README.nhk8815 1.3 KB

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  1. The Nomadik 8815 CPU has a "secure" boot mode where no external access
  2. (not even JTAG) is allowed. The "remap" bits in the evaluation board
  3. are configured in order to boot from the internal ROM memory (in
  4. secure mode).
  5. The boot process as defined by the manufacturer executes external code
  6. (loaded from NAND or OneNAND) that that disables such "security" in
  7. order to run u-boot and later the kernel without constraints. Such
  8. code is a proprietary initial boot loader, called "X-Loader" (in case
  9. anyone wonders, it has no relations with other loaders with the same
  10. name and there is no GPL code inside the ST X-Loader).
  11. SDRAM configuration, PLL setup and initial loading from NAND is
  12. implemented in the X-Loader, so U-Boot is already running in SDRAM
  13. when control is handed over to it.
  14. The Makefile offers two different configurations to be used if you
  15. boot from Nand or OneNand.
  16. make nhk8815_config
  17. make nhk8815_onenand_config
  18. Both support OneNand and Nand. Since U-Boot, running in RAM, can't know
  19. where it was loaded from, the configurations differ in where the filesystem
  20. is looked for by default.
  21. On www.st.com/nomadik and on www.stnwireless.com there are documents,
  22. summary data and white papers on Nomadik. The full datasheet for
  23. STn8815 is not currently available on line but under specific request
  24. to the local ST sales offices.