On Fri, Feb 27, 2015 at 2:44 AM, Daniel Schwierzeck <daniel.schwierzeck@xxxxxxxxx> wrote: > 2015-02-26 19:23 GMT+01:00 Andrew Bresticker <abrestic@xxxxxxxxxxxx>: >> Hi, >> >> On Thu, Feb 26, 2015 at 4:37 AM, Daniel Schwierzeck >> <daniel.schwierzeck@xxxxxxxxx> wrote: >>> 2015-02-26 11:17 GMT+01:00 Paul Burton <paul.burton@xxxxxxxxxx>: >>>> On Thu, Feb 19, 2015 at 01:50:23PM +0000, Matthew Fortune wrote: >>>>> Hi Daniel, >>>>> >>>>> The spec for MIPS Unified Hosting Interface is available here: >>>>> >>>>> http://prplfoundation.org/wiki/MIPS_documentation >>>>> >>>>> As we have previously discussed, this is an ideal place to >>>>> define the handover of device tree data from bootloader to >>>>> kernel. Using a0 == -2 and defining which register(s) you >>>>> need for the actual data will fit nicely. I'll happily >>>>> include whatever is decided into the next version of the spec. >>> >>> this originates from an off-list discussion some months ago started by >>> John Crispin. >>> >>> (CC +John, Ralf, Jonas, linux-mips) >>> >>>> >>>> (CC +Andrew, Ezequiel, James, James) >>>> >>>> On the talk of DT handover, this recent patchset adding support for a >>>> system doing so to Linux is relevant: >>>> >>>> http://www.linux-mips.org/archives/linux-mips/2015-02/msg00312.html >>>> >>>> I'm also working on a system for which I'll need to implement DT >>>> handover very soon. It would be very nice if we could agree on some >>>> standard way of doing so (and eventually if the code on the Linux side >>>> can be generic enough to allow a multiplatform kernel). >> >> +1. I would like to see this happen as well. >> >>> to be conformant with UHI I propose $a0 == -2 and $a1 == address of DT >>> blob. It is a simple extension and should not interfere with the >>> various legacy boot interfaces. >>> >>> U-Boot mainline code is almost ready for DT handover. I have prepared >>> a patch [1] which completes it by implementing my proposal. >> >> Hmm... we decided to follow the ARM convention here ($a0 = 0, $a1 = >> -1, $a2 = physical address of DTB), which is also what the BMIPS >> platform (submitted by Kevin) is using for DT handover. Is there >> already a platform using the protocol you described? > > no, but with its publication the MIPS UHI spec is kind of official. > AFAIK patches to support UHI in gcc, gdb, U-Boot etc. are already > submitted or prepared. Matthew suggested that new boot protocols > should be compliant with UHI. I think the ARM convention does not fit > to UHI. Ok, I think we can change the boot protocol on Pistachio to match UHI then. -Andrew
