[PATCH v8 4/8] drm/fb_dma: Add generic set_scanout_buffer() for drm_panic

[Jocelyn Falempe]

This was initialy done for imx6, but should work on most drivers
using drm_fb_dma_helper.

v8:
 * Replace get_scanout_buffer() logic with drm_panic_set_buffer()
   (Thomas Zimmermann)

Signed-off-by: Jocelyn Falempe <jfale...@redhat.com>
---
 drivers/gpu/drm/drm_fb_dma_helper.c | 37 +++++++++++++++++++++++++++++
 include/drm/drm_fb_dma_helper.h     |  4 ++++
 2 files changed, 41 insertions(+)

diff --git a/drivers/gpu/drm/drm_fb_dma_helper.c 
b/drivers/gpu/drm/drm_fb_dma_helper.c
index 3b535ad1b07c..31ba71644e2b 100644
--- a/drivers/gpu/drm/drm_fb_dma_helper.c
+++ b/drivers/gpu/drm/drm_fb_dma_helper.c
@@ -15,6 +15,7 @@
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem_dma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
+#include <drm/drm_panic.h>
 #include <drm/drm_plane.h>
 #include <linux/dma-mapping.h>
 #include <linux/module.h>
@@ -148,3 +149,39 @@ void drm_fb_dma_sync_non_coherent(struct drm_device *drm,
        }
 }
 EXPORT_SYMBOL_GPL(drm_fb_dma_sync_non_coherent);
+
+#if defined(CONFIG_DRM_PANIC)
+/**
+ * drm_panic_gem_set_scanout_buffer - helper around drm_panic_set_buffer()
+ *
+ * @plane: primary plane registered to drm_panic
+ * @fb: framebuffer attached to the plane state
+ *
+ * Update plane->panic_scanout with the new framebuffer.
+ */
+void drm_panic_gem_set_scanout_buffer(struct drm_plane *plane,
+                                     struct drm_framebuffer *fb)
+{
+       struct drm_gem_dma_object *dma_obj;
+       struct iosys_map map;
+
+       if (!plane->panic_scanout)
+               return;
+
+       if (fb->modifier == DRM_FORMAT_MOD_LINEAR) {
+               dma_obj = drm_fb_dma_get_gem_obj(fb, 0);
+               if (dma_obj && dma_obj->vaddr) {
+                       iosys_map_set_vaddr(&map, dma_obj->vaddr);
+                       drm_panic_set_buffer(plane->panic_scanout, fb, &map);
+                       return;
+               }
+       }
+       drm_panic_unset_buffer(plane->panic_scanout);
+}
+#else
+void drm_panic_gem_set_scanout_buffer(struct drm_plane *plane,
+                                     struct drm_framebuffer *fb)
+{
+}
+#endif
+EXPORT_SYMBOL(drm_panic_gem_set_scanout_buffer);
diff --git a/include/drm/drm_fb_dma_helper.h b/include/drm/drm_fb_dma_helper.h
index d5e036c57801..9f9ec11343cd 100644
--- a/include/drm/drm_fb_dma_helper.h
+++ b/include/drm/drm_fb_dma_helper.h
@@ -7,6 +7,7 @@
 struct drm_device;
 struct drm_framebuffer;
 struct drm_plane_state;
+struct drm_scanout_buffer;
 
 struct drm_gem_dma_object *drm_fb_dma_get_gem_obj(struct drm_framebuffer *fb,
        unsigned int plane);
@@ -19,5 +20,8 @@ void drm_fb_dma_sync_non_coherent(struct drm_device *drm,
                                  struct drm_plane_state *old_state,
                                  struct drm_plane_state *state);
 
+void drm_panic_gem_set_scanout_buffer(struct drm_plane *plane,
+                                    struct drm_framebuffer *fb);
+
 #endif
 
-- 
2.43.0