On Friday 18 December 2015 11:00:19 Hans de Goede wrote:
Hi,
On 18-12-15 02:11, Stefan Brüns wrote:
Start split and complete split tokens need the hub address and the downstream port of the first HS hub (device view).
The core of the function was duplicated in both host/ehci_hcd and musb-new/usb-compat.h.
Signed-off-by: Stefan Brüns stefan.bruens@rwth-aachen.de
Thanks for working on this, I think I've spotted one small bug though, see comments inline.
Ah, sorry for not mentioning this.
Yes, this changes the musb code, but this was on purpose. Rationale:
The ifdef'ed Linux kernel code uses the 1 based port number, whereas U-Boot puts a 0 based port number into the register. The reason the 0 based port number apparently works can probably be taken from the USB 2.0 spec:
8.4.2.2 Start-Split Transaction Token ... The host must correctly set the port field for single and multiple TT hub implementations. A single TT hub implementation *may ignore* the port field.
Actually, as far as I unterstand, a multi TT hub defaults to single TT (bAlternateSetting: 0) until switched via SetInterface, so even "port 42" would work.
I have somewhat verified this assumption by hardcoding the port number and split transactions still work. Used hubs are the RPi onboard SMC9514 and an external "05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB". The former is a multi TT hub, the latter single TT only.
I have no board with musb, but I think a 0 based port number is wrong.
This function is usb-2 controller / hub specific, maybe rename it to: "usb_find_usb2_hub_address_port" to reflect this ?
Yes, sounds reasonable.
Kind regards,
Stefan