From mboxrd@z Thu Jan  1 00:00:00 1970
From: Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH 1/6] pci, thunder: Add support for Thunder PCIe host
 controller
Date: Wed, 24 Sep 2014 17:49:46 +0100
Message-ID: <20140924164946.GI16244@arm.com>
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To: Arnd Bergmann <arnd@arndb.de>
Cc: "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, Robert Richter <rric@kernel.org>, Bjorn Helgaas <bhelgaas@google.com>, "grant.likely@linaro.org" <grant.likely@linaro.org>, Rob Herring <robh+dt@kernel.org>, "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>, Liviu Dudau <Liviu.Dudau@arm.com>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, Robert Richter <rrichter@cavium.com>, "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>, Sunil Goutham <sgoutham@cavium.com>
List-Id: devicetree@vger.kernel.org

On Wed, Sep 24, 2014 at 05:12:26PM +0100, Arnd Bergmann wrote:
> On Wednesday 24 September 2014 17:37:43 Robert Richter wrote:
> > From: Sunil Goutham <sgoutham@cavium.com>
> > 
> > This patch adds support for PCI host controller of Cavium Thunder
> > SoCs.
> 
> I had expected this hardware to be SBSA compliant. Why do you need
> a hardware specific driver, is this a workaround for buggy hardware
> or just noncompliant?

Patches welcome to pci-host-generic.c :) Lorenzo already has code to port
it to Liviu's new API, so do shout if it's not suitable for your needs.

> > +static int thunder_pcie_msi_enable(struct thunder_pcie *pcie,
> > +					struct pci_bus *bus)
> > +{
> > +	struct device_node *msi_node;
> > +
> > +	msi_node = of_parse_phandle(pcie->node, "msi-parent", 0);
> > +	if (!msi_node)
> > +		return -ENODEV;
> > +
> > +	pcie->msi = of_pci_find_msi_chip_by_node(msi_node);
> > +	if (!pcie->msi)
> > +		return -ENODEV;
> > +
> > +	pcie->msi->dev = pcie->dev;
> > +	bus->msi = pcie->msi;
> > +
> > +	return 0;
> > +}
> 
> This is probably something we should add to the generic host driver as well,
> so it can work with SBSA compliant implementations that come with an MSI
> controller. Maybe move it into common code so it can be shared with that
> driver.

Agreed. I've been carrying something similar [1] (based on a hacked-up version
of bios32, so not bothered to post it) whilst I've been waiting for the
arm64 core PCI code to get merged.

Will

[1] https://git.kernel.org/cgit/linux/kernel/git/will/linux.git/commit/drivers/pci/host/pci-host-generic.c?h=iommu/pci&id=b719acf062ceccfbd79ee7b1ae0b7904ea4da27e