Re: [PATCH v3 0/4] DT schema changes for HiKey970 PCIe hardware to work

From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
To: Rob Herring <robh@kernel.org>
Cc: Linuxarm <linuxarm@huawei.com>,
	mauro.chehab@huawei.com, Binghui Wang <wangbinghui@hisilicon.com>,
	Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
	Jingoo Han <jingoohan1@gmail.com>,
	Xiaowei Song <songxiaowei@hisilicon.com>,
	devicetree@vger.kernel.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	PCI <linux-pci@vger.kernel.org>,
	linux-phy@lists.infradead.org
Subject: Re: [PATCH v3 0/4] DT schema changes for HiKey970 PCIe hardware to work
Date: Tue, 10 Aug 2021 11:42:11 +0200	[thread overview]
Message-ID: <20210810114211.01df0246@coco.lan> (raw)
In-Reply-To: <CAL_JsqKso=z8LG3ViaggyS1k+1T2F5aAhP3_RNhumQoUUD+bbg@mail.gmail.com>

Em Fri, 6 Aug 2021 10:23:35 -0600
Rob Herring <robh@kernel.org> escreveu:

> On Thu, Aug 5, 2021 at 1:58 AM Mauro Carvalho Chehab
> <mchehab+huawei@kernel.org> wrote:
> >
> > Em Thu, 5 Aug 2021 09:46:12 +0200
> > Mauro Carvalho Chehab <mchehab+huawei@kernel.org> escreveu:
> >  
> > > Em Wed, 4 Aug 2021 10:28:53 -0600
> > > Rob Herring <robh@kernel.org> escreveu:
> > >  
> > > > On Wed, Aug 04, 2021 at 08:50:45AM +0200, Mauro Carvalho Chehab wrote:  
> > > > > Em Tue, 3 Aug 2021 16:11:42 -0600
> > > > > Rob Herring <robh+dt@kernel.org> escreveu:
> > > > >  
> > > > > > On Mon, Aug 2, 2021 at 10:39 PM Mauro Carvalho Chehab
> > > > > > <mchehab+huawei@kernel.org> wrote:  
> > > > > > >
> > > > > > > Hi Rob,
> > > > > > >
> > > > > > > That's the third version of the DT bindings for Kirin 970 PCIE and its
> > > > > > > corresponding PHY.
> > > > > > >
> > > > > > > It is identical to v2, except by:
> > > > > > >         -          pcie@7,0 { // Lane 7: Ethernet
> > > > > > >         +          pcie@7,0 { // Lane 6: Ethernet  
> > > > > >
> > > > > > Can you check whether you have DT node links in sysfs for the PCI
> > > > > > devices? If you don't, then something is wrong still in the topology
> > > > > > or the PCI core is failing to set the DT node pointer in struct
> > > > > > device. Though you don't rely on that currently, we want the topology
> > > > > > to match. It's possible this never worked on arm/arm64 as mainly
> > > > > > powerpc relied on this.
> > > > > >
> > > > > > I'd like some way to validate the DT matches the PCI topology. We
> > > > > > could have a tool that generates the DT structure based on the PCI
> > > > > > topology.  
> > > > >
> > > > > The of_node node link is on those places:
> > > > >
> > > > >   $ find /sys/devices/platform/soc/f4000000.pcie/ -name of_node
> > > > >   /sys/devices/platform/soc/f4000000.pcie/of_node
> > > > >   /sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/of_node
> > > > >   /sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/pci_bus/0000:01/of_node
> > > > >   /sys/devices/platform/soc/f4000000.pcie/pci0000:00/pci_bus/0000:00/of_node  
> > > >
> > > > Looks like we're missing some...
> > > >
> > > > It's not immediately obvious to me what's wrong here. Only the root
> > > > bus is getting it's DT node set. The relevant code is pci_scan_device(),
> > > > pci_set_of_node() and pci_set_bus_of_node(). Give me a few days to try
> > > > to reproduce and debug it.  
> > >
> > > I added a printk on both pci_set_*of_node() functions:
> > >
> > >       [    4.872991]  (null): pci_set_bus_of_node: of_node: /soc/pcie@f4000000
> > >       [    4.913806]  (null): pci_set_of_node: of_node: /soc/pcie@f4000000
> > >       [    4.978102] pci_bus 0000:01: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
> > >       [    4.990622]  (null): pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
> > >       [    5.052383] pci_bus 0000:02: pci_set_bus_of_node: of_node: (null)
> > >       [    5.059263]  (null): pci_set_of_node: of_node: (null)
> > >       [    5.085552]  (null): pci_set_of_node: of_node: (null)
> > >       [    5.112073]  (null): pci_set_of_node: of_node: (null)
> > >       [    5.138320]  (null): pci_set_of_node: of_node: (null)
> > >       [    5.164673]  (null): pci_set_of_node: of_node: (null)
> > >       [    5.233759] pci_bus 0000:03: pci_set_bus_of_node: of_node: (null)
> > >       [    5.240539]  (null): pci_set_of_node: of_node: (null)
> > >       [    5.310545] pci_bus 0000:04: pci_set_bus_of_node: of_node: (null)
> > >       [    5.324719] pci_bus 0000:05: pci_set_bus_of_node: of_node: (null)
> > >       [    5.338914] pci_bus 0000:06: pci_set_bus_of_node: of_node: (null)
> > >       [    5.345516]  (null): pci_set_of_node: of_node: (null)
> > >       [    5.415795] pci_bus 0000:07: pci_set_bus_of_node: of_node: (null)  
> >
> > The enclosed patch makes the above a clearer:
> >
> >         [    4.800975]  (null): pci_set_bus_of_node: of_node: /soc/pcie@f4000000
> >         [    4.855983] pci 0000:00:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000
> >         [    4.879169] pci_bus 0000:01: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
> >         [    4.900602] pci 0000:01:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
> >         [    4.953086] pci_bus 0000:02: pci_set_bus_of_node: of_node: (null)  
> 
> I believe the issue is we need another bridge node in the DT
> hierarchy. What we have is:
> 
> Bus 0 is node /soc/pcie@f4000000
> Bus 1 is device 0 on bus 0 is node /soc/pcie@f4000000/pcie@0,0
> Bus 2 is device 0 on bus 1 in node ... whoops, there's no device 0
> under /soc/pcie@f4000000/pcie@0,0
> 
> So we need the hierarchy to be: /soc/pcie@f4000000/pcie@0/pcie@0/pcie@{1,5,7}

Adding a child pcie@0 produces the following output from my debug
patches:

[    4.984278]  (null): pci_set_bus_of_node: of_node: /soc/pcie@f4000000
[    5.042992] pci 0000:00:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000
[    5.083738] pci_bus 0000:01: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
[    5.124377] pci 0000:01:00.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0
[    5.168395] pci_bus 0000:02: pci_set_bus_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@0,0
[    5.200719] pci 0000:02:01.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@0,0
[    5.247777] pci 0000:02:04.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@0,0
[    5.276768] pci 0000:02:05.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@0,0
[    5.305018] pci 0000:02:07.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@0,0
[    5.333093] pci 0000:02:09.0: pci_set_of_node: of_node: /soc/pcie@f4000000/pcie@0,0/pcie@0,0
[    5.395620] pci_bus 0000:03: pci_set_bus_of_node: of_node: (null)
[    5.416333] pci 0000:03:00.0: pci_set_of_node: of_node: (null)
[    5.451353] pci_bus 0000:04: pci_set_bus_of_node: of_node: (null)
[    5.473970] pci_bus 0000:05: pci_set_bus_of_node: of_node: (null)
[    5.487765] pci_bus 0000:06: pci_set_bus_of_node: of_node: (null)
[    5.530219] pci 0000:06:00.0: pci_set_of_node: of_node: (null)
[    5.560896] pci_bus 0000:07: pci_set_bus_of_node: of_node: (null)

It produces the following sysfs nodes:

	$ find /sys/devices/platform/soc/f4000000.pcie/ -name of_node
	/sys/devices/platform/soc/f4000000.pcie/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/0000:01:00.0/pci_bus/0000:02/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/0000:00:00.0/pci_bus/0000:01/of_node
	/sys/devices/platform/soc/f4000000.pcie/pci0000:00/pci_bus/0000:00/of_node

I'm enclosing the DT schema I'm using.

Thanks,
Mauro

---

		pcie@f4000000 {
			compatible = "hisilicon,kirin970-pcie";
			reg = <0x0 0xf4000000 0x0 0x1000000>,
			      <0x0 0xfc180000 0x0 0x1000>,
			      <0x0 0xf5000000 0x0 0x2000>;
			reg-names = "dbi", "apb", "config";
			bus-range = <0x00 0xff>;
			#address-cells = <3>;
			#size-cells = <2>;
			device_type = "pci";
			phys = <&pcie_phy>;
			ranges = <0x02000000 0x0 0x00000000
				  0x0 0xf6000000
				  0x0 0x02000000>;
			num-lanes = <1>;
			#interrupt-cells = <1>;
			interrupts = <GIC_SPI 283 IRQ_TYPE_LEVEL_HIGH>;
			interrupt-names = "msi";
			interrupt-map-mask = <0 0 0 7>;
			interrupt-map = <0x0 0 0 1
					 &gic GIC_SPI 282 IRQ_TYPE_LEVEL_HIGH>,
					<0x0 0 0 2
					 &gic GIC_SPI 283 IRQ_TYPE_LEVEL_HIGH>,
					<0x0 0 0 3
					 &gic GIC_SPI 284 IRQ_TYPE_LEVEL_HIGH>,
					<0x0 0 0 4
					 &gic GIC_SPI 285 IRQ_TYPE_LEVEL_HIGH>;
			reset-gpios = <&gpio7 0 0>;
			hisilicon,clken-gpios = <&gpio27 3 0>, <&gpio17 0 0>,
						<&gpio20 6 0>;
			pcie@0,0 { // Lane 0: PCIe switch: Bus 1, Device 0
				reg = <0x80 0 0 0 0>;
				compatible = "pciclass,0604";
				device_type = "pci";
				#address-cells = <3>;
				#size-cells = <2>;
				ranges;
				bus-range = <0x01 0xff>;
				msi-parent = <&its_pcie>;

				pcie@0,0 { // Lane 0: upstream
					reg = <0x010000 0 0 0 0>;
					compatible = "pciclass,0604";
					device_type = "pci";
					#address-cells = <3>;
					#size-cells = <2>;
					ranges;
				};
				pcie@1,0 { // Lane 4: M.2
					reg = <0x010800 0 0 0 0>;
					compatible = "pciclass,0604";
					device_type = "pci";
					reset-gpios = <&gpio3 1 0>;
					#address-cells = <3>;
					#size-cells = <2>;
					ranges;
				};

				pcie@5,0 { // Lane 5: Mini PCIe
					reg = <0x012800 0 0 0 0>;
					compatible = "pciclass,0604";
					device_type = "pci";
					reset-gpios = <&gpio27 4 0 >;
					#address-cells = <3>;
					#size-cells = <2>;
					ranges;
				};

				pcie@7,0 { // Lane 6: Ethernet
					reg = <0x013800 0 0 0 0>;
					compatible = "pciclass,0604";
					device_type = "pci";
					reset-gpios = <&gpio25 2 0 >;
					#address-cells = <3>;
					#size-cells = <2>;
					ranges;
				};
			};
		};