Beaglebone USB driver (Mentor Graphics OTG)
Hans Petter Selasky
hps at bitfrost.no
Sun Apr 7 07:17:58 UTC 2013
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.
--HPS
More information about the freebsd-usb
mailing list