Re: [PATCH v3 2/6] dt-bindings: pci: add the samsung,exynos-pcie binding

From: Marek Szyprowski <m.szyprowski@samsung.com>
To: Rob Herring <robh@kernel.org>
Cc: linux-samsung-soc@vger.kernel.org, linux-pci@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jaehoon Chung <jh80.chung@samsung.com>,
	Jingoo Han <jingoohan1@gmail.com>,
	Krzysztof Kozlowski <krzk@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Vinod Koul <vkoul@kernel.org>,
	Kishon Vijay Abraham I <kishon@ti.com>
Subject: Re: [PATCH v3 2/6] dt-bindings: pci: add the samsung,exynos-pcie binding
Date: Thu, 5 Nov 2020 09:33:18 +0100	[thread overview]
Message-ID: <d89f5f0a-c45e-0bda-4db7-7b0cf9cd49fe@samsung.com> (raw)
In-Reply-To: <20201104213539.GA4144654@bogus>

Hi Rob,

On 04.11.2020 22:35, Rob Herring wrote:
> On Thu, Oct 29, 2020 at 02:40:13PM +0100, Marek Szyprowski wrote:
>> Add dt-bindings for the Samsung Exynos PCIe controller (Exynos5433
>> variant). Based on the text dt-binding posted by Jaehoon Chung.
>>
>> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
>> ---
>>   .../bindings/pci/samsung,exynos-pcie.yaml     | 119 ++++++++++++++++++
>>   1 file changed, 119 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/pci/samsung,exynos-pcie.yaml

>> ...

>> +  num-viewport:
>> +    const: 3
> I'm confused why you need this. This is only used with the iATU except
> for keystone. Platforms like Exynos with their own child bus config
> space accessors don't have an iATU.

Frankly I have no idea, I don't know much about the PCI internals. After 
rebasing onto your latest DW PCI changes I've noticed a following 
warning message:

exynos-pcie 15700000.pcie: Resources exceed number of ATU entries (2)

Here is a complete log:

# dmesg | grep pci
ehci-pci: EHCI PCI platform driver
ohci-pci: OHCI PCI platform driver
exynos-pcie 15700000.pcie: host bridge /soc@0/pcie@15700000 ranges:
exynos-pcie 15700000.pcie:       IO 0x000c001000..0x000c010fff -> 
0x0000000000
exynos-pcie 15700000.pcie:      MEM 0x000c011000..0x000ffffffe -> 
0x000c011000
exynos-pcie 15700000.pcie: Resources exceed number of ATU entries (2)
exynos-pcie 15700000.pcie: Link up
exynos-pcie 15700000.pcie: PCI host bridge to bus 0000:00
pci_bus 0000:00: root bus resource [bus 00-ff]
pci_bus 0000:00: root bus resource [io  0x0000-0xffff]
pci_bus 0000:00: root bus resource [mem 0x0c011000-0x0ffffffe]
pci 0000:00:00.0: [144d:a5e3] type 01 class 0x060400
pci 0000:00:00.0: PME# supported from D0 D3hot D3cold
pci 0000:01:00.0: [14e4:43e9] type 00 class 0x028000
pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x00007fff 64bit]
pci 0000:01:00.0: reg 0x18: [mem 0x00000000-0x003fffff 64bit]
pci 0000:01:00.0: supports D1 D2
pci 0000:01:00.0: PME# supported from D0 D1 D2 D3hot D3cold
pci 0000:00:00.0: BAR 14: assigned [mem 0x0c200000-0x0c7fffff]
pci 0000:01:00.0: BAR 2: assigned [mem 0x0c400000-0x0c7fffff 64bit]
pci 0000:01:00.0: BAR 0: assigned [mem 0x0c200000-0x0c207fff 64bit]
pci 0000:00:00.0: PCI bridge to [bus 01-ff]
pci 0000:00:00.0:   bridge window [mem 0x0c200000-0x0c7fffff]
pci 0000:00:00.0: MSI quirk detected; MSI disabled
pcieport 0000:00:00.0: PME: Signaling with IRQ 97
brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac4358-pcie for chip 
BCM4358/1

When I've increased the numer of viewports it has gone.

If this is not the proper solution, I will removed it.

Best regards

-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland