[RFC] abstract clock subsystem: counter syntonization

cmake/linker_script/common/common-ram.cmake

@@ -54,6 +54,10 @@ if(CONFIG_NETWORKING)
   zephyr_iterable_section(NAME eth_bridge GROUP DATA_REGION ${XIP_ALIGN_WITH_INPUT} SUBALIGN 4)
 endif()
 
+if(CONFIG_NET_TIME_REFERENCE_CLOCK)
+  zephyr_iterable_section(NAME net_time_timer GROUP DATA_REGION ${XIP_ALIGN_WITH_INPUT} SUBALIGN 4)
+endif()
+
 if(CONFIG_SENSING)
   zephyr_iterable_section(NAME sensing_sensor GROUP DATA_REGION ${XIP_ALIGN_WITH_INPUT} SUBALIGN 4)
 endif()

doc/kernel/services/timing/clocks.rst

@@ -27,7 +27,7 @@ read operation is very fast.  The expectation is that very sensitive
 application code might use this in a polling manner to achieve maximal
 precision.  The frequency of this counter is required to be steady
 over time, and is available from
-:c:func:`sys_clock_hw_cycles_per_sec` (which on almost all
+:c:macro:`sys_clock_hw_cycles_per_sec` (which on almost all
 platforms is a runtime constant that evaluates to
 CONFIG_SYS_CLOCK_HW_CYCLES_PER_SEC).
 
@@ -53,10 +53,10 @@ Control of rounding is provided, and each conversion is available in
 "near" (round to nearest).  Finally the output precision can be
 specified as either 32 or 64 bits.
 
-For example: :c:func:`k_ms_to_ticks_ceil32` will convert a
+For example: :c:macro:`k_ms_to_ticks_ceil32` will convert a
 millisecond input value to the next higher number of ticks, returning
 a result truncated to 32 bits of precision; and
-:c:func:`k_cyc_to_us_floor64` will convert a measured cycle count
+:c:macro:`k_cyc_to_us_floor64` will convert a measured cycle count
 to an elapsed number of microseconds in a full 64 bits of precision.
 See the reference documentation for the full enumeration of conversion
 routines.
@@ -370,4 +370,4 @@ value, and should never be called iteratively in a loop.
 API Reference
 *************
 
-.. doxygengroup:: clock_apis
+.. doxygengroup:: sys_clock_apis

drivers/CMakeLists.txt

@@ -74,7 +74,7 @@ add_subdirectory_ifdef(CONFIG_SENSOR sensor)
 add_subdirectory_ifdef(CONFIG_SERIAL serial)
 add_subdirectory_ifdef(CONFIG_SPI spi)
 add_subdirectory_ifdef(CONFIG_SYSCON syscon)
-add_subdirectory_ifdef(CONFIG_SYS_CLOCK_EXISTS timer)
+add_subdirectory_ifdef(CONFIG_TIMEOUT_QUEUE timer)
 add_subdirectory_ifdef(CONFIG_VIDEO video)
 add_subdirectory_ifdef(CONFIG_VIRTUALIZATION virtualization)
 add_subdirectory_ifdef(CONFIG_W1 w1)

include/zephyr/arch/arm/cortex_m/scripts/linker.ld

@@ -215,7 +215,7 @@ SECTIONS
     SECTION_PROLOGUE(padding_section,,)
 	{
 	__rodata_region_end = .;
-	MPU_ALIGN(__rodata_region_end - ADDR(rom_start));
+	. = ALIGN(8);
 	} GROUP_LINK_IN(ROMABLE_REGION)
 #else
 	__rodata_region_end = .;

include/zephyr/drivers/timer/system_timer.h

@@ -24,7 +24,8 @@ extern "C" {
 
 /**
  * @brief System Clock APIs
- * @defgroup clock_apis System Clock APIs
+ * @defgroup sys_clock_apis System Clock APIs
+ * @ingroup kernel_apis
  * @{
  */
 

include/zephyr/kernel.h

@@ -1247,7 +1247,7 @@ const char *k_thread_state_str(k_tid_t thread_id, char *buf, size_t buf_size);
  */
 
 /**
- * @addtogroup clock_apis
+ * @addtogroup sys_clock_apis
  * @{
  */
 
@@ -1463,6 +1463,8 @@ struct k_timer {
 	/* wait queue for the (single) thread waiting on this timer */
 	_wait_q_t wait_q;
 
+	struct k_timeout_api *timeout_api;
+
 	/* runs in ISR context */
 	void (*expiry_fn)(struct k_timer *timer);
 
@@ -1492,6 +1494,7 @@ struct k_timer {
 		.fn = z_timer_expiration_handler, \
 		.dticks = 0, \
 	}, \
+	.timeout_api = &Z_SYS_CLOCK_TIMEOUT_API, \
 	.wait_q = Z_WAIT_Q_INIT(&obj.wait_q), \
 	.expiry_fn = expiry, \
 	.stop_fn = stop, \
@@ -1633,7 +1636,7 @@ __syscall uint32_t k_timer_status_get(struct k_timer *timer);
  */
 __syscall uint32_t k_timer_status_sync(struct k_timer *timer);
 
-#ifdef CONFIG_SYS_CLOCK_EXISTS
+#ifdef CONFIG_TIMEOUT_QUEUE
 
 /**
  * @brief Get next expiration time of a timer, in system ticks
@@ -1683,7 +1686,7 @@ static inline uint32_t k_timer_remaining_get(struct k_timer *timer)
 	return k_ticks_to_ms_floor32(k_timer_remaining_ticks(timer));
 }
 
-#endif /* CONFIG_SYS_CLOCK_EXISTS */
+#endif /* CONFIG_TIMEOUT_QUEUE */
 
 /**
  * @brief Associate user-specific data with a timer.
@@ -1725,8 +1728,7 @@ static inline void *z_impl_k_timer_user_data_get(const struct k_timer *timer)
 /** @} */
 
 /**
- * @addtogroup clock_apis
- * @ingroup kernel_apis
+ * @addtogroup sys_clock_apis
  * @{
  */
 

include/zephyr/linker/common-ram.ld

@@ -12,6 +12,10 @@
 #endif
 #endif /* NETWORKING */
 
+#if defined(CONFIG_NET_TIME_REFERENCE_CLOCK)
+	ITERABLE_SECTION_RAM(net_time_timer, 4)
+#endif
+
 #if defined(CONFIG_GEN_SW_ISR_TABLE) && defined(CONFIG_DYNAMIC_INTERRUPTS)
 	SECTION_DATA_PROLOGUE(sw_isr_table,,)
 	{

include/zephyr/net/ieee802154_radio.h

@@ -1751,6 +1751,10 @@ struct ieee802154_radio_api {
 	 *
 	 * See @ref net_time_t for semantic details.
 	 *
+	 * @note This is an alias for `radio_api->get_time_reference()
+	 * ->get_time()` for drivers that support the network uptime
+	 * reference API.
+	 *
 	 * @note requires IEEE802154_HW_TXTIME and/or IEEE802154_HW_RXTIME
 	 * capabilities. Implementations SHALL be **isr-ok** and MUST NOT
 	 * **sleep**. MAY be called in any interface state once the driver is
@@ -1763,6 +1767,21 @@ struct ieee802154_radio_api {
 	 */
 	net_time_t (*get_time)(const struct device *dev);
 
+	/**
+	 * @brief Provides access to the full API of the underlying network
+	 * uptime reference of the driver.
+	 *
+	 * @note Implementations SHALL be **isr-ok** and MUST NOT **sleep**. MAY
+	 * be called in any interface state once the driver is fully initialized
+	 * ("ready").
+	 *
+	 * @param dev pointer to IEEE 802.15.4 driver device
+	 *
+	 * @returns a pointer to the driver's underlying network uptime
+	 * reference or NULL if not supported.
+	 */
+	const struct net_time_reference_api *(*get_time_reference)(const struct device *dev);
+
 	/**
 	 * @brief Get the current estimated worst case accuracy (maximum ±
 	 * deviation from the nominal frequency) of the network subsystem's