Re: [PATCH 1/2] of_pci_irq: add a check to fallback to standard device tree parsing

From: Ryder Lee <ryder.lee@mediatek.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: devicetree@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
	linux-mediatek@lists.infradead.org, linux-pci@vger.kernel.org,
	Bjorn Helgaas <bhelgaas@google.com>,
	Frank Rowand <frowand.list@gmail.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2] of_pci_irq: add a check to fallback to standard device tree parsing
Date: Fri, 16 Mar 2018 08:58:09 +0800	[thread overview]
Message-ID: <1521161889.13458.1.camel@mtkswgap22> (raw)
In-Reply-To: <20180315174329.GB22176@e107981-ln.cambridge.arm.com>

On Thu, 2018-03-15 at 17:43 +0000, Lorenzo Pieralisi wrote:
> On Wed, Jan 31, 2018 at 03:41:49PM +0800, Ryder Lee wrote:
> > A root complex usually consist of a host bridge and multiple P2P bridges,
> > and someone may express that in the form of a root node with many subnodes
> > and list all four interrupts for each slot (child node) in the root node
> > like this:
> > 
> > 	pcie-controller {
> > 		...
> > 		interrupt-map-mask = <0xf800 0 0 7>;
> > 		interrupt-map = <0x0000 0 0 {INTx} &{interrupt parent} ...>
> > 				 0x0800 0 0 {INTx} &{interrupt parent} ...>;
> > 
> > 		pcie@0,0 {
> > 			reg = <0x0000 0 0 0 0>;
> > 			...
> > 		};
> > 
> > 		pcie@1,0 {
> > 			reg = <0x0800 0 0 0 0>;
> > 			...
> > 		};
> > 	};
> > 
> > As shown above, we'd like to propagate IRQs from a root port to the devices
> > in the hierarchy below it in this way.  However, it seems that the current
> > parser couldn't handle such cases and will get something unexpected below:
> > 
> > 	pcieport 0000:00:01.0: assign IRQ: got 213
> > 	igb 0000:01:00.0: assign IRQ: got 212
> > 
> > There is a device which is connected to 2nd slot, but the port doesn't share
> > the same IRQ with its downstream devices.  The problem here is that, if the
> > loop found a P2P bridge, it wouldn't check whether the reg property exists
> > in ppnode or not but just pass the subordinate devfn to of_irq_parse_raw(),
> > thus the subsequent flow couldn't correctly resolve them.
> > 
> > Fix this by adding a check to fallback to standard device tree parsing.
> > 
> > Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
> > ---
> > Please refer to the previous discussion thread: https://patchwork.ozlabs.org/patch/829108/
> > ---
> >  drivers/of/of_pci_irq.c | 14 ++++++++++++--
> >  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> Hi Ryder,
> 
> from the thread discussion I gather I can drop this series from the PCI
> queue and you will update the DT as agreed with Ben, that looks like
> the most reasonable solution to the problem you are facing, please
> let me know if there is anything I am missing.
> 
> Thanks,
> Lorenzo
> 

Yes, please drop the series.

Thanks

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