[RFC PATCH 2/6] fpga: dfl: export network configuration info for DFL based FPGA

[Xu Yilun <yilun.xu@xxxxxxxxx>]

This patch makes preparation for supporting DFL Ether Group private
feature driver, which reads bitstream_id.vendor_net_cfg field to
determin the interconnection of network components on FPGA device.

Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
---
 drivers/fpga/dfl-fme-main.c | 10 ++--------
 drivers/fpga/dfl.c          | 21 +++++++++++++++++++++
 drivers/fpga/dfl.h          | 12 ++++++++++++
 include/linux/dfl.h         |  2 ++
 4 files changed, 37 insertions(+), 8 deletions(-)

diff --git a/drivers/fpga/dfl-fme-main.c b/drivers/fpga/dfl-fme-main.c
index 77ea04d..a2b8ba0 100644
--- a/drivers/fpga/dfl-fme-main.c
+++ b/drivers/fpga/dfl-fme-main.c
@@ -46,14 +46,8 @@ static DEVICE_ATTR_RO(ports_num);
 static ssize_t bitstream_id_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
-	void __iomem *base;
-	u64 v;
-
-	base = dfl_get_feature_ioaddr_by_id(dev, FME_FEATURE_ID_HEADER);
-
-	v = readq(base + FME_HDR_BITSTREAM_ID);
-
-	return scnprintf(buf, PAGE_SIZE, "0x%llx\n", (unsigned long long)v);
+	return scnprintf(buf, PAGE_SIZE, "0x%llx\n",
+			 (unsigned long long)dfl_get_bitstream_id(dev));
 }
 static DEVICE_ATTR_RO(bitstream_id);
 
diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
index bc35750..ca3c678 100644
--- a/drivers/fpga/dfl.c
+++ b/drivers/fpga/dfl.c
@@ -537,6 +537,27 @@ void dfl_driver_unregister(struct dfl_driver *dfl_drv)
 }
 EXPORT_SYMBOL(dfl_driver_unregister);
 
+int dfl_dev_get_vendor_net_cfg(struct dfl_device *dfl_dev)
+{
+	struct device *fme_dev;
+	u64 v;
+
+	if (!dfl_dev)
+		return -EINVAL;
+
+	if (dfl_dev->type == FME_ID)
+		fme_dev = dfl_dev->dev.parent;
+	else
+		fme_dev = dfl_dev->cdev->fme_dev;
+
+	if (!fme_dev)
+		return -EINVAL;
+
+	v = dfl_get_bitstream_id(fme_dev);
+	return (int)FIELD_GET(FME_BID_VENDOR_NET_CFG, v);
+}
+EXPORT_SYMBOL_GPL(dfl_dev_get_vendor_net_cfg);
+
 #define is_header_feature(feature) ((feature)->id == FEATURE_ID_FIU_HEADER)
 
 /**
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index 2b82c96..6c7a6961 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -104,6 +104,9 @@
 #define FME_CAP_CACHE_SIZE	GENMASK_ULL(43, 32)	/* cache size in KB */
 #define FME_CAP_CACHE_ASSOC	GENMASK_ULL(47, 44)	/* Associativity */
 
+/* FME BITSTREAM_ID Register Bitfield */
+#define FME_BID_VENDOR_NET_CFG	GENMASK_ULL(35, 32)     /* vendor net cfg */
+
 /* FME Port Offset Register Bitfield */
 /* Offset to port device feature header */
 #define FME_PORT_OFST_DFH_OFST	GENMASK_ULL(23, 0)
@@ -397,6 +400,15 @@ static inline bool is_dfl_feature_present(struct device *dev, u16 id)
 	return !!dfl_get_feature_ioaddr_by_id(dev, id);
 }
 
+static inline u64 dfl_get_bitstream_id(struct device *dev)
+{
+	void __iomem *base;
+
+	base = dfl_get_feature_ioaddr_by_id(dev, FME_FEATURE_ID_HEADER);
+
+	return readq(base + FME_HDR_BITSTREAM_ID);
+}
+
 static inline
 struct device *dfl_fpga_pdata_to_parent(struct dfl_feature_platform_data *pdata)
 {
diff --git a/include/linux/dfl.h b/include/linux/dfl.h
index e1b2471..5ee2b1e 100644
--- a/include/linux/dfl.h
+++ b/include/linux/dfl.h
@@ -67,6 +67,8 @@ struct dfl_driver {
 #define to_dfl_dev(d) container_of(d, struct dfl_device, dev)
 #define to_dfl_drv(d) container_of(d, struct dfl_driver, drv)
 
+int dfl_dev_get_vendor_net_cfg(struct dfl_device *dfl_dev);
+
 /*
  * use a macro to avoid include chaining to get THIS_MODULE.
  */
-- 
2.7.4