[PATCH] nvme: hwmon: Add support for throttling temperature feature

[Tokunori Ikegami <ikegami.t@gmail.com>]

NVMe drives support host controlled thermal management feature as optional.
The thermal management temperature are different from the temperature threshold.
So add functionality to set the throttling temperature values.

Signed-off-by: Tokunori Ikegami <ikegami.t@gmail.com>
---
 drivers/hwmon/hwmon.c     |  2 ++
 drivers/nvme/host/core.c  |  1 +
 drivers/nvme/host/hwmon.c | 60 ++++++++++++++++++++++++++++++++++++++-
 drivers/nvme/host/nvme.h  |  1 +
 include/linux/hwmon.h     |  4 +++
 include/linux/nvme.h      |  7 ++++-
 6 files changed, 73 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index 2e2cd79d89eb..be756ed8b71c 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -486,6 +486,8 @@ static const char * const hwmon_temp_attr_templates[] = {
 	[hwmon_temp_reset_history] = "temp%d_reset_history",
 	[hwmon_temp_rated_min] = "temp%d_rated_min",
 	[hwmon_temp_rated_max] = "temp%d_rated_max",
+	[hwmon_temp_throttle_low] = "temp%d_throttle_low",
+	[hwmon_temp_throttle_high] = "temp%d_throttle_high",
 };
 
 static const char * const hwmon_in_attr_templates[] = {
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 2429b11eb9a8..7925f8d3bedf 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3142,6 +3142,7 @@ static int nvme_init_identify(struct nvme_ctrl *ctrl)
 	nvme_set_queue_limits(ctrl, ctrl->admin_q);
 	ctrl->sgls = le32_to_cpu(id->sgls);
 	ctrl->kas = le16_to_cpu(id->kas);
+	ctrl->hctma = le16_to_cpu(id->hctma);
 	ctrl->max_namespaces = le32_to_cpu(id->mnan);
 	ctrl->ctratt = le32_to_cpu(id->ctratt);
 
diff --git a/drivers/nvme/host/hwmon.c b/drivers/nvme/host/hwmon.c
index 0a586d712920..396d6304fde1 100644
--- a/drivers/nvme/host/hwmon.c
+++ b/drivers/nvme/host/hwmon.c
@@ -57,6 +57,50 @@ static int nvme_set_temp_thresh(struct nvme_ctrl *ctrl, int sensor, bool under,
 	return ret;
 }
 
+static int nvme_get_temp_throttle(struct nvme_ctrl *ctrl, int sensor, bool low,
+				  long *temp)
+{
+	struct nvme_feat_hctm hctm;
+	int ret;
+
+	ret = nvme_get_features(ctrl, NVME_FEAT_HCTM, 0, NULL, 0, (u32 *)&hctm);
+	if (ret > 0)
+		return -EIO;
+	if (ret < 0)
+		return ret;
+
+	*temp = kelvin_to_millicelsius(low ? hctm.tmt1 : hctm.tmt2);
+
+	return 0;
+}
+
+static int nvme_set_temp_throttle(struct nvme_ctrl *ctrl, int sensor, bool low,
+				  long temp)
+{
+	struct nvme_feat_hctm hctm;
+	int ret;
+
+	temp = millicelsius_to_kelvin(temp);
+
+	ret = nvme_get_features(ctrl, NVME_FEAT_HCTM, 0, NULL, 0, (u32 *)&hctm);
+	if (ret > 0)
+		return -EIO;
+	if (ret < 0)
+		return ret;
+
+	if (low)
+		hctm.tmt1 = temp;
+	else
+		hctm.tmt2 = temp;
+
+	ret = nvme_set_features(ctrl, NVME_FEAT_HCTM, *(unsigned int *)&hctm,
+				NULL, 0, NULL);
+	if (ret > 0)
+		return -EIO;
+
+	return ret;
+}
+
 static int nvme_hwmon_get_smart_log(struct nvme_hwmon_data *data)
 {
 	return nvme_get_log(data->ctrl, NVME_NSID_ALL, NVME_LOG_SMART, 0,
@@ -83,6 +127,10 @@ static int nvme_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
 	case hwmon_temp_crit:
 		*val = kelvin_to_millicelsius(data->ctrl->cctemp);
 		return 0;
+	case hwmon_temp_throttle_high:
+		return nvme_get_temp_throttle(data->ctrl, channel, false, val);
+	case hwmon_temp_throttle_low:
+		return nvme_get_temp_throttle(data->ctrl, channel, true, val);
 	default:
 		break;
 	}
@@ -122,6 +170,10 @@ static int nvme_hwmon_write(struct device *dev, enum hwmon_sensor_types type,
 		return nvme_set_temp_thresh(data->ctrl, channel, false, val);
 	case hwmon_temp_min:
 		return nvme_set_temp_thresh(data->ctrl, channel, true, val);
+	case hwmon_temp_throttle_high:
+		return nvme_set_temp_throttle(data->ctrl, channel, false, val);
+	case hwmon_temp_throttle_low:
+		return nvme_set_temp_throttle(data->ctrl, channel, true, val);
 	default:
 		break;
 	}
@@ -179,6 +231,11 @@ static umode_t nvme_hwmon_is_visible(const void *_data,
 		if (!channel || data->log.temp_sensor[channel - 1])
 			return 0444;
 		break;
+	case hwmon_temp_throttle_high:
+	case hwmon_temp_throttle_low:
+		if ((!channel && data->ctrl->hctma))
+			return 0644;
+		break;
 	default:
 		break;
 	}
@@ -189,7 +246,8 @@ static const struct hwmon_channel_info *nvme_hwmon_info[] = {
 	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
 	HWMON_CHANNEL_INFO(temp,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
-				HWMON_T_CRIT | HWMON_T_LABEL | HWMON_T_ALARM,
+				HWMON_T_CRIT | HWMON_T_LABEL | HWMON_T_ALARM |
+				HWMON_T_THROTTLE_HIGH | HWMON_T_THROTTLE_LOW,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
 				HWMON_T_LABEL,
 			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_MIN |
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index bdc0ff7ed9ab..9f53f96c1206 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -293,6 +293,7 @@ struct nvme_ctrl {
 	u32 vs;
 	u32 sgls;
 	u16 kas;
+	u16 hctma;
 	u8 npss;
 	u8 apsta;
 	u16 wctemp;
diff --git a/include/linux/hwmon.h b/include/linux/hwmon.h
index 14325f93c6b2..9377682c4b1a 100644
--- a/include/linux/hwmon.h
+++ b/include/linux/hwmon.h
@@ -87,6 +87,8 @@ enum hwmon_temp_attributes {
 	hwmon_temp_reset_history,
 	hwmon_temp_rated_min,
 	hwmon_temp_rated_max,
+	hwmon_temp_throttle_low,
+	hwmon_temp_throttle_high,
 };
 
 #define HWMON_T_ENABLE		BIT(hwmon_temp_enable)
@@ -116,6 +118,8 @@ enum hwmon_temp_attributes {
 #define HWMON_T_RESET_HISTORY	BIT(hwmon_temp_reset_history)
 #define HWMON_T_RATED_MIN	BIT(hwmon_temp_rated_min)
 #define HWMON_T_RATED_MAX	BIT(hwmon_temp_rated_max)
+#define HWMON_T_THROTTLE_LOW	BIT(hwmon_temp_throttle_low)
+#define HWMON_T_THROTTLE_HIGH	BIT(hwmon_temp_throttle_high)
 
 enum hwmon_in_attributes {
 	hwmon_in_enable,
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index ae53d74f3696..7f072fc2644d 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -184,7 +184,7 @@ enum {
  * Submission and Completion Queue Entry Sizes for the NVM command set.
  * (In bytes and specified as a power of two (2^n)).
  */
-#define NVME_ADM_SQES       6
+#define NVME_ADM_SQES		6
 #define NVME_NVM_IOSQES		6
 #define NVME_NVM_IOCQES		4
 
@@ -1079,6 +1079,11 @@ enum {
 	NVME_HOST_MEM_RETURN	= (1 << 1),
 };
 
+struct nvme_feat_hctm {
+	__u16 tmt2;
+	__u16 tmt1;
+};
+
 struct nvme_feat_host_behavior {
 	__u8 acre;
 	__u8 etdas;
-- 
2.34.1