[dpdk-dev] [PATCH v7] bus/pci: nvme on Windows requires class id and bus

[Nick Connolly <nick.connolly@mayadata.io>]

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 <nick.connolly@mayadata.io>
Acked-by: Tal Shnaiderman <talshn@nvidia.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
---
v7:
* Improve comments as per review by Dmitry Kozlyuk

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 | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/bus/pci/windows/pci.c b/drivers/bus/pci/windows/pci.c
index f66258452..bc173af2d 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
  */
@@ -274,23 +277,41 @@ get_pci_hardware_id(HDEVINFO dev_info, PSP_DEVINFO_DATA device_info_data,
 
 /*
  * parse the SPDRP_HARDWAREID output and assign to rte_pci_id
+ *
+ * A list of the device identification string formats can be found at:
+ * https://docs.microsoft.com/en-us/windows-hardware/drivers/install/identifiers-for-pci-devices
  */
 static int
 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) {
+			/*
+			 * If the Programming Interface code is not specified,
+			 * assume that it is zero.
+			 */
+			if (strspn(cp + 4, RTE_PCI_DRV_CLASSID_DIGIT) == 4)
+				class_id <<= 8;
+			break;
+		}
+
 	pci_id->vendor_id = vendor_id;
 	pci_id->device_id = device_id;
 	pci_id->subsystem_device_id = subvendor_id >> 16;
 	pci_id->subsystem_vendor_id = subvendor_id & 0xffff;
+	pci_id->class_id = class_id;
 	return 0;
 }
 
@@ -339,6 +360,7 @@ pci_scan_one(HDEVINFO dev_info, PSP_DEVINFO_DATA device_info_data)
 	if (ret != 0)
 		goto end;
 
+	dev->device.bus = &rte_pci_bus.bus;
 	dev->addr = addr;
 	dev->id = pci_id;
 	dev->max_vfs = 0; /* TODO: get max_vfs */
-- 
2.25.1