[PATCH v2 3/3] scsi: ufs: core: Add sysfs attributes to control WB buffer resize function

Lu Hongfei
2023-09-08T10:25:04Z

The host can control the WB buffer resize through sysfs. To achieve this
goal, three sysfs nodes have been added:
1. wb_buf_resize_hint
2. enable_wb_buf_resize
3. 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 write enable_wb_buf_resize to
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 three nodes can be found in the sysfs
documentation.

Signed-off-by: Lu Hongfei <luhongfei@vivo.com>
---
Documentation/ABI/testing/sysfs-driver-ufs | 52 ++++++++++++++++
drivers/ufs/core/ufs-sysfs.c | 71 ++++++++++++++++++++++
2 files changed, 123 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index 0c7efaf62de0..6e0ecf3a025d 100644
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -1437,6 +1437,58 @@ Description:
If avail_wb_buff < wb_flush_threshold, it indicates that WriteBooster buffer needs to
be flushed, otherwise it is not necessary.

+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@vivo.com>
+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/*/enable_wb_buf_resize
+What: /sys/bus/platform/devices/*.ufs/enable_wb_buf_resize
+Date: Sept 2023
+Contact: Lu Hongfei <luhongfei@vivo.com>
+Description:
+ The host can decrease or increase the WriteBooster Buffer size by setting
+ this file.
+
+ ====== ======================================
+ 00h Idle (There is no resize operation)
+ 01h Decrease WriteBooster Buffer Size
+ 02h Increase WriteBooster Buffer Size
+ Others Reserved
+ ====== ======================================
+
+ The file is write 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@vivo.com>
+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@chromium.org>
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 c95906443d5f..2ecb1e08a5b8 100644
--- a/drivers/ufs/core/ufs-sysfs.c
+++ b/drivers/ufs/core/ufs-sysfs.c
@@ -329,6 +329,71 @@ static ssize_t wb_flush_threshold_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 enable_wb_buf_resize_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct ufs_hba *hba = dev_get_drvdata(dev);
+ unsigned int wb_buf_resize_op;
+
+ if (!ufshcd_is_wb_allowed(hba) || !hba->dev_info.wb_enabled) {
+ dev_err(dev, "The WB is not allowed or disabled!\n");
+ return -EINVAL;
+ }
+
+ if (hba->dev_info.wspecversion < 0x410 ||
+ !hba->dev_info.b_presrv_uspc_en) {
+ dev_err(dev, "The WB buf resize is not allowed!\n");
+ return -EINVAL;
+ }
+
+ if (kstrtouint(buf, 0, &wb_buf_resize_op))
+ return -EINVAL;
+
+ if (wb_buf_resize_op != 0x01 && wb_buf_resize_op != 0x02) {
+ dev_err(dev, "The operation %u is invalid!\n", wb_buf_resize_op);
+ return -EINVAL;
+ }
+
+ ufshcd_wb_buf_resize(hba, wb_buf_resize_op);
+
+ return count;
+}
+
+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);
@@ -339,6 +404,9 @@ static DEVICE_ATTR_RW(auto_hibern8);
static DEVICE_ATTR_RW(wb_on);
static DEVICE_ATTR_RW(enable_wb_buf_flush);
static DEVICE_ATTR_RW(wb_flush_threshold);
+static DEVICE_ATTR_RO(wb_buf_resize_hint);
+static DEVICE_ATTR_WO(enable_wb_buf_resize);
+static DEVICE_ATTR_RO(wb_buf_resize_status);

static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
&dev_attr_rpm_lvl.attr,
@@ -351,6 +419,9 @@ static struct attribute *ufs_sysfs_ufshcd_attrs[] = {
&dev_attr_wb_on.attr,
&dev_attr_enable_wb_buf_flush.attr,
&dev_attr_wb_flush_threshold.attr,
+ &dev_attr_wb_buf_resize_hint.attr,
+ &dev_attr_enable_wb_buf_resize.attr,
+ &dev_attr_wb_buf_resize_status.attr,
NULL
};

--
2.39.0