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

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Message-ID: <1517891471.20869.6.camel@mtkswgap22>
Date:   Tue, 6 Feb 2018 12:31:11 +0800
From:   Ryder Lee <ryder.lee@...iatek.com>
To:     Benjamin Herrenschmidt <benh@...nel.crashing.org>
CC:     "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Arnd Bergmann <arnd@...db.de>, <linux-pci@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Rob Herring <robh+dt@...nel.org>,
        <linux-mediatek@...ts.infradead.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Frank Rowand <frowand.list@...il.com>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 1/2] of_pci_irq: add a check to fallback to standard
 device tree parsing

On Tue, 2018-02-06 at 15:05 +1100, Benjamin Herrenschmidt wrote:
> On Tue, 2018-02-06 at 10:38 +0800, Ryder Lee wrote:
> > 
> > I think the code should look at the bridge address <0x0800 ...> we list
> > in bindings for resolving interrupts in this case, but it seems like it
> > use the 'pdev->defvn << 8' which is not really we want and will lead to
> > mismatch.
> > 
> > 		interrupt-map-mask = <0xf800 0 0 7>;
> > 		interrupt-map = <0x0000 0 0 1 ...>,
> > 				<0x0000 0 0 2 ...>,
> > 				<0x0000 0 0 3 ...>,
> > 				<0x0000 0 0 4 ...>,
> > 
> > 				 0x0800 0 0 1 ...>,
> > 				 0x0800 0 0 2 ...>,
> > 				 0x0800 0 0 3 ...>,
> > 				 0x0800 0 0 4 ...>;
> > 		...
> > 		pcie@1,0 {
> > 			reg = <0x0800 0 0 0 0>;
> > 			...
> > 		};
> > 
> > 
> > Or, alternatively, we could add a interrupt-map property in both child
> > and root node to solve this. The below example is my original version as
> > I don't want to change that function either.
> 
> The code looks at devfn because it's meant to work for PCI including
> when the devices dont have a device node in the DT.
> 
> What I'm trying to figure out is what is it that your parent and
> children are representing here. Which is/are the root complex ?

This is a single root complex with 2 root port (children in DT).

> What is the actual topology as visible on the PCIe bus (is lspci output
> basically) and how does that map to your representation ?

# lspci
00:00.0 Class 0604: 14c3:0801 //1st slot - pcie@0,0
00:01.0 Class 0604: 14c3:0801 //2nd slot - pcie@1,0

01:00.0 Class 0280: 14c3:7603 //A device which is connected to 1st slot
02:00.0 Class 0200: 8086:1521 //A 4 func device which is connected to
2nd slot
02:00.1 Class 0200: 8086:1521
02:00.2 Class 0200: 8086:1521
02:00.3 Class 0200: 8086:1521

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