The optional SMCWD_GET_TIMELEFT command can be used to detect if the watchdog has already been started. See the implementation in OP-TEE secure OS [1].
At probe time, check if the watchdog is already started and then call wdt_set_force_autostart(). This will keep U-Boot pinging the watchdog even when the property 'u-boot,noautostart' is present. Link: https://github.com/OP-TEE/optee_os/commit/a7f2d4bd8632 [1] Signed-off-by: Antonio Borneo <antonio.bor...@foss.st.com> --- drivers/watchdog/arm_smc_wdt.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/watchdog/arm_smc_wdt.c b/drivers/watchdog/arm_smc_wdt.c index 0ea44445700..f6854aa9ac9 100644 --- a/drivers/watchdog/arm_smc_wdt.c +++ b/drivers/watchdog/arm_smc_wdt.c @@ -46,6 +46,8 @@ static int smcwd_call(struct udevice *dev, enum smcwd_call call, return -ENODEV; if (res->a0 == PSCI_RET_INVALID_PARAMS) return -EINVAL; + if (res->a0 == PSCI_RET_DISABLED) + return -ENODATA; if (res->a0 != PSCI_RET_SUCCESS) return -EIO; @@ -99,6 +101,21 @@ static int smcwd_probe(struct udevice *dev) priv->min_timeout = res.a1; priv->max_timeout = res.a2; + /* If already started, then force u-boot to use it */ + err = smcwd_call(dev, SMCWD_GET_TIMELEFT, 0, NULL); + switch (err) { + case 0: + dev_dbg(dev, "Already started\n"); + wdt_set_force_autostart(dev); + break; + case -ENODATA: + dev_dbg(dev, "Not already started\n"); + break; + default: + /* Optional SMCWD_GET_TIMELEFT not implemented */ + break; + } + return 0; } -- 2.34.1
