How to support option usb data in ep0 control command? about raw-gadget

[xairy]

0xc0 has USB_DIR_IN (0x80) bit set, which makes it an IN request. So the host doesn't send data to the device but expects the device to send it. You need to use an OUT request if you want to send data to the device.

[dukezuoHZ]

thanks xairy,but I can't get data when used 0x40 too. how can i do?

[xairy]

I would first make sure that the USB request is sent from the host as expected via usbmon.

How exactly does getting data fail for you? Do you get bad wLength from USB_RAW_IOCTL_EVENT_FETCH? Or does USB_RAW_IOCTL_EP0_READ fail?

[dukezuoHZ]

the wLength received is ok, but when USB_RAW_IOCTL_EP0_READ is wrong,this is my source:
if (event.ctrl.bRequestType==0x40) //add by duke 2023.12.25
{
PTRACE("received customed command! 0x40");
if (ep0_cbFunc!=NULL) //customed command
{
usb_raw_ep0_read(usb_fd, (struct usb_raw_ep_io )&io);
PTRACE("epo read :%s",io.data);
ep0_cbFunc(ep0_cbArgs,event.ctrl.wIndex,event.ctrl.wValue,(char)&io.data[0],event.ctrl.wLength);
}
}
else
{
rv = usb_raw_ep0_read(usb_fd, (struct usb_raw_ep_io *)&io);
printf("ep0: transferred %d bytes (out)\n", rv);
if (event.ctrl.wLength>0)
printf("read control %s\n",io.data[0]);
}
it will print info:
event: control, length: 8
bRequestType: 0x40 (OUT), bRequest: 0x0, wValue: 0x11, wIndex: 0x22, wLength: 12
type = USB_TYPE_VENDOR
req = unknown = 0x0
fail: no response USB_TYPE_VENDOR
11:21:59 : usb_gadget.cpp(968) received customed command! 0x40
ioctl(USB_RAW_IOCTL_EP0_READ): Invalid argument

[xairy]

Invalid argument means there's something wrong with the arguments you provide to USB_RAW_IOCTL_EP0_READ. The code that you shared doesn't show that part, so I don't know what is wrong.

Enabling debug output as described here and potentially adding more debug messages into the USB_RAW_IOCTL_EP0_READ handler should help you figure out what's wrong.

[dukezuoHZ]

ok,I give my full code here which refered from gadget.c:

void usb_gadget::ep0_loop() 
{
	PTRACE("*****enter ep0_read_loop******");
	while (usbRuning) 
	{
		struct usb_raw_control_event event;
		event.inner.type = 0;
		event.inner.length = sizeof(event.ctrl);

		usb_raw_event_fetch(usb_fd, (struct usb_raw_event *)&event);
		log_event((struct usb_raw_event *)&event);

		if (event.inner.type == USB_RAW_EVENT_CONNECT) {
			process_eps_info(usb_fd);
			continue;
		}

		if (event.inner.type != USB_RAW_EVENT_CONTROL)
			continue;

		struct usb_raw_control_io io;
		io.inner.ep = 0;
		io.inner.flags = 0;
		io.inner.length = 0;//event.ctrl.wLength;//0;

		bool reply = ep0_request(usb_fd, &event, &io);
		if (!reply) {
			printf("ep0: stalling\n");
			usb_raw_ep0_stall(usb_fd);
			continue;
		}

		if (event.ctrl.wLength < io.inner.length)
			io.inner.length = event.ctrl.wLength;

		int rv = -1;
#if 1
		if (event.ctrl.bRequestType & USB_DIR_IN) //to host
		{	
			if (event.ctrl.bRequestType==0xc0) //add by duke 2023.12.25
			{	
				PTRACE("received customed command! 0xc0");
				if (ep0_cbFunc!=NULL) //customed command
				{
					 //if (event.ctrl.wLength>0)
					// usb_raw_ep0_read(usb_fd, (struct usb_raw_ep_io *)&io);
					ep0_cbFunc(ep0_cbArgs,event.ctrl.wIndex,event.ctrl.wValue,(char *)&io.data[0],event.ctrl.wLength);
				}
			}
			//else
			{			
				rv = usb_raw_ep0_write(usb_fd, (struct usb_raw_ep_io *)&io);
				printf("ep0: transferred %d bytes (in)\n", rv);
			}
		} 
		else //to device 
		{
			if (event.ctrl.bRequestType==0x40) //add by duke 2023.12.25
			{	
				PTRACE("received customed command! 0x40");
				if (ep0_cbFunc!=NULL) //customed command
				{
					usb_raw_ep0_read(usb_fd, (struct usb_raw_ep_io *)&io);
					PTRACE("epo read :%s",io.data);
					ep0_cbFunc(ep0_cbArgs,event.ctrl.wIndex,event.ctrl.wValue,(char*)&io.data[0],event.ctrl.wLength);
				}
			}
			else
			{
				rv = usb_raw_ep0_read(usb_fd, (struct usb_raw_ep_io *)&io);
				printf("ep0: transferred %d bytes (out)\n", rv);			
				if (event.ctrl.wLength>0)
					printf("read control %s\n",io.data[0]);	
			}
		}
#else
		if (event.ctrl.bRequestType & USB_DIR_IN) {
			rv = usb_raw_ep0_write(usb_fd, (struct usb_raw_ep_io *)&io);
			printf("ep0: transferred %d bytes (in)\n", rv);
		} else {
			rv = usb_raw_ep0_read(usb_fd, (struct usb_raw_ep_io *)&io);
			printf("ep0: transferred %d bytes (out)\n", rv);
		}
#endif
		
		if ((event.ctrl.bRequestType & USB_TYPE_MASK) ==
				USB_TYPE_VENDOR &&
					event.ctrl.bRequest == VENDOR_REQ_OUT)
			memcpy(&vendor_buffer[0], &io.data[0], rv);
	}
	PTRACE("*****exit ep0_read_loop******");
}

[xairy]

Do you initialize io->inner.length to be event.ctrl.wLength in ep0_request for your custom requests? If not, you need to do this.

If fixing this doesn't help, please enable the debug output for the Raw Gadget module and share the messages it prints to the kernel log.

[dukezuoHZ]

thanks xairy, I can got "hello world!" ,it fee well. now when i add one code in ep0_request()
default:
io->inner.length = event->ctrl.wLength;//add by duke 2024.1.9
printf("fail: no response USB_TYPE_VENDOR\n");
//exit(EXIT_FAILURE);
break;

If i ack the usb control , How can i return usb_ctrlrequest data?

[dukezuoHZ]

Hi,xairy,We used ctrl endpoint to chat with host PC,I have write a function send_ctrl_data(),but if i called ,crashed....I post my code file here.please help me review it.thanks a lot!
gadget_test.zip

[dukezuoHZ]

to xairy: in our project,we need ep0 control channel to chat with pc for most customed command,We have done it ok in movidus platform,now we change device from movidus platform to nvidia platform

[xairy]

Hi,xairy,We used ctrl endpoint to chat with host PC,I have write a function send_ctrl_data(),but if i called ,crashed....I post my code file here.please help me review it.thanks a lot!

I'd be happy to answer any Raw Gadget-related questions, but I don't have the throughput to debug crashes in your code unfortunately :(

If i ack the usb control , How can i return usb_ctrlrequest data?

If I understand your question correctly: When you fetch a USB_RAW_EVENT_CONNECT event, usb_ctrlrequest is provided in the data field of usb_raw_event. This happens before you ack the request via USB_RAW_IOCTL_EP0_WRITE/READ.

[dukezuoHZ]

I have debug ok and it work now

[dukezuoHZ]

but i find it work on usb2.0,not work usb3.0..... ^_^,print error:
event: control, length: 8
bRequestType: 0x0 (OUT), bRequest: 0x9, wValue: 0x1, wIndex: 0x0, wLength: 0
type = USB_TYPE_STANDARD
req = USB_REQ_SET_CONFIGURATION
ioctl(USB_RAW_IOCTL_EP_ENABLE): Invalid argument
bulk_out: ep = #-1

[xairy]

Raw Gadget doesn't support USB 3, see #61. You can enable debugging output for the Raw Gadget module to see what exactly is failing. I would expect that the USB stack expects a USB endpoint companion descriptor, which Raw Gadget doesn't provide.