Re: sysbus usb xhci

[Philippe Mathieu-Daudé]

On 1/8/20 4:32 PM, Sai Pavan Boddu wrote:
> Hi Gred/Philippe,
>
> In the process of making hcd-xhci.c free of pci wrapper, I came across a dma command 
> " ldq_le_pci_dma" for which I don’t see any low level alternative to replace.
> Even I cannot find the source of it, do you have any thoughts on this ?

Isn't it ldq_le_phys()?

I think you want to extract the address space first in a common method. 
See in sdhci_pci_realize():

    s->dma_as = pci_get_address_space(dev);

And in sdhci_sysbus_realize():

    if (s->dma_mr) {
        s->dma_as = &s->sysbus_dma_as;
        address_space_init(s->dma_as, s->dma_mr, "sdhci-dma");
    } else {
        /* use system_memory() if property "dma" not set */
        s->dma_as = &address_space_memory;
    }

> > -----Original Message-----
> > From: Sai Pavan Boddu
> > Sent: Friday, January 3, 2020 10:44 AM
> > To: Philippe Mathieu-Daudé <address@hidden>; address@hidden
> > Cc: address@hidden; address@hidden
> > Subject: RE: sysbus usb xhci
> >
> > Thanks Philippe & Gred. I would start with the below pointers.
> >
> > Regards,
> > Sai Pavan
> >
> > > -----Original Message-----
> > > From: Philippe Mathieu-Daudé <address@hidden>
> > > Sent: Thursday, January 2, 2020 4:56 PM
> > > To: address@hidden; Sai Pavan Boddu <address@hidden>
> > > Cc: address@hidden; address@hidden
> > > Subject: Re: sysbus usb xhci
> > >
> > > On 1/2/20 10:45 AM, address@hidden wrote:
> > > > 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, ...)
> > >
> > > The SDHCI commits b635d98cf32..8b7455c75e seem similar to what you
> > > want to achieve (see also commit ce8646034).