X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;ds=sidebyside;f=doc%2FREADME.falcon;h=e9f8a7583c721cd96eb364ff23d591c0284c70b3;hb=960c3cac7f2b4b667dc835402045f9af428c5451;hp=93e855d20eac55a4779c583f7da68c3299c11055;hpb=3e1b393976ba59045e477fdea0beb69bd29b9102;p=u-boot diff --git a/doc/README.falcon b/doc/README.falcon index 93e855d20e..e9f8a7583c 100644 --- a/doc/README.falcon +++ b/doc/README.falcon @@ -31,9 +31,10 @@ informed to load it before running the kernel. To boot the kernel, these steps under a Falcon-aware U-Boot are required: 1. Boot the board into U-Boot. -Use the "spl export" command to generate the kernel parameters area or the DT. -U-Boot runs as when it boots the kernel, but stops before passing the control -to the kernel. +After loading the desired legacy-format kernel image into memory (and DT as +well, if used), use the "spl export" command to generate the kernel parameters +area or the DT. U-Boot runs as when it boots the kernel, but stops before +passing the control to the kernel. 2. Save the prepared snapshot into persistent media. The address where to save it must be configured into board configuration @@ -41,6 +42,8 @@ file (CONFIG_CMD_SPL_NAND_OFS for NAND). 3. Boot the board into Falcon Mode. SPL will load the kernel and copy the parameters which are saved in the persistent area to the required address. +If a valid uImage is not found at the defined location, U-Boot will be +booted instead. It is required to implement a custom mechanism to select if SPL loads U-Boot or another image. @@ -78,6 +81,19 @@ spl_start_uboot() : required Returns "0" if SPL should start the kernel, "1" if U-Boot must be started. +Environment variables +--------------------- + +A board may chose to look at the environment for decisions about falcon +mode. In this case the following variables may be supported: + +boot_os : Set to yes/Yes/true/True/1 to enable booting to OS, + any other value to fall back to U-Boot (including + unset) +falcon_args_file : Filename to load as the 'args' portion of falcon mode + rather than the hard-coded value. +falcon_image_file : Filename to load as the OS image portion of falcon + mode rather than the hard-coded value. Using spl command -----------------