Re: [linux-sunxi] [PATCH v3 02/28] clk: sunxi-ng: Adjust MP clock parent rate when allowed

From: Jernej Åkrabec
Date: Mon Jan 21 2019 - 13:13:16 EST

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In reply to: Priit Laes: "Re: [linux-sunxi] [PATCH v3 02/28] clk: sunxi-ng: Adjust MP clock parent rate when allowed"
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Dne ponedeljek, 21. januar 2019 ob 14:34:33 CET je Priit Laes napisal(a):
> On Mon, Jan 21, 2019 at 08:37:29AM +0000, Priit Laes wrote:
> > On Fri, Jan 18, 2019 at 10:51:10PM +0100, Jernej Åkrabec wrote:
> > > Dne Äetrtek, 17. januar 2019 ob 08:24:02 CET je Priit Laes napisal(a):
> > > > On Wed, Jan 16, 2019 at 06:00:32PM +0100, Jernej Åkrabec 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 Åkrabec wrote:
> > > > > > > Dne Äetrtek, 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
>
> But it works, when I allow mmc2 clock to set parent rate:

Strange, I checked both pre- and post- patch clk_summary you sent me and in
both cases both mmc2 parent clocks have same rate as before. This would need a
more detailed analysis with a lot of debug print, but don't have such board.

CLK_SET_PARENT rate might be viable solution, but you have to be sure that
any clock using pll-periph as a parent is in expected range.

On the plus side, if this works, eMMC will work faster due to 8 MHz clock rate
increase :)

>
> pll-periph-base 3 3 0 312000000 0
> 0 50000 mbus 1 1 0 78000000
> 0 0 50000 pll-periph-sata 1 1 0
> 26000000 0 0 50000 sata 1 1
> 0 26000000 0 0 50000 pll-periph 5
> 5 0 156000000 0 0 50000 mmc2 0
> 0 0 52000000 0 0 50000 mmc2_sample 0
> 0 0 52000000 0 120 50000 mmc2_output
> 0 0 0 52000000 0 120 50000 mmc0
> 0 0 0 39000000 0 0 50000 mmc0_sample
> 0 0 0 39000000 0 90 50000 mmc0_output
> 0 0 0 39000000 0 90 50000
>
>
> Now, what I don't understand is why the `enable count` does not increase :(

mmc has suspend/resume functionality which might power down mmc when not in
use and thus disable clocks. Try initiate some big transfer from/to eMMC and
check clocks in between.

BR,
Jernej

>
> ---
> diff --git a/drivers/clk/sunxi-ng/ccu-sun4i-a10.c
> b/drivers/clk/sunxi-ng/ccu-sun4i-a10.c index 129ebd2588fd..605e13b4ef90
> 100644
> --- a/drivers/clk/sunxi-ng/ccu-sun4i-a10.c
> +++ b/drivers/clk/sunxi-ng/ccu-sun4i-a10.c
> @@ -498,7 +498,7 @@ static SUNXI_CCU_MP_WITH_MUX_GATE(mmc2_clk, "mmc2",
> mod0_default_parents, 0x090, 16, 2, /* P */
> 24, 2, /* mux */
> BIT(31), /* gate */
> - 0);
> + CLK_SET_RATE_PARENT);
>
> /* MMC output and sample clocks are not present on A10 */
> static SUNXI_CCU_PHASE(mmc2_output_clk, "mmc2_output", "mmc2",
>
> > > Best regards,
> > > Jernej

Next message: Sergei Shtylyov: "Re: [PATCH v6 1/2] spi: Add Renesas R-Car Gen3 RPC-IF SPI controller driver"
Previous message: Jerome Brunet: "Re: [PATCH 0/2] arm64: dts: meson: g12a: enable pinctrl"
In reply to: Priit Laes: "Re: [linux-sunxi] [PATCH v3 02/28] clk: sunxi-ng: Adjust MP clock parent rate when allowed"
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