soc: ti_simplelink: system power management for cc13x2_cc26x2

Add support for sleep states. Sleep state 1 corresponds to idle mode,
and Sleep state 2 corresponds to standby mode, as per the Technical
Reference Manual.

Signed-off-by: Vincent Wan <vincent.wan@linaro.org>

soc/arm/ti_simplelink/cc13x2_cc26x2/CMakeLists.txt

@@ -4,3 +4,5 @@
 
 zephyr_sources(soc.c)
 zephyr_sources(ccfg.c)
+
+zephyr_library_sources_ifdef(CONFIG_SYS_POWER_MANAGEMENT    power.c)

soc/arm/ti_simplelink/cc13x2_cc26x2/Kconfig.series

@@ -12,5 +12,7 @@ config SOC_SERIES_CC13X2_CC26X2
 	select SOC_FAMILY_TISIMPLELINK
 	select HAS_CC13X2_CC26X2_SDK
 	select HAS_TI_CCFG
+	select HAS_SYS_POWER_STATE_SLEEP_1
+	select HAS_SYS_POWER_STATE_SLEEP_2
 	help
 	  Enable support for TI SimpleLink CC13x2 / CC26x2 SoCs

soc/arm/ti_simplelink/cc13x2_cc26x2/power.c

@@ -0,0 +1,156 @@
+/*
+ * Copyright (c) 2019 Linaro Limited.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include <zephyr.h>
+#include <init.h>
+#include <power/power.h>
+
+#include <ti/drivers/Power.h>
+#include <ti/drivers/power/PowerCC26X2.h>
+
+#include <ti/drivers/dpl/ClockP.h>
+
+#include <ti/devices/cc13x2_cc26x2/driverlib/cpu.h>
+#include <ti/devices/cc13x2_cc26x2/driverlib/vims.h>
+#include <ti/devices/cc13x2_cc26x2/driverlib/sys_ctrl.h>
+
+#include <logging/log.h>
+#define LOG_LEVEL CONFIG_SOC_LOG_LEVEL
+LOG_MODULE_REGISTER(soc);
+
+/* Configuring TI Power module to not use its policy function (we use Zephyr's
+ * instead), and disable oscillator calibration functionality for now.
+ */
+const PowerCC26X2_Config PowerCC26X2_config = {
+	.policyInitFxn      = NULL,
+	.policyFxn          = NULL,
+	.calibrateFxn       = NULL,
+	.enablePolicy       = false,
+	.calibrateRCOSC_LF  = false,
+	.calibrateRCOSC_HF  = false
+};
+
+extern PowerCC26X2_ModuleState PowerCC26X2_module;
+
+/*
+ * Power state mapping:
+ * SYS_POWER_STATE_SLEEP_1: Idle
+ * SYS_POWER_STATE_SLEEP_2: Standby
+ */
+
+/* Invoke Low Power/System Off specific Tasks */
+void sys_set_power_state(enum power_states state)
+{
+#ifdef CONFIG_SYS_POWER_SLEEP_STATES
+	u32_t modeVIMS;
+	u32_t constraints;
+#endif
+
+	LOG_DBG("SoC entering power state %d", state);
+
+	/* Switch to using PRIMASK instead of BASEPRI register, since
+	 * we are only able to wake up from standby while using PRIMASK.
+	 */
+	/* Set PRIMASK */
+	CPUcpsid();
+	/* Set BASEPRI to 0 */
+	irq_unlock(0);
+
+	switch (state) {
+#ifdef CONFIG_SYS_POWER_SLEEP_STATES
+	case SYS_POWER_STATE_SLEEP_1:
+		/* query the declared constraints */
+		constraints = Power_getConstraintMask();
+		/* 1. Get the current VIMS mode */
+		do {
+			modeVIMS = VIMSModeGet(VIMS_BASE);
+		} while (modeVIMS == VIMS_MODE_CHANGING);
+
+		/* 2. Configure flash to remain on in IDLE or not and keep
+		 *    VIMS powered on if it is configured as GPRAM
+		 * 3. Always keep cache retention ON in IDLE
+		 * 4. Turn off the CPU power domain
+		 * 5. Ensure any possible outstanding AON writes complete
+		 * 6. Enter IDLE
+		 */
+		if ((constraints & (1 << PowerCC26XX_NEED_FLASH_IN_IDLE)) ||
+			(modeVIMS == VIMS_MODE_DISABLED)) {
+			SysCtrlIdle(VIMS_ON_BUS_ON_MODE);
+		} else {
+			SysCtrlIdle(VIMS_ON_CPU_ON_MODE);
+		}
+
+		/* 7. Make sure MCU and AON are in sync after wakeup */
+		SysCtrlAonUpdate();
+		break;
+
+	case SYS_POWER_STATE_SLEEP_2:
+		/* schedule the wakeup event */
+		ClockP_start(ClockP_handle((ClockP_Struct *)
+			&PowerCC26X2_module.clockObj));
+
+		/* go to standby mode */
+		Power_sleep(PowerCC26XX_STANDBY);
+		ClockP_stop(ClockP_handle((ClockP_Struct *)
+			&PowerCC26X2_module.clockObj));
+		break;
+#endif
+	default:
+		LOG_DBG("Unsupported power state %u", state);
+		break;
+	}
+
+	LOG_DBG("SoC leaving power state %d", state);
+}
+
+/* Handle SOC specific activity after Low Power Mode Exit */
+void _sys_pm_power_state_exit_post_ops(enum power_states state)
+{
+	/*
+	 * System is now in active mode. Reenable interrupts which were disabled
+	 * when OS started idling code.
+	 */
+	CPUcpsie();
+}
+
+/* Initialize TI Power module */
+static int power_initialize(struct device *dev)
+{
+	unsigned int ret;
+
+	ARG_UNUSED(dev);
+
+	ret = irq_lock();
+	Power_init();
+	irq_unlock(ret);
+
+	return 0;
+}
+
+/*
+ *  ======== PowerCC26XX_schedulerDisable ========
+ */
+void PowerCC26XX_schedulerDisable(void)
+{
+	/*
+	 * We are leaving this empty because Zephyr's
+	 * scheduler would not get to run with interrupts being disabled
+	 * in the context of Power_sleep() in any case.
+	 */
+}
+
+/*
+ *  ======== PowerCC26XX_schedulerRestore ========
+ */
+void PowerCC26XX_schedulerRestore(void)
+{
+	/*
+	 * We are leaving this empty because Zephyr's
+	 * scheduler would not get to run with interrupts being disabled
+	 * in the context of Power_sleep() in any case.
+	 */
+}
+
+SYS_INIT(power_initialize, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);