Sound: Add command for audio playback

[karo-tx-uboot.git] / doc / README.commands

diff --git a/doc/README.commands b/doc/README.commands
index 27815d2ba18faada4344e68ed65ac3b188569797..923418b1a455a4dc610c4efd4c5f59b5d5da6263 100644 (file)
--- a/doc/README.commands
+++ b/doc/README.commands
@@ -15,17 +15,24 @@ help:        Long description. This is a string
 
 **** Behind the scene ******
 
-The structure created is named with a special prefix (__u_boot_cmd_)
+The structure created is named with a special prefix (__u_boot_list_cmd_)
 and placed by the linker in a special section.
 
 This makes it possible for the final link to extract all commands
 compiled into any object code and construct a static array so the
-command can be found in an array starting at __u_boot_cmd_start.
+command can be found in an array starting at _u_boot_list_cmd__start.
+
+To ensure that the linker does not discard these symbols when linking
+full U-Boot we generate a list of all the commands we have built (based
+on the sections mentioned above) and use that to force the linker to
+first enter the symbol as undefined in the output object so that there
+is then a need for the symbol to be kept (this is the UNDEF_SYM logic in
+the Makefile).
 
 If a new board is defined do not forget to define the command section
 by writing in u-boot.lds ($(TOPDIR)/board/boardname/u-boot.lds) these
 3 lines:
 
-       __u_boot_cmd_start = .;
-       .u_boot_cmd : { *(.u_boot_cmd) }
-       __u_boot_cmd_end = .;
+       .u_boot_list : {
+       #include "u-boot.lst";
+       }