Attaching to an NVMe disk on Windows using SPDK requires the
PCI class ID and device.bus fields. Decode the class ID from the PCI
device info strings if it is present and set device.bus.

Signed-off-by: Nick Connolly <redacted>
Acked-by: Tal Shnaiderman <redacted>
---
v6:
* no changes - resending to resolve spurious iol-testing failure

v5:
* Add missing version history

v4:
* Use #define to determine length of Class ID

v3:
* Put version history at top - v2 mistakenly had it after the diffs

v2:
* If only a 4-digit class ID is available, convert it to 6-digit format

 drivers/bus/pci/windows/pci.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/pci/windows/pci.c b/drivers/bus/pci/windows/pci.c
index f66258452..dceb0f4b2 100644
--- a/drivers/bus/pci/windows/pci.c
+++ b/drivers/bus/pci/windows/pci.c

@@ -23,6 +23,9 @@ DEFINE_DEVPROPKEY(DEVPKEY_Device_Numa_Node, 0x540b947e, 0x8b40, 0x45bc,
  * the registry hive for PCI devices.
  */
 
+/* Class ID consists of hexadecimal digits */
+#define RTE_PCI_DRV_CLASSID_DIGIT	"0123456789abcdefABCDEF"
+
 /* The functions below are not implemented on Windows,
  * but need to be defined for compilation purposes
  */

@@ -280,17 +283,29 @@ parse_pci_hardware_id(const char *buf, struct rte_pci_id *pci_id)
 {
 	int ids = 0;
 	uint16_t vendor_id, device_id;
-	uint32_t subvendor_id = 0;
+	uint32_t subvendor_id = 0, class_id = 0;
+	const char *cp;
 
 	ids = sscanf_s(buf, "PCI\\VEN_%" PRIx16 "&DEV_%" PRIx16 "&SUBSYS_%"
 		PRIx32, &vendor_id, &device_id, &subvendor_id);
 	if (ids != 3)
 		return -1;
 
+	/* Try and find PCI class ID */
+	for (cp = buf; !(cp[0] == 0 && cp[1] == 0); cp++)
+		if (*cp == '&' && sscanf_s(cp,
+				"&CC_%" PRIx32, &class_id) == 1) {
+			/* Convert 4-digit class IDs to 6-digit format */
+			if (strspn(cp + 4, RTE_PCI_DRV_CLASSID_DIGIT) == 4)
+				class_id <<= 8;
+			break;
+		}
+