[PATCH v4] 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.

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Can Guo <quic_cang@quicinc.com>
---

v3 -> v4:
Incorporated comments from Bart and Mani

v2 -> v3:
1. For mode/gear/rate/dev_pm/link_status, print texts instead of numbers
2. Removed number<->text explanations for mode/rate/gear/dev_pm/link_status in Documentation/ABI/testing/sysfs-driver-ufs

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

---

 Documentation/ABI/testing/sysfs-driver-ufs |  49 ++++++++++++
 drivers/ufs/core/ufs-sysfs.c               | 120 +++++++++++++++++++++++++++++
 include/ufs/unipro.h                       |   4 +-
 3 files changed, 171 insertions(+), 2 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-driver-ufs b/Documentation/ABI/testing/sysfs-driver-ufs
index 0c7efaf..b73067b 100644
--- a/Documentation/ABI/testing/sysfs-driver-ufs
+++ b/Documentation/ABI/testing/sysfs-driver-ufs
@@ -1223,6 +1223,55 @@ 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 PA power mode of UFS.
+
+		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.
+
+		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.
+
+		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.
+
+		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.
+
+		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..05b10ca 100644
--- a/drivers/ufs/core/ufs-sysfs.c
+++ b/drivers/ufs/core/ufs-sysfs.c
@@ -7,9 +7,56 @@
 #include <asm/unaligned.h>
 
 #include <ufs/ufs.h>
+#include <ufs/unipro.h>
 #include "ufs-sysfs.h"
 #include "ufshcd-priv.h"
 
+static const char *ufs_pa_pwr_mode_to_string(enum ufs_pa_pwr_mode mode)
+{
+	switch (mode) {
+	case FAST_MODE:		return "FAST_MODE";
+	case SLOW_MODE:		return "SLOW_MODE";
+	case FASTAUTO_MODE:	return "FASTAUTO_MODE";
+	case SLOWAUTO_MODE:	return "SLOWAUTO_MODE";
+	default:		return "UNKNOWN";
+	}
+}
+
+static const char *ufs_hs_gear_rate_to_string(enum ufs_hs_gear_rate rate)
+{
+	switch (rate) {
+	case PA_HS_MODE_A:	return "HS_RATE_A";
+	case PA_HS_MODE_B:	return "HS_RATE_B";
+	default:		return "UNKNOWN";
+	}
+}
+
+static const char *ufs_pwm_gear_to_string(enum ufs_pwm_gear_tag gear)
+{
+	switch (gear) {
+	case UFS_PWM_G1:	return "PWM_GEAR1";
+	case UFS_PWM_G2:	return "PWM_GEAR2";
+	case UFS_PWM_G3:	return "PWM_GEAR3";
+	case UFS_PWM_G4:	return "PWM_GEAR4";
+	case UFS_PWM_G5:	return "PWM_GEAR5";
+	case UFS_PWM_G6:	return "PWM_GEAR6";
+	case UFS_PWM_G7:	return "PWM_GEAR7";
+	default:		return "UNKNOWN";
+	}
+}
+
+static const char *ufs_hs_gear_to_string(enum ufs_hs_gear_tag gear)
+{
+	switch (gear) {
+	case UFS_HS_G1:	return "HS_GEAR1";
+	case UFS_HS_G2:	return "HS_GEAR2";
+	case UFS_HS_G3:	return "HS_GEAR3";
+	case UFS_HS_G4:	return "HS_GEAR4";
+	case UFS_HS_G5:	return "HS_GEAR5";
+	default:	return "UNKNOWN";
+	}
+}
+
 static const char *ufshcd_uic_link_state_to_string(
 			enum uic_link_state state)
 {
@@ -628,6 +675,78 @@ static const struct attribute_group ufs_sysfs_monitor_group = {
 	.attrs = ufs_sysfs_monitor_attrs,
 };
 
+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, "%s\n", ufs_pa_pwr_mode_to_string(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, "%s\n", ufs_hs_gear_rate_to_string(hba->pwr_info.hs_rate));
+}
+
+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, "%s\n", hba->pwr_info.hs_rate ?
+			  ufs_hs_gear_to_string(hba->pwr_info.gear_rx) :
+			  ufs_pwm_gear_to_string(hba->pwr_info.gear_rx));
+}
+
+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, "%s\n", ufshcd_ufs_dev_pwr_mode_to_string(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, "%s\n", ufshcd_uic_link_state_to_string(hba->uic_link_state));
+}
+
+static DEVICE_ATTR_RO(lane);
+static DEVICE_ATTR_RO(mode);
+static DEVICE_ATTR_RO(rate);
+static DEVICE_ATTR_RO(gear);
+static DEVICE_ATTR_RO(dev_pm);
+static DEVICE_ATTR_RO(link_state);
+
+static struct attribute *ufs_power_info_attrs[] = {
+	&dev_attr_lane.attr,
+	&dev_attr_mode.attr,
+	&dev_attr_rate.attr,
+	&dev_attr_gear.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 +1352,7 @@ 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,
diff --git a/include/ufs/unipro.h b/include/ufs/unipro.h
index 256eb3a..360e124 100644
--- a/include/ufs/unipro.h
+++ b/include/ufs/unipro.h
@@ -193,7 +193,7 @@
 #define DME_LocalAFC0ReqTimeOutVal		0xD043
 
 /* PA power modes */
-enum {
+enum ufs_pa_pwr_mode {
 	FAST_MODE	= 1,
 	SLOW_MODE	= 2,
 	FASTAUTO_MODE	= 4,
@@ -205,7 +205,7 @@ enum {
 #define PWRMODE_RX_OFFSET	4
 
 /* PA TX/RX Frequency Series */
-enum {
+enum ufs_hs_gear_rate {
 	PA_HS_MODE_A	= 1,
 	PA_HS_MODE_B	= 2,
 };
-- 
2.7.4