fpga: dfl: fme: add header sub feature support

The Header Register set is always present for FPGA Management Engine (FME),
this patch implements init and uinit function for header sub feature and
introduces several read-only sysfs interfaces for the capability and
status.

Sysfs interfaces:
* /sys/class/fpga_region/<regionX>/<dfl-fme.x>/ports_num
  Read-only. Number of ports implemented

* /sys/class/fpga_region/<regionX>/<dfl-fme.x>/bitstream_id
  Read-only. Bitstream (static FPGA region) identifier number. It contains
  the detailed version and other information of this static FPGA region.

* /sys/class/fpga_region/<regionX>/<dfl-fme.x>/bitstream_metadata
  Read-only. Bitstream (static FPGA region) meta data. It contains the
  synthesis date, seed and other information of this static FPGA region.
Signed-off-by: Tim Whisonant <tim.whisonant@intel.com>
Signed-off-by: Enno Luebbers <enno.luebbers@intel.com>
Signed-off-by: Shiva Rao <shiva.rao@intel.com>
Signed-off-by: Christopher Rauer <christopher.rauer@intel.com>
Signed-off-by: Kang Luwei <luwei.kang@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

+What:		/sys/bus/platform/devices/dfl-fme.0/ports_num
+Date:		June 2018
+KernelVersion:  4.19
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Read-only. One DFL FPGA device may have more than 1
+		port/Accelerator Function Unit (AFU). It returns the
+		number of ports on the FPGA device when read it.
+
+What:		/sys/bus/platform/devices/dfl-fme.0/bitstream_id
+Date:		June 2018
+KernelVersion:  4.19
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Read-only. It returns Bitstream (static FPGA region)
+		identifier number, which includes the detailed version
+		and other information of this static FPGA region.
+
+What:		/sys/bus/platform/devices/dfl-fme.0/bitstream_metadata
+Date:		June 2018
+KernelVersion:  4.19
+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.

drivers/fpga/dfl-fme-main.c

@@ -19,10 +19,77 @@
 
 #include "dfl.h"
 
+static ssize_t ports_num_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 scnprintf(buf, PAGE_SIZE, "%u\n",
+			 (unsigned int)FIELD_GET(FME_CAP_NUM_PORTS, v));
+}
+static DEVICE_ATTR_RO(ports_num);
+
+/*
+ * Bitstream (static FPGA region) identifier number. It contains the
+ * detailed version and other information of this static FPGA region.
+ */
+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);
+}
+static DEVICE_ATTR_RO(bitstream_id);
+
+/*
+ * Bitstream (static FPGA region) meta data. It contains the synthesis
+ * date, seed and other information of this static FPGA region.
+ */
+static ssize_t bitstream_metadata_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_MD);
+
+	return scnprintf(buf, PAGE_SIZE, "0x%llx\n", (unsigned long long)v);
+}
+static DEVICE_ATTR_RO(bitstream_metadata);
+
+static const struct attribute *fme_hdr_attrs[] = {
+	&dev_attr_ports_num.attr,
+	&dev_attr_bitstream_id.attr,
+	&dev_attr_bitstream_metadata.attr,
+	NULL,
+};
+
 static int fme_hdr_init(struct platform_device *pdev,
 			struct dfl_feature *feature)
 {
+	void __iomem *base = feature->ioaddr;
+	int ret;
+
 	dev_dbg(&pdev->dev, "FME HDR Init.\n");
+	dev_dbg(&pdev->dev, "FME cap %llx.\n",
+		(unsigned long long)readq(base + FME_HDR_CAP));
+
+	ret = sysfs_create_files(&pdev->dev.kobj, fme_hdr_attrs);
+	if (ret)
+		return ret;
 
 	return 0;
 }
@@ -31,6 +98,7 @@ static void fme_hdr_uinit(struct platform_device *pdev,
 			  struct dfl_feature *feature)
 {
 	dev_dbg(&pdev->dev, "FME HDR UInit.\n");
+	sysfs_remove_files(&pdev->dev.kobj, fme_hdr_attrs);
 }
 
 static const struct dfl_feature_ops fme_hdr_ops = {