From: Arnd Bergmann <arnd@arndb.de>
To: Tomasz Nowicki <tn@semihalf.com>
Cc: Jayachandran C <jchandra@broadcom.com>,
        linux-arm-kernel@lists.infradead.org,
        Bjorn Helgaas <helgaas@kernel.org>, Will Deacon <will.deacon@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>, rafael@kernel.org,
        Hanjun Guo <hanjun.guo@linaro.org>,
        Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>,
        Sinan Kaya <okaya@codeaurora.org>, jiang.liu@linux.intel.com,
        Jon Masters <jcm@redhat.com>, linaro-acpi@lists.linaro.org,
        linux-pci@vger.kernel.org, Liviu.Dudau@arm.com,
        David Daney <ddaney@caviumnetworks.com>, linux-kernel@vger.kernel.org,
        linux-acpi@vger.kernel.org, robert.richter@caviumnetworks.com,
        Suravee.Suthikulpanit@amd.com, msalter@redhat.com,
        Wangyijing <wangyijing@huawei.com>, Marcin Wojtas <mw@semihalf.com>
Subject: Re: [PATCH V6 08/13] PCI: generic, thunder: update to use generic ECAM API
Date: Mon, 18 Apr 2016 16:44:13 +0200
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On Monday 18 April 2016 15:03:51 Tomasz Nowicki wrote:
> On 16.04.2016 16:36, Jayachandran C wrote:
> > On Sat, Apr 16, 2016 at 1:01 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> >> On Saturday 16 April 2016 12:50:13 Jayachandran C wrote:
> > The whole pci-thunder-*.c is to support thunder PCI quirks since the
> > generic OF is handled by pci-host-common.c and generic ECAM is now
> > separated -  duplicating the whole file for ACPI will be bad.
> 
> Yes, it would be too much code duplication. Also, we already know 
> drivers which need quirks.
> 
> We really need to agree on best approach here. Here are requirements 
> which came up (please correct me if misunderstood sth):
> 
> Arnd:
> 1. Initial DT driver should be standalone [Arnd]
> 2. No exported symbols [Arnd]
> 3. Duplicate necessary code to ACPI framework.

Correct.

> JC:
> 1. Adding linker section is wrong.
> 2. Quirks should be exported (pci_thunder_ecam_ops), then no need for 
> adding linker section
> 3. To much duplication to copy code into the ACPI framework.
> 
> My opinion:
> 1. I like linker section because it is easy to maintain and no need to 
> export symbols.
> 2. We need more sophisticated algorithm for matching quirks (DMI is not 
> enough and not only for ThunderX drivers). Of course I am open to any 
> new suggestions.

Agreed.

> 3. To much duplication to copy code into the ACPI framework.
> 
> Thanks in advance for any pointers.

Can you be more specific about what code actually would need to
be duplicated? Anything besides the config space operations?

	Arnd