On Tue, Jan 7, 2014 at 2:44 PM, Marek Vasut marex@denx.de wrote:
On Tuesday, January 07, 2014 at 09:55:37 AM, Vivek Gautam wrote:
HI Marek,
On Mon, Jan 6, 2014 at 9:24 PM, Marek Vasut marex@denx.de wrote:
Thanks for reviewing this. :-)
On Monday, January 06, 2014 at 10:29:43 AM, Vivek Gautam wrote:
Update USB_MAX_CONTROLLER_COUNT to be '2' to enable support for both usb 3.0 controllers on exynos5420.
NOTE: To use EHCI on exynos5420, this change will need to be reverted, since there's only one EHCI controller available on exynos5420.
OK, this I seriously dislike. Hence a question ... my feeling is the XHCI and EHCI code for handling multiple controllers and multiple ports is almost the same. Can this code be adjusted to handle both EHCI and XHCI controllers indiscriminately ?
The controller count is actually used by the usb core (common/usb*) framework, right ? There's a need to add support for multiple controller types actually (so that EHCI and XHCI can be enabled simultaneously). Is that what you mean here ?
Yes. That should not be too much of a problem though.
True :-)
This would result in having CONFIG_USB_MAX_CONTROLLER_COUNT 3 on this board and being able to use both EHCI and XHCI . Would this be possible for you to implement please ? Thanks !
Ok, so you mean get all the controllers present on the board (EHCI and XHCI) setup.
Yes
I think right now, the way USB core handles the controller count is quite different, so that 'CONFIG_USB_MAX_CONTROLLER_COUNT' helps in probing multiple controllers of the same type.
The only problem is, that both EHCI and XHCI core implement:
submit_control_msg() submit_bulk_msg() submit_int_msg() usb_lowlevel_init() usb_lowlevel_stop()
exactly.
How I'd do this:
- Rename all these submit_*() functions to usb_submit_*()
- Rename all five usb_*() functions to ehci_*() resp. xhci_*()
This will happen in each controller drivers (ehci/xhci) which would eventually be called fro upper translation layer you mentioned below, right ?
- Implement translation layer, where the common code would still call usb_*() and the layer would determine whether to call ehci_*() or xhci_*() call.
Surely, you'd need to change the probe() logic a bit, the controller drivers would have to call some "usb_register_driver()" function for each controller. This function would generate a new entry in a linked list of all controllers registered and would add a flag whether this controller is EHCI or XHCI.
Ok, i can understand this. Will try to put up code for this.
Effectively, this would even remove the need for CONFIG_USB_MAX_CONTROLLER_COUNT at all, since you'd be tracking all the USB controllers in the USB core code and in a linked list.
Yeah, right. We won't need the controller count in this case.
I had plans to add support to use controllers of different types (EHCI and XHCI etc) simultaneously. But haven't really put a code for that yet. Can you suggest some pointers about how would you like to see EHCI and XHCI or even OHCI work together :-) I can take up this.
Thank you, see above please. OHCI might be nastier, but should happen along these lines above as well.
Ok, so first i will take up EHCI and XHCI then, and later 'll see the OHCI part.
Best regards, Marek Vasut