[nrf fromtree] soc: nordic: common: vpr: Option to select the default sleep mode

VPR after boot has default sleep mode set to WAIT which is the most
power hungry sleep mode. Typically, user expects to see low current
when system enters system-on-idle state. Set sleep mode that is
more suitable: DEEPSLEEP by default for nRF54H20 PPR which allows to
reach <5 uA idle current and has almost the same wake up time as WAIT,
HIBERNATE for other VPRs on non-NRF54H20. It allows to get <5 uA
currents in system-on-idle.

Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
(cherry picked from commit f28e027)

Author: nordic-krch

soc/nordic/common/vpr/Kconfig

@@ -17,3 +17,33 @@ config RISCV_CORE_NORDIC_VPR
 	imply XIP
 	help
 	  Enable support for the RISC-V Nordic VPR core.
+
+choice NORDIC_VPR_SLEEP_MODE
+	prompt "Default sleep mode"
+	depends on RISCV_CORE_NORDIC_VPR
+	default NORDIC_VPR_SLEEP if SOC_NRF54H20_CPUFLPR
+	default NORDIC_VPR_DEEPSLEEP if SOC_NRF54H20_CPUPPR
+	default NORDIC_VPR_HIBERNATE
+
+config NORDIC_VPR_SLEEP
+	bool "Sleep"
+	help
+	  Significantly higher power consumption but very short wake up time.
+
+config NORDIC_VPR_DEEPSLEEP
+	bool "Deep sleep"
+	depends on SOC_NRF54H20_CPUPPR
+	help
+	  Deep sleep can reach less than 5 uA in system-on-idle state only on nRF54H20.
+	  Wake up time is comparable to the 'sleep' mode.
+
+config NORDIC_VPR_HIBERNATE
+	bool "Hibernation"
+	depends on !SOC_NRF54H20
+	help
+	  It has the lowest power consumption and it must be used to reach less than 5 uA in
+	  the system-on-idle state on targets other than nRF54H20. It has slightly longer
+	  wake up time (additional 1 us). Hibernation is using a RAM block to store the VPR
+	  state and parent core must configure the memory so that it is powered on and retained.
+
+endchoice

soc/nordic/common/vpr/soc_init.c

@@ -8,6 +8,18 @@
 
 static int vpr_init(void)
 {
+	uint32_t sleep_mode;
+
+	if (IS_ENABLED(CONFIG_NORDIC_VPR_DEEPSLEEP)) {
+		sleep_mode = VPRCSR_NORDIC_VPRNORDICSLEEPCTRL_SLEEPSTATE_DEEPSLEEP;
+	} else if (IS_ENABLED(CONFIG_NORDIC_VPR_HIBERNATE)) {
+		sleep_mode = VPRCSR_NORDIC_VPRNORDICSLEEPCTRL_SLEEPSTATE_HIBERNATE;
+	} else {
+		sleep_mode = VPRCSR_NORDIC_VPRNORDICSLEEPCTRL_SLEEPSTATE_SLEEP;
+	}
+
+	csr_write(VPRCSR_NORDIC_VPRNORDICSLEEPCTRL, sleep_mode);
+
 	/* RT peripherals for VPR all share one enable.
 	 * To prevent redundant calls, do it here once.
 	 */