Re: [PATCH v5 2/3] firmware: zynqmp: Add documentation for runtime feature config

From: Michal Simek
Date: Wed Feb 09 2022 - 04:35:10 EST




On 2/9/22 09:27, Ronak Jain wrote:
Add documentation for sysfs entries like feature_config_id and
feature_config_value for runtime feature configuration. The support is
added for an over temperature and external watchdog features.

Signed-off-by: Ronak Jain <ronak.jain@xxxxxxxxxx>
---
Changes in v5:
- Update kernel version for sysfs documentation

Changes in v4:
- Add separate sysfs entries for runtime feature config
- Update commit message

Changes in v3:
- None

Changes in v2:
- Update commit message
---
.../ABI/stable/sysfs-driver-firmware-zynqmp | 141 ++++++++++++++++++
1 file changed, 141 insertions(+)

diff --git a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
index f5724bb5b462..c3fec3c835af 100644
--- a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
+++ b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
@@ -113,3 +113,144 @@ Description:
# echo 0 > /sys/devices/platform/firmware\:zynqmp-firmware/health_status
Users: Xilinx
+
+What: /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+Date: Feb 2022
+KernelVersion: 5.18
+Contact: "Ronak Jain" <ronak.jain@xxxxxxxxxx>
+Description:
+ This sysfs interface allows user to configure features at
+ runtime. The user can enable or disable features running at
+ firmware as well as the user can configure the parameters of
+ the features at runtime. The supported features are over
+ temperature and external watchdog. Here, the external watchdog
+ is completely different than the /dev/watchdog as the external
+ watchdog is running on the firmware and it is used to monitor
+ the health of firmware not APU(Linux). Also, the external
+ watchdog is interfaced outside of the zynqmp soc.
+
+ The supported config ids are for the feature configuration is,
+ 1. PM_FEATURE_OVERTEMP_STATUS = 1, the user can enable or
+ disable the over temperature feature.
+ 2. PM_FEATURE_OVERTEMP_VALUE = 2, the user can configure the
+ over temperature limit in Degree Celsius.
+ 3. PM_FEATURE_EXTWDT_STATUS = 3, the user can enable or disable
+ the external watchdog feature.
+ 4. PM_FEATURE_EXTWDT_VALUE = 4, the user can configure the
+ external watchdog feature.
+
+ Usage:
+
+ Select over temperature config ID to enable/disable feature
+ # echo 1 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+
+ Check over temperature config ID is selected or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ The expected result is 1.
+
+ Select over temperature config ID to configure OT limit
+ # echo 2 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+
+ Check over temperature config ID is selected or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ The expected result is 2.
+
+ Select external watchdog config ID to enable/disable feature
+ # echo 3 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+
+ Check external watchdog config ID is selected or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ The expected result is 3.
+
+ Select external watchdog config ID to configure time interval
+ # echo 4 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+
+ Check external watchdog config ID is selected or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ The expected result is 4.
+
+Users: Xilinx
+
+What: /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+Date: Feb 2022
+KernelVersion: 5.18
+Contact: "Ronak Jain" <ronak.jain@xxxxxxxxxx>
+Description:
+ This sysfs interface allows to configure features at runtime.
+ The user can enable or disable features running at firmware.
+ Also, the user can configure the parameters of the features
+ at runtime. The supported features are over temperature and
+ external watchdog. Here, the external watchdog is completely
+ different than the /dev/watchdog as the external watchdog is
+ running on the firmware and it is used to monitor the health
+ of firmware not APU(Linux). Also, the external watchdog is
+ interfaced outside of the zynqmp soc.
+
+ By default the features are disabled in the firmware. The user
+ can enable features by querying appropriate config id of the
+ features.
+
+ The default limit for the over temperature is 90 Degree Celsius.
+ The default timer interval for the external watchdog is 570ms.
+
+ The supported config ids are for the feature configuration is,
+ 1. PM_FEATURE_OVERTEMP_STATUS = 1, the user can enable or
+ disable the over temperature feature.
+ 2. PM_FEATURE_OVERTEMP_VALUE = 2, the user can configure the
+ over temperature limit in Degree Celsius.
+ 3. PM_FEATURE_EXTWDT_STATUS = 3, the user can enable or disable
+ the external watchdog feature.
+ 4. PM_FEATURE_EXTWDT_VALUE = 4, the user can configure the
+ external watchdog feature.
+
+ Usage:
+
+ Enable over temperature feature
+ # echo 1 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ # echo 1 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+
+ Check whether the over temperature feature is enabled or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+ The expected result is 1.
+
+ Disable over temperature feature
+ # echo 1 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ # echo 0 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+
+ Check whether the over temperature feature is disabled or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+ The expected result is 0.
+
+ Configure over temperature limit to 50 Degree Celsius
+ # echo 2 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ # echo 50 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+
+ Check whether the over temperature limit is configured or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+ The expected result is 50.
+
+ Enable external watchdog feature
+ # echo 3 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ # echo 1 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+
+ Check whether the external watchdog feature is enabled or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+ The expected result is 1.
+
+ Disable external watchdog feature
+ # echo 3 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ # echo 0 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+
+ Check whether the external watchdog feature is disabled or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+ The expected result is 0.
+
+ Configure external watchdog timer interval to 500ms
+ # echo 4 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_id
+ # echo 500 > /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+
+ Check whether the external watchdog timer interval is configured or not
+ # cat /sys/devices/platform/firmware\:zynqmp-firmware/feature_config_value
+ The expected result is 500.
+
+Users: Xilinx


Acked-by: Michal Simek <michal.simek@xxxxxxxxxx>

Thanks,
Michal