On 08/23/2012 05:52 AM, Christian Riesch wrote: > Hi Tom, > > On Thu, Aug 23, 2012 at 1:19 AM, Tom Rini <tr...@ti.com> wrote: >> This file documents when to build for da850evm and when to build for >> da850_am18xxevm. It also documents how to write the u-boot.ais file to >> persistent storage (such as SPI), in some cases as well as how to write >> a recovery image. >> >> Signed-off-by: Tom Rini <tr...@ti.com> >> --- >> Changes in v2: >> - Add >> >> Changes in v3: >> - Fix thinko, Nand -> SPI (spotted by Prabhakar Lad) >> - Rename to README.da850, add more direct recovery method (Christian Riesch) >> >> board/davinci/da8xxevm/README.da850 | 62 >> +++++++++++++++++++++++++++++++++++ >> 1 file changed, 62 insertions(+) >> create mode 100644 board/davinci/da8xxevm/README.da850 >> >> diff --git a/board/davinci/da8xxevm/README.da850 >> b/board/davinci/da8xxevm/README.da850 >> new file mode 100644 >> index 0000000..55291f3 >> --- /dev/null >> +++ b/board/davinci/da8xxevm/README.da850 >> @@ -0,0 +1,62 @@ >> +Summary >> +======= >> +The README is for the boot procedure used for various DA850 (or compatible >> +parts such as the AM1808) based boards. >> + >> +The board is booted in three stages. The initial bootloader which executes >> +upon reset is the ROM Boot Loader (RBL) which sits in the internal ROM. The >> +RBL initializes the memory and then depending on the exact board will > > The RBL can initialize the PLLs and the memory (I assume you are > talking about DDR/SDRAM here), but only if the AIS tells it to do so > and provides the configuration data like timing etc. However, for the > da850evm configuration the AIS only tells the RBL to copy the SPL to > the internal SRAM of the SoC. Then, the SPL initializes the DDR > memory. > > Actually we wouldn't need SPL to boot from SPI on the da850. We could > as well do memory initialization with AIS/RBL and then let the RBL > copy u-boot to DDR memory. The reason why I introduced SPL for booting > from SPI here is that it gives us more flexibility, e.g. on my custom > board I must check the board revision before configuring the PLLs > because I have different oscillator frequencies on different > revisions.
True. I suppose this is what I get for copy/pasting docs from a similar board and focusing more on the "write these bits to hardware" rather than "what do these bits do exactly" :) Thanks, I'll re-word things a bit more. >> +initialize another controller (such as SPI or NAND) to continue the boot >> +process. >> + >> +AIS is an image format defined by TI for the images that are to be >> +loaded to memory by the RBL. The image is divided into a series of >> +sections and the image's entry point is specified. Each section comes >> +with meta data like the target address the section is to be copied to >> +and the size of the section, which is used by the RBL to load the >> +image. At the end of the image the RBL jumps to the image entry >> +point. >> + >> +The secondary stage bootloader (SPL) which is loaded by the RBL then > > ... initializes the PLLs and the memory controller and ... > >> loads >> +the u-boot from a predefined location in persistent storage to DDR and >> +jumps to the u-boot entry point. >> + >> + >> +Compilation >> +=========== >> +The exact build target you need will depend on the board you have. For >> +Logic PD boards, or other boards which store the ethernet MAC address at >> +the end of SPI flash, run 'make da850evm'. For boards which store the >> +ethernet MAC address in the i2c EEPROM located at 0x50, run >> +'make da850_am18xxevm'. Once this build completes you will have a >> +u-boot.ais file that needs to be written to the correct persistent >> +storage. >> + >> + >> +Flashing the images to SPI >> +========================== >> +The AIS image can be written to SPI flash using the following commands. >> +Assuming that the network is configured and enabled and the u-boot.ais file >> +is tftp'able. >> + >> +U-Boot > sf probe 0 >> +U-Boot > sf erase 0 +320000 >> +U-Boot > tftp u-boot.ais >> +U-Boot > sf write c0700000 0 $filesize >> + >> + >> +Recovery >> +======== >> + >> +In the case of a "bricked" board, you need to use the TI tools found >> +here[1] to write the u-boot.ais file. An example of recovering to the SPI >> +flash would be: >> + >> +$ mono sfh_OMAP-L138.exe -targetType AM1808 -p /dev/ttyUSB0 \ >> + -flash_noubl /path/to/u-boot.ais >> + > > I believe for the OMAP-L138 boards you will need -targetType OMAPL138 > (or just omit the option because OMAPL138 is the default). Indeed, I should say it's an example for AM1808. -- Tom _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
