Hi Paul, Am 09.06.2015 um 01:52 schrieb Paul Boddie <p...@boddie.org.uk>:
> Hello, > > As you might have noticed, I haven't been looking at the jz4730-related > efforts in recent months, but I very recently got back into looking at the > initialisation code for the jz4740 (or rather jz4720, as I have a Ben > NanoNote), being inspired by the following collection of blog articles about > getting code to run on the MIPS Creator CI20 board: > > The CI20 bare-metal project > http://code.lardcave.net/2015/03/31/1/ > > Since the Ben NanoNote has been supported by a U-Boot variant (maybe only > really available via OpenWrt), and since Linux kernel support is also present > (although that doesn't help with things like PLL and SDRAM initialisation), I > thought it might be informative to bring the Ben up without U-Boot using a > minimal amount of code (as opposed to using the entirety of the continuously > changing beast that is U-Boot). > > So far, I've managed to make a USB bootable stage 1 initialising the PLL and > SDRAM (as featured in that blog series) and to glue the framebuffer > initialisation code from U-Boot (originally from Ingenic) to a stage 2 > payload > in order to show a nice pattern on the screen. Figuring out what the USB boot > mechanism actually does, and what the limitations really are, is pretty > awkward as the blog author found out. > > I'm now intending to extend this work to cover the jz4730 and the Letux 400. > It rather looks like the LCD support is mostly the same, and hopefully with > some appropriate settings and some SoC-specific adjustments, I can repeat the > achievement on the Letux. However, I'm using the USB boot mechanism on the > Ben: > > http://en.qi-hardware.com/wiki/Boot_Modes > http://en.qi-hardware.com/wiki/USB_BOOT_mode > > Does anyone know if it is possible to invoke this mode on the Letux, or > whether the bootloader supports a “software" variant? Not that I am aware of. We might have to develop and install our own U-Boot which is a high risk of bricking the device. I remember that I did try to understand how boot works, but it is too long ago that I remember details and wasn’t well documented :( BR, Nikolaus _______________________________________________ Mipsbook-devel mailing list Mipsbook-devel@linuxtogo.org http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/mipsbook-devel
