AMD-Xilinx MPSoC的器件里，提供了內(nèi)置的Watchdog。在Vivado里選擇Watchdog，并在設(shè)備樹里使能Watchdog，還不能在Linux中正常使用。

pmu-firmware修改

如果要在Linux中使用Watchdog，需要在project-spec/meta-user/recipes-bsp/embeddedsw/pmu-firmware_%.bbappend中添加如下內(nèi)容：

2021.1以前的版本：

#pmu-firmware_%.bbappendcontent
YAML_COMPILER_FLAGS_append="-DENABLE_EM-DENABLE_SCHEDULER"

2022.1及以后的版本：

#pmu-firmware_%.bbappendcontent
YAML_COMPILER_FLAGS:append="-DENABLE_EM-DENABLE_SCHEDULER"

Devicetree

檢查Devicetree，確保其中的status為"okay"， 也有屬性reset-on-timeout。

watchdog@fd4d0000{
clocks=<0x03?0x4b>;
compatible="cdns,wdt-r1p2";
interrupt-parent=<0x04>;
interrupts=<0x00?0x71?0x01>;
phandle=<0x76>;
reg=<0x00?0xfd4d0000?0x00?0x1000>;
reset-on-timeout;
status="okay";
timeout-sec=<0x3c>;
};

watchdog@ff150000{
clocks=<0x03?0x70>;
compatible="cdns,wdt-r1p2";
interrupt-parent=<0x04>;
interrupts=<0x00?0x34?0x01>;
phandle=<0x77>;
reg=<0x00?0xff150000?0x00?0x1000>;
status="okay";
timeout-sec=<0x0a>;
};

啟動(dòng)信息

使用命令“dmesg”檢查啟動(dòng)信息，有如下信息。

#dmesg-c|grepwatchdog
[539.845269]watchdog:watchdog0:watchdogdidnotstop!
[691.897271]watchdog:watchdog1:watchdogdidnotstop!
[702.136679]cdns-wdtff150000.watchdog:Watchdogtimedout.Internalresetnotenabled

通過設(shè)備節(jié)點(diǎn)控制Watchdog

通過設(shè)備節(jié)點(diǎn)“/dev/watchdog0”可以控制Watchdog。

執(zhí)行命令“echo s > /dev/watchdog0”，能啟動(dòng)Watchdog，但是沒有清狗操作。時(shí)間久了，單板會(huì)自動(dòng)重啟動(dòng)。

#echos>/dev/watchdog0
[154.773229]watchdog:watchdog0:watchdogdidnotstop!

#dmesg-c|tail-n20
[154.773229]watchdog:watchdog0:watchdogdidnotstop!

#dmesg-c|tail-n20

#cat/proc/uptime
193.70738.72
#XilinxZynqMPFirstStageBootLoader
Release2022.1Apr112022-09:29:50
NOTICE:BL31:v2.6(release):v1.1-9207-g67ca59c67

執(zhí)行命令“echo 'V' > /dev/watchdog0”，能停止Watchdog，單板再也不會(huì)自動(dòng)重啟動(dòng)。

#echos>/dev/watchdog0&&cat/proc/uptime

[1850.817370]watchdog:watchdog0:watchdogdidnotstop!
1850.697364.03

#sleep1

#echo'V'>/dev/watchdog0&&cat/proc/uptime
1852.407370.84

#cat/proc/uptime
1887.117509.61
#cat/proc/uptime
1971.677847.72
#cat/proc/uptime
2159.968600.54

通過應(yīng)用程序控制Watchdog

Linux也提供了應(yīng)用程序watchdog控制Watchdog，啟動(dòng)Watchdog并清狗。下面是啟動(dòng)Watchdog的示例。如果由于特殊原因，應(yīng)用程序watchdog異常退出，就會(huì)導(dǎo)致單板復(fù)位。下面的例子中，使用kill命令殺死了應(yīng)用程序watchdog的進(jìn)程，導(dǎo)致單板復(fù)位。

#watchdog-T10-t3/dev/watchdog0
#ps-A|grepwatchdog
95?00:00:00watchdogd
1159?00:00:00watchdog

#cat/proc/uptime
1880.187481.78

#cat/proc/uptime
1895.657543.65

#kill-91159
#[1904.549498]watchdog:watchdog0:watchdogdidnotstop!

#XilinxZynqMPFirstStageBootLoader
Release2022.1Apr112022-09:29:50
NOTICE:BL31:v2.6(release):v1.1-9207-g67ca59c67

通過系統(tǒng)腳本啟動(dòng)Watchdog并清狗

Linux也提供系統(tǒng)腳本/etc/init.d/watchdog-init控制Watchdog。
系統(tǒng)腳本/etc/init.d/watchdog-init也使用了應(yīng)用程序控制Watchdog。如果使用kill命令殺死應(yīng)用程序watchdog的進(jìn)程，也會(huì)導(dǎo)致單板復(fù)位。

#/etc/init.d/watchdog-initstart&&cat/proc/uptime
Sethealthybit
/etc/init.d/watchdog-init:line92:/sys/firmware/zynqmp/health_status:Permissiondenied
StartingWDT
2199.548758.78

#ps-A|grepwatchdog
95?00:00:00watchdogd
1110?00:00:00watchdog

#sleep5

#/etc/init.d/watchdog-initstop&&cat/proc/uptime
StopingWDT
2204.628779.08

#cat/proc/uptime
2299.329157.71

#cat/proc/uptime
2628.2210472.73

參考文檔

Cadence WDT Driver

測(cè)試單板

KV260 2022.1 BSP


審核編輯：湯梓紅