RPI U-boot run sd card application

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Prepare application

There is an example application "hello_world.c" that is provided in u-boot.

• update the Makefile, with your standalone application. In this case hello_world is already built:

 ELF-y        := hello_world

• re-compile

 ./doit

• check that the build directory has a .bin version

 uboot$ ll build/examples/standalone/hello_world.*
 -rwxrwxr-x 1 arrizza arrizza  594 Jun 19 21:22 build/examples/standalone/hello_world.bin*
 -rw-rw-r-- 1 arrizza arrizza 5616 Jun 19 21:22 build/examples/standalone/hello_world.o
 -rwxrwxr-x 1 arrizza arrizza 1904 Jun 19 21:22 build/examples/standalone/hello_world.srec*
 -rw-rw-r-- 1 arrizza arrizza   41 Jun 19 21:22 build/examples/standalone/hello_world.su

• copy the hello_world.bin to the SD card

determine the load address

• read u-boot-pi-rpi/doc/README.standalone It says ARM based boards default load and start address is 0x0C100000
• if there is any doubt load the s-rec version first, see RPI U-boot run s-rec application to see how to do it:

 U-Boot> loads
 ## Ready for S-Record download ...

 ## First Load Addr = 0x0C100000
 ## Last  Load Addr = 0x0C10024E
 ## Total Size      = 0x0000024F = 591 Bytes
 ## Start Addr      = 0x0C100000
 U-Boot> 

• Note that the Start address is 0x0C100000

load the bin

• start the RPI
• check the .bin is in the sd card

  mmc rescan
  fatls mmc 0

• load it

  U-Boot> load mmc 0 0x0c100000 hello_world.bin
  reading hello_world.bin
  594 bytes read in 11916 ms (0 Bytes/s)

run it

 U-Boot> go 0x0c100000
 ## Starting application at 0x0C100000 ...
 Example expects ABI version 6
 Actual U-Boot ABI version 6
 Hello World
 argc = 1
 argv[0] = "0x0c100000"
 argv[1] = "<NULL>"
 Hit any key to exit ... 
 
 ## Application terminated, rc = 0x0
 U-Boot>

• TODO: change the start address