Hi Ravi, > Hi Lukasz > > >> The problem here is, how o flash the images first time to fresh > >> boards to QSPI or eMMC device, where there is no MMC/SD > >> boot option available. The solution to this problem is use > >> peripheral USB boot mode (configuring sysboot switches), where the > >> ROM loads the intial SPL(+DFU builtin for spi/eMMC) to IRAM, then > >> run dfu/sf or dfu/eMMC to flash the binaries from PC using USB > >> interface. Refer to SPL-DFU support based on 2014.07 u-boot > >> http://www.ti.com/lit/an/sprac33/sprac33.pdf. > > >I know about similar bootstrap (on TI board), which uses serial > >instead of USB. > > >In this approach MLO was loaded by serial, then it loaded u-boot, > >which was responsible for factory setting of the device (flashing > >rootfs, boot and other partitions). > > >One question: > > >Would it be possible to develop SPL (MLO) for your platform, which > >does following things: > > >1. Loads the full-fledge u-boot to SDRAM 2. Starts the u-boot and 3. > >u-boot flash all the needed stuff > > >By using such approach we could restrict our dfu support in SPL > >u-boot only to receiving data and uploading it to SDRAM (i.e. we > >wouldn't need to add write support for ext, fat and eMMC). > > > This is not possible, because combining MLO and u-boot.img will not > fit in IRAM (512k). The u-boot.img itself is around 640K.
My point here is to first load SPL u-boot (which size is around 110 KiB), and then download via DFU full-featured u-boot, which would be placed in SDRAM. Then u-boot downloads and flash all needed images. One big advantage is that our SPL DFU support can be minimal - we don't need to implement fat, ext ,emmc write support. > > Regards > Ravi > -- Best regards, Lukasz Majewski Samsung R&D Institute Poland (SRPOL) | Linux Platform Group _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
