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From:   Ronak Jain <ronak.jain@xilinx.com>
To:     <michal.simek@xilinx.com>, <linux-kernel@vger.kernel.org>
CC:     <gregkh@linuxfoundation.org>, <rajan.vaja@xilinx.com>,
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        <arnd@arndb.de>, <lakshmi.sai.krishna.potthuri@xilinx.com>,
        Ronak Jain <ronak.jain@xilinx.com>
Subject: [PATCH 2/3] firmware: zynqmp: Add sysfs entry for runtime features
Date:   Tue, 17 Aug 2021 06:05:52 -0700
Message-ID: <20210817130553.20219-3-ronak.jain@xilinx.com>
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Create sysfs entry for runtime feature configuration. Here the support
 is added for an over temperature and external watchdog feature.

The below listed path is used for runtime features configuration:
/sys/devices/platform/firmware\:zynqmp-firmware/*

Here there are two files to configure features at runtime.
1. feature_config_id
2. feature_config_value

In order to configure an over temperature or external watchdog
 features, first the user need to select the valid config id and then
 the user can configure the value for selected feature config id.

Signed-off-by: Ronak Jain <ronak.jain@xilinx.com>
---
 .../ABI/stable/sysfs-driver-firmware-zynqmp   | 84 +++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp b/Docume=
ntation/ABI/stable/sysfs-driver-firmware-zynqmp
index f5724bb5b462..2fde354715a5 100644
--- a/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
+++ b/Documentation/ABI/stable/sysfs-driver-firmware-zynqmp
@@ -113,3 +113,87 @@ Description:
                    # echo 0 > /sys/devices/platform/firmware\:zynqmp-firmw=
are/health_status

 Users:         Xilinx
+
+What:          /sys/devices/platform/firmware\:zynqmp-firmware/feature_con=
fig_*
+Date:          Aug 2021
+KernelVersion: 5.14
+Contact:       "Ronak Jain" <ronak.jain@xilinx.com>
+Description:
+               This sysfs interface allows to configure features at runtim=
e.
+               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 completel=
y
+               different than the /dev/watchdog as the external watchdog i=
s
+               running on the firmware and it is used to monitor the healt=
h
+               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 u=
ser
+               can enable features by querying appropriate config id of th=
e
+               features.
+
+               The default limit for the over temperature is 90 Degree Cel=
sius.
+               The default timer interval for the external watchdog is 570=
ms.
+
+               The supported config ids are for the feature configuration =
is,
+               1. PM_FEATURE_OVERTEMP_STATUS =3D 1, the user can enable or
+               disable the over temperature feature.
+               2. PM_FEATURE_OVERTEMP_VALUE =3D 2, the user can configure =
the
+               over temperature limit in Degree Celsius.
+               3. PM_FEATURE_EXTWDT_STATUS =3D 3, the user can enable or d=
isable
+               the external watchdog feature.
+               4. PM_FEATURE_EXTWDT_VALUE =3D 4, the user can configure th=
e
+               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 no=
t
+               # cat /sys/devices/platform/firmware\:zynqmp-firmware/featu=
re_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 n=
ot
+               # cat /sys/devices/platform/firmware\:zynqmp-firmware/featu=
re_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 n=
ot
+               # cat /sys/devices/platform/firmware\:zynqmp-firmware/featu=
re_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 n=
ot
+               # cat /sys/devices/platform/firmware\:zynqmp-firmware/featu=
re_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/featu=
re_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-firmwar=
e/feature_config_value
+
+               Check whether the external watchdog timer interval is confi=
gured or not
+               # cat /sys/devices/platform/firmware\:zynqmp-firmware/featu=
re_config_value
+               The expected result is 500.
+
+Users:         Xilinx
--
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