From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de> To: Russell King - ARM Linux <linux@armlinux.org.uk> Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, Shawn Guo <shawnguo@kernel.org>, Javier Martinez Canillas <javier@osg.samsung.com>, Sascha Hauer <kernel@pengutronix.de>, Fabio Estevam <fabio.estevam@nxp.com>, Fabio Estevam <festevam@gmail.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org> Subject: Re: [PATCH v2] ARM: dts: imx: Pass 'chosen' and 'memory' nodes Date: Thu, 19 Jan 2017 17:14:41 +0100 [thread overview] Message-ID: <20170119161441.jcctgig7np4v7sam@pengutronix.de> (raw) In-Reply-To: <20170119145642.GC27312@n2100.armlinux.org.uk> On Thu, Jan 19, 2017 at 02:56:42PM +0000, Russell King - ARM Linux wrote: > On Thu, Jan 19, 2017 at 03:46:41PM +0100, Uwe Kleine-König wrote: > > On Thu, Jan 19, 2017 at 12:35:40PM -0200, Fabio Estevam wrote: > > > Hi Uwe, > > > > > > On Thu, Jan 19, 2017 at 12:13 PM, Uwe Kleine-König > > > <u.kleine-koenig@pengutronix.de> wrote: > > > > > > > Would it be nice to add a comment about why this was added? Something to > > > > prevent a cleanup like "remove empty nodes and invalid memory > > > > configurations". > > > > > > Do you mean something like this? > > > > > > /* "chosen" and "memory" nodes are mandatory */ > > > chosen {}; > > > memory { device_type = "memory"; reg = <0 0>; }; > > > > Not very helpful comment. Something like: > > > > /* > > * The decompressor relies on a pre-existing chosen node to be > > * available to insert the command line and merge other ATAGS > > * info. > > */ > > > > Is it difficult to fix the decompressor? > > ... and that comment would be wrong. Yes, the decompressor relies on it, > as do some uboot versions. Good that we talked about this, otherwise I would have removed that once the decompressor is fixed. So the comment must be /* * The decompressor and also some versions of U-Boot rely on a * pre-existing /chosen node to be available to insert the * command line and merge other ATAGS info. * Also for U-Boot there must be a pre-existing /memory node. */ > > I didn't understood the breakage regarding the memory node good enough > > to suggest a comment for that. > > A missing memory node appears to prevent some uboot versions supplying > any kind of memory layout to the kernel, which then causes the kernel to > crash very early during boot. > > Again, this is not using appended DTB - this is using a separately loaded > DTB in uboot. uboot fails to update the dtb if these nodes are missing. > > Frankly, I think the original change (removing the skeleton.dtsi include) > was misguided and needs to be reverted - the change is imho built upon an > incorrect assumption that nothing in skeleton.dtsi is required. That's > clearly false. I tend to agree as I assume it's not only U-Boot on i.MX but on all ARM platforms. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
WARNING: multiple messages have this Message-ID (diff)
From: u.kleine-koenig@pengutronix.de (Uwe Kleine-König) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2] ARM: dts: imx: Pass 'chosen' and 'memory' nodes Date: Thu, 19 Jan 2017 17:14:41 +0100 [thread overview] Message-ID: <20170119161441.jcctgig7np4v7sam@pengutronix.de> (raw) In-Reply-To: <20170119145642.GC27312@n2100.armlinux.org.uk> On Thu, Jan 19, 2017 at 02:56:42PM +0000, Russell King - ARM Linux wrote: > On Thu, Jan 19, 2017 at 03:46:41PM +0100, Uwe Kleine-K?nig wrote: > > On Thu, Jan 19, 2017 at 12:35:40PM -0200, Fabio Estevam wrote: > > > Hi Uwe, > > > > > > On Thu, Jan 19, 2017 at 12:13 PM, Uwe Kleine-K?nig > > > <u.kleine-koenig@pengutronix.de> wrote: > > > > > > > Would it be nice to add a comment about why this was added? Something to > > > > prevent a cleanup like "remove empty nodes and invalid memory > > > > configurations". > > > > > > Do you mean something like this? > > > > > > /* "chosen" and "memory" nodes are mandatory */ > > > chosen {}; > > > memory { device_type = "memory"; reg = <0 0>; }; > > > > Not very helpful comment. Something like: > > > > /* > > * The decompressor relies on a pre-existing chosen node to be > > * available to insert the command line and merge other ATAGS > > * info. > > */ > > > > Is it difficult to fix the decompressor? > > ... and that comment would be wrong. Yes, the decompressor relies on it, > as do some uboot versions. Good that we talked about this, otherwise I would have removed that once the decompressor is fixed. So the comment must be /* * The decompressor and also some versions of U-Boot rely on a * pre-existing /chosen node to be available to insert the * command line and merge other ATAGS info. * Also for U-Boot there must be a pre-existing /memory node. */ > > I didn't understood the breakage regarding the memory node good enough > > to suggest a comment for that. > > A missing memory node appears to prevent some uboot versions supplying > any kind of memory layout to the kernel, which then causes the kernel to > crash very early during boot. > > Again, this is not using appended DTB - this is using a separately loaded > DTB in uboot. uboot fails to update the dtb if these nodes are missing. > > Frankly, I think the original change (removing the skeleton.dtsi include) > was misguided and needs to be reverted - the change is imho built upon an > incorrect assumption that nothing in skeleton.dtsi is required. That's > clearly false. I tend to agree as I assume it's not only U-Boot on i.MX but on all ARM platforms. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-K?nig | Industrial Linux Solutions | http://www.pengutronix.de/ |
next prev parent reply other threads:[~2017-01-19 16:14 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-01-19 14:02 [PATCH v2] ARM: dts: imx: Pass 'chosen' and 'memory' nodes Fabio Estevam 2017-01-19 14:02 ` Fabio Estevam 2017-01-19 14:13 ` Uwe Kleine-König 2017-01-19 14:13 ` Uwe Kleine-König 2017-01-19 14:35 ` Fabio Estevam 2017-01-19 14:35 ` Fabio Estevam [not found] ` <CAOMZO5AdgM9eFnerLRdYxwE7gsOE5OvkWs6rCR4zta1XmXHj1A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2017-01-19 14:46 ` Uwe Kleine-König 2017-01-19 14:46 ` Uwe Kleine-König 2017-01-19 14:56 ` Russell King - ARM Linux 2017-01-19 14:56 ` Russell King - ARM Linux 2017-01-19 15:57 ` Fabio Estevam 2017-01-19 15:57 ` Fabio Estevam 2017-01-19 16:14 ` Uwe Kleine-König [this message] 2017-01-19 16:14 ` Uwe Kleine-König [not found] ` <20170119161441.jcctgig7np4v7sam-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> 2017-01-25 21:13 ` Frank Rowand 2017-01-25 21:13 ` Frank Rowand [not found] ` <588914F3.7050909-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> 2017-01-25 22:46 ` Rob Herring 2017-01-25 22:46 ` Rob Herring [not found] ` <CAL_JsqL4+OZo0JTU8gnTEHxqNgNoBRnuHr1i99n72BKG30V9Eg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> 2017-01-26 0:30 ` Frank Rowand 2017-01-26 0:30 ` Frank Rowand 2017-01-30 18:54 ` Russell King - ARM Linux 2017-01-30 18:54 ` Russell King - ARM Linux [not found] ` <20170130185444.GF27312-l+eeeJia6m9URfEZ8mYm6t73F7V6hmMc@public.gmane.org> 2017-01-30 19:07 ` Fabio Estevam 2017-01-30 19:07 ` Fabio Estevam 2017-01-30 19:47 ` Uwe Kleine-König 2017-01-30 19:47 ` Uwe Kleine-König 2017-02-01 13:30 ` Stefan Wahren 2017-02-01 13:30 ` Stefan Wahren 2017-02-06 10:49 ` Stefan Wahren 2017-02-06 10:49 ` Stefan Wahren [not found] ` <13787b59-6bfc-d020-9853-ae37074009dc-eS4NqCHxEME@public.gmane.org> 2017-02-06 11:05 ` Fabio Estevam 2017-02-06 11:05 ` Fabio Estevam 2017-02-07 15:19 ` Arnd Bergmann 2017-02-07 15:19 ` Arnd Bergmann
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