How to enable wake on usb (remote wakeup) in android? - linux-kernel

I have an AOSP tree compiled on my board. I bought a wireless keyboard and connected it to my board via usb port. I expect when the board is in the suspend state, it will wakeup by pressing a key on keyboard. But it is not so.
I tried several ways in my bootloader (uboot), kernel, etc. But no effect. Additionally I made an experiment and found out that in the sleep state, my usb port (which has a dongle in it) has just 1-5 mA. But it should be higher for the dongle to work!
Has anyone experienced this? How to enable remote wakeup for usb in android?
Thanks
More info:
The uboot supports usb host controller interface. I tweaked kernel build options. but these two actions has no effect.
EDIT : I work on p212 reference board of amlogic. Its SoC is Amlogic S905X.
EDIT 2 : I tested the board (which is a tv box actually) using my phone and its charger and I found that when the box goes to sleep, the charging is stopped!! So I can deduce that the dongle has not enough power to stay alive! (yet to send wake signal to SoC !)
Then I carried out a second experiment: I connected the phone using a USB charger which only has two pin instead of four. (Just voltage supply; differential pins (signal pins) are disconnected). The result: my phone is charging now!! It seems when the SoC is suspending, it sends a signal to USB peripherals telling them to not draw power. Am I correct? How can I configure my AOSP tree and Linux kernel and uboot bootloader to avoid happening this?
Please guide me how to fix it in kernel or other parts of stack!
EDIT 3 :
I have pasted my kernel config here. I configured these options to y but has no effect:
CONFIG_PM_RUNTIME=y
CONFIG_PM_AUTOSLEEP=y
CONFIG_PM_DEBUG=y
CONFIG_USB_OTG_WAKELOCK=y
CONFIG_USB_DEBUG=y
CONFIG_USB_OTG=y
Also this link is my device tree files. (in kernel. NOT uboot)

Related

Why is my STM32F407 not being recognized by computer (Windows 10)?

Overview
I need to program a recently purchased STM32F407ZGT6 board
In 'normal mode' my computer doesn't recognizing the board as a Ports (COM & LPT)/STMElectronics Virtual COM Port when connected via USB (I'm using a Windows 10 Pro). The LEDs turn on and I can get it into 'DFU mode'. When I try to debug the code, I get the "No ST-LINK detected!" message in either mode.
This is my first time connecting the board and also my first time dealing with STM32
Despite the instructions, I want to program the board using C directly from the STM32CubeIDE
Here is what I found
I found this question [1] where Device Manager reads the STM as Disk drives/STM32. My PC identifies it as mass storage and portable devices on Windows 10 Pro. When in DFU mode, I can see it as Universal Serial Bus Device/STM32 BOOTLOADER on Device Manager.
The tutorial [2] uses Flash Loader Demo and this older tutorial [3] uses STSW-STM32080, but both of the drivers are tagged as obsolete on the ST Website. STM32CuberProgrammer is indicated instead, but I would like to flash and debug directly from the IDE. Another forum reply [4] says that "you need a ST-link V2 programmer to program the brand new chip".
In summary
I can see the solution being one of the following options:
correct answer I need to use the ST-LINK-V2 to program from the IDE and that's the only way
I need to flash a bootloader via STM32CubeProgrammer to get it to work via IDE (is there a standard code for this?)
I have to build the cross-compiler for MicroPython [5] before I get to program it in C
What are your thoughts? Any other driver or idea that I might be missing?
Update
I went on and got my hands on a ST-LINK V2. I made the connection via the JTAG/SWD connector (see schematic) and I also tried connecting directly with the pins:
ST-Link
JTAG/SWD
Pins
SWCLK
9
PA14
SWDIO
7
PA13
GND
10
GND
3.3V
1
3.3V
RST
3
PB4
The ST-Link is not recognized. The ST-Link blinks and the board is powered up, but that's it. Device manager before and after shows the same.
So I went on checking if I was missing any new driver/program. I installed the STSW-LINK004 (STM32 ST-LINK Utility v4.6.0.0) based on these instructions, but no luck, Utility cannot find it either. I've reseted the computer after each driver installation. If I connect my boardvia USB in DFU mode, it is still recognized as STM32 BOOTLOADER, if I do it with the ST-Link, nothing changes.
Update solution
It turned out the ST-Link was faulty and therefore not connecting. After finding another ST-LINK/V2, the computer can recognize the board under Universal Serial Bus devices/STM32 STLink.
Debugging with STM32CubeIDE will always need an ST-LINK or other JTAG or SWD debug probe.
The bootloader allows you to program the microcontroller with a binary image, and that's it. The IDE will happily produce such a binary image, and possibly even have a wizard for transferring it via DFU. But that's only programming, no debugging And only be when the bootloader is running. If you did debug-like things like reading RAM contents, you'd get what the bootloader stores there while it is running, not the variables that your own program uses.
The ROM bootloader supports several ways of receiving new code to flash -- USB (DFU), CAN, I2C, SPI, UART. That last is not a USB Virtual COM port, it is honest-to-God UART using the USART peripheral in the microcontroller and RX/TX pins.
If you want a virtual COM port for your custom firmware to use to send data to the PC, you have to program the USB peripheral.

How to tell linux retrain and scan PCIe bus?

We have an embedded board that has an iMX8M-Plus Processor and Linux v5.4.161. This board has one PCIe bus and that one is connected to an FPGA. When we power up the board, the FPGA is not yet configured, so it acts as if it was not on the PCIe bus.
Once the Linux is fully booted, we configure the FPGA and only after that it starts acting as a PCIe endpoint (device).
At this point, when I run lspci -> it returns nothing.
When I first execute echo "1" > /sys/bus/pci/rescan as suggested here and here and then lspci, I still get nothing.
But if I reboot the linux without reseting the FPGA, it starts being visible in the lspci list. Rebooting the linux is not an option for us. Somehow I need to tell the linux that whatever it's doing at the boot time, please do it again at runtime. But I couldn't find a solution for this so far.
According to the Texas Instrument support forum, they said if the PCIe link is not trained at the boot time, rescan command never works.
At the boot time, while linux loads a pci driver, it tries to establish a PCIe link, I can see that with an oscilloscope, PERST pin is asserted and PCIE_CLK generated for a while and then stops if it can not detect any device. But the rescan command never does that.
Also in the system there is no pcie device to executeecho 1 > $pcidevice/remove in order to make rescan functional. Or there is no device or bus to set power off and on back like echo 0 > /sys/bus/pci/slots/.../power
I also learned that there was a method in old linux times (v2.6) called adding a Fake PCIe Device which physically doesn't exist to solve this problem. For that I took the fakephp.c driver from an old linux repo and ported it to ours. After solving a couple of deprecated function problems, it is compiled for Linux Kernel v5.4. modprobe fakephp worked and driver loaded but somehow I didn't get this fake device in my device list. Here it is mentioned that the fakephp driver was removed from mainstream linux since PCI core has similar functionality, but he never mentioned how.
Short of the story is that, I am stuck here, I need my FPGA to be visible in the lspci list without restarting the linux.
I recommend configuring the FPGA in u-boot to get away from these kinds of problems. Connect up SPI pins to FPGA's config pins & run it in Slave configuration mode.

A way to stop stm32 nucleo l4r5zi from supply 5v out

I have A STM32 Nucleo l4r5zi.
It is placed somewhere and I have only control over the PC who the Nucleo is connected to.
I want the Nucleo to stop supply 5v out from his pin IN ANY WAY.
I don't care to restart the nucleo or shut it down. just somehow stop for a 10 second the supply power from his 5v pinout.
How can I do this ?
I tried to solve it from the OS (by stoping supply the USB with power) but i could not manage to do so.
I can only change the code or change things on the os. no any physical modification
As the schematics prove, you cannot reprogram the "main" STM32 controller (in your case, STM32L4R5ZI) to switch off the '+5V' signal.
Instead, you have to reprogram the ST-Link controller on the nucleo board (STM32F103CBT6) so that it controls pin PB15. Note that this will probably render your nucleo board useless (apart from the use not to drive the 5V pin...). I'm not aware how simple it is to reprogram the ST-Link controller. If this really is what you want to achieve, you should post another question if/how an arbitrary firmware can be flashed on nucleo's st-link controller.
Of course, you can remove the jumper JP6, but as I understand your question, you don't have physical access to the board.
If by "on the os", you mean to change the configuration of the USB port on some PC attached to the board, this question appears to me to be off-topic, so I don't follow this path any further here.

Windows PC as a USB slave to emulate a thumbdrive

I need to create a application that will allow a Windows PC (XP/Vista) to emulate a thumbdrive. That is, when the PC is plugged into either another Windows system, or in this case, a piece of hardware that allows for USB thumbdrives to be plugged in, a folder on the computer looks like a giant thumbdrive. Any thoughts on where a guy would start to investigate this?
Update (more specific description):
I need to connect my PC to one of the newer multifuction devices that support scanning to a USB thumbdrive that is inserted into the front of the device. These units do not support WIA or TWAIN via the rear USB connector that you'd typically use for connectivity to a PC.
Most USB controllers in regular pc's dont have the possibility to function as an USB slave. So I'd start with investigating what kind of hardware you're going to use.
Another way to go: there are USB Link cables to link up 2 pc's over USB, maybe that's usable for you?
You cannot do this in an application. At the lowest level, the USB ports on your computer are controlled by an Host Controller Interface. This chip will manage up to 127 slave USB devices. You would need to seriously reprogram this chip before it implements the slave side of the USB protocol. Of course, at that point any USB hub in your PC will break down - those 8 USB ports you probably have are usually implemented by 2 smart USB hubs connecting to both USB1 and USB2 host controllers. Next, your USB keyboard and mouse will stop working.
Take an MCU with two Slave USBs. Write a simple frimware which makes one USB act as a Special Device Class and wait until PC on this USB provides mandatory data (including Device Class, of course) for the other USB. Write a PC program which connects to the Special Device (your MCU), uploads Mass Storage Device Class and redirects I/O to a dedicated partition. The other USB on the MCU will become an emulated Mass Storage Device.
Some of those code can be taken from Linux.

USB Debugging

I'm looking for a very specific USB device for debugging systems that may use USB but not with a regular computer (proprietary hardware). I want a device that has a USB host controller and two USB device connections. The device to be debugged is connected to the USB host controller and one of the device connections is connected to another device with it's own host controller on it. The the other device connection is connected to a pc. The point being that all USB data travelling through the device (from the device connected to the host controller to the device connected to the first device connection) is reported to the pc.
I'll happily write software to do the logging (in fact I want to) but I can't seem to find a board like this anywhere. Can anyone help?
I have an Ellisys USB analyser, which isn't exactly what you describe internally, but does sit between a peripheral and a host and use a separate PC to collect the data.
(i.e. it has two 'B' and one 'A' connectors on it.)
Excellent product, and very helpful company.
Sniffing the USB shouldn't be too hard if you have the right hardware. And that is the tricky question. I haven't seen anything that describes the USB breakout box that you want. However I can say that this is in the realm of the following two magazines:
Nuts and Volts
Circuit Cellar
If they don't have a USB breakout box project in their archives, then at least they will have advertisements for small cheap single board computers that would have multiple USB ports that you can use for buffering the signals and reporting it back to your PC.
Alternatively is it possible to just wire your PC up to the middle of your two devices and write a custom drive that echos data back and forth while sniffing off a stream for you?
Sorry for the long delay in my reply -- I checked out one of our USB developer's toolchain, and he uses a Beagle USB Sniffer. He seems happy with it.
You're looking for a USB device with two upstream outputs. I think according to the USB spec, this is not possible. You will have two USB hosts trying to send messages and control the USB devices at the same time.
What if you were to look for a device which allowed you to view the data going through a hub via something other than a usb output?
If you're building something custom, take a look at this USB chip site. The chips are programmable via a windows application. Once you define how you want it to operate, it's saved on an EPROM on the dev board ($30-$50).
Sorry if this isn't helpful!

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