Dear Christian Riesch, In message <banlktimhjss_urkzb-q5y7gqzawswe0...@mail.gmail.com> you wrote: > > > What is AIS ? > > I apologize for using that many abbreviations in my mail and not > explaining them :-/ > > AIS is short for Application Image Script [1]. It is a boot script > that is processed by the ROM bootloader on Texas Instrument's > AM1808/DA850/OMAP-L138 processors. The script allows configuration of > boot modes, PLLs, DDR memory, Pinmuxes etc and loading the an > application like u-boot from flash to RAM and executing it. Using a > suitable AIS one can configure PLL and DDR memory and then directly > start u-boot on these processors, without using Texas Instruments's > user boot loader (UBL) [2]. > > In the default configuration of the da850evm the boot sequence is like this: > 1) ROM bootloader (RBL): starts reading from flash > 2) In the SPI-flash, a very simple AIS is present. This AIS tells the > RBL to load the UBL from flash and to start it. > 3) The UBL does a lot of hardware initialization and then loads u-boot > from flash and starts it. > 4) u-boot does a lot of hardware initialization that has already been > done by the UBL and then loads the Linux kernel. > > For my application I would like to get rid of the UBL since most of > the configuration it does is also done by u-boot (although there seems > to be a bug in it) or can be done by AIS (like PLL and DDR memory > configuration), the resulting boot sequence will be: > 1) ROM bootloader (RBL): starts reading from flash > 2) In the SPI-flash, an AIS is present. This AIS tells the RBL to > configure PLLs and DDR memory and to load u-boot from flash and to > start it. > 3) u-boot loads the Linux kernel.
Thanks for the explanations. You might want to synchronize your efforts with Heiko Schocher (on cc:) who might be working on similar things. Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de Any time things appear to be going better, you have overlooked some- thing. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
