Re: dwc3 gadget and USB3

[Thinh Nguyen <Thinh.Nguyen@synopsys.com>]

On Sat, Mar 11, 2023, Joakim Tjernlund wrote:
> On Fri, 2023-03-10 at 22:58 +0000, Thinh Nguyen wrote:
> > On Fri, Mar 10, 2023, Joakim Tjernlund wrote:
> > > On Thu, 2023-03-09 at 21:09 +0000, Thinh Nguyen wrote:
> > > > On Thu, Mar 09, 2023, Joakim Tjernlund wrote:
> > > > > On Thu, 2023-03-09 at 19:56 +0000, Thinh Nguyen wrote:
> > > > > > On Thu, Mar 09, 2023, Joakim Tjernlund wrote:
> > > > > > > On Thu, 2023-03-09 at 17:32 +0100, Joakim Tjernlund wrote:
> > > > > > > > On Wed, 2023-03-08 at 22:26 +0100, Joakim Tjernlund wrote:
> > > > > > > > > On Wed, 2023-03-08 at 19:58 +0100, gregkh@linuxfoundation.org wrote:
> > > > > > > > > > On Wed, Mar 08, 2023 at 06:12:51PM +0000, Joakim Tjernlund wrote:
> > > > > > > > > > > On Wed, 2023-03-08 at 18:25 +0100, Greg KH wrote:
> > > > > > > > > > > > On Wed, Mar 08, 2023 at 05:10:17PM +0000, Joakim Tjernlund wrote:
> > > > > > > > > > > > 
> > 
> SNIP ...
> 
> > > 
> > > 
> > > While I remember, I tried to create both a NCM and a ttyACM on top of my dwc3 gadget
> > > but then I got som bind error when activating the UDC. Is that expected ?
> > > I figured both could live on the same device and would just mux the two protocols.
> > > 
> > 
> > I'm not clear what you meant here. The gadget driver and the UDC driver
> > should be separated and abstracted from each other.
> > 
> > Also, please note that all this talking points are based on the
> > assumption that the issue is due to the host putting the device in
> > suspend base on your experiment. We didn't review the logs.
> > 
> > IMO, the best option should be to prevent suspend from the host side as
> > it looks like your device may operate in usb3 speed also?
> > 
> > BR,
> > Thinh
> 
> This script best explain I think:
> #! /bin/sh
> 
> stop() {
>     g="/sys/kernel/config/usb_gadget/g1"
>     if [ -e "${g}"/UDC ]; then
> 	echo "" >  "${g}"/UDC
> 	rm -f "${g}"/os_desc/c.1
> 	rm -f "${g}"/configs/c.1/ncm.usb0
> 	rm -f "${g}"/configs/c.1/acm.GS0
> 	[ -d "${g}"/configs/c.1/strings/0x409 ] && rmdir "${g}"/configs/c.1/strings/0x409
> 	[ -d "${g}"/functions/acm.GS0 ] && rmdir "${g}"/functions/acm.GS0
> 	[ -d "${g}"/functions/ncm.usb0 ] && rmdir "${g}"/functions/ncm.usb0
> 	[ -d "${g}"/c.1/strings ] && rmdir "${g}"/c.1/strings
> 	[ -d "${g}"/c.1/strings/0x409 ] && rmdir "${g}"/c.1/strings/0x409
> 	[ -d "${g}"/configs/c.1 ] && rmdir "${g}"/configs/c.1
> 	[ -d "${g}" ] && rmdir  "${g}"
>     fi
> }
> 
> start() {
>     mkdir -p /sys/kernel/config/usb_gadget/g1
>     cd /sys/kernel/config/usb_gadget/g1
> 
>     ###############################
>     # Populate Device-Level Stuff #
>     ###############################
> 
>     #Setting device class/subclass/protocol to these values
>     # alerts the OS that this is a composite device with
>     # IADs in it's firmware.
>     # ref: https://urldefense.com/v3/__https://docs.microsoft.com/en-us/windows-hardware/drivers/usbcon/usb-interface-association-descriptor__;!!A4F2R9G_pg!f2DmukBCz-n2dXRTDTd22YjHdXgKXWZwCLtuwoB4SdjW-U7s2s9Cyez4-JjmHJNzhetxdX06a6iohV_1yj7bpq2Ha28LvwALSw$ 
>     echo "0xEF" > bDeviceClass
>     echo "0x02" > bDeviceSubClass
>     echo "0x01" > bDeviceProtocol
> 
>     echo "0x15A2" > idVendor
>     echo "0x0001" > idProduct
> 
>     #mkdir strings/0x409
>     #echo "1234567" > strings/0x409/serialnumber
>     #echo "Infinera" > strings/0x409/manufacturer
>     #echo "NDU" > strings/0x409/product
> 
>     #enable use of os_desc's (important for RNDIS & NCM enablement on Windows):
>     echo 1       > os_desc/use
>     echo 0xbc    > os_desc/b_vendor_code #or 0xcd ?
>     echo MSFT100 > os_desc/qw_sign
> 
>     #################################
>     # Populate Individual Functions #
>     #################################
> 
>     #The order functions are populated here will be reflected in the
>     # order of descriptors written.
> 
>     #########
>     # RNDIS #
>     #########
>     #Note! If RNDIS is enabled, it *has* to be the first function! Otherwise, Windows 10 will report error 10 (failed to start device).
>     # (It's unclear why this is the case..)
>     # https://urldefense.com/v3/__https://docs.microsoft.com/en-us/answers/questions/474108/does-rndis-need-to-be-listed-as-the-first-function.html__;!!A4F2R9G_pg!f2DmukBCz-n2dXRTDTd22YjHdXgKXWZwCLtuwoB4SdjW-U7s2s9Cyez4-JjmHJNzhetxdX06a6iohV_1yj7bpq2Ha28URWCTNQ$ 
>     # https://urldefense.com/v3/__https://stackoverflow.com/questions/68365739/windows-rndis-compatible-device-does-rndis-need-to-be-listed-as-the-first-funct__;!!A4F2R9G_pg!f2DmukBCz-n2dXRTDTd22YjHdXgKXWZwCLtuwoB4SdjW-U7s2s9Cyez4-JjmHJNzhetxdX06a6iohV_1yj7bpq2Ha2-HtzzXog$ 
>     if [ 0 = 1 ]
>     then
> 	mkdir functions/rndis.usb0
> 	mkdir -p functions/rndis.usb0/os_desc/interface.rndis
> 
> 	# Set compatible / sub-compatible id's so that Windows can match this
> 	# function to RNDIS6 driver more easily.
> 	echo RNDIS   > functions/rndis.usb0/os_desc/interface.rndis/compatible_id
> 	echo 5162001 > functions/rndis.usb0/os_desc/interface.rndis/sub_compatible_id
> 
> 	mkdir -p configs/c.1
> 	mkdir -p configs/c.1/strings/0x409
> 	echo "0xC0" > configs/c.1/bmAttributes # Self powered
> 	echo "conf1" > configs/c.1/strings/0x409/configuration
> 	ln -s functions/rndis.usb0 configs/c.1
> 	if [ ! -L os_desc/c.1 ]
> 	then
> 	    ln -s configs/c.1 os_desc
> 	fi
>     fi
> 
>     #########
>     # NCM   #
>     #########
>     #Usually I test with *either* RNDIS or NCM enabled, but not both, hence the if(0) here..
>     if [ 1 = 1 ]
>     then
> 	mkdir functions/ncm.usb0
> 	mkdir -p functions/ncm.usb0/os_desc/interface.ncm
> 	# Set compatible id so that Windows 10 can match this function to
> 	# NCM driver more easily.
> 	echo WINNCM   > functions/ncm.usb0/os_desc/interface.ncm/compatible_id
> 
> 	mkdir -p configs/c.1
> 	mkdir -p configs/c.1/strings/0x409
> 	echo "0xC0" > configs/c.1/bmAttributes # Self powered
> 	echo "conf1" > configs/c.1/strings/0x409/configuration
> 	ln -s functions/ncm.usb0 configs/c.1
> 	if [ ! -L os_desc/c.1 ]
> 	then
> 	    ln -s configs/c.1 os_desc
> 	fi
>     fi
> 
>     #########
>     # ACM   #
>     #########
>     if [ 1 = 1 ]
>     then
> 	mkdir -p functions/acm.GS0
> 
> 	mkdir -p configs/c.1
> 	mkdir -p configs/c.1/strings/0x409
> 	echo "0xC0" > configs/c.1/bmAttributes # Self powered
> 	ln -fs functions/acm.GS0 configs/c.1
> 	if [ ! -L os_desc/c.1 ]
> 	then
> 	    ln -s configs/c.1 os_desc
> 	fi
>     fi
> 
>     #Activate/bind USB gadget
>     echo 2f00000.usb > UDC
> }
> command=$@
> 
> case ${command} in
>     start)
> 	echo "Starting usb-lc"
> 	start
> 	#ifconfig lc 169.254.100.101 netmask 255.255.255.252 # for debug
>     ;;
>     stop)
> 	echo "Stopping usb-lc"
> 	stop
>     ;;
>     restart)
> 	stop
> 	start
> 	;;
> 
>     *)
> 	echo "Create USB Gadget device dual NCM and rndis V0.1.1 for MAC, Linux and Windows"
> 	exit 1
> 	;;
> esac
> 
> 
> This gives me an error:
> 
> ./config_gadget.sh start
> Starting usb-lc
> sh: write error: Device or resource busy
> 
> the line causing that is:
> echo 2f00000.usb > UDC
> 
> Just create either NCM or ACM works, but not both

Not sure. You may need to trace through the code path and see where it
fails.

BR,
Thinh