Re: sysbus usb xhci

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On Thu, Jan 02, 2020 at 07:13:25AM +0000, Sai Pavan Boddu wrote:
> Hi Gred,
> 
> We are seeing of options to reuse the hcd-xhci model and use it over system 
> bus interface rather than pci. (for Xilinx ZynqMP SOC, usb emulation)
> Are there any plans of implementing a sysbus device ? if none it would be 
> good if provided few pointers to start.

There have been some discussions about this for a (IIRC) sbsa machine,
but I'm not sure whenever that where just ideas or some code exists.

> Im looking at hcd-ehci/ochi as a reference, let me know if there are any know 
> limitations for this usecase.

Yep, the path for xhci would be quite simliar:  Create a new
XHCIPciState struct, move over all pci-specific bits from XHCIState,
leaving the generic stuff in XHCIState for sharing with sysbus.
Possibly move all pci-specific code bits into a new source file (for
cleanup, will also allow to build qemu with CONFIG_PCI=n and still have
XHCI enabled).

Once this separation is done you should be able to create a sysbus
device, reusing the generic xhci code and adding sysbus plumbing
(mmio, irq, ...)

cheers,
  Gerd