drm: add KGDB/KDB support

Implement the callbacks for KDB entry/exit via the drm helpers.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

1 files changed, 74 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index 719662034bbf..6245add3768a 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -241,6 +241,80 @@ static int drm_fb_helper_parse_command_line(struct drm_fb_helper *fb_helper)
         return 0;
 }
 
+int drm_fb_helper_debug_enter(struct fb_info *info)
+{
+        struct drm_fb_helper *helper = info->par;
+        struct drm_crtc_helper_funcs *funcs;
+        int i;
+
+        if (list_empty(&kernel_fb_helper_list))
+                return false;
+
+        list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
+                for (i = 0; i < helper->crtc_count; i++) {
+                        struct drm_mode_set *mode_set =
+                                &helper->crtc_info[i].mode_set;
+
+                        if (!mode_set->crtc->enabled)
+                                continue;
+
+                        funcs = mode_set->crtc->helper_private;
+                        funcs->mode_set_base_atomic(mode_set->crtc,
+                                                    mode_set->fb,
+                                                    mode_set->x,
+                                                    mode_set->y);
+
+                }
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(drm_fb_helper_debug_enter);
+
+/* Find the real fb for a given fb helper CRTC */
+static struct drm_framebuffer *drm_mode_config_fb(struct drm_crtc *crtc)
+{
+        struct drm_device *dev = crtc->dev;
+        struct drm_crtc *c;
+
+        list_for_each_entry(c, &dev->mode_config.crtc_list, head) {
+                if (crtc->base.id == c->base.id)
+                        return c->fb;
+        }
+
+        return NULL;
+}
+
+int drm_fb_helper_debug_leave(struct fb_info *info)
+{
+        struct drm_fb_helper *helper = info->par;
+        struct drm_crtc *crtc;
+        struct drm_crtc_helper_funcs *funcs;
+        struct drm_framebuffer *fb;
+        int i;
+
+        for (i = 0; i < helper->crtc_count; i++) {
+                struct drm_mode_set *mode_set = &helper->crtc_info[i].mode_set;
+                crtc = mode_set->crtc;
+                funcs = crtc->helper_private;
+                fb = drm_mode_config_fb(crtc);
+
+                if (!crtc->enabled)
+                        continue;
+
+                if (!fb) {
+                        DRM_ERROR("no fb to restore??\n");
+                        continue;
+                }
+
+                funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x,
+                                            crtc->y);
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(drm_fb_helper_debug_leave);
+
 bool drm_fb_helper_force_kernel_mode(void)
 {
         int i = 0;