Re: [PATCH v9 4/4] PCI: hisi: blacklist hip06/hip07 controllers behind SMMUv3

From: Bjorn Helgaas <helgaas@kernel.org>
To: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Cc: lorenzo.pieralisi@arm.com, marc.zyngier@arm.com,
	sudeep.holla@arm.com, will.deacon@arm.com, robin.murphy@arm.com,
	joro@8bytes.org, bhelgaas@google.com,
	gabriele.paoloni@huawei.com, john.garry@huawei.com,
	iommu@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org, linux-acpi@vger.kernel.org,
	linux-pci@vger.kernel.org, devel@acpica.org, linuxarm@huawei.com,
	wangzhou1@hisilicon.com, guohanjun@huawei.com
Subject: Re: [PATCH v9 4/4] PCI: hisi: blacklist hip06/hip07 controllers behind SMMUv3
Date: Tue, 10 Oct 2017 05:51:57 -0500	[thread overview]
Message-ID: <20171010105157.GT25517@bhelgaas-glaptop.roam.corp.google.com> (raw)
In-Reply-To: <20171006140450.89652-5-shameerali.kolothum.thodi@huawei.com>

On Fri, Oct 06, 2017 at 03:04:50PM +0100, Shameer Kolothum wrote:
> The HiSilicon erratum 161010801 describes the limitation of
> HiSilicon platforms hip06/hip07 to support the SMMUv3 mappings
> for MSI transactions.
> 
> PCIe controller on these platforms has to differentiate the MSI
> payload against other DMA payload and has to modify the MSI
> payload. This basically makes it difficult for this platforms to
> have a SMMU translation for MSI. In order to workaround this, ARM
> SMMUv3 driver requires a quirk to treat the MSI regions separately.
> Such a quirk is currently missing for DT based systems and therefore
> we need to blacklist the hip06/hip07 PCIe controllers.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

> ---
>  drivers/pci/dwc/pcie-hisi.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/pci/dwc/pcie-hisi.c b/drivers/pci/dwc/pcie-hisi.c
> index a201791..6800747 100644
> --- a/drivers/pci/dwc/pcie-hisi.c
> +++ b/drivers/pci/dwc/pcie-hisi.c
> @@ -270,6 +270,12 @@ static int hisi_pcie_probe(struct platform_device *pdev)
>  	struct resource *reg;
>  	int ret;
>  
> +	if ((IS_BUILTIN(CONFIG_ARM_SMMU_V3)) &&
> +			of_property_read_bool(dev->of_node, "iommu-map")) {
> +		dev_warn(dev, "HiSilicon erratum 161010801: blacklisting PCIe controllers behind SMMUv3\n");
> +		return -ENODEV;
> +	}
> +
>  	hisi_pcie = devm_kzalloc(dev, sizeof(*hisi_pcie), GFP_KERNEL);
>  	if (!hisi_pcie)
>  		return -ENOMEM;
> @@ -340,6 +346,12 @@ static int hisi_pcie_almost_ecam_probe(struct platform_device *pdev)
>  	struct device *dev = &pdev->dev;
>  	struct pci_ecam_ops *ops;
>  
> +	if ((IS_BUILTIN(CONFIG_ARM_SMMU_V3)) &&
> +			of_property_read_bool(dev->of_node, "iommu-map")) {
> +		dev_warn(dev, "HiSilicon erratum 161010801: blacklisting PCIe controllers behind SMMUv3\n");
> +		return -ENODEV;
> +	}
> +
>  	ops = (struct pci_ecam_ops *)of_device_get_match_data(dev);
>  	return pci_host_common_probe(pdev, ops);
>  }
> -- 
> 1.9.1
> 
> 
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