linux-kernel - Re: [PATCH V2 RESEND] clk: mxs: Fix invalid 32-bit access to frac registers

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Message-ID: <1705379122.406018.1423686677196.JavaMail.open-xchange@oxbaltgw01.schlund.de>
Date:	Wed, 11 Feb 2015 21:31:17 +0100 (CET)
From:	Stefan Wahren <stefan.wahren@...e.com>
To:	Fabio Estevam <festevam@...il.com>
Cc:	Sascha Hauer <kernel@...gutronix.de>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Shawn Guo <shawn.guo@...aro.org>,
	Mike Turquette <mturquette@...aro.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Marek Vasut <marex@...x.de>, Zhi Li <lznuaa@...il.com>
Subject: Re: [PATCH V2 RESEND] clk: mxs: Fix invalid 32-bit access to frac
 registers

Hi Fabio,

> Fabio Estevam <festevam@...il.com> hat am 11. Februar 2015 um 17:58
> geschrieben:
>
>
> Hi Stefan,
>
> On Tue, Feb 10, 2015 at 7:24 PM, Stefan Wahren <stefan.wahren@...e.com> wrote:
> > Hi Fabio,
> >
> >> Fabio Estevam <festevam@...il.com> hat am 10. Februar 2015 um 16:06
> >> geschrieben:
> >>
> >>
> >> Hi Stefan,
> >>
> >> On Tue, Feb 10, 2015 at 11:55 AM, Stefan Wahren <stefan.wahren@...e.com>
> >> wrote:
> >>
> >> > Could you apply only the clk-imx28.c part of my patch and see what
> >> > happens?
> >>
> >> If I apply only the clk-imx28.c part of your patch I can successfully
> >> probe the SPI NOR.
> >
> > thanks this is very helpful. I built the linux-next for my Duckbill and add
> > the
> > SSP2 section from imx28-evk.dts into imx28-duckbill.dts.
> >
> > Without my patch i get the following for HW_CLKCTRL_FRAC0:
> >
> > ./memwatch -a 0x800401B0
> >
> > 0x800401b0: 0x5e5b5513
> >
> > With my patch i get:
> >
> > ./memwatch -a 0x800401B0
> >
> > 0x800401b0: 0x5e1b5513
>
> I always get 0x5e5b5513 with or without your patch.

very strange. Do you have any idea why IO1_STABLE is permanent low?

Here are the register dumps as requested by Mike.

Without this patch after boot

0x80040000: 0x00060000
0x80040010: 0x800004b1
0x80040050: 0x00011001
0x80040080: 0x64000001
0x80040090: 0x00000001
0x800400a0: 0x80000001
0x800400b0: 0x00000002
0x800400c0: 0xa0000001
0x800401b0: 0x5e5b5513
0x800401c0: 0x00929292
0x800401d0: 0x00004104

With this patch after boot

0x80040000: 0x00060000
0x80040010: 0x800004b1
0x80040050: 0x00011001
0x80040080: 0x64000001
0x80040090: 0x00000001
0x800400a0: 0x80000001
0x800400b0: 0x00000002
0x800400c0: 0xa0000001
0x800401b0: 0x5e1b5513
0x800401c0: 0x00929292
0x800401d0: 0x00004104

So only IO1_STABLE (0x800401b0) is different.

If i restore clk_ref_set_rate() from clk-ref.c after the complete patch is
applied, the issue with the IO1_STABLE bit disappears.

Can you confirm the behavior according to your flash issue?

I think it would be the best to revert my patch. Sorry for the trouble.

Stefan

>
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