[PATCH v2] scsi: ufs: ufs-sysfs: Expose UFS power info

[Can Guo <quic_cang@quicinc.com>]

Having UFS power info available in sysfs makes it easier to tell the state
of the link during runtime considering we have a bunch of power saving
features and various combinations for backward compatibility.

Signed-off-by: Can Guo <quic_cang@quicinc.com>
---

v1 -> v2:
1. Incorporated comments from Bart, Nitin and Mani.
2. Added explanations for gear/lane/rate/dev_pm/link_status in Documentation/ABI/testing/sysfs-driver-ufs

---
 Documentation/ABI/testing/sysfs-driver-ufs | 88 ++++++++++++++++++++++++++++++
 drivers/ufs/core/ufs-sysfs.c               | 71 ++++++++++++++++++++++++
 2 files changed, 159 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index 0c7efaf..dd2cbac 100644
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -1223,6 +1223,94 @@ Description:	This file shows the total latency (in micro seconds) of write
 
 		The file is read only.
 
+What:		/sys/bus/platform/drivers/ufshcd/*/power_info/lane
+What:		/sys/bus/platform/devices/*.ufs/power_info/lane
+Date:		September 2023
+Contact:	Can Guo <quic_cang@quicinc.com>
+Description:	This file shows how many lanes are enabled on the UFS link,
+		i.e., an output 2 means UFS link is operating with 2 lanes.
+
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/power_info/mode
+What:		/sys/bus/platform/devices/*.ufs/power_info/mode
+Date:		September 2023
+Contact:	Can Guo <quic_cang@quicinc.com>
+Description:	This file shows the UniPro power mode of UFS link:
+		==  ====================================================
+		1   FAST_MODE
+		2   SLOW_MODE
+		4   FASTAUTO_MODE
+		5   SLOWAUTO_MODE
+		==  ====================================================
+
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/power_info/rate
+What:		/sys/bus/platform/devices/*.ufs/power_info/rate
+Date:		September 2023
+Contact:	Can Guo <quic_cang@quicinc.com>
+Description:	This file shows the speed rate of UFS link:
+		==  ====================================================
+		0   Indicates that the gear is in PWM mode
+		1   HS_MODE_A - High Speed Rate A
+		2   HS_MODE_B - High Speed Rate B
+		==  ====================================================
+
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/power_info/gear
+What:		/sys/bus/platform/devices/*.ufs/power_info/gear
+Date:		September 2023
+Contact:	Can Guo <quic_cang@quicinc.com>
+Description:	This file shows the gear of UFS link. 'rate' indicates whether
+		the gear is in PWM mode or High-Speed mode.
+		==  ====================================================
+		1   PWM_GEAR1
+		2   PWM_GEAR2
+		3   PWM_GEAR3
+		4   PWM_GEAR4
+		5   PWM_GEAR5
+		6   PWM_GEAR6
+		7   PWM_GEAR7
+		==  ====================================================
+		1   HS_GEAR1
+		2   HS_GEAR2
+		3   HS_GEAR3
+		4   HS_GEAR4
+		5   HS_GEAR5
+		==  ====================================================
+
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/power_info/dev_pm
+What:		/sys/bus/platform/devices/*.ufs/power_info/dev_pm
+Date:		September 2023
+Contact:	Can Guo <quic_cang@quicinc.com>
+Description:	This file shows the UFS device power mode:
+		==  ====================================================
+		1   ACTIVE_PWR_MODE
+		2   SLEEP_PWR_MODE
+		3   POWERDOWN_PWR_MODE
+		4   DEEPSLEEP_PWR_MODE
+		==  ====================================================
+
+		The file is read only.
+
+What:		/sys/bus/platform/drivers/ufshcd/*/power_info/link_state
+What:		/sys/bus/platform/devices/*.ufs/power_info/link_state
+Date:		September 2023
+Contact:	Can Guo <quic_cang@quicinc.com>
+Description:	This file shows the state of UFS link:
+		==  ====================================================
+		0   UIC_LINK_OFF_STATE
+		1   UIC_LINK_ACTIVE_STATE
+		2   UIC_LINK_HIBERN8_STATE
+		3   UIC_LINK_BROKEN_STATE
+		==  ====================================================
+
+		The file is read only.
+
 What:		/sys/bus/platform/drivers/ufshcd/*/device_descriptor/wb_presv_us_en
 What:		/sys/bus/platform/devices/*.ufs/device_descriptor/wb_presv_us_en
 Date:		June 2020
diff --git a/drivers/ufs/core/ufs-sysfs.c b/drivers/ufs/core/ufs-sysfs.c
index c959064..53af490 100644
--- a/drivers/ufs/core/ufs-sysfs.c
+++ b/drivers/ufs/core/ufs-sysfs.c
@@ -628,6 +628,76 @@ static const struct attribute_group ufs_sysfs_monitor_group = {
 	.attrs = ufs_sysfs_monitor_attrs,
 };
 
+static ssize_t gear_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n", hba->pwr_info.gear_rx);
+}
+
+static ssize_t lane_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n", hba->pwr_info.lane_rx);
+}
+
+static ssize_t mode_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n", hba->pwr_info.pwr_rx);
+}
+
+static ssize_t rate_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%u\n", hba->pwr_info.hs_rate);
+}
+
+static ssize_t dev_pm_show(struct device *dev, struct device_attribute *attr,
+			   char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", hba->curr_dev_pwr_mode);
+}
+
+static ssize_t link_state_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct ufs_hba *hba = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", hba->uic_link_state);
+}
+
+static DEVICE_ATTR_RO(gear);
+static DEVICE_ATTR_RO(lane);
+static DEVICE_ATTR_RO(mode);
+static DEVICE_ATTR_RO(rate);
+static DEVICE_ATTR_RO(dev_pm);
+static DEVICE_ATTR_RO(link_state);
+
+static struct attribute *ufs_power_info_attrs[] = {
+	&dev_attr_gear.attr,
+	&dev_attr_lane.attr,
+	&dev_attr_mode.attr,
+	&dev_attr_rate.attr,
+	&dev_attr_dev_pm.attr,
+	&dev_attr_link_state.attr,
+	NULL
+};
+
+static const struct attribute_group ufs_sysfs_power_info_group = {
+	.name = "power_info",
+	.attrs = ufs_power_info_attrs,
+};
+
 static ssize_t ufs_sysfs_read_desc_param(struct ufs_hba *hba,
 				  enum desc_idn desc_id,
 				  u8 desc_index,
@@ -1233,6 +1303,7 @@ static const struct attribute_group *ufs_sysfs_groups[] = {
 	&ufs_sysfs_default_group,
 	&ufs_sysfs_capabilities_group,
 	&ufs_sysfs_monitor_group,
+	&ufs_sysfs_power_info_group,
 	&ufs_sysfs_device_descriptor_group,
 	&ufs_sysfs_interconnect_descriptor_group,
 	&ufs_sysfs_geometry_descriptor_group,
-- 
2.7.4