sunxi: video: Add support for video-mode environment variable

Add support for the standard video-mode environment variable using the
videomodes.c video_get_ctfb_res_modes() helper function.

This will allow users to specify the resolution e.g. :

setenv video-mode sunxi:video-mode=1280x1024-24@60
saveenv

Also make the reserved fb mem slightly larger to allow 1920x1200 to work.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Acked-by: Anatolij Gustschin <agust@denx.de>
diff --git a/drivers/video/sunxi_display.c b/drivers/video/sunxi_display.c
index cedb56e..cf81e45 100644
--- a/drivers/video/sunxi_display.c
+++ b/drivers/video/sunxi_display.c
@@ -358,7 +358,9 @@
 void *video_hw_init(void)
 {
 	static GraphicDevice *graphic_device = &sunxi_display.graphic_device;
-	const struct ctfb_res_modes *mode = &res_mode_init[RES_MODE_1024x768];
+	const struct ctfb_res_modes *mode;
+	const char *options;
+	unsigned int depth;
 	int ret;
 
 	memset(&sunxi_display, 0, sizeof(struct sunxi_display));
@@ -367,14 +369,22 @@
 	       CONFIG_SUNXI_FB_SIZE >> 10);
 	gd->fb_base = gd->ram_top;
 
+	video_get_ctfb_res_modes(RES_MODE_1024x768, 24, &mode, &depth, &options);
+
 	ret = sunxi_hdmi_hpd_detect();
 	if (!ret)
 		return NULL;
 
 	printf("HDMI connected.\n");
-	sunxi_display.enabled = true;
 
-	printf("Setting up a %dx%d console.\n", mode->xres, mode->yres);
+	if (mode->vmode != FB_VMODE_NONINTERLACED) {
+		printf("Only non-interlaced modes supported, falling back to 1024x768\n");
+		mode = &res_mode_init[RES_MODE_1024x768];
+	} else {
+		printf("Setting up a %dx%d console\n", mode->xres, mode->yres);
+	}
+
+	sunxi_display.enabled = true;
 	sunxi_engines_init();
 	sunxi_mode_set(mode, gd->fb_base - CONFIG_SYS_SDRAM_BASE);