Beaglebone USB driver (Mentor Graphics OTG)

[Oleksandr Tymoshenko]

On 2013-04-07, at 12:04 AM, Hans Petter Selasky <hps at bitfrost.no> wrote:

> On 04/06/13 22:50, Oleksandr Tymoshenko wrote:
>> Hello,
>> 
>> This is first iteration of Host Mode support for Mentor Graphics
>> OTG USB controller. I tested it by building kernel with USB memory
>> stick mounted as /usr/obj, resulting kernel was bootable and worked fine.
>> I reused some ideas (mostly for channel-management) from
>> DWT OTG driver.
>> 
>> Some pieces are still missing:
>> - Support for SPLIT transactions, I don not have high speed hub
>>     right now to test it, but implementing it should be really
>> straighforward.
>> - Isochronous transfers. I do not have hardware to test this. Does
>>     anybody have any suggestion about simple use case?
>> - Control Data OUT transaction
>> - Wrapper for atmel HW has not ben synced with new core logic requirements
>>     yet
>> 
>> Please review and test. I tested it only with gcc-built kernel/world.
>> Now when
>> first iteration is finished I'm going to update all my boards to new
>> world order
>> (clang/EABI) and re-test this stuff.
>> 
>> Patch:
>> http://people.freebsd.org/~gonzo/arm/patches/beaglebone-musb.diff
> 
> Hi,
> 
> Looks like you've got the grasp of the USB controller stuff :-)
> 
> Some comments:
> 
> 1) Use DPRINTFN(-1, ...) instead of printf() for all printf() that are not part of boot dmesg.
> 
> +				break;
> +			default:
> +				td->transfer_type = 0;
> +				printf("Invalid USB speed: %d\n", speed);
> +				break;
> +		}
> 
> 
> 2) You should implement if HOST mode, support for SUSPEND and RESUME. See EHCI driver. Basically what you need is:
> 
> a) USB transfers are stopped/paused. I know there is a hack you need if the host transfer cancel hangs, and that is to write a dummy device address and wait for the USB transfer to error out after 250 us max.
> 
> b) switch on USB suspend signalling.
> 
> 
> At resume:
> 
> c) do resume signalling, similar to EHCI/UHCI I think.
> 
> d) switch on channel tokens.
> 
>  	case UHF_PORT_SUSPEND:
> +		if (sc->sc_mode == MUSB2_HOST_MODE)
> +			printf("TODO: Set UHF_PORT_SUSPEND\n");
> +		break;
> 
> 
> 
> 3) Make sure that channels are not generating tokens if they are aborted / cancelled / timedout. This can not be verified using a USB mass storage device. Verify this by connecting a USB serial adapter. Try to open/close /dev/cuaU0. Make sure it does not loose any bytes and that channel cancel does not hang forever.


Thanks for review. Took  me quite some time to get back 
to the driver but here is updated version that addresses some 
of the issues you've mentioned:
http://people.freebsd.org/~gonzo/arm/patches/beaglebone-usb-20130626.diff

It fixes several bugs, adds proper SPLIT transactions support and 
suspend/resume signalling.  I tested it with urtwn-based WiFi chip,
mass storage device, USB keyboard connected directly and using 
high-speed hub.

Suspend/resume is not 100% complete though. I can use USB serial 
port adapter if it's suspended/resumed unconnected. But it stuck if I do 
the test while connected. Is it the right way to test it? 

On the related note: can somebody suggest budget USB protocol analyzer
with support for high-speed bus?