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>
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 1500938..5e001bb 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -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;