[PATCH v9 4/4] PCI: hisi: blacklist hip06/hip07 controllers behind SMMUv3
From: helgaas@kernel.org (Bjorn Helgaas)
Date: 2017-10-09 23:54:52
Also in:
linux-acpi, linux-iommu, linux-pci
Please change subject line: - PCI: hisi: blacklist hip06/hip07 controllers behind SMMUv3 + PCI: hisi: Blacklist hip06/hip07 controllers behind SMMUv3 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.
I don't suppose there's a URL for this erratum, is there?
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.
I don't understand the DT connection here. If this is a hardware erratum, I assume the a quirk would be required whether the system uses DT, ACPI, etc.
Signed-off-by: Shameer Kolothum <redacted>
I assume this will go via some non-PCI tree. If I were applying this, I would look for an ack from Zhou or Gabriele in addition to mine.
quoted hunk ↗ jump to hunk
--- 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")) {
Does the presence of "iommu-map" tell you this is an SMMUv3? Could it have a different type of IOMMU? I can't tell from reading Documentation/devicetree/bindings/pci/pci-iommu.txt. Why do you care whether CONFIG_ARM_SMMU_V3 is set? Does MSI work correctly if SMMUv3 is present but not used? Is it really necessary to ignore the PCIe controller completely? Could you use the devices below it as long as you disable MSI for them? I know there are probably devices that require MSI, so maybe it's easier to just ignore everything than to respond to reports of "my device doesn't work because it requires MSI."
quoted hunk ↗ jump to hunk
+ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html