[PATCH v7 2/3] fpga: dfl: fme: add thermal management support

Wu Hao
2019-10-14T06:01:09Z

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@intel.com>
Signed-off-by: Russ Weight <russell.h.weight@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Moritz Fischer <mdf@kernel.org>
---
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.
v4: use HWMON_CHANNEL_INFO.
rebase, and update date in sysfs doc.
v5: no change.
v6: rebased, and clean up (remove empty uinit function).
update date in sysfs doc.
v7: update kernel version and date in sysfs doc.
---
Documentation/ABI/testing/sysfs-platform-dfl-fme | 64 ++++++++
drivers/fpga/Kconfig | 2 +-
drivers/fpga/dfl-fme-main.c | 178 +++++++++++++++++++++++
3 files changed, 243 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-platform-dfl-fme b/Documentation/ABI/testing/sysfs-platform-dfl-fme
index 72634d3..8eb6d03 100644
--- a/Documentation/ABI/testing/sysfs-platform-dfl-fme
+++ b/Documentation/ABI/testing/sysfs-platform-dfl-fme
@@ -106,3 +106,67 @@ KernelVersion: 5.4
Contact: Wu Hao <hao.wu@intel.com>
Description: Read-only. Read this file to get the second error detected by
hardware.
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/name
+Date: October 2019
+KernelVersion: 5.5
+Contact: Wu Hao <hao.wu@intel.com>
+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: October 2019
+KernelVersion: 5.5
+Contact: Wu Hao <hao.wu@intel.com>
+Description: Read-Only. It returns FPGA device temperature in millidegrees
+ Celsius.
+
+What: /sys/bus/platform/devices/dfl-fme.0/hwmon/hwmonX/temp1_max
+Date: October 2019
+KernelVersion: 5.5
+Contact: Wu Hao <hao.wu@intel.com>
+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: October 2019
+KernelVersion: 5.5
+Contact: Wu Hao <hao.wu@intel.com>
+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: October 2019
+KernelVersion: 5.5
+Contact: Wu Hao <hao.wu@intel.com>
+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: October 2019
+KernelVersion: 5.5
+Contact: Wu Hao <hao.wu@intel.com>
+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: October 2019
+KernelVersion: 5.5
+Contact: Wu Hao <hao.wu@intel.com>
+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: October 2019
+KernelVersion: 5.5
+Contact: Wu Hao <hao.wu@intel.com>
+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 73c779e..72380e1 100644
--- a/drivers/fpga/Kconfig
+++ b/drivers/fpga/Kconfig
@@ -156,7 +156,7 @@ 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 4d78e18..752d71c 100644
--- a/drivers/fpga/dfl-fme-main.c
+++ b/drivers/fpga/dfl-fme-main.c
@@ -14,6 +14,8 @@
* Henry Mitchel <henry.mitchel@intel.com>
*/

+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/uaccess.h>
@@ -181,6 +183,178 @@ 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 struct hwmon_channel_info *thermal_hwmon_info[] = {
+ HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_EMERGENCY |
+ HWMON_T_MAX | HWMON_T_MAX_ALARM |
+ HWMON_T_CRIT | HWMON_T_CRIT_ALARM),
+ 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;
+
+ /*
+ * 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 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,
+};
+
static struct dfl_feature_driver fme_feature_drvs[] = {
{
.id_table = fme_hdr_id_table,
@@ -195,6 +369,10 @@ static long fme_hdr_ioctl(struct platform_device *pdev,
.ops = &fme_global_err_ops,
},
{
+ .id_table = fme_thermal_mgmt_id_table,
+ .ops = &fme_thermal_mgmt_ops,
+ },
+ {
.ops = NULL,
},
};
--
1.8.3.1