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Date:   Mon, 21 Jan 2019 08:37:29 +0000
From:   Priit Laes <plaes@plaes.org>
To:     Jernej =?utf-8?Q?=C5=A0krabec?= <jernej.skrabec@siol.net>
Cc:     maxime.ripard@bootlin.com, wens@csie.org, robh+dt@kernel.org,
        mturquette@baylibre.com, sboyd@kernel.org, airlied@linux.ie,
        architt@codeaurora.org, a.hajda@samsung.com,
        Laurent.pinchart@ideasonboard.com, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-clk@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-sunxi@googlegroups.com
Subject: Re: [linux-sunxi] [PATCH v3 02/28] clk: sunxi-ng: Adjust MP clock
 parent rate when allowed
Message-ID: <20190121083729.7qsmj7drxvmnjoye@plaes.org>
References: <20181104182705.18047-1-jernej.skrabec@siol.net>
 <11550554.k1qAFTnke5@jernej-laptop>
 <20190117072402.ognqxsxewjg3kyyg@plaes.org>
 <3212171.R3YZLKKLtu@jernej-laptop>
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On Fri, Jan 18, 2019 at 10:51:10PM +0100, Jernej Škrabec wrote:
> Dne četrtek, 17. januar 2019 ob 08:24:02 CET je Priit Laes napisal(a):
> > On Wed, Jan 16, 2019 at 06:00:32PM +0100, Jernej Škrabec wrote:
> > > Dne sreda, 16. januar 2019 ob 13:09:58 CET je Priit Laes napisal(a):
> > > > On Thu, Jan 10, 2019 at 06:10:59PM +0100, Jernej Škrabec wrote:
> > > > > Dne četrtek, 10. januar 2019 ob 10:15:48 CET je Priit Laes napisal(a):
> > > > > > On Sun, Nov 04, 2018 at 07:26:39PM +0100, Jernej Skrabec wrote:
> > > > > > > Currently MP clocks don't consider adjusting parent rate even if
> > > > > > > they
> > > > > > > are allowed to do so. Such behaviour considerably lowers amount of
> > > > > > > possible rates, which is very inconvenient when such clock is used
> > > > > > > for
> > > > > > > pixel clock, for example.
> > > > > > > 
> > > > > > > In order to improve the situation, adjusting parent rate is
> > > > > > > considered
> > > > > > > when allowed.
> > > > > > > 
> > > > > > > This code is inspired by clk_divider_bestdiv() function, which
> > > > > > > does
> > > > > > > basically the same thing for different clock type.
> > > > > > 
> > > > > > This patch seems to break the eMMC support on Olinuxino-Lime2-eMMC
> > > > > > boards:
> > > > > > 
> > > > > > EXT4-fs (mmcblk1p4): INFO: recovery required on readonly filesystem
> > > > > > EXT4-fs (mmcblk1p4): write access will be enabled during recovery
> > > > > > sunxi-mmc 1c11000.mmc: data error, sending stop command
> > > > > > sunxi-mmc 1c11000.mmc: send stop command failed
> > > > > 
> > > > > I'm not familiar with A20. What is interesting is that emmc clocks
> > > > > don't
> > > > > have CLK_SET_RATE_PARENT flag set, so you shouldn't see any
> > > > > difference.
> > > > > 
> > > > > Can you post content of clk_summary with and without this patch?
> > > > 
> > > > In both cases I booted from FEL with rootfs on sdcard and tried to mount
> > > > partition from eMMC to /mnt. With your patch, last step it fails.
> > > > 
> > > > pre-patch working:
> > > > pll-ddr-other[768MHz] -> mmc2[512MHz]. (For some reason ahb-mmc2 is
> > > > off?)
> > > > 
> > > > post-patch not working:
> > > > pll-periph[600MHz] ->  mmc2[500Mhz], (ahb-mmc2 is enabled)
> > > > 
> > > > Also, attached the logs.
> > > 
> > > Thanks. Just one more request. Can you enable debug messages in mmc
> > > driver?
> > > I'm interested in output of this line:
> > > 
> > > dev_dbg(mmc_dev(mmc), "setting clk to %d, rounded %ld\n",
> > > 
> > > 		clock, rate);
> > 
> > 1c11000 is eMMC:
> > [snip]
> > [    1.961644] sunxi-mmc 1c11000.mmc: setting clk to 400000, rounded 400000
> > [    2.004091] sunxi-mmc 1c11000.mmc: setting clk to 400000, rounded 400000
> > [    2.020296] sunxi-mmc 1c11000.mmc: setting clk to 400000, rounded 400000
> > [    2.039917] sunxi-mmc 1c11000.mmc: setting clk to 400000, rounded 400000
> > [    2.047847] sunxi-mmc 1c11000.mmc: setting clk to 400000, rounded 400000
> > [    2.055053] sunxi-mmc 1c11000.mmc: setting clk to 400000, rounded 400000
> > [    2.065256] sunxi-mmc 1c11000.mmc: setting clk to 400000, rounded 400000
> > [    2.092351] sunxi-mmc 1c11000.mmc: setting clk to 400000, rounded 400000
> > [    2.168725] sunxi-mmc 1c11000.mmc: setting clk to 400000, rounded 400000
> > [    2.189403] sunxi-mmc 1c11000.mmc: setting clk to 52000000, rounded
> > 52000000 [    2.203340] sunxi-mmc 1c11000.mmc: setting clk to 52000000,
> > rounded 52000000 [    2.211412] sunxi-mmc 1c11000.mmc: setting clk to
> > 52000000, rounded 52000000 [    4.967865] sunxi-mmc 1c11000.mmc: setting
> > clk to 52000000, rounded 52000000 [    8.755345] sunxi-mmc 1c11000.mmc:
> > setting clk to 52000000, rounded 52000000 [    9.082510] sunxi-mmc
> > 1c11000.mmc: setting clk to 52000000, rounded 52000000
> > 
> > Here I tried to mount partition from eMMC...
> > 
> > [   72.167311] sunxi-mmc 1c11000.mmc: setting clk to 52000000, rounded
> > 52000000 [   72.269629] sunxi-mmc 1c11000.mmc: data error, sending stop
> > command [   73.268999] sunxi-mmc 1c11000.mmc: send stop command failed
> > [/snip]
> > 
> > And clock tree:
> > [snip]
> > 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 mmc2_sample           1        1        0   
> > 50000000          0   120  50000 mmc2_output           1        1        0 
> >   50000000          0    60  50000 ahb                     18       18     
> >   0   300000000          0     0  50000 ahb-mmc2              1        1   
> >     0   300000000          0     0  50000 [/snip]
> > 
> > 
> > And without patch:
> > [snip]
> > [    2.003341] sunxi-mmc 1c11000.mmc: XXX: setting clk to 400000, rounded
> > 400000 [    2.019479] sunxi-mmc 1c11000.mmc: XXX: setting clk to 400000,
> > rounded 400000 [    2.039144] sunxi-mmc 1c11000.mmc: XXX: setting clk to
> > 400000, rounded 400000 [    2.047129] sunxi-mmc 1c11000.mmc: XXX: setting
> > clk to 400000, rounded 400000 [    2.054324] sunxi-mmc 1c11000.mmc: XXX:
> > setting clk to 400000, rounded 400000 [    2.064481] sunxi-mmc 1c11000.mmc:
> > XXX: setting clk to 400000, rounded 400000 [    2.091624] sunxi-mmc
> > 1c11000.mmc: XXX: setting clk to 400000, rounded 400000 [    2.168067]
> > sunxi-mmc 1c11000.mmc: XXX: setting clk to 400000, rounded 400000 [   
> > 2.188239] sunxi-mmc 1c11000.mmc: XXX: setting clk to 52000000, rounded
> > 51200000 [    2.202779] sunxi-mmc 1c11000.mmc: XXX: setting clk to
> > 52000000, rounded 51200000 [    2.210817] sunxi-mmc 1c11000.mmc: XXX:
> > setting clk to 52000000, rounded 51200000 [    5.103358] sunxi-mmc
> > 1c11000.mmc: XXX: setting clk to 52000000, rounded 51200000 [    8.950237]
> > sunxi-mmc 1c11000.mmc: XXX: setting clk to 52000000, rounded 51200000 [   
> > 9.376201] sunxi-mmc 1c11000.mmc: XXX: setting clk to 52000000, rounded
> > 51200000 [  113.618387] sunxi-mmc 1c11000.mmc: XXX: setting clk to
> > 52000000, rounded 51200000 [  113.707979] EXT4-fs (mmcblk1p4): recovery
> > complete
> > [  113.728162] EXT4-fs (mmcblk1p4): mounted filesystem with ordered data
> > mode. Opts: (null) [/snip]
> > 
> > And clock tree:
> > [snip]
> > pll-ddr-base                   2        2        0   768000000          0   
> >  0  50000 pll-ddr-other               1        1        0   768000000      
> >    0     0  50000 mmc2                     0        0        0    51200000 
> >         0     0  50000 mmc2_sample           0        0        0   
> > 51200000          0   120  50000 mmc2_output           0        0        0 
> >   51200000          0    72  50000 [/snip]
> > 
> 
> It seems to me that clock rate is set properly. It's even better than before 
> since there is no error between wanted and real clock. I bet that if you call 
> clk_get_rate() directly behind clk_set_rate() in mmc driver, you'll get 
> correct value.
> 
> However, it seems that at some point some other peripheral changes it's parent 
> clock rate, which inadvertely changes emmc2 clock rate too. The only possible 
> clock which could interfere is sata. Can you disable driver in you kernel 
> config and try again?

OK, tried following things in succession, but SATA disabling does not work:

a) Marked all ahci stuff in devicetree as disabled
b) Disable CONFIG_AHCI_SUNXI in kernel
c) Even disabled SATA stuff in u-boot

> 
> Best regards,
> Jernej