scsi: ufs: sysfs: string descriptors

This patch introduces a sysfs group entry for the UFS string descriptors.
The group adds "string_descriptors" folder under the UFS driver
sysfs entry (/sys/bus/platform/drivers/ufshcd/*). The folder will contain
5 files that will show string values defined by the UFS spec:
a manufacturer name, a product name, an OEM id, a serial number and a
product revision.  The full information about the string descriptors
could be found at UFS specifications 2.1.
Signed-off-by: Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Documentation/ABI/testing/sysfs-driver-ufs

@@ -451,3 +451,42 @@ Description:	This file shows maximum VCC, VCCQ and VCCQ2 value for
 		power descriptor parameters. The full information about
 		the descriptor could be found at UFS specifications 2.1.
 		The file is read only.
+
+
+What:		/sys/bus/platform/drivers/ufshcd/*/string_descriptors/manufacturer_name
+Date:		February 2018
+Contact:	Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
+Description:	This file contains a device manufactureer name string.
+		The full information about the descriptor could be found at
+		UFS specifications 2.1.
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/string_descriptors/product_name
+Date:		February 2018
+Contact:	Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
+Description:	This file contains a product name string. The full information
+		about the descriptor could be found at UFS specifications 2.1.
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/string_descriptors/oem_id
+Date:		February 2018
+Contact:	Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
+Description:	This file contains a OEM ID string. The full information
+		about the descriptor could be found at UFS specifications 2.1.
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/string_descriptors/serial_number
+Date:		February 2018
+Contact:	Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
+Description:	This file contains a device serial number string. The full
+		information about the descriptor could be found at
+		UFS specifications 2.1.
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/string_descriptors/product_revision
+Date:		February 2018
+Contact:	Stanislav Nijnikov <stanislav.nijnikov@wdc.com>
+Description:	This file contains a product revision string. The full
+		information about the descriptor could be found at
+		UFS specifications 2.1.
+		The file is read only.

drivers/scsi/ufs/ufs-sysfs.c

@@ -484,6 +484,61 @@ static const struct attribute_group ufs_sysfs_power_descriptor_group = {
 	.attrs = ufs_sysfs_power_descriptor,
 };
 
+#define UFS_STRING_DESCRIPTOR(_name, _pname)				\
+static ssize_t _name##_show(struct device *dev,				\
+	struct device_attribute *attr, char *buf)			\
+{									\
+	u8 index;							\
+	struct ufs_hba *hba = dev_get_drvdata(dev);			\
+	int ret;							\
+	int desc_len = QUERY_DESC_MAX_SIZE;				\
+	u8 *desc_buf;							\
+	desc_buf = kzalloc(QUERY_DESC_MAX_SIZE, GFP_ATOMIC);		\
+	if (!desc_buf)							\
+		return -ENOMEM;						\
+	ret = ufshcd_query_descriptor_retry(hba,			\
+		UPIU_QUERY_OPCODE_READ_DESC, QUERY_DESC_IDN_DEVICE,	\
+		0, 0, desc_buf, &desc_len);				\
+	if (ret) {							\
+		ret = -EINVAL;						\
+		goto out;						\
+	}								\
+	index = desc_buf[DEVICE_DESC_PARAM##_pname];			\
+	memset(desc_buf, 0, QUERY_DESC_MAX_SIZE);			\
+	if (ufshcd_read_string_desc(hba, index, desc_buf,		\
+		QUERY_DESC_MAX_SIZE, true)) {				\
+		ret = -EINVAL;						\
+		goto out;						\
+	}								\
+	ret = snprintf(buf, PAGE_SIZE, "%s\n",				\
+		desc_buf + QUERY_DESC_HDR_SIZE);			\
+out:									\
+	kfree(desc_buf);						\
+	return ret;							\
+}									\
+static DEVICE_ATTR_RO(_name)
+
+UFS_STRING_DESCRIPTOR(manufacturer_name, _MANF_NAME);
+UFS_STRING_DESCRIPTOR(product_name, _PRDCT_NAME);
+UFS_STRING_DESCRIPTOR(oem_id, _OEM_ID);
+UFS_STRING_DESCRIPTOR(serial_number, _SN);
+UFS_STRING_DESCRIPTOR(product_revision, _PRDCT_REV);
+
+static struct attribute *ufs_sysfs_string_descriptors[] = {
+	&dev_attr_manufacturer_name.attr,
+	&dev_attr_product_name.attr,
+	&dev_attr_oem_id.attr,
+	&dev_attr_serial_number.attr,
+	&dev_attr_product_revision.attr,
+	NULL,
+};
+
+static const struct attribute_group ufs_sysfs_string_descriptors_group = {
+	.name = "string_descriptors",
+	.attrs = ufs_sysfs_string_descriptors,
+};
+
+
 static const struct attribute_group *ufs_sysfs_groups[] = {
 	&ufs_sysfs_default_group,
 	&ufs_sysfs_device_descriptor_group,
@@ -491,6 +546,7 @@ static const struct attribute_group *ufs_sysfs_groups[] = {
 	&ufs_sysfs_geometry_descriptor_group,
 	&ufs_sysfs_health_descriptor_group,
 	&ufs_sysfs_power_descriptor_group,
+	&ufs_sysfs_string_descriptors_group,
 	NULL,
 };
 

drivers/scsi/ufs/ufshcd.c

@@ -2873,7 +2873,7 @@ static int __ufshcd_query_descriptor(struct ufs_hba *hba,
  * The buf_len parameter will contain, on return, the length parameter
  * received on the response.
  */
-static int ufshcd_query_descriptor_retry(struct ufs_hba *hba,
+int ufshcd_query_descriptor_retry(struct ufs_hba *hba,
 				  enum query_opcode opcode,
 				  enum desc_idn idn, u8 index,
 				  u8 selector,
@@ -3093,7 +3093,7 @@ static int ufshcd_read_device_desc(struct ufs_hba *hba, u8 *buf, u32 size)
  * Return 0 in case of success, non-zero otherwise
  */
 #define ASCII_STD true
-static int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index,
+int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index,
 			    u8 *buf, u32 size, bool ascii)
 {
 	int err = 0;

drivers/scsi/ufs/ufshcd.h

@@ -842,6 +842,12 @@ static inline bool ufshcd_is_hs_mode(struct ufs_pa_layer_attr *pwr_info)
 }
 
 /* Expose Query-Request API */
+int ufshcd_query_descriptor_retry(struct ufs_hba *hba,
+				  enum query_opcode opcode,
+				  enum desc_idn idn, u8 index,
+				  u8 selector,
+				  u8 *desc_buf, int *buf_len);
+
 int ufshcd_read_desc_param(struct ufs_hba *hba,
 			   enum desc_idn desc_id,
 			   int desc_index,
@@ -850,6 +856,9 @@ int ufshcd_read_desc_param(struct ufs_hba *hba,
 			   u8 param_size);
 int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode,
 	enum flag_idn idn, bool *flag_res);
+int ufshcd_read_string_desc(struct ufs_hba *hba, int desc_index,
+			    u8 *buf, u32 size, bool ascii);
+
 int ufshcd_hold(struct ufs_hba *hba, bool async);
 void ufshcd_release(struct ufs_hba *hba);