *export_and_register_object(struct drm_device *dev,
                 return dmabuf;
         }
 
-        if (dev->driver->gem_prime_export)
+        if (obj->funcs && obj->funcs->export)
+                dmabuf = obj->funcs->export(obj, flags);
+        else if (dev->driver->gem_prime_export)
                 dmabuf = dev->driver->gem_prime_export(dev, obj, flags);
         else
                 dmabuf = drm_gem_prime_export(dev, obj, flags);