From: Priit Laes <plaes@plaes.org>
To: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Chen-Yu Tsai <wens@csie.org>,
Michael Turquette <mturquette@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-clk <linux-clk@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Jernej Skrabec <jernej.skrabec@siol.net>
Subject: Re: [RFC PATCH] clk: sunxi-ng: sun4i: Use CLK_SET_RATE_PARENT for mmc2 clock
Date: Tue, 12 Feb 2019 09:45:46 +0000 [thread overview]
Message-ID: <20190212094546.n2w7pffytzdgpx3e@plaes.org> (raw)
In-Reply-To: <20190211153402.s5qij5idvhbtsw2y@flea>
On Mon, Feb 11, 2019 at 04:34:02PM +0100, Maxime Ripard wrote:
> On Mon, Feb 11, 2019 at 02:35:52PM +0000, Priit Laes wrote:
> > On Wed, Feb 06, 2019 at 04:52:27PM +0100, Maxime Ripard wrote:
> > > Hi,
> > >
> > > On Wed, Feb 06, 2019 at 10:03:09AM +0000, Priit Laes wrote:
> > > > > > I'm concerned for other users of the PLL-PERIPH clock. AFAIK
> > > > > > all of them, except the HRTIMER, expect the clock rate to stay
> > > > > > the same and not change underneath them. And SATA expects it to
> > > > > > be at 600 MHz, as the datasheet says. And while it may not directly
> > > > > > apply to the LIME2, eMMC on newer SoCs / boards run at the slightly
> > > > > > reduced rate of 50 MHz just fine.
> > > > > >
> > > > > > In the commit in question, clocks without CLK_SET_RATE_PARENT
> > > > > > should be using the old code (now in the if conditional block),
> > > > > > i.e. the behavior should not have changed.
> > > > > >
> > > > > > I don't think this actually "fixes" whatever bug was introduced,
> > > > > > but only papers over the issue, and possible introduces further
> > > > > > issues for other users.
> > > > >
> > > > > You're right, I've overlooked that it was pll-periph being
> > > > > affected. I've dropped it for now.
> > > >
> > > > Any ideas what could be done. I currently have no time to debug it,
> > > > but it affects existing systems.
> > >
> > > I can't find what would change with that commit either if the flag
> > > isn't set, so looking at the register state before and after that
> > > commit would help I guess?
> >
> > Register dump without the patch:
> >
> > $ busybox devmem 0x01c20090
> > 0x0250030E
> >
> > pll-ddr-base 2 2 0 768000000 0 0 50000
> > pll-ddr-other 1 1 0 768000000 0 0 50000
> > mmc2 3 3 0 51200000 0 0 50000
> >
> > Register dump with patch applied, booted from mmc0 and after mounting emmc:
> >
> > $ busybox devmem 0x01c20090
> > 0x8140020B
> >
> > pll-periph-base 3 3 0 1200000000 0 0 50000
> > pll-periph 6 6 0 600000000 0 0 50000
> > mmc2 3 3 0 50000000 0 0 50000
>
> I meant the whole Clock controller, ideally a diff between the two
> states would be great.
I have uploaded the raw files here:
https://gist.github.com/plaes/3465386d8aa55fa70fd3997310719828
The test scenario is following:
1) Boot via FEL (u-boot + zImage + boot.scr) and load root fs from
sd-card / mmc0
2) ssh into machine and dump register space
- no-patch-before-mount.dump
- no-patch-post-mount.dump
3) Attempt to mount emmc / mmc2 and dump ccu register space
- with-patch-before-mount.dump
- with-patch-post-mount.dump
Firstly, I noticed that first 0x200 bits are mirrored:
0x1c20000 = 0x1c20200
0x1c20004 = 0x1c20204
...
01xc201fc = 0x1c203fc
And here come the diffs:
a) Diff before mount vs patch / reverted patch:
mmc2:
-0x1c20090: 0x0250030E
+0x1c20090: 0x0140020B
unk1: (mirrored ahb?, this one's flaky due to mmc runtime suspend)
-0x1c20260: 0x1200C17F
+0x1c20260: 0x1200C07F
unk2: (mirrored mmc2?)
-0x1c20290: 0x0250030E
+0x1c20290: 0x0140020B
b) Diff post-mount vs patch / reverted patch:
ahb (this one's flaky, possibly due to runtime suspend for mmc):
-0x1c20060: 0x1200C07F or 0x1200C17F
+0x1c20060: 0x1200C47F
mmc2:
-0x1c20090: 0x0250030E
+0x1c20090: 0x8140020B
unk1:
-0x1c20260: 0x1200C07F
+0x1c20260: 0x1200C47F
unk3:
-0x1c20288: 0x8140030B
+0x1c20288: 0x0140030B
unk2: (mirrored mmc2?)
-0x1c20290: 0x0250030E
+0x1c20290: 0x8140020B
prev parent reply other threads:[~2019-02-12 9:45 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-02 15:52 [RFC PATCH] clk: sunxi-ng: sun4i: Use CLK_SET_RATE_PARENT for mmc2 clock Priit Laes
2019-02-05 9:45 ` Maxime Ripard
2019-02-05 13:44 ` Chen-Yu Tsai
2019-02-06 9:20 ` Maxime Ripard
2019-02-06 10:03 ` Priit Laes
2019-02-06 15:52 ` Maxime Ripard
2019-02-11 14:35 ` Priit Laes
2019-02-11 15:34 ` Maxime Ripard
2019-02-12 9:45 ` Priit Laes [this message]
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