On 5/12/23 15:43, Patrick DELAUNAY wrote:
Hi,
Hi,
+ /* Ping IWDG2 and ACK pretimer IRQ */ + if (iwdg2_wake) { + writel(IWDG_KR_RELOAD_KEY, STM32_IWDG2_BASE + IWDG_KR); + writel(IWDG_EWCR_EWIC, STM32_IWDG2_BASE + IWDG_EWCR); + } + } writel(0x3, STM32_RCC_BASE + RCC_MP_SREQCLRR); ddr_sw_self_refresh_exit();
Reviewed-by: Patrice Chotard patrice.chotard@foss.st.com
I feel like maybe I need to whack the IWDG also BEFORE entering suspend, expect a V2 shortly.
Do you think this IWDG approach is fine to keep the system from rebooting in suspend ? Or do you see any better option for the MP1 ?
I think it is fine if you want to have watchdog running in STANDBY even this patch force a wakeup.
but if IWDG 1 or 2 should be not running in STANDBY (but also for STOP) for your product,
Why ?
I want the watchdog to monitor that the platform is still OK, even in suspend. Also, as far as I can tell, once the IWDG is started, it cannot be stopped, right ?
it can be managed directly by the hardware with OTP, to freeze watchdog.
=> it is a decision for each product of the desired behavior of the IWDG in low power mode.
See Ref Manual: 48.3 IWDG implementation
Table 332. STM32MP157x IWDG features
Option bytes to control the activity in Standby mode (6)
- Controlled via option bytes OTP_IWDG1_FZ_STANDBY and
OTP_IWDG2_FZ_STANDBY, respectively, for IWDG1 and IWDG2.
and in Table17 => OTP 18 = HW2 bit 5 to 8
I saw the OTP fuses, but I don't want to blow them. Or is that really the suggestion ST would provide for suspend/resume, blow the fuses ?
(I wonder, why isn't the logic of those fuses inverted then, i.e. by default stop the watchdog in suspend AND blow fuses to keep it running in suspend?)