Re: [PATCH v3] PCI: Xilinx-NWL-PCIe: Added support for Xilinx NWL PCIe Host Controller

From: Marc Zyngier <marc.zyngier@arm.com>
To: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"pawel.moll@arm.com" <pawel.moll@arm.com>,
	"mark.rutland@arm.com" <mark.rutland@arm.com>,
	"ijc+devicetree@hellion.org.uk" <ijc+devicetree@hellion.org.uk>,
	"galak@codeaurora.org" <galak@codeaurora.org>,
	Michal Simek <michals@xilinx.com>,
	Soren Brinkmann <sorenb@xilinx.com>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	"arnd@arndb.de" <arnd@arndb.de>,
	"tinamdar@apm.com" <tinamdar@apm.com>,
	"treding@nvidia.com" <treding@nvidia.com>,
	"rjui@broadcom.com" <rjui@broadcom.com>,
	"Minghuan.Lian@freescale.com" <Minghuan.Lian@freescale.com>,
	"m-karicheri2@ti.com" <m-karicheri2@ti.com>,
	"hauke@hauke-m.de" <hauke@hauke-m.de>
Cc: "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Ravikiran Gummaluri <rgummal@xilinx.com>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3] PCI: Xilinx-NWL-PCIe: Added support for Xilinx NWL PCIe Host Controller
Date: Fri, 09 Oct 2015 10:02:39 +0100	[thread overview]
Message-ID: <561782AF.4080408@arm.com> (raw)
In-Reply-To: <8520D5D51A55D047800579B09414719801690D3D@XAP-PVEXMBX01.xlnx.xilinx.com>

On 09/10/15 09:51, Bharat Kumar Gogada wrote:
>> On 09/10/15 06:11, Bharat Kumar Gogada wrote:
>>>>>> +struct nwl_msi {                  /* struct nwl_msi - MSI information
>>>> */
>>>>>> +  struct msi_controller chip;     /* chip: MSI controller */
>>>>>
>>>>>> We're moving away from msi_controller altogether, as the kernel now
>>>>>> has all the necessary infrastructure to do this properly.
>>>>>
>>>>> Our current GIC version does not have separate msi controller (we
>>>>> are not using GICv2m or GICv3), so is it necessary to have separate
>>>>> msi controller node ? Please give me clarity on this.
>>>>
>>>> This has nothing to do with the version of the GIC you are using
>>>> (XGene doesn't have GICv2m or v3 either). This is about reducing code
>>>> duplication and having something that we can maintain. See also
>>>> https://lkml.org/lkml/2015/9/20/193 for yet another example.
>>>>
>>>> I still plan to kill msi_controller, and I'd like to avoid more
>>>> dependencies with it. MSI domains are the way to do it.
>>>>
>>> Sorry previously I haven't configured my email client properly so resending.
>>
>> Thanks for doing so, much appreciated.
>>
>>> Since we don't have separate MSI controller, and our PCIe controller
>>> is handling MSI, is it necessary to create a separate MSI controller
>>> node because we don't have any 'reg' space.
>>
>> No, your PCI controller can perfectly be part of the PCIe node.
> You meant 'msi-controller' property to be part of PCIe node?

Yeah, sorry. Too early, not enough coffee.

>>
>>> Please let me know whether we require a separate msi file as suggested
>>> in your previous comments to separate MSI controller and PCIE
>>> controller in two files, if we don't have separate node. If we do not
>>> need a separate node do we need to embed MSI controller child node  in
>>> PCIe controller node itself, and what properties does this child node
>>> will require other than 'interrupts'.
>>
>> If you want to keep them in the same file, please at least have two separate
>> patches. These are two different functions, and they should be reviewed
>> separately.
>>
> What I meant is if we don't have separate msi node do we need separate file? 

That's up to you. Nodes and source code files don't have to match at all.

> If you meant msi controller to be part of same node then we will use single file and will
> try to have two separate patches.

That's fine by me.

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...