Zephyr rtos threads
Keywords: Zephyr thread analyzer module :: thread resource use :: thread stack monitoring
Contents
^ OVERVIEW
Kinda limited tutorials on Zephyr RTOS threads, but seemingly solid documentation on zephyrproject.org site. A specific example starting point may be among Zephyr source tree's samples directory . . . `$ grep -nr k_thread_create ./*` shows thread creation in a SPI Bluetooth driver sample. Path from root Zephyr RTOS source tree is zephyr/drivers/bluetooth/hci.
Also worth noting Zephyr provides a thread analyzer module for Zephyr based apps.
Passing data between Zephyr threads:
On this top level page there is mention of passing data between threads:
Zephyr queues:
^ Zephyr RTOS Thread API
Some Zephyr RTOS API functions to learn:
- k_sem_take(<e_connected, K_FOREVER);
- k_work_schedule(&connect_work, K_NO_WAIT);
Additionally some further Zephyr thread entities and mostly API functions include:
- k_thread
- K_THREAD_STACK versus K_KERNEL_STACK
- k_thread_create()
- k_thread_
- k_thread_join()
- k_thread_abort()
- k_thread_suspend()
- k_thread_resume()
Unsure whether this routine a Zephyr one:
work_init();
Following non-function entities from aws_iot main.c appear important:
77 static struct k_work_delayable shadow_update_work; 78 static struct k_work_delayable connect_work; 79 static struct k_work shadow_update_version_work;
^ Specific Zephyr documentation pages
- https://docs.zephyrproject.org/latest/reference/kernel/threads/index.html#lifecycle
- https://docs.zephyrproject.org/latest/reference/kernel/threads/workqueue.html?highlight=k_work_reschedule#c.k_work_reschedule
Following example code block matches k_thread_create() code in zephyr/drivers/bluetooth/hci/spi.c:519:
^ Example Zephyr Thread Creation
Rough search narrowing in on specific thread creation and use in aws_iot sample project from nRF Connect SDK:
cpguest@ubuntu-vm-0p2:/mnt/host-os-dev-area/pulse-pro/firmware-stage1/aws-iot-stand-alone/src$ grep -nr k_ ./*.c 30:static struct k_work_delayable shadow_update_work; 31:static struct k_work_delayable connect_work; 32:static struct k_work shadow_update_version_work; 150:static void connect_work_fn(struct k_work *work) 166: k_work_schedule(&connect_work, 170:static void shadow_update_work_fn(struct k_work *work) 186: k_work_schedule(&shadow_update_work, 190:static void shadow_update_version_work_fn(struct k_work *work) 242: (void)k_work_cancel_delayable(&connect_work); 258: k_work_submit(&shadow_update_version_work); 262: k_work_schedule(&shadow_update_work, 283: (void)k_work_cancel_delayable(&shadow_update_work); 284: k_work_schedule(&connect_work, K_NO_WAIT); 335:static void work_init(void) 337: k_work_init_delayable(&shadow_update_work, shadow_update_work_fn); 338: k_work_init_delayable(&connect_work, connect_work_fn); 339: k_work_init(&shadow_update_version_work, shadow_update_version_work_fn); 356: k_sem_give(<e_connected); 513: work_init(); 523: k_sem_take(<e_connected, K_FOREVER); 528: k_work_schedule(&connect_work, K_NO_WAIT); cpguest@ubuntu-vm-0p2:/mnt/host-os-dev-area/pulse-pro/firmware-stage1/aws-iot-stand-alone/src$ grep -n connect_work ./*.c 31:static struct k_work_delayable connect_work; 150:static void connect_work_fn(struct k_work *work) 166: k_work_schedule(&connect_work, 242: (void)k_work_cancel_delayable(&connect_work); 284: k_work_schedule(&connect_work, K_NO_WAIT); 338: k_work_init_delayable(&connect_work, connect_work_fn); 528: k_work_schedule(&connect_work, K_NO_WAIT); cpguest@ubuntu-vm-0p2:/mnt/host-os-dev-area/pulse-pro/firmware-stage1/aws-iot-stand-alone/src$
. . .
^ Specific Function Associated With Zephyr Thread
150 static void connect_work_fn(struct k_work *work)
151 {
152 int err;
153
154 if (cloud_connected) {
155 return;
156 }
157
158 err = aws_iot_connect(NULL);
159 if (err) {
160 printk("aws_iot_connect, error: %d\n", err);
161 }
162
163 printk("Next connection retry in %d seconds\n",
164 CONFIG_CONNECTION_RETRY_TIMEOUT_SECONDS);
165
166 k_work_schedule(&connect_work,
167 K_SECONDS(CONFIG_CONNECTION_RETRY_TIMEOUT_SECONDS));
168 }
150:static void connect_work_fn(struct k_work *work) 338: k_work_init_delayable(&connect_work, connect_work_fn);
^ Issue with Counter Timer in Zephyr Thread - dwt.h
5���_�_yϗ���Uߗ���5�_]����������Օ���}����ߧ�߿��ϯ���U�����u�����u�����U����u����������������땥����]��w����w����w�����u�7�w�U���u���W� * The AWS IoT sample started, version: v1.0.0 Zephyr thread create routine returns 536955992 for LED blink thread, - SUCCESS - found Kionix accelerometer and device is ready uart task at loop iteration 0x00000000 LTE cell changed: Cell ID: -1, Tracking area: -1 uart task at loop iteration 0x00000001 uart task at loop iteration 0x00000002 thread_kionix_accel - Kionix sensor reports manufacturer ID string: " K i o n " ( spaces added around characters, ID four bytes long. ) *** *** TEST 2p1 *** X accel 184, Y accel 65341, Z accel 16409 *** ASSERTION FAIL @ WEST_TOPDIR/zephyr/arch/arm/include/aarch32/cortex_m/dwt.h:103 E: r0/a1: 0x00000004 r1/a2: 0x00000067 r2/a3: 0x00000001 E: r3/a4: 0x00000000 r12/ip: 0xa0000000 r14/lr: 0x00027439 E: xpsr: 0x41000000 E: Faulting instruction address (r15/pc): 0x00039590 E: >>> ZEPHYR FATAL ERROR 4: Kernel panic on CPU 0 E: Current thread: 0x20014d88 (unknown)
Looking at `dwt.h`:
88
89 /**
90 * @brief Initialize and Enable the DWT cycle counter
91 *
92 * This routine enables the cycle counter and initializes its value to zero.
93 *
94 * @return 0
95 */
96 static inline int z_arm_dwt_init_cycle_counter(void)
97 {
98 /* Clear and enable the cycle counter */
99 DWT->CYCCNT = 0;
100 DWT->CTRL |= DWT_CTRL_CYCCNTENA_Msk;
101
102 /* Assert that the cycle counter is indeed implemented. */
103 __ASSERT((DWT->CTRL & DWT_CTRL_NOCYCCNT_Msk) != 0,
104 "DWT implements no cycle counter. "
105 "Cannot be used for cycle counting\n");
106
107 return 0;
108 }
109
What does this mean? Hello, a Nordic Devzone post and reply from Sigurd of Nordic provides an answer to this specific problem:
