2015-11-16 11:52 GMT+01:00 Albert ARIBAUD <albert.u.b...@aribaud.net>: > Hello Wojciech, > > On Mon, 16 Nov 2015 10:42:50 +0100, Wojciech Zabolotny > <wza...@gmail.com> wrote: >> Hi, >> >> I need to use U-Boot (or barebox) as a bootloader in a Raspberry Pi >> based system to extend booting flexibility. >> The problem however is that certain kernel boot arguments are prepared >> by the previous stage bootloader (start.elf) >> basing on the properties of the individual board. >> For example in one of the boards I use, the kernel command line when a >> standard kernel is booted, looks as follows (MAC address and serial >> number are partially masked for privacy): >> >> dma.dmachans=0x7f35 bcm2708_fb.fbwidth=720 bcm2708_fb.fbheight=480 >> bcm2708.boardrev=0xd bcm2708.serial=0x6f15XXXX >> smsc95xx.macaddr=B8:27:EB:XX:XX:XX bcm2708_fb.fbswap=1 >> sdhci-bcm2708.emmc_clock_freq=250000000 vc_mem.mem_base=0x1ec00000 >> vc_mem.mem_size=0x20000000 console=ttyAMA0 root=/dev/mmcblk0p2 >> rootwait >> >> Only the "console=ttyAMA0 root=/dev/mmcblk0p2 rootwait" is provided by >> the user (in the cmdline.txt file). The rest is generated by the >> start.elf. >> >> Of course when I boot the u-boot.bin instead of zImage, the same >> parameters are passed to it, but the U-Boot is not able to read them >> and to pass them to the finally booted kernel. >> As U-Boot shares a lot of code with the Linux kernel it should be >> possible to add necessary functions. >> It could be useful in all applications where U-Boot is used as an >> additional stage in the boot chain e.g., to add new booting >> functionalities (booting from the network, booting from the flash disk >> etc.). >> >> I have found a nice description, how the paremeters are passed in ARM >> architecture: >> http://www.simtec.co.uk/products/SWLINUX/files/booting%5Farticle.html >> but of course the solution should be probably portable (or implemented >> for each platform independently with unified API). > > Not sure what kind of answer you're asking for here. Do you want to > know if what you're suggesting is feasible? Are you looking for someone > to implement it? Are you going to implement it yourself but asking for > feedback? > >> -- > > (aside: if the above should be a signature delimiter, then it lacks a > space after the dashes) > > Amicalement, > -- > Albert.
Dear Albert, Yes the first question is if this feature is feasible. If yes, then I'd like to propose such functionality as a possible improvement. I think that may be more people interested in such a feature. I'll appreciate any sugestions/pointers regarding the possible implementation. Probably I can try to implement it. Of course if there are other interested users who can do it, I'll be definitely happy to discuss that with them. Regards, -- Wojciech M. Zabołotny My GPG/PGP keys: standard: 8192R/FE58A848 (0720 9430 85DB 7CCD F4C5 5F1E 5107 91FB FE58 A848) confidential: 16384R/C76D2FB0 (C4E7 9597 CF22 7B5D 28BF 4656 FED7 A63F C76D 2FB0) _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
