PCI: xgene: Fix CRS SV comment
Configuration Request Retry Status ("CRS") must be supported by all PCIe devices. CRS Software Visibility is an optional feature that enables a Root Port to make CRS visible to software by returning a special data value to complete a config read. Clarify a comment to say that it is "CRS SV", not "CRS", that can be enabled. Link: https://lore.kernel.org/r/20210126213503.2922848-1-helgaas@kernel.org Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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@ -173,12 +173,13 @@ static int xgene_pcie_config_read32(struct pci_bus *bus, unsigned int devfn,
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/*
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* The v1 controller has a bug in its Configuration Request
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* Retry Status (CRS) logic: when CRS is enabled and we read the
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* Vendor and Device ID of a non-existent device, the controller
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* fabricates return data of 0xFFFF0001 ("device exists but is not
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* ready") instead of 0xFFFFFFFF ("device does not exist"). This
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* causes the PCI core to retry the read until it times out.
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* Avoid this by not claiming to support CRS.
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* Retry Status (CRS) logic: when CRS Software Visibility is
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* enabled and we read the Vendor and Device ID of a non-existent
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* device, the controller fabricates return data of 0xFFFF0001
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* ("device exists but is not ready") instead of 0xFFFFFFFF
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* ("device does not exist"). This causes the PCI core to retry
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* the read until it times out. Avoid this by not claiming to
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* support CRS SV.
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*/
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if (pci_is_root_bus(bus) && (port->version == XGENE_PCIE_IP_VER_1) &&
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((where & ~0x3) == XGENE_V1_PCI_EXP_CAP + PCI_EXP_RTCTL))
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