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From: Thierry Reding <thierry.reding@gmail.com>
To: Stephen Warren <swarren@wwwdotorg.org>
Cc: Grant Likely <grant.likely@secretlab.ca>,
	Rob Herring <rob.herring@calxeda.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Russell King <linux@arm.linux.org.uk>,
	Andrew Murray <andrew.murray@arm.com>,
	Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Thomas Petazzoni <thomas.petazzoni@free-electrons.com>,
	devicetree-discuss@lists.ozlabs.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-tegra@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH v3 07/12] PCI: tegra: Move PCIe driver to drivers/pci/host
Date: Wed, 12 Jun 2013 23:23:10 +0200	[thread overview]
Message-ID: <20130612212308.GA27681@manwe> (raw)
In-Reply-To: <51B89D26.9070605@wwwdotorg.org>

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On Wed, Jun 12, 2013 at 10:09:10AM -0600, Stephen Warren wrote:
> On 06/12/2013 06:30 AM, Thierry Reding wrote:
> > On Mon, Apr 15, 2013 at 12:28:12PM -0600, Stephen Warren wrote:
> >> On 04/03/2013 08:45 AM, Thierry Reding wrote:
> >>> Move the PCIe driver from arch/arm/mach-tegra into the
> >>> drivers/pci/host directory. The motivation is to collect
> >>> various host controller drivers in the same location in order
> >>> to facilitate refactoring.
> >>> 
> >>> The Tegra PCIe driver has been largely rewritten, both in order
> >>> to turn it into a proper platform driver and to add MSI (based
> >>> on code by Krishna Kishore <kthota@nvidia.com>) as well as
> >>> device tree support.
> ...
> >>> +static irqreturn_t tegra_pcie_msi_irq(int irq, void *data)
> >> ...
> >>> +	return IRQ_HANDLED;
> >> 
> >> Shouldn't this function return IRQ_NONE if no MSI status bits
> >> were found set?
> > 
> > The IRQ isn't marked IRQF_SHARED, so I don't think this is needed.
> 
> Isn't it still useful to detect unexpected/stuck interrupts?

Yes, you're right. I can't think of a nicer way to do it, though, so
I'll go with a processed IRQ counter or a flag.

> >>> +static int tegra_pcie_probe(struct platform_device *pdev)
> >> ...
> >>> +	pcibios_min_mem = 0;
> >> 
> >> What does that mean/do? I wonder if that should be set to
> >> 0x80000000 by the Tegra30 patches?
> > 
> > ARM defines PCIBIOS_MIN_MEM to that variable. That macro in turn is
> > only used by pci_bus_alloc_resource() AFAICT, which uses it to
> > override the start of a resource when allocating if res->start ==
> > 0. As such it designates a lower-bound of valid PCI memory
> > addresses, so 0 on Tegra20 and 0x80000000 on Tegra30 don't seem
> > like good values. Maybe we need to set them to the lowest of the
> > prefetchable and non-prefetchable memory areas as defined in the
> > DT?
> > 
> > It doesn't currently seem to matter at all, though, since we never
> > pass in a range that's 0, so the start address of resources can
> > never be 0 and therefore PCIBIOS_MIN_MEM is never used.
> 
> Hmmm. I guess ignore it then. If the value won't ever be used, 0 is as
> good a value as any?

Alright, I'll do that then.

Thierry

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  reply	other threads:[~2013-06-12 21:23 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-04-03 14:45 [PATCH v3 00/12] Rewrite Tegra PCIe driver Thierry Reding
2013-04-03 14:45 ` [PATCH v3 01/12] of/pci: Provide support for parsing PCI DT ranges property Thierry Reding
2013-04-03 14:45 ` [PATCH v3 02/12] of/pci: Add of_pci_get_devfn() function Thierry Reding
2013-04-03 14:45 ` [PATCH v3 03/12] of/pci: Add of_pci_parse_bus_range() function Thierry Reding
2013-04-03 14:45 ` [PATCH v3 04/12] PCI: Introduce new MSI chip infrastructure Thierry Reding
2013-04-03 14:45 ` [PATCH v3 05/12] ARM: tegra: Move tegra_pcie_xclk_clamp() to PMC Thierry Reding
2013-04-03 14:45 ` [PATCH v3 06/12] ARM: tegra: Move pmc.h to include/linux/tegra-pmc.h Thierry Reding
2013-04-03 14:45 ` [PATCH v3 07/12] PCI: tegra: Move PCIe driver to drivers/pci/host Thierry Reding
2013-04-04 21:28   ` Stephen Warren
2013-04-04 21:30     ` Stephen Warren
2013-04-05  6:03       ` Thierry Reding
2013-04-10 22:46         ` Stephen Warren
2013-04-05  7:37     ` Thierry Reding
2013-04-05  7:53       ` Thierry Reding
2013-04-10 23:05       ` Stephen Warren
2013-04-15 18:28   ` Stephen Warren
2013-06-12 12:30     ` Thierry Reding
2013-06-12 16:09       ` Stephen Warren
2013-06-12 21:23         ` Thierry Reding [this message]
2013-04-03 14:45 ` [PATCH v3 08/12] ARM: tegra: tamonten: Add PCIe support Thierry Reding
2013-04-03 14:45 ` [PATCH v3 09/12] ARM: tegra: tec: " Thierry Reding
2013-04-03 14:45 ` [PATCH v3 10/12] ARM: tegra: harmony: Initialize PCIe from DT Thierry Reding
2013-04-03 14:45 ` [PATCH v3 11/12] ARM: tegra: trimslice: " Thierry Reding
2013-04-03 14:45 ` [PATCH v3 12/12] ARM: tegra: Update default configuration (PCIe) Thierry Reding

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