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Re: sysbus usb xhci

From: Philippe Mathieu-Daudé
Subject: Re: sysbus usb xhci
Date: Wed, 8 Jan 2020 16:51:06 +0100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2

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.

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,
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

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).

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