drm/ast: Initialized data needed to map fbdev memory

Due to a missing initialization there was no way to map fbdev memory.
Thus for example using the Xserver with the fbdev driver failed.
This fix adds initialization for fix.smem_start and fix.smem_len
in the fb_info structure, which fixes this problem.

Requested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: stable@vger.kernel.org
Signed-off-by: Egbert Eich <eich@suse.de>
[pulled from SuSE tree by me - airlied]
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/ast/ast_drv.h

@@ -315,6 +315,7 @@ int ast_framebuffer_init(struct drm_device *dev,
 int ast_fbdev_init(struct drm_device *dev);
 void ast_fbdev_fini(struct drm_device *dev);
 void ast_fbdev_set_suspend(struct drm_device *dev, int state);
+void ast_fbdev_set_base(struct ast_private *ast, unsigned long gpu_addr);
 
 struct ast_bo {
 	struct ttm_buffer_object bo;

drivers/gpu/drm/ast/ast_fb.c

@@ -365,3 +365,10 @@ void ast_fbdev_set_suspend(struct drm_device *dev, int state)
 
 	drm_fb_helper_set_suspend(&ast->fbdev->helper, state);
 }
+
+void ast_fbdev_set_base(struct ast_private *ast, unsigned long gpu_addr)
+{
+	ast->fbdev->helper.fbdev->fix.smem_start =
+		ast->fbdev->helper.fbdev->apertures->ranges[0].base + gpu_addr;
+	ast->fbdev->helper.fbdev->fix.smem_len = ast->vram_size - gpu_addr;
+}

drivers/gpu/drm/ast/ast_main.c

@@ -448,6 +448,7 @@ int ast_driver_load(struct drm_device *dev, unsigned long flags)
 	dev->mode_config.min_height = 0;
 	dev->mode_config.preferred_depth = 24;
 	dev->mode_config.prefer_shadow = 1;
+	dev->mode_config.fb_base = pci_resource_start(ast->dev->pdev, 0);
 
 	if (ast->chip == AST2100 ||
 	    ast->chip == AST2200 ||

drivers/gpu/drm/ast/ast_mode.c

@@ -547,6 +547,8 @@ static int ast_crtc_do_set_base(struct drm_crtc *crtc,
 		ret = ttm_bo_kmap(&bo->bo, 0, bo->bo.num_pages, &bo->kmap);
 		if (ret)
 			DRM_ERROR("failed to kmap fbcon\n");
+		else
+			ast_fbdev_set_base(ast, gpu_addr);
 	}
 	ast_bo_unreserve(bo);