[PATCH v4 4/4] drm/mgag200: Add drm_panic support

[Jocelyn Falempe]

Add support for the drm_panic module, which displays a message to
the screen when a kernel panic occurs.

Signed-off-by: Jocelyn Falempe <jfale...@redhat.com>
---
 drivers/gpu/drm/mgag200/mgag200_drv.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c 
b/drivers/gpu/drm/mgag200/mgag200_drv.c
index 976f0ab2006b..229d9c116b42 100644
--- a/drivers/gpu/drm/mgag200/mgag200_drv.c
+++ b/drivers/gpu/drm/mgag200/mgag200_drv.c
@@ -12,10 +12,12 @@
 #include <drm/drm_aperture.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_fbdev_generic.h>
+#include <drm/drm_framebuffer.h>
 #include <drm/drm_file.h>
 #include <drm/drm_ioctl.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_module.h>
+#include <drm/drm_panic.h>
 #include <drm/drm_pciids.h>
 
 #include "mgag200_drv.h"
@@ -83,6 +85,27 @@ resource_size_t mgag200_probe_vram(void __iomem *mem, 
resource_size_t size)
        return offset - 65536;
 }
 
+static int mgag200_get_scanout_buffer(struct drm_device *dev,
+                                     struct drm_scanout_buffer *sb)
+{
+       struct drm_plane *plane;
+       struct mga_device *mdev = to_mga_device(dev);
+       struct iosys_map map = IOSYS_MAP_INIT_VADDR_IOMEM(mdev->vram);
+
+       /* mgag200 has only one plane */
+       drm_for_each_plane(plane, dev) {
+               if (!plane->state || !plane->state->fb)
+                       return -ENODEV;
+               sb->format = plane->state->fb->format;
+               sb->width = plane->state->fb->width;
+               sb->height = plane->state->fb->height;
+               sb->pitch = plane->state->fb->pitches[0];
+               sb->map = map;
+               return 0;
+       }
+       return -ENODEV;
+}
+
 /*
  * DRM driver
  */
@@ -98,6 +121,7 @@ static const struct drm_driver mgag200_driver = {
        .major = DRIVER_MAJOR,
        .minor = DRIVER_MINOR,
        .patchlevel = DRIVER_PATCHLEVEL,
+       .get_scanout_buffer = mgag200_get_scanout_buffer,
        DRM_GEM_SHMEM_DRIVER_OPS,
 };
 
-- 
2.41.0