From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@citrix.com>
Subject: Re: [RFC PATCH v3 10/18] xen/arm: ITS: Add APIs to add
 and assign device
Date: Thu, 2 Jul 2015 11:30:30 +0100
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To: Ian Campbell <ian.campbell@citrix.com>, Vijay Kilari <vijay.kilari@gmail.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>, Prasun Kapoor <Prasun.Kapoor@caviumnetworks.com>, Vijaya Kumar K <vijaya.kumar@caviumnetworks.com>, Tim Deegan <tim@xen.org>, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, Stefano Stabellini <stefano.stabellini@citrix.com>, manish.jaggi@caviumnetworks.com
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On 02/07/15 10:01, Ian Campbell wrote:
> On Thu, 2015-07-02 at 14:10 +0530, Vijay Kilari wrote:
>> On Mon, Jun 29, 2015 at 5:59 PM, Ian Campbell <ian.campbell@citrix.com> wrote:
>>> CIOn Mon, 2015-06-22 at 17:31 +0530, vijay.kilari@gmail.com wrote:
>>>> +/* Device assignment. Should be called from pci_device_add */
>>>> +int its_add_device(struct domain *d, u32 devid)
>>>> +{
>>>
>>> Prior to the PCI series landing, and to enable dom0 to use ITS it might
>>> be possible to call this from xen/arch/arm/platforms/thunderx.c via the
>>> specific_mappings platform hook, which would also expose the PCI
>>> controller to dom0 via a series of specific mmio mappings (look at
>>> xen/arch/arm/platforms/xgene-storm.c for the sort of thing I mean).
>>>
>>> That would, I think, give basic PCI functionality for dom0 (i.e.
>>> allowing us to boot on thunderx) and decouple things from the PCI series
>>> somewhat, which ought to make things easier overall IMHO.
>>
>>   In case ThunderX, mmio mappings PCI RC is parsed to find devices.
>> How do we know device ids upfront to call its_add_device?
> 
> Ah yes, this approach probably doesn't work for ITS. Which is a shame.

I guess the number of device IDs supported by thunderX is bounded and
not so big. So you could do a loop which register all the IDs from 0 to N.

Though, it may be possible to be smarter.

Regards,

-- 
Julien Grall