Re: [PATCH] MIPS: DTS: CI20: Raise VDDCORE voltage to 1.125 volts
From: H. Nikolaus Schaller
Date: Fri Jun 23 2023 - 12:14:37 EST
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
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.
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.
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).
Best regards,
Nikolaus
>
> 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
>