fpga: dfl: fme: add capability sysfs interfaces

This patch adds 3 read-only sysfs interfaces for FPGA Management Engine
(FME) block for capabilities including cache_size, fabric_version and
socket_id.
Signed-off-by: Luwei Kang <luwei.kang@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Link: https://lore.kernel.org/r/1564914022-3710-11-git-send-email-hao.wu@intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/ABI/testing/sysfs-platform-dfl-fme

@@ -21,3 +21,26 @@ Contact:	Wu Hao <hao.wu@intel.com>
 Description:	Read-only. It returns Bitstream (static FPGA region) meta
 		data, which includes the synthesis date, seed and other
 		information of this static FPGA region.
+
+What:		/sys/bus/platform/devices/dfl-fme.0/cache_size
+Date:		August 2019
+KernelVersion:  5.4
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Read-only. It returns cache size of this FPGA device.
+
+What:		/sys/bus/platform/devices/dfl-fme.0/fabric_version
+Date:		August 2019
+KernelVersion:  5.4
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Read-only. It returns fabric version of this FPGA device.
+		Userspace applications need this information to select
+		best data channels per different fabric design.
+
+What:		/sys/bus/platform/devices/dfl-fme.0/socket_id
+Date:		August 2019
+KernelVersion:  5.4
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Read-only. It returns socket_id to indicate which socket
+		this FPGA belongs to, only valid for integrated solution.
+		User only needs this information, in case standard numa node
+		can't provide correct information.

drivers/fpga/dfl-fme-main.c

@@ -73,10 +73,58 @@ static ssize_t bitstream_metadata_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(bitstream_metadata);
 
+static ssize_t cache_size_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_CAP);
+
+	return sprintf(buf, "%u\n",
+		       (unsigned int)FIELD_GET(FME_CAP_CACHE_SIZE, v));
+}
+static DEVICE_ATTR_RO(cache_size);
+
+static ssize_t fabric_version_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_CAP);
+
+	return sprintf(buf, "%u\n",
+		       (unsigned int)FIELD_GET(FME_CAP_FABRIC_VERID, v));
+}
+static DEVICE_ATTR_RO(fabric_version);
+
+static ssize_t socket_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_CAP);
+
+	return sprintf(buf, "%u\n",
+		       (unsigned int)FIELD_GET(FME_CAP_SOCKET_ID, v));
+}
+static DEVICE_ATTR_RO(socket_id);
+
 static struct attribute *fme_hdr_attrs[] = {
 	&dev_attr_ports_num.attr,
 	&dev_attr_bitstream_id.attr,
 	&dev_attr_bitstream_metadata.attr,
+	&dev_attr_cache_size.attr,
+	&dev_attr_fabric_version.attr,
+	&dev_attr_socket_id.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(fme_hdr);