[PATCH 1/4] cxl/pci: Introduce cxl_gpf_get_dvsec()

[Davidlohr Bueso <dave@stgolabs.net>]

Add a helper to fetch the port/device GPF dvsecs. This is
currently only used for ports, but a later patch to export
dirty count to users will make use of the device one.

Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
---
 drivers/cxl/core/pci.c | 38 ++++++++++++++++++++++++++++----------
 drivers/cxl/cxl.h      |  2 ++
 2 files changed, 30 insertions(+), 10 deletions(-)

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index a5c65f79db18..2226cca3382d 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -1072,6 +1072,27 @@ int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct access_coordinate *c)
 #define GPF_TIMEOUT_BASE_MAX 2
 #define GPF_TIMEOUT_SCALE_MAX 7 /* 10 seconds */
 
+int cxl_gpf_get_dvsec(struct device *dev, bool port)
+{
+	struct pci_dev *pdev;
+	int dvsec;
+
+	if (!dev_is_pci(dev))
+		return -EINVAL;
+
+	pdev = to_pci_dev(dev);
+	if (!pdev)
+		return -EINVAL;
+
+	dvsec = pci_find_dvsec_capability(pdev, PCI_VENDOR_ID_CXL,
+			port ? CXL_DVSEC_PORT_GPF : CXL_DVSEC_DEVICE_GPF);
+	if (!dvsec)
+		pci_warn(pdev, "%s GPF DVSEC not present\n",
+			 port ? "Port" : "Device");
+	return dvsec;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_gpf_get_dvsec, "CXL");
+
 static int update_gpf_port_dvsec(struct pci_dev *pdev, int dvsec, int phase)
 {
 	u64 base, scale;
@@ -1116,26 +1137,23 @@ int cxl_gpf_port_setup(struct device *dport_dev, struct cxl_port *port)
 {
 	struct pci_dev *pdev;
 
-	if (!dev_is_pci(dport_dev))
-		return 0;
-
-	pdev = to_pci_dev(dport_dev);
-	if (!pdev || !port)
+	if (!port)
 		return -EINVAL;
 
 	if (!port->gpf_dvsec) {
 		int dvsec;
 
-		dvsec = pci_find_dvsec_capability(pdev, PCI_VENDOR_ID_CXL,
-						  CXL_DVSEC_PORT_GPF);
-		if (!dvsec) {
-			pci_warn(pdev, "Port GPF DVSEC not present\n");
+		dvsec = cxl_gpf_get_dvsec(dport_dev, true);
+		if (dvsec <= 0)
 			return -EINVAL;
-		}
 
 		port->gpf_dvsec = dvsec;
 	}
 
+	pdev = to_pci_dev(dport_dev);
+	if (!pdev)
+		return -EINVAL;
+
 	update_gpf_port_dvsec(pdev, port->gpf_dvsec, 1);
 	update_gpf_port_dvsec(pdev, port->gpf_dvsec, 2);
 
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 6baec4ba9141..acbbba41356d 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -901,4 +901,6 @@ bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port);
 #define __mock static
 #endif
 
+int cxl_gpf_get_dvsec(struct device *dev, bool port);
+
 #endif /* __CXL_H__ */
-- 
2.39.5