Scott Wood <scottw...@freescale.com> wrote on 08/13/2013 08:04:30 AM:
> From: Scott Wood <scottw...@freescale.com> > To: Stephen N Chivers <schiv...@csc.com.au> > Cc: Chris Proctor <cproc...@csc.com.au>, Kumar Gala > <ga...@kernel.crashing.org>, <linuxppc-dev@lists.ozlabs.org>, > <pau...@samba.org> > Date: 08/13/2013 08:04 AM > Subject: Re: [RFC PATCH 1/1] powerpc/embedded6xx: Add support for > Motorola/Emerson MVME5100. > > On Tue, 2013-08-13 at 08:57 +1100, Stephen N Chivers wrote: > > Scott Wood <scottw...@freescale.com> wrote on 08/09/2013 04:07:24 AM: > > > > > From: Scott Wood <scottw...@freescale.com> > > > To: Kumar Gala <ga...@kernel.crashing.org> > > > Cc: Stephen N Chivers <schiv...@csc.com.au>, <pau...@samba.org>, > > > <linuxppc-dev@lists.ozlabs.org>, Chris Proctor <cproc...@csc.com.au> > > > Date: 08/09/2013 04:08 AM > > > Subject: Re: [RFC PATCH 1/1] powerpc/embedded6xx: Add support for > > > Motorola/Emerson MVME5100. > > > > > > On Thu, 2013-08-08 at 10:30 -0500, Kumar Gala wrote: > > > > Also, we don't take full defconfigs in the tree, look at 'make > > > savedefconfig' > > > > > > Why does this board need its own defconfig at all? Just add it to > > > ppc6xx_defconfig. > > > > The boards firmware as stated above is PPCBug. PPCBug is not Open Firmware > > compatible. > > > > There is no U-Boot support for the board. > > I'm not sure why that precludes the use of ppc6xx_defconfig... > > > In ppc6xx_defconfig the e100 network device and NFS support is modular and > > that forces the use of an initrd. > > OK, then let's enable those in ppc6xx_defconfig. We do in a lot of the > other defconfigs (such as 85xx and derivatives). > > > PPCBugs network boot command takes only one file argument and so makes > > it difficult to use an initrd. > > > > So the choices are: > > - Providing a defconfig for the board, > > - Building the kernel with the initrd embedded in it, > > - Finding an alternative boot loader, > > - Doing the board support for U-Boot. > > The first choice is simple and documents the configuration of the > > board without mixing it into ppc6xx_defconfig. > > The first choice means your board would get much less build-testing, and > would increase maintenance costs of defconfig changes (and/or lead to > divergence from other defconfigs that doesn't actually have anything to > do with this board or its use cases). > > The fifth choice is "add what you need to ppc6xx_defconfig". Within > reason of course, but I think a common PCI network device and NFS root > support is reasonable. Thanks for the suggestion. I have tried it and ppc6xx_defconfig does generate a viable kernel for the MVME5100 but there is a total lack of serial console messages. The reason is due to the requirement for a register shift to access the UART register(s) on (via) the HAWK ASIC. The HAWK ASIC is very likely to be a MPC107/TSI107, making it compatible with "tsi-bridge". The TSI bridges also require register shifts to access their "built-in" UARTS. I will check the MPC107 data sheet against the TSI107 datasheet and the MVME5100 programmers manual later today. The serial console setup in 'legacy_serial' does not support reg-shift or reg-offset properties and so a preferred_console is not added by it. The DTS file for the board does specify the register shift so that 'of_serial' will correctly setup the UARTS. But that is too late, the preferred console will be tty0 as the .config derived from ppc6xx_defconfig has CONF_VT_CONSOLE set. In the test kernels I have built 'con_init' in the VT support is always called before serial8250_console_init. I did try modifying legacy_serial to correctly support the tsi-bridge UARTS and add the preferred console but encountered even more problems in 8250_core when registering the serial console (to the point of having a silently panic'ing kernel). So I think for the moment, the board will need its own default config. I think similar problems would occur for the Holly and MPC7448_HPC2 boards as these also have tsi-bridges, but their dts files do not specify the reg-shift properties. This begs the question do the serial consoles for Holly and MPC7448_HPC2 actually work? > > -Scott > > > _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
