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