Re: [PATCH 0/9] MIPS: CI20: Add WiFi / Bluetooth support

[H. Nikolaus Schaller]

Hi Paul,

> Am 16.06.2023 um 22:21 schrieb H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>:

> - 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 = 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 
 eth0_power                       1    1      0 unknown  3300mV     0mA  3300mV  3300mV 
    16000000.dm9000-vcc           1                                 0mA     0mV     0mV
 otg_power                        0    0      0 unknown  5000mV     0mA  5000mV  5000mV 
 vcc_33v                          4    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  1200mV     0mA  1200mV  1200mV 
    DCDC2                         0    0      0 standby  1500mV     0mA     0mV     0mV 
    DCDC3                         0    0      0 unknown  3300mV     0mA     0mV     0mV 
    LDO5                          0    0      0 unknown  2500mV     0mA     0mV     0mV 
    LDO6                          0    0      0  normal  1800mV     0mA  1800mV  1800mV 
    LDO7                          0    0      0 unknown  3300mV     0mA     0mV     0mV 
    LDO8                          0    0      0 unknown  3300mV     0mA     0mV     0mV 
 SUDCDC_REG4                      0    0      0  normal  5000mV     0mA     0mV     0mV 
 LDO_REG9                         1    0      0 unknown  3300mV     0mA  3300mV  3300mV 
 LDO_REG10                        1    0      0 unknown  1200mV     0mA  1200mV  1200mV 
 bt_power                         0    0      0 unknown  3300mV     0mA  3300mV  3300mV 
root@letux:~# 

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