Re: sysbus usb xhci

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

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 <philmd@redhat.com>; kraxel@redhat.com
>> Cc: peter.maydell@linaro.org; qemu-devel@nongnu.org
>> Subject: RE: sysbus usb xhci
>>
>> Thanks Philippe & Gred. I would start with the below pointers.
>>
>> Regards,
>> Sai Pavan
>>
>>> -----Original Message-----
>>> From: Philippe Mathieu-Daudé <philmd@redhat.com>
>>> Sent: Thursday, January 2, 2020 4:56 PM
>>> To: kraxel@redhat.com; Sai Pavan Boddu <saipava@xilinx.com>
>>> Cc: peter.maydell@linaro.org; qemu-devel@nongnu.org
>>> Subject: Re: sysbus usb xhci
>>>
>>> On 1/2/20 10:45 AM, kraxel@redhat.com 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).
>