rk screen: add the judgement if the variable rk_screen is null pointer

diff --git a/drivers/video/rockchip/screen/rk_screen.c b/drivers/video/rockchip/screen/rk_screen.c
index 242ba4fb668ad68b431abfa63a6723f9a723bd7f..0c031275d414fbdc4b753424c6b266681704a950 100755 (executable)
--- a/drivers/video/rockchip/screen/rk_screen.c
+++ b/drivers/video/rockchip/screen/rk_screen.c
@@ -7,12 +7,18 @@
 static struct rk_screen *rk_screen;
 int  rk_fb_get_prmry_screen(struct rk_screen *screen)
 {
+       if (unlikely(!rk_screen) || unlikely(!screen))
+               return -1;
+
        memcpy(screen, rk_screen, sizeof(struct rk_screen));
        return 0;
 }
 
 int rk_fb_set_prmry_screen(struct rk_screen *screen)
 {
+       if (unlikely(!rk_screen) || unlikely(!screen))
+               return -1;
+
        rk_screen->lcdc_id = screen->lcdc_id;
        rk_screen->screen_id = screen->screen_id;
        rk_screen->x_mirror = screen->x_mirror;
@@ -27,16 +33,22 @@ int rk_fb_set_prmry_screen(struct rk_screen *screen)
 size_t get_fb_size(void)
 {
        size_t size = 0;
-       int xres = rk_screen->mode.xres;
-       int yres = rk_screen->mode.yres;
+       u32 xres = 0;
+       u32 yres = 0;
+
+       if (unlikely(!rk_screen))
+               return 0;
+
+       xres = rk_screen->mode.xres;
+       yres = rk_screen->mode.yres;
 
-       /*align as 64 bytes(16*4) in an odd number of times*/
+       /* align as 64 bytes(16*4) in an odd number of times */
        xres = ALIGN_64BYTE_ODD_TIMES(xres, ALIGN_PIXEL_64BYTE_RGB8888);
 
        #if defined(CONFIG_THREE_FB_BUFFER)
-               size = (xres * yres << 2) * 3; //three buffer
+               size = (xres * yres << 2) * 3;  /* three buffer */
        #else
-               size = (xres * yres << 2) << 1; //two buffer
+               size = (xres * yres << 2) << 1; /* two buffer */
        #endif
        return ALIGN(size, SZ_1M);
 }