Rockchip RK3588 打开硬件watchdog

kernel开启watchdog模块

RK3588 硬件watchdog默认 没有开启，如果需要打开watchdog功能，可以在dts中打开wdt节点即可：

--- a/arch/arm64/boot/dts/rockchip/rk3588-evb1-lp4.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3588-evb1-lp4.dtsi
@@ -735,3 +735,7 @@
 &usbhost_dwc3_0 {
        status = "disabled";
 };
+
+&wdt {
+       status = "okay";
+};
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开启后用如下命令可以测试watchdog是否生效

输入如下命令后系统不再喂狗，watchdog会自动重启。

echo A > /dev/watchdog , 这里写入的是除大写V以外的任意字符。
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Android层启动watchdogd进程

Android层的watchdog进程默认也没有启动，按如下修改可以启动watchdogd进程，当系统卡住时会停止喂狗来触发系统重启

@sys2_206:~/3_Android12_29_debug/device/rockchip/common$ git diff
diff --git a/rootdir/init.rockchip.rc b/rootdir/init.rockchip.rc
index 0ce612a8..b5e05069 100755
--- a/rootdir/init.rockchip.rc
+++ b/rootdir/init.rockchip.rc
@@ -27,9 +27,9 @@ service charger /system/bin/charger
     file /proc/last_kmsg r
 
 # Set watchdog timer to 30 seconds and pet it every 10 seconds to get a 20 second margin
-service watchdogd /sbin/watchdogd 10 20
+service watchdogd system/bin/watchdogd 10 20    //这里10 20表示喂狗的超时时间是10s+20s=30s
     class core
-    disabled
+#    disabled
     seclabel u:r:watchdogd:s0
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android上面watchdogd的代码实现，可以参考这个代码在自己的应用中使用watchdog

@sys2_206:~/3_Android12_29_debug$ vim system/core/watchdogd/watchdogd.cpp 
/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/*
 * Copyright (C) 2012 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <errno.h>
#include <fcntl.h>
#include <linux/watchdog.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <android-base/logging.h>

#define DEV_NAME "/dev/watchdog"

int main(int argc, char** argv) {
    android::base::InitLogging(argv, &android::base::KernelLogger);

    int interval = 10;
    if (argc >= 2) interval = atoi(argv[1]);

    int margin = 10;
    if (argc >= 3) margin = atoi(argv[2]);

    LOG(INFO) << "watchdogd started (interval " << interval << ", margin " << margin << ")!";

    int fd = open(DEV_NAME, O_RDWR | O_CLOEXEC);
    if (fd == -1) {
        PLOG(ERROR) << "Failed to open " << DEV_NAME;
        return 1;
    }

    int timeout = interval + margin;
    int ret = ioctl(fd, WDIOC_SETTIMEOUT, &timeout);
    if (ret) {
        PLOG(ERROR) << "Failed to set timeout to " << timeout;
        ret = ioctl(fd, WDIOC_GETTIMEOUT, &timeout);
        if (ret) {
            PLOG(ERROR) << "Failed to get timeout";
        } else {
            if (timeout > margin) {
                interval = timeout - margin;
            } else {
                interval = 1;
            }
            LOG(WARNING) << "Adjusted interval to timeout returned by driver: "
                         << "timeout " << timeout << ", interval " << interval << ", margin "
                         << margin;
        }
    }

    while (true) {
        write(fd, "", 1);
        sleep(interval);
    }
}
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测试watchdog是否生效

1. 关掉系统panic重启

echo 0 > /sys/module/kernel/parameters/panic
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2. 人为制作一个panic使系统卡住

echo c > proc/sysrq-trigger
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3. 等待30s看系统是否重启，如果重启则表示watchdog正常工作了