[PATCH v4 3/8] char: rpmb: add device attributes

[Tomas Winkler <tomas.winkler@intel.com>]

Add attribute type that displays underlay storage type technology
EMMC, UFS, and attribute id, that displays underlay storage device id.
For EMMC this would be content of CID and for UFS serial number from
the device descriptor.

V2: resend
V3: set the kernel version to 4.7
V4: set the kernel version to 4.8

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
 Documentation/ABI/testing/sysfs-class-rpmb | 24 +++++++++++
 drivers/char/rpmb/core.c                   | 64 ++++++++++++++++++++++++++++++
 2 files changed, 88 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-rpmb b/Documentation/ABI/testing/sysfs-class-rpmb
index 44ee4d31dc0b..e9027f37ca5b 100644
--- a/Documentation/ABI/testing/sysfs-class-rpmb
+++ b/Documentation/ABI/testing/sysfs-class-rpmb
@@ -18,3 +18,27 @@ Contact:	Tomas Winkler <tomas.winkler@intel.com>
 Description:
 		The /sys/class/rpmb/rpmbN directory is created for
 		each RPMB registered device
+
+What:		/sys/class/rpmb/rpmbN/id
+Date:		Maj 2016
+KernelVersion:	4.7
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:
+		The /sys/class/rpmb/rpmbN/id file contains device id
+		in a binary form
+
+What:		/sys/class/rpmb/rpmbN/type
+Date:		Jun 2016
+KernelVersion:	4.8
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:
+		The /sys/class/rpmb/rpmbN/type file contains device
+		underlay storage type technology: EMMC, UFS
+
+What:		/sys/class/rpmb/rpmbN/reliable_wr_cnt
+Date:		Jun 2016
+KernelVersion:	4.8
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:
+		The /sys/class/rpmb/rpmbN/reliable_wr_cnt file contains
+		number of blocks that can be written in a single request
diff --git a/drivers/char/rpmb/core.c b/drivers/char/rpmb/core.c
index c9ea30aca6be..fb401331d345 100644
--- a/drivers/char/rpmb/core.c
+++ b/drivers/char/rpmb/core.c
@@ -230,6 +230,68 @@ struct rpmb_dev *rpmb_dev_find_by_device(struct device *parent)
 }
 EXPORT_SYMBOL_GPL(rpmb_dev_find_by_device);
 
+static ssize_t type_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct rpmb_dev *rdev = to_rpmb_dev(dev);
+	ssize_t ret;
+
+	switch (rdev->ops->type) {
+	case RPMB_TYPE_EMMC:
+		ret = scnprintf(buf, PAGE_SIZE, "EMMC\n");
+		break;
+	case RPMB_TYPE_UFS:
+		ret = scnprintf(buf, PAGE_SIZE, "UFS\n");
+		break;
+	default:
+		ret = scnprintf(buf, PAGE_SIZE, "UNKNOWN\n");
+		break;
+	}
+
+	return ret;
+}
+static DEVICE_ATTR_RO(type);
+
+static ssize_t id_show(struct device *dev,
+		       struct device_attribute *attr, char *buf)
+{
+	struct rpmb_dev *rdev = to_rpmb_dev(dev);
+	size_t sz = min_t(size_t, rdev->ops->dev_id_len, PAGE_SIZE);
+
+	if (!rdev->ops->dev_id)
+		return 0;
+
+	memcpy(buf, rdev->ops->dev_id, sz);
+	return sz;
+}
+static DEVICE_ATTR_RO(id);
+
+static ssize_t reliable_wr_cnt_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct rpmb_dev *rdev = to_rpmb_dev(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%u\n", rdev->ops->reliable_wr_cnt);
+}
+static DEVICE_ATTR_RO(reliable_wr_cnt);
+
+
+static struct attribute *rpmb_attrs[] = {
+	&dev_attr_type.attr,
+	&dev_attr_id.attr,
+	&dev_attr_reliable_wr_cnt.attr,
+	NULL,
+};
+
+static struct attribute_group rpmb_attr_group = {
+	.attrs = rpmb_attrs,
+};
+
+static const struct attribute_group *rpmb_attr_groups[] = {
+	&rpmb_attr_group,
+	NULL
+};
+
 /**
  * rpmb_dev_unregister - unregister RPMB partition from the RPMB subsystem
  *
@@ -300,6 +362,8 @@ struct rpmb_dev *rpmb_dev_register(struct device *dev,
 	dev_set_name(&rdev->dev, "rpmb%d", id);
 	rdev->dev.class = &rpmb_class;
 	rdev->dev.parent = dev;
+	rdev->dev.groups = rpmb_attr_groups;
+
 	ret = device_register(&rdev->dev);
 	if (ret)
 		goto exit;
-- 
2.5.5