Re: [PATCH 6/9] ARM: dts: wheat: Drop MTD partitioning from DT

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, May 30, 2018 at 12:13:31PM +0200, Marek Vasut wrote:
> On 05/28/2018 11:36 AM, Simon Horman wrote:
> > On Mon, May 28, 2018 at 10:54:57AM +0200, Geert Uytterhoeven wrote:
> >> Hi Simon,
> >>
> >> On Mon, May 28, 2018 at 10:41 AM, Simon Horman <horms@xxxxxxxxxxxx> wrote:
> >>> On Thu, May 24, 2018 at 04:52:59PM +0200, Marek Vasut wrote:
> >>>> On 05/23/2018 08:25 AM, Geert Uytterhoeven wrote:
> >>>>> On Wed, May 23, 2018 at 12:01 AM, Marek Vasut <marek.vasut@xxxxxxxxx> wrote:
> >>>>>> On 05/22/2018 04:43 PM, Geert Uytterhoeven wrote:
> >>>>>>> On Tue, May 22, 2018 at 2:02 PM, Marek Vasut <marek.vasut@xxxxxxxxx> wrote:
> >>>>>>>> Drop the MTD partitioning from DT, since it does not describe HW
> >>>>>>>> and to give way to a more flexible kernel command line partition
> >>>>>>>> passing.
> >>>>>>>>
> >>>>>>>> To retain the original partitioning, assure you have enabled
> >>>>>>>> CONFIG_MTD_CMDLINE_PARTS in your kernel config and add the
> >>>>>>>> following to your kernel command line:
> >>>>>>>>
> >>>>>>>>   mtdparts=spi0.0:256k@0(loader),4096k(user),-(flash)
> >>>>>>>
> >>>>>>> I think the "@0" can be dropped, as it's optional?
> >>>>>>> 4m?
> >>>>>>
> >>>>>> My take on this is that the loader is actually at offset 0x0 of the MTD
> >>>>>> device and we explicitly state that in the mtdparts to anchor the first
> >>>>>> partition within the MTD device and all the other partitions are at
> >>>>>> offset +(sum of the sizes of all partitions listed before the current
> >>>>>> one) relative to that first partition.
> >>>>>
> >>>>> Where is this explicitly states for the first partition?
> >>>>>
> >>>>>> Removing the @0 feels fragile at best and it seems to depend on the
> >>>>>> current behavior of the code.
> >>>>>
> >>>>> Better, it also depends on the documented behavior:
> >>>>>
> >>>>> Documentation/admin-guide/kernel-parameters.txt refers to
> >>>>> drivers/mtd/cmdlinepart.c, which states:
> >>>>>
> >>>>>  * <offset>  := standard linux memsize
> >>>>>  *              if omitted the part will immediately follow the previous part
> >>>>>  *              or 0 if the first part
> >>>>>
> >>>>> None of the examples listed there or under the MTD_CMDLINE_PARTS Kconfig
> >>>>> help text, or in a defconfig bundled with the kernel, use @0 for the first
> >>>>> partition.
> >>>>
> >>>> I think this is exceptionally fragile and dangerous to depend on this,
> >>>> but so be it.
> >>>
> >>> Could you respin with this change?
> >>>
> >>> I would also like to ask for another change, in light of recent
> >>> feedback from Olof Johansson ("Re: [GIT PULL] Renesas ARM64 Based SoC DT
> >>> Updates for v4.18").
> >>>
> >>> Please consolidate the dts patches into a single patch?
> >>
> >> I think it's better to keep them split, as each commit description mentions
> >> what needs to be passed on the kernel command line for the corresponding
> >> board.
> >>
> >> Combining it in a single patch makes it much harder to extract this information.
> >> Unless you're fine with a list:
> >>
> >>    koelsch: ...
> >>    wheat: mtdparts=spi0.0:256k@0(loader),4096k(user),-(flash)
> > 
> > Lets try a list.
> 
> Reposted with a list, twice :/

Thanks, got it :)
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux