firmware: zynqmp: Add documentation for runtime feature config

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.

Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Ronak Jain <ronak.jain@xilinx.com>
Link: https://lore.kernel.org/r/20220209082709.32378-3-ronak.jain@xilinx.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
index f5724bb..c3fec3c 100644 (file)
--- 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@xilinx.com>
+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@xilinx.com>
+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