drivers: timer: Add support for cc23x0 systim

Add support for systim to cc23x0 SoC.

Signed-off-by: Lars Thalian Morstad <l-morstad@ti.com>
Signed-off-by: Vebjorn Myklebust <v.myklebust@ti.com>
Signed-off-by: Stoyan Bogdanov <sbogdanov@baylibre.com>
Signed-off-by: Julien Panis <jpanis@baylibre.com>

drivers/timer/CMakeLists.txt

@@ -12,6 +12,7 @@ zephyr_library_sources_ifdef(CONFIG_ARCV2_TIMER arcv2_timer0.c)
 zephyr_library_sources_ifdef(CONFIG_ARM_ARCH_TIMER arm_arch_timer.c)
 zephyr_library_sources_ifdef(CONFIG_INTEL_ADSP_TIMER intel_adsp_timer.c)
 zephyr_library_sources_ifdef(CONFIG_CC13XX_CC26XX_RTC_TIMER cc13xx_cc26xx_rtc_timer.c)
+zephyr_library_sources_ifdef(CONFIG_CC23X0_SYSTIM_TIMER cc23x0_systim_timer.c)
 zephyr_library_sources_ifdef(CONFIG_CH32V00X_SYSTICK wch_systick_ch32v00x.c)
 zephyr_library_sources_ifdef(CONFIG_CORTEX_M_SYSTICK cortex_m_systick.c)
 zephyr_library_sources_ifdef(CONFIG_ESP32_SYS_TIMER esp32_sys_timer.c)

drivers/timer/Kconfig

@@ -70,6 +70,7 @@ source "drivers/timer/Kconfig.arcv2"
 source "drivers/timer/Kconfig.arm_arch"
 source "drivers/timer/Kconfig.cavs"
 source "drivers/timer/Kconfig.cc13xx_cc26xx_rtc"
+source "drivers/timer/Kconfig.cc23x0_systim"
 source "drivers/timer/Kconfig.wch_ch32v00x"
 source "drivers/timer/Kconfig.cortex_m_systick"
 source "drivers/timer/Kconfig.esp32"

drivers/timer/Kconfig.cc23x0_systim

@@ -0,0 +1,13 @@
+# Copyright (c) 2024 Texas Instruments Incorporated
+# Copyright (c) 2024 BayLibre, SAS
+#
+# SPDX-License-Identifier: Apache-2.0
+
+config CC23X0_SYSTIM_TIMER
+	bool "TI SimpleLink CC23X0 system clock timer"
+	default y
+	depends on HAS_CC23X0_SDK
+	select TICKLESS_CAPABLE
+	help
+	  This module provides the "system clock driver" interfaces
+	  for the TI Simplelink CC23X0 devices.

drivers/timer/cc23x0_systim_timer.c

@@ -0,0 +1,154 @@
+/*
+ * Copyright (c) 2024 Texas Instruments Incorporated
+ * Copyright (c) 2024 BayLibre, SAS
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT ti_cc23x0_systim_timer
+
+/*
+ * TI SimpleLink CC23X0 timer driver based on SYSTIM
+ */
+
+#include <soc.h>
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/clock_control.h>
+#include <zephyr/drivers/timer/system_timer.h>
+#include <zephyr/irq.h>
+#include <zephyr/spinlock.h>
+#include <zephyr/sys_clock.h>
+#include <zephyr/sys/util.h>
+
+#include <inc/hw_types.h>
+#include <inc/hw_memmap.h>
+#include <inc/hw_systim.h>
+#include <inc/hw_evtsvt.h>
+
+/* Kernel tick period in microseconds (same timebase as systim) */
+#define TICK_PERIOD_MICRO_SEC (1000000 / CONFIG_SYS_CLOCK_TICKS_PER_SEC)
+
+/*
+ * Max number of systim ticks into the future
+ *
+ * Under the hood, the kernel timer uses the SysTimer whose events trigger
+ * immediately if the compare value is less than 2^22 systimer ticks in the past
+ * (4.194sec at 1us resolution). Therefore, the max number of SysTimer ticks you
+ * can schedule into the future is 2^32 - 2^22 - 1 ticks (~= 4290 sec at 1us
+ * resolution).
+ */
+#define SYSTIM_TIMEOUT_MAX 0xFFBFFFFFU
+
+/* Set systim interrupt to lowest priority */
+#define SYSTIM_ISR_PRIORITY 3U
+
+/* Keep track of systim counter at previous announcement to the kernel */
+static uint32_t last_systim_count;
+
+static void systim_isr(const void *arg);
+static int sys_clock_driver_init(void);
+
+/*
+ * Set system clock timeout.
+ */
+void sys_clock_set_timeout(int32_t ticks, bool idle)
+{
+	ARG_UNUSED(idle);
+
+	/* If timeout is necessary */
+	if (ticks != K_TICKS_FOREVER) {
+		/* Get current value as early as possible */
+		uint32_t now_tick = HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U);
+		uint32_t timeout = ticks * TICK_PERIOD_MICRO_SEC;
+
+		if (timeout > SYSTIM_TIMEOUT_MAX) {
+			timeout = SYSTIM_TIMEOUT_MAX;
+		}
+		/* This should wrap around */
+		HWREG(SYSTIM_BASE + SYSTIM_O_CH0CC) = now_tick + timeout;
+	}
+}
+
+uint32_t sys_clock_elapsed(void)
+{
+	/* Get current value as early as possible */
+	uint32_t current_systim_count = HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U);
+	uint32_t elapsed_systim;
+
+	if (current_systim_count >= last_systim_count) {
+		elapsed_systim = current_systim_count - last_systim_count;
+	} else {
+		elapsed_systim = (UINT32_MAX - last_systim_count) + current_systim_count;
+	}
+
+	int32_t elapsed_ticks = elapsed_systim / TICK_PERIOD_MICRO_SEC;
+
+	return elapsed_ticks;
+}
+
+uint32_t sys_clock_cycle_get_32(void)
+{
+	return HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U);
+}
+
+void systim_isr(const void *arg)
+{
+	/* Get current value as early as possible */
+	uint32_t current_systim_count = HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U);
+	uint32_t elapsed_systim;
+
+	if (current_systim_count >= last_systim_count) {
+		elapsed_systim = current_systim_count - last_systim_count;
+	} else {
+		elapsed_systim = (UINT32_MAX - last_systim_count) + current_systim_count;
+	}
+
+	int32_t elapsed_ticks = elapsed_systim / TICK_PERIOD_MICRO_SEC;
+
+	sys_clock_announce(elapsed_ticks);
+
+	last_systim_count = current_systim_count;
+
+	/* Do not re-arm systim. Zephyr will do so through sys_clock_set_timeout */
+}
+
+static int sys_clock_driver_init(void)
+{
+	uint32_t now_tick;
+
+	/* Get current value as early as possible */
+	now_tick = HWREG(SYSTIM_BASE + SYSTIM_O_TIME1U);
+	last_systim_count = now_tick;
+
+	/* Clear any pending interrupts on SysTimer channel 0 */
+	HWREG(SYSTIM_BASE + SYSTIM_O_ICLR) = SYSTIM_ICLR_EV0_CLR;
+
+	/*
+	 * Configure SysTimer channel 0 to compare mode with timer
+	 * resolution of 1 us.
+	 */
+	HWREG(SYSTIM_BASE + SYSTIM_O_CH0CFG) = 0;
+
+	/* Make SysTimer halt on CPU debug halt */
+	HWREG(SYSTIM_BASE + SYSTIM_O_EMU) = SYSTIM_EMU_HALT_STOP;
+
+	HWREG(EVTSVT_BASE + EVTSVT_O_CPUIRQ16SEL) = EVTSVT_CPUIRQ16SEL_PUBID_SYSTIM0;
+
+	/*
+	 * Set IMASK for channel 0. IMASK is used by the power driver to know
+	 * which systimer channels are active.
+	 */
+	HWREG(SYSTIM_BASE + SYSTIM_O_IMSET) = SYSTIM_IMSET_EV0_SET;
+
+	/* This should wrap around and set a maximum timeout */
+	HWREG(SYSTIM_BASE + SYSTIM_O_CH0CC) = now_tick + SYSTIM_TIMEOUT_MAX;
+
+	/* Take configurable interrupt IRQ16 for systimer */
+	IRQ_CONNECT(CPUIRQ16_IRQn, SYSTIM_ISR_PRIORITY, systim_isr, 0, 0);
+	irq_enable(CPUIRQ16_IRQn);
+
+	return 0;
+}
+
+SYS_INIT(sys_clock_driver_init, PRE_KERNEL_2, CONFIG_SYSTEM_CLOCK_INIT_PRIORITY);

dts/bindings/timer/ti,cc23x0-timer.yaml

@@ -0,0 +1,15 @@
+# Copyright (c) 2024 Baylibre SAS
+# SPDX-License-Identifier: Apache-2.0
+
+description: TI SimpleLink CC23x0 Timer Node
+
+compatible: "ti,cc23x0-systim-timer"
+
+include: base.yaml
+
+properties:
+  reg:
+    required: true
+
+  interrupts:
+    required: true