render-device: Add API to allocate DMA buffers

Only possible with the gbm implementation; aims to make it easier for
users of render devices to allocate DMA buffers.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1854>

src/backends/native/meta-backend-native-types.h

@@ -31,6 +31,7 @@ typedef struct _MetaCrtcVirtual MetaCrtcVirtual;
 typedef struct _MetaCrtcModeVirtual MetaCrtcModeVirtual;
 typedef struct _MetaDevicePool MetaDevicePool;
 typedef struct _MetaDeviceFile MetaDeviceFile;
+typedef struct _MetaDrmBuffer MetaDrmBuffer;
 
 typedef enum _MetaSeatNativeFlag
 {

src/backends/native/meta-render-device-gbm.c

@@ -26,6 +26,7 @@
 #include <gbm.h>
 
 #include "backends/meta-backend-private.h"
+#include "backends/native/meta-drm-buffer-gbm.h"
 
 struct _MetaRenderDeviceGbm
 {
@@ -115,6 +116,36 @@ meta_render_device_gbm_create_egl_display (MetaRenderDevice  *render_device,
   return egl_display;
 }
 
+static MetaDrmBuffer *
+meta_render_device_gbm_allocate_dma_buf (MetaRenderDevice    *render_device,
+                                         int                  width,
+                                         int                  height,
+                                         uint32_t             format,
+                                         MetaDrmBufferFlags   flags,
+                                         GError             **error)
+{
+  MetaRenderDeviceGbm *render_device_gbm =
+    META_RENDER_DEVICE_GBM (render_device);
+  MetaDeviceFile *device_file;
+  struct gbm_bo *gbm_bo;
+  MetaDrmBufferGbm *buffer_gbm;
+
+  gbm_bo = gbm_bo_create (render_device_gbm->gbm_device,
+                          width, height, format,
+                          GBM_BO_USE_RENDERING | GBM_BO_USE_LINEAR);
+  if (!gbm_bo)
+    {
+      g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+                   "Failed to gbm_bo: %s", g_strerror (errno));
+      return NULL;
+    }
+
+  device_file = meta_render_device_get_device_file (render_device);
+  buffer_gbm = meta_drm_buffer_gbm_new_take (device_file, gbm_bo, flags,
+                                             error);
+  return META_DRM_BUFFER (buffer_gbm);
+}
+
 static void
 meta_render_device_gbm_finalize (GObject *object)
 {
@@ -135,6 +166,8 @@ meta_render_device_gbm_class_init (MetaRenderDeviceGbmClass *klass)
 
   render_device_class->create_egl_display =
     meta_render_device_gbm_create_egl_display;
+  render_device_class->allocate_dma_buf =
+    meta_render_device_gbm_allocate_dma_buf;
 }
 
 static void

src/backends/native/meta-render-device-private.h

@@ -26,6 +26,7 @@
 
 #include "backends/meta-egl.h"
 #include "backends/native/meta-device-pool.h"
+#include "backends/native/meta-drm-buffer.h"
 #include "backends/native/meta-render-device.h"
 
 struct _MetaRenderDeviceClass
@@ -34,6 +35,13 @@ struct _MetaRenderDeviceClass
 
   EGLDisplay (* create_egl_display) (MetaRenderDevice  *render_device,
                                      GError           **error);
+
+  MetaDrmBuffer * (* allocate_dma_buf) (MetaRenderDevice    *render_device,
+                                        int                  width,
+                                        int                  height,
+                                        uint32_t             format,
+                                        MetaDrmBufferFlags   flags,
+                                        GError             **error);
 };
 
 #endif /* META_RENDER_DEVICE_PRIVATE_H */

src/backends/native/meta-render-device.c

@@ -24,6 +24,7 @@
 
 #include "backends/meta-backend-private.h"
 #include "backends/meta-egl.h"
+#include "backends/native/meta-backend-native-types.h"
 
 enum
 {
@@ -338,3 +339,28 @@ meta_render_device_get_name (MetaRenderDevice *render_device)
   else
     return "(device-less)";
 }
+
+MetaDrmBuffer *
+meta_render_device_allocate_dma_buf (MetaRenderDevice    *render_device,
+                                     int                  width,
+                                     int                  height,
+                                     uint32_t             format,
+                                     MetaDrmBufferFlags   flags,
+                                     GError             **error)
+{
+  MetaRenderDeviceClass *klass = META_RENDER_DEVICE_GET_CLASS (render_device);
+
+  if (klass->allocate_dma_buf)
+    {
+      return klass->allocate_dma_buf (render_device,
+                                      width, height, format,
+                                      flags,
+                                      error);
+    }
+
+  g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
+               "Render device '%s' doesn't support allocating DMA buffers",
+               meta_render_device_get_name (render_device));
+
+  return NULL;
+}

src/backends/native/meta-render-device.h

@@ -24,6 +24,7 @@
 #include <glib-object.h>
 
 #include "backends/meta-backend-types.h"
+#include "backends/native/meta-backend-native-types.h"
 
 #define META_TYPE_RENDER_DEVICE (meta_render_device_get_type ())
 G_DECLARE_DERIVABLE_TYPE (MetaRenderDevice, meta_render_device,
@@ -40,4 +41,11 @@ gboolean meta_render_device_is_hardware_accelerated (MetaRenderDevice *render_de
 
 MetaDeviceFile * meta_render_device_get_device_file (MetaRenderDevice *render_device);
 
+MetaDrmBuffer * meta_render_device_allocate_dma_buf (MetaRenderDevice    *render_device,
+                                                     int                  width,
+                                                     int                  height,
+                                                     uint32_t             format,
+                                                     MetaDrmBufferFlags   flags,
+                                                     GError             **error);
+
 #endif /* META_RENDER_DEVICE_H */