pm: policy: add check for device busy in policy

Add check for device busy when CONFIG_PM_NEED_ALL_DEVICES_IDLE is
set to y because one or more devices may still in busy and causes
problem when system go into low power in Intel ISH platform.

Signed-off-by: Leifu Zhao <leifu.zhao@intel.com>

soc/x86/intel_ish/intel_ish5/pm/Kconfig.pm

@@ -18,4 +18,7 @@ config GDT_RESERVED_NUM_ENTRIES
 config REBOOT
 	default y
 
+config PM_NEED_ALL_DEVICES_IDLE
+	default y
+
 endif

subsys/pm/Kconfig

@@ -37,6 +37,13 @@ config PM_S2RAM
 	help
 	  This option enables suspend-to-RAM (S2RAM).
 
+config PM_NEED_ALL_DEVICES_IDLE
+	bool "System Low Power Mode Needs All Devices Idle"
+	depends on PM_DEVICE && !SMP
+	help
+	  When this option is enabled, check that no devices are busy before
+	  entering into system low power mode.
+
 choice PM_POLICY
 	prompt "Idle State Power Management Policy"
 	default PM_POLICY_DEFAULT

subsys/pm/policy.c

@@ -14,6 +14,7 @@
 #include <zephyr/sys/time_units.h>
 #include <zephyr/sys/atomic.h>
 #include <zephyr/toolchain.h>
+#include <zephyr/pm/device.h>
 
 #if DT_HAS_COMPAT_STATUS_OKAY(zephyr_power_state)
 
@@ -136,6 +137,12 @@ const struct pm_state_info *pm_policy_next_state(uint8_t cpu, int32_t ticks)
 	uint8_t num_cpu_states;
 	const struct pm_state_info *cpu_states;
 
+#ifdef CONFIG_PM_NEED_ALL_DEVICES_IDLE
+	if (pm_device_is_any_busy()) {
+		return NULL;
+	}
+#endif
+
 	if (ticks != K_TICKS_FOREVER) {
 		cyc = k_ticks_to_cyc_ceil32(ticks);
 	}