From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Subject: Re: [PATCH 6/9] ARM: dts: wheat: Drop MTD partitioning from DT Date: Mon, 28 May 2018 10:54:57 +0200 Message-ID: References: <20180522120257.13232-1-marek.vasut+renesas@gmail.com> <20180522120257.13232-6-marek.vasut+renesas@gmail.com>

<7e1563c3-3e13-235b-3071-c3936502530f@gmail.com> <20180528084135.q5xng5eaypprsypr@verge.net.au> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180528084135.q5xng5eaypprsypr@verge.net.au> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Simon Horman Cc: "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Geert Uytterhoeven , Wolfram Sang , Richard Weinberger , Boris Brezillon , Linux-Renesas , Marek Vasut , Laurent Pinchart , Linux ARM , Marek Vasut List-Id: devicetree@vger.kernel.org Hi Simon, On Mon, May 28, 2018 at 10:41 AM, Simon Horman 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 wrote: >> >> On 05/22/2018 04:43 PM, Geert Uytterhoeven wrote: >> >>> On Tue, May 22, 2018 at 2:02 PM, Marek Vasut 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: >> > >> > * := 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) Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-Version: 1.0 In-Reply-To: <20180528084135.q5xng5eaypprsypr@verge.net.au> References: <20180522120257.13232-1-marek.vasut+renesas@gmail.com> <20180522120257.13232-6-marek.vasut+renesas@gmail.com>

<7e1563c3-3e13-235b-3071-c3936502530f@gmail.com> <20180528084135.q5xng5eaypprsypr@verge.net.au> From: Geert Uytterhoeven Date: Mon, 28 May 2018 10:54:57 +0200 Message-ID: Subject: Re: [PATCH 6/9] ARM: dts: wheat: Drop MTD partitioning from DT To: Simon Horman Cc: Marek Vasut , Linux ARM , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Marek Vasut , Geert Uytterhoeven , Laurent Pinchart , Wolfram Sang , Linux-Renesas , Richard Weinberger , Boris Brezillon Content-Type: text/plain; charset="UTF-8" Sender: devicetree-owner@vger.kernel.org List-ID: Hi Simon, On Mon, May 28, 2018 at 10:41 AM, Simon Horman 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 wrote: >> >> On 05/22/2018 04:43 PM, Geert Uytterhoeven wrote: >> >>> On Tue, May 22, 2018 at 2:02 PM, Marek Vasut 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: >> > >> > * := 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) Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds From mboxrd@z Thu Jan 1 00:00:00 1970 From: geert@linux-m68k.org (Geert Uytterhoeven) Date: Mon, 28 May 2018 10:54:57 +0200 Subject: [PATCH 6/9] ARM: dts: wheat: Drop MTD partitioning from DT In-Reply-To: <20180528084135.q5xng5eaypprsypr@verge.net.au> References: <20180522120257.13232-1-marek.vasut+renesas@gmail.com> <20180522120257.13232-6-marek.vasut+renesas@gmail.com>

<7e1563c3-3e13-235b-3071-c3936502530f@gmail.com> <20180528084135.q5xng5eaypprsypr@verge.net.au> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Simon, On Mon, May 28, 2018 at 10:41 AM, Simon Horman 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 wrote: >> >> On 05/22/2018 04:43 PM, Geert Uytterhoeven wrote: >> >>> On Tue, May 22, 2018 at 2:02 PM, Marek Vasut 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 at 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: >> > >> > * := 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 at 0(loader),4096k(user),-(flash) Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds