cxl: Ignore probes for virtual afu pci devices

BugLink: http://bugs.launchpad.net/bugs/1588468

Add a check at the beginning of cxl_probe function to ignore virtual pci
devices created for each afu registered. This fixes the the errors
messages logged about missing CXL vsec, when cxl probe is unable to
find necessary vsec entries in device pci config space. The error
message logged are of the form :

cxl-pci 0004:00:00.0: ABORTING: CXL VSEC not found!
cxl-pci 0004:00:00.0: cxl_init_adapter failed: -19

Cc: Ian Munsie <imunsie@au1.ibm.com>
Cc: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Reviewed-by: fbarrat@linux.vnet.ibm.com
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from commit 17eb3eef)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

drivers/misc/cxl/cxl.h

@@ -881,4 +881,6 @@ extern const struct cxl_backend_ops cxl_native_ops;
 extern const struct cxl_backend_ops cxl_guest_ops;
 extern const struct cxl_backend_ops *cxl_ops;
 
+/* check if the given pci_dev is on the the cxl vphb bus */
+bool cxl_pci_is_vphb_device(struct pci_dev *dev);
 #endif

drivers/misc/cxl/pci.c

@@ -1287,6 +1287,11 @@ static int cxl_probe(struct pci_dev *dev, const struct pci_device_id *id)
 	int slice;
 	int rc;
 
+	if (cxl_pci_is_vphb_device(dev)) {
+		dev_dbg(&dev->dev, "cxl_init_adapter: Ignoring cxl vphb device\n");
+		return -ENODEV;
+	}
+
 	if (cxl_verbose)
 		dump_cxl_config_space(dev);
 

drivers/misc/cxl/vphb.c

@@ -272,6 +272,15 @@ void cxl_pci_vphb_remove(struct cxl_afu *afu)
 	pcibios_free_controller(phb);
 }
 
+bool cxl_pci_is_vphb_device(struct pci_dev *dev)
+{
+	struct pci_controller *phb;
+
+	phb = pci_bus_to_host(dev->bus);
+
+	return (phb->ops == &cxl_pcie_pci_ops);
+}
+
 struct cxl_afu *cxl_pci_to_afu(struct pci_dev *dev)
 {
 	struct pci_controller *phb;