Re: [PATCH] ARM: OMAP2+: Fix warnings with broken omap2_set_init_voltage()

From: Andreas Kemnade <andreas@kemnade.info>
To: "H. Nikolaus Schaller" <hns@goldelico.com>
Cc: "Tony Lindgren" <tony@atomide.com>,
	Linux-OMAP <linux-omap@vger.kernel.org>,
	arm-soc <linux-arm-kernel@lists.infradead.org>,
	"Adam Ford" <aford173@gmail.com>,
	"André Roth" <neolynx@gmail.com>, "Nishanth Menon" <nm@ti.com>,
	"Tero Kristo" <t-kristo@ti.com>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Discussions about the Letux Kernel"
	<letux-kernel@openphoenux.org>
Subject: Re: [PATCH] ARM: OMAP2+: Fix warnings with broken omap2_set_init_voltage()
Date: Mon, 2 Dec 2019 23:15:22 +0100	[thread overview]
Message-ID: <20191202231522.5e7fe3f8@aktux> (raw)
In-Reply-To: <8FFD44DB-73F8-4807-91E1-C97DA8F781BA@goldelico.com>

On Mon, 2 Dec 2019 22:09:26 +0100
"H. Nikolaus Schaller" <hns@goldelico.com> wrote:

> Hi Tony,
> 
> > Am 25.09.2019 um 01:32 schrieb Tony Lindgren <tony@atomide.com>:
> > 
> > This code is currently unable to find the dts opp tables as ti-cpufreq
> > needs to set them up first based on speed binning.
> > 
> > We stopped initializing the opp tables with platform code years ago for
> > device tree based booting with commit 92d51856d740 ("ARM: OMAP3+: do not
> > register non-dt OPP tables for device tree boot"), and all of mach-omap2
> > is now booting using device tree.
> > 
> > We currently get the following errors on init:
> > 
> > omap2_set_init_voltage: unable to find boot up OPP for vdd_mpu
> > omap2_set_init_voltage: unable to set vdd_mpu
> > omap2_set_init_voltage: unable to find boot up OPP for vdd_core
> > omap2_set_init_voltage: unable to set vdd_core
> > omap2_set_init_voltage: unable to find boot up OPP for vdd_iva
> > omap2_set_init_voltage: unable to set vdd_iva
> > 
> > Let's just drop the unused code. Nowadays ti-cpufreq should be used to
> > to initialize things properly.
> > 
> > Cc: Adam Ford <aford173@gmail.com>
> > Cc: André Roth <neolynx@gmail.com>
> > Cc: "H. Nikolaus Schaller" <hns@goldelico.com>
> > Cc: Nishanth Menon <nm@ti.com>
> > Cc: Tero Kristo <t-kristo@ti.com>
> > Signed-off-by: Tony Lindgren <tony@atomide.com>
> > ---
> > 
> > Guys, please check and ack if we can really do this to get rid of some
> > pointless dmesg -l3 errors without affecting the ongoing cpufreq and
> > voltage work.  
> 
> unfortunately we did not yet test in combination with the 1GHz OPP
> patches for omap3630 (queued for v5.5-rc1) and it appears that this
> patch breaks the 1GHz OPP.
> 
> The symptom is that it works fine on a dm3730 with 800MHz rating
> but results in spurious kernel panics, stack corruption, virtual memory
> failures, OneNAND DMA timeouts etc. on a dm3730 with 1GHz speed grade.
> 
I #if 0'ed the 1Ghz opp and found out that the OneNAND DMA timeouts
are independant of 1Ghz. But the result is interesting:
With this patch
xxd /dev/mtd0 shows only ff
without this patch gives content, it is slower.
In both cases I see
[  476.533477] omap2-onenand 4000000.onenand: timeout waiting for DMA

Regards,
Andreas