Re: [PATCH] MIPS: DTS: CI20: Raise VDDCORE voltage to 1.125 volts
From: Paul Cercueil
Date: Fri Jun 23 2023 - 12:31:56 EST
Hi Nikolaus,
Le vendredi 23 juin 2023 à 18:13 +0200, H. Nikolaus Schaller a écrit :
> Hi Paul, Thomas,
> here are my test results.
>
> > Am 22.06.2023 um 19:59 schrieb Paul Cercueil
> > <paul@xxxxxxxxxxxxxxx>:
> >
> > Commit 08384e80a70f ("MIPS: DTS: CI20: Fix ACT8600 regulator node
> > names") caused the VDDCORE power supply (regulated by the ACT8600's
> > DCDC1 output) to drop from a voltage of 1.2V configured by the
> > bootloader, to the 1.1V set in the Device Tree.
> >
> > According to the documentation, the VDDCORE supply should be
> > between
> > 0.99V and 1.21V; both values are therefore within the supported
> > range.
> >
> > However, VDDCORE being 1.1V results in the CI20 being very
> > unstable,
> > with corrupted memory, failures to boot, or reboots at random.
>
> ... and damaging the file system on SD card.
>
> > The
> > reason might be succint drops of the voltage below the minimum
> > required.
>
> 1. with your patches (except this one) on top of upstream v6.4-rc7
> and
> ci20_defconfig I can still not boot with 1.100V.
>
> 2. but also not at 1.125V as by this patch.
> [ 0.647637] DCDC1: Bringing 1200000uV into 1125000-1125000uV
>
> 3. my board needs 1.150V as minimum, reporting:
> [ 0.647627] DCDC1: Bringing 1200000uV into 1150000-1150000uV
Heh. I was fearing this would be the case.
>
> That is good news that it does not need 1.200V at the upper limit.
>
> 4. next, with this setup I can see the bluetooth chip (with default
> MAC
> address 43:30:B1:00:00:00), but it is not useable (maybe my user
> space).
>
> And there no WiFi. Rather, I have to disable the brcmfmac driver or
> otherwise I can't even complete boot (hangs in a later stage) at all.
Most likely it's because of an invalid firmware file. It happened to me
with every single firmware file (including the one in the linux-
firmware repository at that time) except the one found on the CI20's
Debian image.
Since then Broadcom guys updated the firmware in linux-firmware to the
newest one they had, which works fine.
> 5. finally the mysterious result:
>
> With all this merged with the letux-os kernel (and manually fixing
> minor
> merge conflicts) and using letux_defconfig I can boot. Even with
> 1.100V
> in the device tree, checked with /sys/kernel/debug):
>
> root@letux:~# cat /sys/kernel/debug/regulator/regulator_summary
> regulator use open bypass opmode voltage
> current min max
> ---------------------------------------------------------------------
> ------------------
> regulator-dummy 3 2 0 unknown 0mV
> 0mA 0mV 0mV
> 13500000.usb-vusb_a 1
> 0mA 0mV 0mV
> 13500000.usb-vusb_d 1
> 0mA 0mV 0mV
> eth0_power 1 1 0 unknown 3300mV
> 0mA 3300mV 3300mV
> 16000000.dm9000-vcc 1
> 0mA 0mV 0mV
> otg_power 1 2 0 unknown 5000mV
> 0mA 5000mV 5000mV
> 1000003c.usb-phy-vcc 1
> 0mA 0mV 0mV
> usb_phy-vcc 0
> 0mA 0mV 0mV
> vcc_33v 8 9 0 unknown 3300mV
> 0mA 3300mV 3300mV
> 13450000.mmc-vqmmc 1
> 0mA 0mV 0mV
> 13450000.mmc-vmmc 1
> 0mA 3300mV 3400mV
> DCDC1 1 0 0 standby 1100mV
> 0mA 1100mV 1100mV
> DCDC2 1 0 0 standby 1500mV
> 0mA 1500mV 1500mV
> DCDC3 1 0 0 unknown 3300mV
> 0mA 3300mV 3300mV
> LDO5 1 0 0 unknown 2500mV
> 0mA 2500mV 2500mV
> LDO6 1 1 0 normal 1800mV
> 0mA 1800mV 1800mV
> 13460000.mmc-vqmmc 1
> 0mA 0mV 0mV
> LDO7 0 0 0 unknown 2800mV
> 0mA 2800mV 2800mV
> LDO8 0 0 0 unknown 1500mV
> 0mA 1500mV 1500mV
> SUDCDC_REG4 2 1 0 normal 5000mV
> 0mA 5000mV 5000mV
> bt_power 2 1 0 unknown 3300mV
> 0mA 3300mV 3300mV
> wifi_power 2 1 0 unknown 3300mV
> 0mA 3300mV 3300mV
> 13460000.mmc-vmmc 1
> 0mA 3300mV 3400mV
> LDO_REG9 1 0 0 unknown 3300mV
> 0mA 3300mV 3300mV
> LDO_REG10 1 0 0 unknown 1200mV
> 0mA 1200mV 1200mV
> root@letux:~# uname -a
> Linux letux 6.4.0-rc7-letux-ci20+ #13881 SMP PREEMPT Fri Jun 23
> 17:23:42 CEST 2023 mips GNU/Linux
> root@letux:~#
>
> And I there have WiFi working fine.
>
> But no Bluetooth interface at all (although driver is compiled).
>
> A potential hint could be that DCDC1 is enabled a little later during
> boot than with ci20_defconfig:
>
> [ 1.077926] DCDC1: Bringing 1200000uV into 1100000-1100000uV
> [ 1.096997] DCDC1: 1100 mV, enabled
>
> And another test with trying 1.000V hangs immediately after this:
>
> [ 1.032846] DCDC1: Bringing 1200000uV into 1000000-1000000uV
>
> Maybe it is a too big step during operation.
1.0V is about as low as you can get with theorically perfect power
supply, I doubt that you can use this voltage in the real world.
It's strange that your letux kernel can set 1.1V and be stable, while
you need 1.15V with the upstream kernel. I wonder what could be the
cause.
>
> For the records:
>
> - I just swapped the clean compiled uImage, kernel modules and
> ci20.dtb
> between all these tests (and fsck the SD card before).
>
> - we have some experimental SMP patches by Yanjie Zhou (and other
> nice
> stuff not pushed upstream) in the Letux kernel so that any of thes
> may have an influence.
>
> So I'd say let's postpone this 1.125V patch until your other patches
> arrive upstream. Then I will rebase our Letux kernel anyways and then
> I can analyse a little easier what makes all these differences
> (because
> then no merge and manual conflict resolution is involved any more and
> there are better chances for a bisect to be helpful).
Thomas already merged it, so I guess we have 1.125V now.
Which is better than nothing; instead of not working on both our
boards, at least now v6.4 will work on one of them ;)
Note that I was testing my patches on top of the vanilla kernel,
without any local patches.
>
> Best regards,
> Nikolaus
Cheers,
-Paul
>
> > Raising the minimum voltage to 1.125 volts seems to be enough to
> > address
> > this issue, while still keeping a relatively low core voltage which
> > helps for power consumption and thermals.
> >
> > Fixes: 08384e80a70f ("MIPS: DTS: CI20: Fix ACT8600 regulator node
> > names")
> > Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >
> > ---
> > Cc: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
> > ---
> > arch/mips/boot/dts/ingenic/ci20.dts | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/mips/boot/dts/ingenic/ci20.dts
> > b/arch/mips/boot/dts/ingenic/ci20.dts
> > index cec0caa2350c..a141a699b790 100644
> > --- a/arch/mips/boot/dts/ingenic/ci20.dts
> > +++ b/arch/mips/boot/dts/ingenic/ci20.dts
> > @@ -298,8 +298,8 @@ act8600: act8600@5a {
> >
> > regulators {
> > vddcore: DCDC1 {
> > - regulator-min-microvolt =
> > <1100000>;
> > - regulator-max-microvolt =
> > <1100000>;
> > + regulator-min-microvolt =
> > <1125000>;
> > + regulator-max-microvolt =
> > <1125000>;
> > vp1-supply = <&vcc_33v>;
> > regulator-always-on;
> > };
> > --
> > 2.40.1
> >
>