Commit 62bc6a6f authored Aug 29, 2017 by Sinan Kaya Committed by Bjorn Helgaas Aug 29, 2017

PCI: Add pci_bus_crs_vendor_id() to detect CRS response data



Add pci_bus_crs_vendor_id() to determine whether data returned for a config
read of the Vendor ID indicates a Configuration Request Retry Status (CRS)
response.

Per PCIe r3.1, sec 2.3.2, this data is only returned if:

  - CRS Software Visibility is enabled,
  - a config read includes both bytes of the Vendor ID, and
  - the read receives a CRS completion

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
[bhelgaas: changelog, change name to pci_bus_crs_vendor_id(), make static
in probe.c, use it in pci_bus_read_dev_vendor_id()]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

parent 9f982756

drivers/pci/probe.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -1853,6 +1853,11 @@ struct pci_dev pci_alloc_dev(struct pci_bus bus)
		}
		EXPORT_SYMBOL(pci_alloc_dev);

		static bool pci_bus_crs_vendor_id(u32 l)
		{
		return (l & 0xffff) == 0x0001;
		}

		bool pci_bus_read_dev_vendor_id(struct pci_bus bus, int devfn, u32 l,
		int crs_timeout)
		{
		@@ -1872,7 +1877,7 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus bus, int devfn, u32 l,
		* by the PCIe spec. Ignore the device ID and only check for
		* (vendor id == 1).
		*/
		while ((*l & 0xffff) == 0x0001) {
		while (pci_bus_crs_vendor_id(*l)) {
		if (!crs_timeout)
		return false;

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