[PATCH v3 2/3] fpga: dfl: fme: add thermal management support

From: Wu Hao
Date: Mon May 27 2019 - 02:30:20 EST

This patch adds support to thermal management private feature for DFL
FPGA Management Engine (FME). This private feature driver registers
a hwmon for thermal/temperature monitoring (hwmon temp1_input).
If hardware automatic throttling is supported by this hardware, then
driver also exposes sysfs interfaces under hwmon for thresholds
(temp1_max/ crit/ emergency), threshold alarms (temp1_max_alarm/
temp1_crit_alarm) and throttling policy (temp1_max_policy).

Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx>
Signed-off-by: Russ Weight <russell.h.weight@xxxxxxxxx>
Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
----
v2: create a dfl_fme_thermal hwmon to expose thermal information.
move all sysfs interfaces under hwmon
tempareture --> hwmon temp1_input
threshold1 --> hwmon temp1_alarm
threshold2 --> hwmon temp1_crit
trip_threshold --> hwmon temp1_emergency
threshold1_status --> hwmon temp1_alarm_status
threshold2_status --> hwmon temp1_crit_status
threshold1_policy --> hwmon temp1_alarm_policy
v3: rename some hwmon sysfs interfaces to follow hwmon ABI.
temp1_alarm --> temp1_max
temp1_alarm_status --> temp1_max_alarm
temp1_crit_status --> temp1_crit_alarm
temp1_alarm_policy --> temp1_max_policy
update sysfs doc for above sysfs interface changes.
replace scnprintf with sprintf in sysfs interface.
---
Documentation/ABI/testing/sysfs-platform-dfl-fme | 64 ++++++++
drivers/fpga/Kconfig | 2 +-
drivers/fpga/dfl-fme-main.c | 196 +++++++++++++++++++++++
3 files changed, 261 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-platform-dfl-fme b/Documentation/ABI/testing/sysfs-platform-dfl-fme
index 63a02cb..0a0b7b9 100644
--- a/Documentation/ABI/testing/sysfs-platform-dfl-fme
+++ b/Documentation/ABI/testing/sysfs-platform-dfl-fme
@@ -212,3 +212,67 @@ Description: Read-Write. Read this file for current status of port level
fabric counters. Write "1" to enable port level fabric counters.
Once port level fabric counters are enabled, device level fabric
counters will be disabled automatically.
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/name
+Date: May 2019
+KernelVersion: 5.3
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-Only. Read this file to get the name of hwmon device, it
+ supports values:
+ 'dfl_fme_thermal' - thermal hwmon device name
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/temp1_input
+Date: May 2019
+KernelVersion: 5.3
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-Only. It returns FPGA device temperature in millidegrees
+ Celsius.
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/temp1_max
+Date: May 2019
+KernelVersion: 5.3
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-Only. It returns hardware threshold1 temperature in
+ millidegrees Celsius. If temperature rises at or above this
+ threshold, hardware starts 50% or 90% throttling (see
+ 'temp1_max_policy').
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/temp1_crit
+Date: May 2019
+KernelVersion: 5.3
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-Only. It returns hardware threshold2 temperature in
+ millidegrees Celsius. If temperature rises at or above this
+ threshold, hardware starts 100% throttling.
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/temp1_emergency
+Date: May 2019
+KernelVersion: 5.3
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-Only. It returns hardware trip threshold temperature in
+ millidegrees Celsius. If temperature rises at or above this
+ threshold, a fatal event will be triggered to board management
+ controller (BMC) to shutdown FPGA.
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/temp1_max_alarm
+Date: May 2019
+KernelVersion: 5.3
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-only. It returns 1 if temperature is currently at or above
+ hardware threshold1 (see 'temp1_max'), otherwise 0.
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/temp1_crit_alarm
+Date: May 2019
+KernelVersion: 5.3
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-only. It returns 1 if temperature is currently at or above
+ hardware threshold2 (see 'temp1_crit'), otherwise 0.
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/temp1_max_policy
+Date: May 2019
+KernelVersion: 5.3
+Contact: Wu Hao <hao.wu@xxxxxxxxx>
+Description: Read-Only. Read this file to get the policy of hardware threshold1
+ (see 'temp1_max'). It only supports two values (policies):
+ 0 - AP2 state (90% throttling)
+ 1 - AP1 state (50% throttling)
diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
index d892f3e..36551d6 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -154,7 +154,7 @@ config FPGA_DFL

config FPGA_DFL_FME
tristate "FPGA DFL FME Driver"
- depends on FPGA_DFL
+ depends on FPGA_DFL && HWMON
help
The FPGA Management Engine (FME) is a feature device implemented
under Device Feature List (DFL) framework. Select this option to
diff --git a/drivers/fpga/dfl-fme-main.c b/drivers/fpga/dfl-fme-main.c
index 4a5b25d..91152d5 100644
--- a/drivers/fpga/dfl-fme-main.c
+++ b/drivers/fpga/dfl-fme-main.c
@@ -14,6 +14,8 @@
* Henry Mitchel <henry.mitchel@xxxxxxxxx>
*/

+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/uaccess.h>
@@ -217,6 +219,196 @@ static long fme_hdr_ioctl(struct platform_device *pdev,
.ioctl = fme_hdr_ioctl,
};

+#define FME_THERM_THRESHOLD 0x8
+#define TEMP_THRESHOLD1 GENMASK_ULL(6, 0)
+#define TEMP_THRESHOLD1_EN BIT_ULL(7)
+#define TEMP_THRESHOLD2 GENMASK_ULL(14, 8)
+#define TEMP_THRESHOLD2_EN BIT_ULL(15)
+#define TRIP_THRESHOLD GENMASK_ULL(30, 24)
+#define TEMP_THRESHOLD1_STATUS BIT_ULL(32) /* threshold1 reached */
+#define TEMP_THRESHOLD2_STATUS BIT_ULL(33) /* threshold2 reached */
+/* threshold1 policy: 0 - AP2 (90% throttle) / 1 - AP1 (50% throttle) */
+#define TEMP_THRESHOLD1_POLICY BIT_ULL(44)
+
+#define FME_THERM_RDSENSOR_FMT1 0x10
+#define FPGA_TEMPERATURE GENMASK_ULL(6, 0)
+
+#define FME_THERM_CAP 0x20
+#define THERM_NO_THROTTLE BIT_ULL(0)
+
+#define MD_PRE_DEG
+
+static bool fme_thermal_throttle_support(void __iomem *base)
+{
+ u64 v = readq(base + FME_THERM_CAP);
+
+ return FIELD_GET(THERM_NO_THROTTLE, v) ? false : true;
+}
+
+static umode_t thermal_hwmon_attrs_visible(const void *drvdata,
+ enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ const struct dfl_feature *feature = drvdata;
+
+ /* temperature is always supported, and check hardware cap for others */
+ if (attr == hwmon_temp_input)
+ return 0444;
+
+ return fme_thermal_throttle_support(feature->ioaddr) ? 0444 : 0;
+}
+
+static int thermal_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct dfl_feature *feature = dev_get_drvdata(dev);
+ u64 v;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ v = readq(feature->ioaddr + FME_THERM_RDSENSOR_FMT1);
+ *val = (long)(FIELD_GET(FPGA_TEMPERATURE, v) * 1000);
+ break;
+ case hwmon_temp_max:
+ v = readq(feature->ioaddr + FME_THERM_THRESHOLD);
+ *val = (long)(FIELD_GET(TEMP_THRESHOLD1, v) * 1000);
+ break;
+ case hwmon_temp_crit:
+ v = readq(feature->ioaddr + FME_THERM_THRESHOLD);
+ *val = (long)(FIELD_GET(TEMP_THRESHOLD2, v) * 1000);
+ break;
+ case hwmon_temp_emergency:
+ v = readq(feature->ioaddr + FME_THERM_THRESHOLD);
+ *val = (long)(FIELD_GET(TRIP_THRESHOLD, v) * 1000);
+ break;
+ case hwmon_temp_max_alarm:
+ v = readq(feature->ioaddr + FME_THERM_THRESHOLD);
+ *val = (long)FIELD_GET(TEMP_THRESHOLD1_STATUS, v);
+ break;
+ case hwmon_temp_crit_alarm:
+ v = readq(feature->ioaddr + FME_THERM_THRESHOLD);
+ *val = (long)FIELD_GET(TEMP_THRESHOLD2_STATUS, v);
+ break;
+ default:
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static const struct hwmon_ops thermal_hwmon_ops = {
+ .is_visible = thermal_hwmon_attrs_visible,
+ .read = thermal_hwmon_read,
+};
+
+static const u32 thermal_hwmon_temp_config[] = {
+ HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT | HWMON_T_EMERGENCY |
+ HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM,
+ 0
+};
+
+static const struct hwmon_channel_info hwmon_temp_info = {
+ .type = hwmon_temp,
+ .config = thermal_hwmon_temp_config,
+};
+
+static const struct hwmon_channel_info *thermal_hwmon_info[] = {
+ &hwmon_temp_info,
+ NULL
+};
+
+static const struct hwmon_chip_info thermal_hwmon_chip_info = {
+ .ops = &thermal_hwmon_ops,
+ .info = thermal_hwmon_info,
+};
+
+static ssize_t temp1_max_policy_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct dfl_feature *feature = dev_get_drvdata(dev);
+ u64 v;
+
+ v = readq(feature->ioaddr + FME_THERM_THRESHOLD);
+
+ return sprintf(buf, "%u\n",
+ (unsigned int)FIELD_GET(TEMP_THRESHOLD1_POLICY, v));
+}
+
+static DEVICE_ATTR_RO(temp1_max_policy);
+
+static struct attribute *thermal_extra_attrs[] = {
+ &dev_attr_temp1_max_policy.attr,
+ NULL,
+};
+
+static umode_t thermal_extra_attrs_visible(struct kobject *kobj,
+ struct attribute *attr, int index)
+{
+ struct device *dev = kobj_to_dev(kobj);
+ struct dfl_feature *feature = dev_get_drvdata(dev);
+
+ return fme_thermal_throttle_support(feature->ioaddr) ? attr->mode : 0;
+}
+
+static const struct attribute_group thermal_extra_group = {
+ .attrs = thermal_extra_attrs,
+ .is_visible = thermal_extra_attrs_visible,
+};
+__ATTRIBUTE_GROUPS(thermal_extra);
+
+static int fme_thermal_mgmt_init(struct platform_device *pdev,
+ struct dfl_feature *feature)
+{
+ struct device *hwmon;
+
+ dev_dbg(&pdev->dev, "FME Thermal Management Init.\n");
+
+ /*
+ * create hwmon to allow userspace monitoring temperature and other
+ * threshold information.
+ *
+ * temp1_input -> FPGA device temperature
+ * temp1_max -> hardware threshold 1 -> 50% or 90% throttling
+ * temp1_crit -> hardware threshold 2 -> 100% throttling
+ * temp1_emergency -> hardware trip_threshold to shutdown FPGA
+ * temp1_max_alarm -> hardware threshold 1 alarm
+ * temp1_crit_alarm -> hardware threshold 2 alarm
+ *
+ * create device specific sysfs interfaces, e.g. read temp1_max_policy
+ * to understand the actual hardware throttling action (50% vs 90%).
+ *
+ * If hardware doesn't support automatic throttling per thresholds,
+ * then all above sysfs interfaces are not visible except temp1_input
+ * for temperature.
+ */
+ hwmon = devm_hwmon_device_register_with_info(&pdev->dev,
+ "dfl_fme_thermal", feature,
+ &thermal_hwmon_chip_info,
+ thermal_extra_groups);
+ if (IS_ERR(hwmon)) {
+ dev_err(&pdev->dev, "Fail to register thermal hwmon\n");
+ return PTR_ERR(hwmon);
+ }
+
+ return 0;
+}
+
+static void fme_thermal_mgmt_uinit(struct platform_device *pdev,
+ struct dfl_feature *feature)
+{
+ dev_dbg(&pdev->dev, "FME Thermal Management UInit.\n");
+}
+
+static const struct dfl_feature_id fme_thermal_mgmt_id_table[] = {
+ {.id = FME_FEATURE_ID_THERMAL_MGMT,},
+ {0,}
+};
+
+static const struct dfl_feature_ops fme_thermal_mgmt_ops = {
+ .init = fme_thermal_mgmt_init,
+ .uinit = fme_thermal_mgmt_uinit,
+};
+
static struct dfl_feature_driver fme_feature_drvs[] = {
{
.id_table = fme_hdr_id_table,
@@ -235,6 +427,10 @@ static long fme_hdr_ioctl(struct platform_device *pdev,
.ops = &fme_perf_ops,
},
{
+ .id_table = fme_thermal_mgmt_id_table,
+ .ops = &fme_thermal_mgmt_ops,
+ },
+ {
.ops = NULL,
},
};
--
1.8.3.1