scsi: ufs: core: Add WB buffer resize support

Follow JESD220G, support a WB buffer resize function through sysfs. The
host can obtain resize hint and resize status, and enable the resize
operation. Add three sysfs nodes:

	1. wb_resize_enable

	2. wb_resize_hint

	3. wb_resize_status

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

Signed-off-by: Huan Tang <tanghuan@vivo.com>
Signed-off-by: Lu Hongfei <luhongfei@vivo.com>
Link: https://lore.kernel.org/r/20250411092924.1116-1-tanghuan@vivo.com
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Documentation/ABI/testing/sysfs-driver-ufs

@@ -1604,3 +1604,52 @@ Description:
 		prevent the UFS from frequently performing clock gating/ungating.
 
 		The attribute is read/write.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/wb_resize_enable
+What:		/sys/bus/platform/devices/*.ufs/wb_resize_enable
+Date:		April 2025
+Contact:	Huan Tang <tanghuan@vivo.com>
+Description:
+		The host can enable the WriteBooster buffer resize by setting this
+		attribute.
+
+		========  ======================================
+		idle      There is no resize operation
+		decrease  Decrease WriteBooster buffer size
+		increase  Increase WriteBooster buffer size
+		========  ======================================
+
+		The file is write only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/attributes/wb_resize_hint
+What:		/sys/bus/platform/devices/*.ufs/attributes/wb_resize_hint
+Date:		April 2025
+Contact:	Huan Tang <tanghuan@vivo.com>
+Description:
+		wb_resize_hint indicates hint information about which type of resize
+		for WriteBooster buffer is recommended by the device.
+
+		=========  ======================================
+		keep       Recommend keep the buffer size
+		decrease   Recommend to decrease the buffer size
+		increase   Recommend to increase the buffer size
+		=========  ======================================
+
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/attributes/wb_resize_status
+What:		/sys/bus/platform/devices/*.ufs/attributes/wb_resize_status
+Date:		April 2025
+Contact:	Huan Tang <tanghuan@vivo.com>
+Description:
+		The host can check the resize operation status of the WriteBooster
+		buffer by reading this attribute.
+
+		================  ========================================
+		idle              Resize operation is not issued
+		in_progress       Resize operation in progress
+		complete_success  Resize operation completed successfully
+		general_failure   Resize operation general failure
+		================  ========================================
+
+		The file is read only.

drivers/ufs/core/ufs-sysfs.c

@@ -57,6 +57,36 @@ static const char *ufs_hs_gear_to_string(enum ufs_hs_gear_tag gear)
 	}
 }
 
+static const char *ufs_wb_resize_hint_to_string(enum wb_resize_hint hint)
+{
+	switch (hint) {
+	case WB_RESIZE_HINT_KEEP:
+		return "keep";
+	case WB_RESIZE_HINT_DECREASE:
+		return "decrease";
+	case WB_RESIZE_HINT_INCREASE:
+		return "increase";
+	default:
+		return "unknown";
+	}
+}
+
+static const char *ufs_wb_resize_status_to_string(enum wb_resize_status status)
+{
+	switch (status) {
+	case WB_RESIZE_STATUS_IDLE:
+		return "idle";
+	case WB_RESIZE_STATUS_IN_PROGRESS:
+		return "in_progress";
+	case WB_RESIZE_STATUS_COMPLETE_SUCCESS:
+		return "complete_success";
+	case WB_RESIZE_STATUS_GENERAL_FAILURE:
+		return "general_failure";
+	default:
+		return "unknown";
+	}
+}
+
 static const char *ufshcd_uic_link_state_to_string(
 			enum uic_link_state state)
 {
@@ -411,6 +441,44 @@ static ssize_t wb_flush_threshold_store(struct device *dev,
 	return count;
 }
 
+static const char * const wb_resize_en_mode[] = {
+	[WB_RESIZE_EN_IDLE]	= "idle",
+	[WB_RESIZE_EN_DECREASE]	= "decrease",
+	[WB_RESIZE_EN_INCREASE]	= "increase",
+};
+
+static ssize_t wb_resize_enable_store(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf, size_t count)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+	int mode;
+	ssize_t res;
+
+	if (!ufshcd_is_wb_allowed(hba) || !hba->dev_info.wb_enabled
+		|| !hba->dev_info.b_presrv_uspc_en
+		|| !(hba->dev_info.ext_wb_sup & UFS_DEV_WB_BUF_RESIZE))
+		return -EOPNOTSUPP;
+
+	mode = sysfs_match_string(wb_resize_en_mode, buf);
+	if (mode < 0)
+		return -EINVAL;
+
+	down(&hba->host_sem);
+	if (!ufshcd_is_user_access_allowed(hba)) {
+		res = -EBUSY;
+		goto out;
+	}
+
+	ufshcd_rpm_get_sync(hba);
+	res = ufshcd_wb_set_resize_en(hba, mode);
+	ufshcd_rpm_put_sync(hba);
+
+out:
+	up(&hba->host_sem);
+	return res < 0 ? res : count;
+}
+
 /**
  * pm_qos_enable_show - sysfs handler to show pm qos enable value
  * @dev: device associated with the UFS controller
@@ -476,6 +544,7 @@ 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_WO(wb_resize_enable);
 static DEVICE_ATTR_RW(rtc_update_ms);
 static DEVICE_ATTR_RW(pm_qos_enable);
 static DEVICE_ATTR_RO(critical_health);
@@ -491,6 +560,7 @@ 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_resize_enable.attr,
 	&dev_attr_rtc_update_ms.attr,
 	&dev_attr_pm_qos_enable.attr,
 	&dev_attr_critical_health.attr,
@@ -1495,6 +1565,67 @@ static inline bool ufshcd_is_wb_attrs(enum attr_idn idn)
 		idn <= QUERY_ATTR_IDN_CURR_WB_BUFF_SIZE;
 }
 
+static int wb_read_resize_attrs(struct ufs_hba *hba,
+			enum attr_idn idn, u32 *attr_val)
+{
+	u8 index = 0;
+	int ret;
+
+	if (!ufshcd_is_wb_allowed(hba) || !hba->dev_info.wb_enabled
+		|| !hba->dev_info.b_presrv_uspc_en
+		|| !(hba->dev_info.ext_wb_sup & UFS_DEV_WB_BUF_RESIZE))
+		return -EOPNOTSUPP;
+
+	down(&hba->host_sem);
+	if (!ufshcd_is_user_access_allowed(hba)) {
+		up(&hba->host_sem);
+		return -EBUSY;
+	}
+
+	index = ufshcd_wb_get_query_index(hba);
+	ufshcd_rpm_get_sync(hba);
+	ret = ufshcd_query_attr(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+			idn, index, 0, attr_val);
+	ufshcd_rpm_put_sync(hba);
+
+	up(&hba->host_sem);
+	return ret;
+}
+
+static ssize_t wb_resize_hint_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+	int ret;
+	u32 value;
+
+	ret = wb_read_resize_attrs(hba,
+			QUERY_ATTR_IDN_WB_BUF_RESIZE_HINT, &value);
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%s\n", ufs_wb_resize_hint_to_string(value));
+}
+
+static DEVICE_ATTR_RO(wb_resize_hint);
+
+static ssize_t wb_resize_status_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+	int ret;
+	u32 value;
+
+	ret = wb_read_resize_attrs(hba,
+			QUERY_ATTR_IDN_WB_BUF_RESIZE_STATUS, &value);
+	if (ret)
+		return ret;
+
+	return sysfs_emit(buf, "%s\n", ufs_wb_resize_status_to_string(value));
+}
+
+static DEVICE_ATTR_RO(wb_resize_status);
+
 #define UFS_ATTRIBUTE(_name, _uname)					\
 static ssize_t _name##_show(struct device *dev,				\
 	struct device_attribute *attr, char *buf)			\
@@ -1568,6 +1699,8 @@ static struct attribute *ufs_sysfs_attributes[] = {
 	&dev_attr_wb_avail_buf.attr,
 	&dev_attr_wb_life_time_est.attr,
 	&dev_attr_wb_cur_buf.attr,
+	&dev_attr_wb_resize_hint.attr,
+	&dev_attr_wb_resize_status.attr,
 	NULL,
 };
 

drivers/ufs/core/ufshcd.c

@@ -6080,6 +6080,21 @@ int ufshcd_wb_toggle_buf_flush(struct ufs_hba *hba, bool enable)
 	return ret;
 }
 
+int ufshcd_wb_set_resize_en(struct ufs_hba *hba, enum wb_resize_en en_mode)
+{
+	int ret;
+	u8 index;
+
+	index = ufshcd_wb_get_query_index(hba);
+	ret = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
+				QUERY_ATTR_IDN_WB_BUF_RESIZE_EN, index, 0, &en_mode);
+	if (ret)
+		dev_err(hba->dev, "%s: Enable WB buf resize operation failed %d\n",
+			__func__, ret);
+
+	return ret;
+}
+
 static bool ufshcd_wb_presrv_usrspc_keep_vcc_on(struct ufs_hba *hba,
 						u32 avail_buf)
 {
@@ -8100,6 +8115,9 @@ static void ufshcd_wb_probe(struct ufs_hba *hba, const u8 *desc_buf)
 	 */
 	dev_info->wb_buffer_type = desc_buf[DEVICE_DESC_PARAM_WB_TYPE];
 
+	dev_info->ext_wb_sup =  get_unaligned_be16(desc_buf +
+						DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP);
+
 	dev_info->b_presrv_uspc_en =
 		desc_buf[DEVICE_DESC_PARAM_WB_PRESRV_USRSPC_EN];
 

include/ufs/ufs.h

@@ -180,7 +180,10 @@ enum attr_idn {
 	QUERY_ATTR_IDN_AVAIL_WB_BUFF_SIZE       = 0x1D,
 	QUERY_ATTR_IDN_WB_BUFF_LIFE_TIME_EST    = 0x1E,
 	QUERY_ATTR_IDN_CURR_WB_BUFF_SIZE        = 0x1F,
-	QUERY_ATTR_IDN_TIMESTAMP		= 0x30
+	QUERY_ATTR_IDN_TIMESTAMP		= 0x30,
+	QUERY_ATTR_IDN_WB_BUF_RESIZE_HINT	= 0x3C,
+	QUERY_ATTR_IDN_WB_BUF_RESIZE_EN		= 0x3D,
+	QUERY_ATTR_IDN_WB_BUF_RESIZE_STATUS	= 0x3E,
 };
 
 /* Descriptor idn for Query requests */
@@ -289,6 +292,7 @@ enum device_desc_param {
 	DEVICE_DESC_PARAM_PRDCT_REV		= 0x2A,
 	DEVICE_DESC_PARAM_HPB_VER		= 0x40,
 	DEVICE_DESC_PARAM_HPB_CONTROL		= 0x42,
+	DEVICE_DESC_PARAM_EXT_WB_SUP		= 0x4D,
 	DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP	= 0x4F,
 	DEVICE_DESC_PARAM_WB_PRESRV_USRSPC_EN	= 0x53,
 	DEVICE_DESC_PARAM_WB_TYPE		= 0x54,
@@ -383,6 +387,11 @@ enum {
 	UFSHCD_AMP		= 3,
 };
 
+/* Possible values for wExtendedWriteBoosterSupport */
+enum {
+	UFS_DEV_WB_BUF_RESIZE	= BIT(0),
+};
+
 /* Possible values for dExtendedUFSFeaturesSupport */
 enum {
 	UFS_DEV_HIGH_TEMP_NOTIF		= BIT(4),
@@ -454,6 +463,28 @@ enum ufs_ref_clk_freq {
 	REF_CLK_FREQ_INVAL	= -1,
 };
 
+/* bWriteBoosterBufferResizeEn attribute */
+enum wb_resize_en {
+	WB_RESIZE_EN_IDLE	= 0,
+	WB_RESIZE_EN_DECREASE	= 1,
+	WB_RESIZE_EN_INCREASE	= 2,
+};
+
+/* bWriteBoosterBufferResizeHint attribute */
+enum wb_resize_hint {
+	WB_RESIZE_HINT_KEEP	= 0,
+	WB_RESIZE_HINT_DECREASE	= 1,
+	WB_RESIZE_HINT_INCREASE	= 2,
+};
+
+/* bWriteBoosterBufferResizeStatus attribute */
+enum wb_resize_status {
+	WB_RESIZE_STATUS_IDLE	= 0,
+	WB_RESIZE_STATUS_IN_PROGRESS	= 1,
+	WB_RESIZE_STATUS_COMPLETE_SUCCESS	= 2,
+	WB_RESIZE_STATUS_GENERAL_FAILURE	= 3,
+};
+
 /* Query response result code */
 enum {
 	QUERY_RESULT_SUCCESS                    = 0x00,
@@ -578,6 +609,7 @@ struct ufs_dev_info {
 	bool    wb_buf_flush_enabled;
 	u8	wb_dedicated_lu;
 	u8      wb_buffer_type;
+	u16	ext_wb_sup;
 
 	bool	b_rpm_dev_flush_capable;
 	u8	b_presrv_uspc_en;

include/ufs/ufshcd.h

@@ -1468,6 +1468,7 @@ int ufshcd_advanced_rpmb_req_handler(struct ufs_hba *hba, struct utp_upiu_req *r
 				     struct scatterlist *sg_list, enum dma_data_direction dir);
 int ufshcd_wb_toggle(struct ufs_hba *hba, bool enable);
 int ufshcd_wb_toggle_buf_flush(struct ufs_hba *hba, bool enable);
+int ufshcd_wb_set_resize_en(struct ufs_hba *hba, enum wb_resize_en en_mode);
 int ufshcd_suspend_prepare(struct device *dev);
 int __ufshcd_suspend_prepare(struct device *dev, bool rpm_ok_for_spm);
 void ufshcd_resume_complete(struct device *dev);