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Subject: Re: [PATCH 0/9] MIPS: CI20: Add WiFi / Bluetooth support
From:   "H. Nikolaus Schaller" <hns@goldelico.com>
In-Reply-To: <5EF6B0D2-2B84-4C98-B799-88062E035EC1@goldelico.com>
Date:   Sat, 17 Jun 2023 12:45:44 +0200
Cc:     list@opendingux.net, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        Conor Dooley <conor+dt@kernel.org>, linux-mips@vger.kernel.org,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Paul Boddie <paul@boddie.org.uk>
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Message-Id: <43DCEEA5-C013-44BE-85C7-D61A980B0EA5@goldelico.com>
References: <20230615084006.79194526F801@goldelico.com>
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To:     Paul Cercueil <paul@crapouillou.net>
Precedence: bulk

Hi Paul,

> Am 16.06.2023 um 22:21 schrieb H. Nikolaus Schaller =
<hns@goldelico.com>:

> - But renaming the DT nodes (e.g. SUDCDC1 -> DCDC1) (with or without =
regulator_name) makes
> boot hang with strange errors which indicate that the processor power =
supply is not stable.
> Once a while it did even automatically reboot. In most cases there are =
some EXT4 errors
> afterwards.

I am coming closer, I think. I have now touched only the DCDC1 node =
name.

a) with "SUDCDC1" -> "DCDC1" (bad bood):

regulator_of_get_init_node() returns the child node

Then:
[    0.666962] act8865 0-005a: Looking up vp1-supply from device tree
[    0.673191] DCDC1: supplied by vcc_33v
[    0.727070] DCDC1: Bringing 1200000uV into 1100000-1100000uV
[    0.739398] DCDC1: 1100 mV, enabled

b) without patch/series or reverted (good boot):

regulator_of_get_init_node() returns NULL

Then:
[    1.016487] DCDC1: at 1200 mV, enabled
[    1.020578] act8865 0-005a: Looking up vp1-supply from device tree
[    1.026917] DCDC1: supplied by vcc_33v

So at least for my board the patched series seems to reduce DCDC1 =
voltage
to 1.1V which may trigger the boot and stability problems on my board =
while
it is fine for yours. This could explain the hardware dependency.

Now I have no data sheets or information which voltages are the right =
ones
and where the 1200mV come from (most likely some default programmed
into the PMU chip).

And the issue seems to be that without matching the node names the
voltages in the device tree may have been ignored completely all the
time... Now it sets up voltages, which should happen. But different
ones for my board which breaks boot.

Finally I did risk (I have no replacement CI20 board and they are no =
longer
on sale... RS part# was 125-3305 Mouser 456-VL-62851) to run a test with
rename to "DCDC1" but changing the voltage to 1200mV. And this version =
boots.

Still without WiFi/Bluetooth but that may be related to missing rename
of the other regulators.

So I tried renaming all regulators as by your [PATCH 2/9], and now I
see something from WiFi (haven't installed firmware yet) and the =
Bluetooth chip:

[    1.977876] mmc1: new high speed SDIO card at address 0001

[   11.341994] Bluetooth: hci0: BCM: chip id 62
[   11.348811] Bluetooth: hci0: BCM: features 0x0f
[   11.376698] Bluetooth: hci0: BCM4330B1
[   11.380662] Bluetooth: hci0: BCM4330B1 (002.001.003) build 0000
[   11.392053] Bluetooth: hci0: BCM4330B1 'brcm/BCM4330B1.hcd' Patch

[   12.145330] brcmfmac mmc1:0001:1: Direct firmware load for =
brcm/brcmfmac4330-sdio.img,ci20.bin failed with error -2
[   12.208001] brcmfmac mmc1:0001:1: Direct firmware load for =
brcm/brcmfmac4330-sdio.clm_blob failed with error -2

Unfortunatley systemd bailed out starting Bluetooth service but
failed to provide a login:

In summary it looks like a potential fix could be to replace the DCDC1
min/max range by 1.0 - 1.2V instead of 1.1 - 1.1V but we need deeper
understanding first. Usually this has something to do with dynamic =
voltage
scaling depending on processor clock and lower voltages are only allowed
for lower frequencies but max. clock requires the highest possible =
voltage.
AFAIK we have no cpufreq integrated and therefore always run at max. =
speed.

BR,
Nikolaus

PS: here is what I read back from the regulator voltages (for DCDC1  =
min/max =3D 1.2V):

root@letux:~# cat /sys/kernel/debug/regulator/regulator_summary
 regulator                      use open bypass  opmode voltage current  =
   min     max
=
--------------------------------------------------------------------------=
-------------
 regulator-dummy                  1    0      0 unknown     0mV     0mA  =
   0mV     0mV=20
 eth0_power                       1    1      0 unknown  3300mV     0mA  =
3300mV  3300mV=20
    16000000.dm9000-vcc           1                                 0mA  =
   0mV     0mV
 otg_power                        0    0      0 unknown  5000mV     0mA  =
5000mV  5000mV=20
 vcc_33v                          4    9      0 unknown  3300mV     0mA  =
3300mV  3300mV=20
    13450000.mmc-vqmmc            1                                 0mA  =
   0mV     0mV
    13450000.mmc-vmmc             1                                 0mA  =
3300mV  3400mV
    DCDC1                         1    0      0 standby  1200mV     0mA  =
1200mV  1200mV=20
    DCDC2                         0    0      0 standby  1500mV     0mA  =
   0mV     0mV=20
    DCDC3                         0    0      0 unknown  3300mV     0mA  =
   0mV     0mV=20
    LDO5                          0    0      0 unknown  2500mV     0mA  =
   0mV     0mV=20
    LDO6                          0    0      0  normal  1800mV     0mA  =
1800mV  1800mV=20
    LDO7                          0    0      0 unknown  3300mV     0mA  =
   0mV     0mV=20
    LDO8                          0    0      0 unknown  3300mV     0mA  =
   0mV     0mV=20
 SUDCDC_REG4                      0    0      0  normal  5000mV     0mA  =
   0mV     0mV=20
 LDO_REG9                         1    0      0 unknown  3300mV     0mA  =
3300mV  3300mV=20
 LDO_REG10                        1    0      0 unknown  1200mV     0mA  =
1200mV  1200mV=20
 bt_power                         0    0      0 unknown  3300mV     0mA  =
3300mV  3300mV=20
root@letux:~#=20

This matches device tree except DCDC1, LDO7 and LDO8 (camera).