char: rpmb: add device attributes

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 kernel version to 4.7
V4: update target date to Maj
V5: update date and kernel version
V6: 1. Add simulation device type
    2. Update date and kernel version
    3. Use binary attribute for id
    4. use simple sprintf instead of scnprintf
    5. Add more verbose documenation
V7: resend
V8: update date and kernel version
V9: 1. update date and kernel version
    2. add new rd_cnt_max and wr_cnt_max attributes.
    3. Use SIM as a suffix of the device type.
V10: update date and kernel version

Change-Id: If25a96f1371d8fea5820f6e06366bc0945d32faa
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>

2 files changed, 121 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-rpmb b/Documentation/ABI/testing/sysfs-class-rpmb
index a017b15eabb3..00e76ff3cddf 100644
--- a/Documentation/ABI/testing/sysfs-class-rpmb
+++ b/Documentation/ABI/testing/sysfs-class-rpmb
@@ -18,3 +18,40 @@ 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/type
+Date:		May 2019
+KernelVersion:	5.2
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:
+		The /sys/class/rpmb/rpmbN/type file contains device
+		underlying storage type technology: EMMC, UFS, NVMe.
+		In case of simulated device it will have :SIM suffix
+		i.e EMMC:SIM.
+
+What:		/sys/class/rpmb/rpmbN/id
+Date:		May 2019
+KernelVersion:	5.2
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:
+		The /sys/class/rpmb/rpmbN/id file contains unique device id
+		in a binary form as defined by underlying storage device.
+		In case of multiple RPMB devices a user can determine correct
+		device.
+		The content can be parsed according the storage device type.
+
+What:		/sys/class/rpmb/rpmbN/wr_cnt_max
+Date:		May 2019
+KernelVersion:	5.2
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:
+		The /sys/class/rpmb/rpmbN/wr_cnt_max file contains
+		number of blocks that can be reliable written in a single request.
+
+What:		/sys/class/rpmb/rpmbN/rd_cnt_max
+Date:		May 2019
+KernelVersion:	5.2
+Contact:	Tomas Winkler <tomas.winkler@intel.com>
+Description:
+		The /sys/class/rpmb/rpmbN/rd_cnt_max file contains
+		number of blocks that can be read in a single request.
diff --git a/drivers/char/rpmb/core.c b/drivers/char/rpmb/core.c
index c9e62193b8d1..dd0afa0a3e24 100644
--- a/drivers/char/rpmb/core.c
+++ b/drivers/char/rpmb/core.c
@@ -218,6 +218,88 @@ struct rpmb_dev *rpmb_dev_find_by_device(struct device *parent, u8 target)
 }
 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);
+	const char *sim;
+	ssize_t ret;
+
+	sim = (rdev->ops->type & RPMB_TYPE_SIM) ? ":SIM" : "";
+	switch (RPMB_TYPE_HW(rdev->ops->type)) {
+	case RPMB_TYPE_EMMC:
+		ret = sprintf(buf, "EMMC%s\n", sim);
+		break;
+	case RPMB_TYPE_UFS:
+		ret = sprintf(buf, "UFS%s\n", sim);
+		break;
+	case RPMB_TYPE_NVME:
+		ret = sprintf(buf, "NVMe%s\n", sim);
+		break;
+	default:
+		ret = sprintf(buf, "UNKNOWN\n");
+		break;
+	}
+
+	return ret;
+}
+static DEVICE_ATTR_RO(type);
+
+static ssize_t id_read(struct file *file, struct kobject *kobj,
+		       struct bin_attribute *attr, char *buf,
+		       loff_t off, size_t count)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	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;
+
+	return memory_read_from_buffer(buf, count, &off, rdev->ops->dev_id, sz);
+}
+static BIN_ATTR_RO(id, 0);
+
+static ssize_t wr_cnt_max_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct rpmb_dev *rdev = to_rpmb_dev(dev);
+
+	return sprintf(buf, "%u\n", rdev->ops->wr_cnt_max);
+}
+static DEVICE_ATTR_RO(wr_cnt_max);
+
+static ssize_t rd_cnt_max_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct rpmb_dev *rdev = to_rpmb_dev(dev);
+
+	return sprintf(buf, "%u\n", rdev->ops->rd_cnt_max);
+}
+static DEVICE_ATTR_RO(rd_cnt_max);
+
+static struct attribute *rpmb_attrs[] = {
+	&dev_attr_type.attr,
+	&dev_attr_wr_cnt_max.attr,
+	&dev_attr_rd_cnt_max.attr,
+	NULL,
+};
+
+static struct bin_attribute *rpmb_bin_attributes[] = {
+	&bin_attr_id,
+	NULL,
+};
+
+static struct attribute_group rpmb_attr_group = {
+	.attrs = rpmb_attrs,
+	.bin_attrs = rpmb_bin_attributes,
+};
+
+static const struct attribute_group *rpmb_attr_groups[] = {
+	&rpmb_attr_group,
+	NULL
+};
+
 /**
  * rpmb_dev_unregister() - unregister RPMB partition from the RPMB subsystem
  * @rdev: the rpmb device to unregister
@@ -337,6 +419,8 @@ struct rpmb_dev *rpmb_dev_register(struct device *dev, u8 target,
 	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;