Re: [RFC PATCH 00/10] Tegra XHCI support

On Thu, May 15, 2014 at 12:33 PM, Stephen Warren [off-list ref] wrote:

On 05/14/2014 06:32 PM, Andrew Bresticker wrote:

quoted

This is a first pass at the host and PHY drivers necessary for USB3.0
support on Tegra114 and Tegra124.  The Tegra XHCI host controller requires
external firmware [1] which must be loaded before using any USB ports owned
by the controller.  The XUSB PHY driver handles mapping and enabling of
the UTMI, HSIC, and SuperSpeed pads to the XHCI controller.

Tested on a Venice2 with a variety of USB2.0 and USB3.0 memory sticks
and ethernet dongles.

Notes:
 - I've included support for Tegra114, but since I don't have Tegra114-based
   hardware, it is completely untested.
 - The PCIe and SATA PHYs also are programmed using the XUSB_PADCTL space
   as well.  At least some of the code can be re-used, specifically with
   respect to lane programming.  I believe Thierry is working on the PCIe
   parts of this.

If I understand the HW correctly, there's a separate "pad control" HW
block that provides routing/sharing of signals from USB2(?), USB3, SATA,
and PCIe to the pads.

I believe Thierry is working on exposing this block as a pinctrl driver,
or at least something that the other drivers can call into in order to
configure that block. It'd be good if you can co-ordinate with him to
rebase this driver on top of that, rather than (I assume; haven't read
the code yet...) directly manipulating the padctrl registers inside each
of the different drivers.

Yes, ideally i'd like to rebase this on top of Theirry's series once
it's ready.  It sounds like there will be a pinctrl driver which
handles the lane muxing between XUSB, PCIe, and SATA and a generic PHY
driver will deal wit the actual PHY programming.  I'm not sure what
the PCIe and SATA PHY drivers will look like, but the XUSB one
requires quite a bit of USB-specific programming of the padctl
registers, so I'm not sure we'll be able to fit all three PHY types
into a single PHY provider driver.  Either way, there's probably a
good deal of PHY code that could be broken out and shared among the
three.
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html