Am 10.03.21 um 16:58 schrieb Jiaxun Yang: > > > 在 2021/3/10 21:26, Oleksij Rempel 写道: > [...] >> I would like to understand, why it is impossible. Do fw_arg0 provide memory address or some kind of >> count/size? Can it be negative? >> >> We already had same situation with ARM and it was fixed. Why this can't be done for MIPS or LS? > > Well we can fix it for future MIPS systems but not present Loongson. > > Actually I've talked to several Chinese MIPS chip vendors and they > all agreed to unify the booting protcol. > > I raised the same question to Loongson ~3 years ago but got > negative response. > The idea got reject in a recent private discussions with Loongson > about 2K1000 upstream stuff. > > Also I realized Loongson's chip comes with too many ISA level > custom designs which makes it impossible to use MIPS generic > kernel. > > >>>> This protocol is described here on page 15, "3. Boot protocols" >>>> https://docplayer.net/62444141-Unified-hosting-interface-md01069-reference-manual.html >>>> >>>> According to this protocol, you should have: >>>> fw_arg0 = -2 >>>> fw_arg1 = Virtual (kseg0) address of Device Tree Blob >>>> >>>> This would made LS a first grade resident for many boot loaders and >>>> save a lot of needles headaches. >>>> >>> Loongson is stepping away from MIPS and it seems like they're going to use EDK-II for their Loongarch. >>> >> It seems to be UEFI related, it seems to be not related to the CPU arch, or do i'm missing something? > I meant they won't invest much to MIPS based chips :-( >> In any case, if this is true, then it means, that Loongsoon is about to drop support for old boot >> loaders (PMON?) and do new thing (one more boot protocol?). So argumentation, we upstream old own >> protocol, but will drop it to make some thing new is not really good example :) > Yes, actually many new Loongson desktop machines (3A3000/3A4000) are shipped > with UEFI and relies on second stage bootloader to convert to old boot > protocol. > > I'm againt to upstraming the "new" protocol as it's non-standard UEFI > with many > nonsense design. > > >>> TBH I've checked Loongson's PMON code and realized it can't be ported to other projects easily. >>> Tons of unregonized assembly code. >>> >> No need to port it. Here is example of working clean code: >> https://git.pengutronix.de/cgit/barebox/tree/arch/mips/boards/loongson-ls1b/lowlevel.S > I've ported U-Boot to LS1C as well. But LS1B/LS1C is Loongson32. > Loongson64 based systems like LS2K is much more complex than it. > The bootloader is fullfilled with assembly and mostly undocumented. > LS2K's PMON contains ~50k lines of assembly. OK, i hope i'll never have customers using this chips. Are there any reason why do we wont to keep it alive? :D -- Regards, Oleksij
