xref: /OK3568_Linux_fs/u-boot/doc/README.splashprepare (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun---------------------------------------------------------------------
2*4882a593SmuzhiyunSplash Screen
3*4882a593Smuzhiyun---------------------------------------------------------------------
4*4882a593SmuzhiyunThe splash_screen_prepare() function is a weak function defined in
5*4882a593Smuzhiyuncommon/splash.c. It is called as part of the splash screen display
6*4882a593Smuzhiyunsequence. It gives the board an opportunity to prepare the splash
7*4882a593Smuzhiyunimage data before it is processed and sent to the frame buffer by
8*4882a593SmuzhiyunU-Boot. Define your own version to use this feature.
9*4882a593Smuzhiyun
10*4882a593SmuzhiyunCONFIG_SPLASH_SOURCE
11*4882a593Smuzhiyun
12*4882a593SmuzhiyunUse the splash_source.c library. This library provides facilities to declare
13*4882a593Smuzhiyunboard specific splash image locations, routines for loading splash image from
14*4882a593Smuzhiyunsupported locations, and a way of controlling the selected splash location
15*4882a593Smuzhiyunusing the "splashsource" environment variable.
16*4882a593Smuzhiyun
17*4882a593Smuzhiyunsplashsource works as follows:
18*4882a593Smuzhiyun- If splashsource is set to a supported location name as defined by board code,
19*4882a593Smuzhiyun  use that splash location.
20*4882a593Smuzhiyun- If splashsource is undefined, use the first splash location as default.
21*4882a593Smuzhiyun- If splashsource is set to an unsupported value, do not load a splash screen.
22*4882a593Smuzhiyun
23*4882a593SmuzhiyunA splash source location can describe either storage with raw data, a storage
24*4882a593Smuzhiyunformatted with a file system or a FIT image. In case of a filesystem, the splash
25*4882a593Smuzhiyunscreen data is loaded as a file. The name of the splash screen file can be
26*4882a593Smuzhiyuncontrolled with the environment variable "splashfile".
27*4882a593Smuzhiyun
28*4882a593SmuzhiyunTo enable loading the splash image from a FIT image, CONFIG_FIT must be
29*4882a593Smuzhiyunenabled. Struct splash_location field 'name' should match the splash image
30*4882a593Smuzhiyunname within the FIT and the FIT should start at the 'offset' field address in
31*4882a593Smuzhiyunthe specified storage.
32