Seeedstudio ReComputer RK3576 - MiniPCIE

[boobypi]

Hello,

I just received my SeedStudio Recomputer RK3576 and I have a well working machine thanks to the armbian team using the debian Forky image.
I try to understand why i cannot connect a (usb) minipcie modem (already testing 1 year use with Radxa zero 3 W), all usb ports not working anymore!

There is a strange note on schematic pdf : 

If the PCIe1 or SATA1 function of Combo PHY1 is
selected, the USB3 OTG1 function cannot be used,
and even the USB2 PHY1 function cannot be used

But they also notice the support of usb link on this minipcie : 
 

LTE LoRa Module: Module:EC20/EC25
WM1302 SPI/USB Version
Zigbee: USB Version

  

 

The miniPCIe is connected on USBHUB_HOST3 <- USB HUB external chip -> USB2_HOST1 (RK3576 soc).
All USB phy fail, even USB PHY not related to this usb hub.
lsusb didn't show my usb modem, even if there no usb devices connected.

I bought this nice machine as my home router with internal 4G modem quectel EC200A-EU but at this time ,my plan fail.
The idle powerdraw with nvme onboard is under 2W and wifi sta active, Nice dietpi hardware!

Thanks for your input (how to make this minipcie working, disable usb port is a possible tradeoff for me)
Seb

[boobypi]

Maybe it's just relative to reset pin on the LTE modem, locking down all the shared USB BUS.

On the dts, we can activate LTE_RESET : 

&i2c4 {
	status = "okay";
	pinctrl-0 = <&i2c4m3_xfer>;

	gpio_xten: gpio_xten@21 {
		compatible = "nxp,pca9535";
		reg = <0x21>;
		gpio-controller;
		#gpio-cells = <2>;
		
		interrupt-controller;
		gpio-line-names =
		"MIPI_DPHY_CSI0_IO1"	,"USB_USB30_PWREN_H",
		"USB_HOST_PWREN_H"	,"BRD_ID_WP",
		"LTE_RESET"	,"P05",
		"P06"	,"LoRaWan_sx1262_CS",
		"USER_LED_R"	,"USER_LED_B",
		"USER_LED_G"	,"P13",
		"P14"	,"P15",
		"P16"	,"P17";
		
		gpio-line-offsets = <0>, <1>, <2>, <3>, <4>, <5>, <6>, <7>, <8>, <9>, <10>, <11>, <12>, <13>, <14>, <15>;
	};

 

On the LTE modem manual, reset is active when LTE_RESET is low, and pullup to vcc in normal operation.

If LTE_RESET stay low with onboard modem connected, LTE modem may lock all USB ports.
How can I define LTE_RESET to 1 at the boot? 

 

[boobypi]

At the finnest, i cut the reset pin (22) on my minipcie module. Same all USB port lockdown.
I put this modified lte modem in my external usb case, modem always working fine.

So i take a spare new LTE modem and i connect it "hotplug" on the recomputer minipcie while already booted : lsusb see my Quectel LTE module!  
 

Edited 4 hours ago by boobypi

[eselarm]

My thinking is that with a standard example tool from libgpiod (gpioset) it should be possible to toggle a GPIO line. I see 'P05' that seems a pad number of the RK3576. I remember I had to dig deep in internet fora for something similar for BananaPi M1 to see what to put in armbianEnv.txt. Or NanoPi-NEO. The later I use with those example gpioset to toggle a GPIO to switch some own electronics on/off.

You could also use lgpio (rpigpio successor or any other that can toggle pin states). Note that formally, you need to threat a GPIO line like a file, claim, open, close etc. After that state is undefined, but most SBC kernels keep the state, but formally undefined. See many many discussions on wiringpi etc.

 

W.r.t. this combPHY: the RK3576/RK3588: those can act as several SerDes, it is sort of multiplexed, so cannot be all at the same time. But you need to look in schematics. I use the SATA<> PCIE2x1 swap (on E-key slot on ROCK5B and ROCK3A) but it very much depends on what firmware/bootloader and DTB(O) and kernel. For the ROCK3A for example, I still don't have it working according to I wish with mainline based U-Boot+kernel. Only vendor 6.1 and legacy U-Boot. I see on the SeeedStudio page: preloaded with Armbian, so this topics is a sort of test-case IMO: is that claim with mainline based or vendor/legacy Rockchip; I guess the latter, so maybe list versions of various system software. 'Forky' is not released, so a moving target or rolling release, others don't know what versions you use so not possible to reproduce the issue(s).

[boobypi]

Thanks for your input,

I never really use gpio lib and i don't know if gpio over i2c is userland playable or there are reserved to the kernel.

The fact on the schematic is VSYS_3V3_EXP is the first rail powering up because it's supply I2Cs bus and the GPIO over I2C to switch ON or reseting thing.

 

VCC5V0_DEVICE_S0 For FAN & HDMI & USB & TYPE-C, USB HUB (Total: 3A) switch on by RK806S over I2C (PMIC_PWR_CTRL2)
VSYS_3V3_EXP For CSI & DSI & RPi 40Pin (Total: 4A)  <======== I2Cs GPIO (LTE RESET), Minipcie is supplied here! , switch on by RK3576 gpio (VSYS_3V3_EXP_EN)

VCC3V3_PCIE For PCIE-M.2 (nvme), switch on by RK3576 gpio (PCIE_PWREN_H_GPIO0B5)

The design flaw is here : you need I2C up to put LTE modem (already on by the same I2C power supply) in reset state before switch on USB PHY, then release LTE_RESET.
Why they didn't put LTE modem supply, triggering a 3.3vcc mosfet from USB 5V rail ready signal after usb init like normal usb device, too easy?

[eselarm]

8 minutes ago, boobypi said:

The design flaw is here : you need I2C up to put LTE modem (already on by the same I2C power supply) in reset state before switch on USB PHY, then release LTE_RESET.
Why they didn't put LTE modem supply, triggering a 3.3vcc mosfet from USB 5V rail ready signal after usb init like normal usb device, too easy?

OK, I did not look into further details, I don't have any of this HW. I only have same experience 10 years ago, 4G module works in USB adapter, did not get it to work in mPCIE slot.

 

I am not sure if a DeviceTree patch/change can fix it, don't know enough of that description principles. As indicated, SeeedStudio can read this, it is their HW, maybe they should fix it for you.

[boobypi]

Quote

I only have same experience 10 years ago, 4G module works in USB adapter, did not get it to work in mPCIE slot.

Totally agree, too little or niche market!
I 'm thinking about soldering simcard directly on these cheap minipci lte modem and use a regular usb2.0 cable, what a joke!