[PATCH v3 3/3] scsi: ufs: core: Add sysfs attributes to get the hint information and status of WB buffer resize

[Lu Hongfei]

The host can get the hint information and status of WB buffer resize
through sysfs. To achieve this goal, two sysfs nodes have been added:
    1. wb_buf_resize_hint
    2. wb_buf_resize_status

The host can read wb_buf_resize_hint, obtain the hint information about
which type of resize for wb buffer, and enable wb buffer resize based on
the hint information. Considering that this process may take a long time,
the host can confirm the resize status by reading wb_buf_resize_status.

The detailed definition of the two nodes can be found in the sysfs
documentation.

Signed-off-by: Lu Hongfei <luhongfei@xxxxxxxx>
---
 Documentation/ABI/testing/sysfs-driver-ufs | 35 ++++++++++++++++++++
 drivers/ufs/core/ufs-sysfs.c               | 38 ++++++++++++++++++++++
 2 files changed, 73 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index b8bd7e844cb0..4b03f4b8cd49 100644
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -1454,6 +1454,41 @@ Description:
 
 		The file is write only.
 
+What:		/sys/bus/platform/drivers/ufshcd/*/wb_buf_resize_hint
+What:		/sys/bus/platform/devices/*.ufs/wb_buf_resize_hint
+Date:		Sept 2023
+Contact:	Lu Hongfei <luhongfei@xxxxxxxx>
+Description:
+		wb_buf_resize_hint indicates hint information about which type of resize for
+		WriteBooster Buffer is recommended by the device.
+
+		======  ======================================
+		   00h  Recommend keep the buffer size
+		   01h  Recommend to decrease the buffer size
+		   02h  Recommend to increase the buffer size
+		Others: Reserved
+		======  ======================================
+
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/wb_buf_resize_status
+What:		/sys/bus/platform/devices/*.ufs/wb_buf_resize_status
+Date:		Sept 2023
+Contact:	Lu Hongfei <luhongfei@xxxxxxxx>
+Description:
+		The host can check the Resize operation status of the WriteBooster Buffer
+		by reading this file.
+
+		======  ========================================
+		   00h  Idle (resize operation is not issued)
+		   01h  Resize operation in progress
+		   02h  Resize operation completed successfully
+		   03h  Resize operation general failure
+		Others  Reserved
+		======  ========================================
+
+		The file is read only.
+
 Contact:	Daniil Lunev <dlunev@xxxxxxxxxxxx>
 What:		/sys/bus/platform/drivers/ufshcd/*/capabilities/
 What:		/sys/bus/platform/devices/*.ufs/capabilities/
diff --git a/drivers/ufs/core/ufs-sysfs.c b/drivers/ufs/core/ufs-sysfs.c
index c14da6770316..e416b9802ad3 100644
--- a/drivers/ufs/core/ufs-sysfs.c
+++ b/drivers/ufs/core/ufs-sysfs.c
@@ -359,6 +359,40 @@ static ssize_t wb_buf_resize_control_store(struct device *dev,
 	return count;
 }
 
+static ssize_t wb_buf_resize_hint_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+	u32 value;
+	u8 index = ufshcd_wb_get_query_index(hba);
+
+	if (ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+			QUERY_ATTR_IDN_WB_BUF_RESIZE_HINT, index, 0, &value)) {
+		dev_err(hba->dev, "Read WB Buffer Resize Hint info failed\n");
+		return  -EINVAL;
+	}
+
+	return sysfs_emit(buf, "%u\n", value);
+}
+
+static ssize_t wb_buf_resize_status_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+	u32 value;
+	u8 index = ufshcd_wb_get_query_index(hba);
+
+	if (ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+			QUERY_ATTR_IDN_WB_BUF_RESIZE_STATUS, index, 0, &value)) {
+		dev_err(hba->dev, "Read WB Buffer Resize Status info failed\n");
+		return -EINVAL;
+	}
+
+	return sysfs_emit(buf, "%u\n", value);
+}
+
 static DEVICE_ATTR_RW(rpm_lvl);
 static DEVICE_ATTR_RO(rpm_target_dev_state);
 static DEVICE_ATTR_RO(rpm_target_link_state);
@@ -370,6 +404,8 @@ static DEVICE_ATTR_RW(wb_on);
 static DEVICE_ATTR_RW(enable_wb_buf_flush);
 static DEVICE_ATTR_RW(wb_flush_threshold);
 static DEVICE_ATTR_WO(wb_buf_resize_control);
+static DEVICE_ATTR_RO(wb_buf_resize_hint);
+static DEVICE_ATTR_RO(wb_buf_resize_status);
 
 static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
 	&dev_attr_rpm_lvl.attr,
@@ -383,6 +419,8 @@ static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
 	&dev_attr_enable_wb_buf_flush.attr,
 	&dev_attr_wb_flush_threshold.attr,
 	&dev_attr_wb_buf_resize_control.attr,
+	&dev_attr_wb_buf_resize_hint.attr,
+	&dev_attr_wb_buf_resize_status.attr,
 	NULL
 };
 
-- 
2.39.0