kernel: POSIX: Compatibility layer for POSIX timer APIs.

This patch provides POSIX timer APIs for POSIX 1003.1 PSE52 standard.

Signed-off-by: Youvedeep Singh <youvedeep.singh@intel.com>

arch/posix/include/posix_cheats.h

@@ -33,7 +33,10 @@
 #define pthread_attr_t         zap_pthread_attr_t
 #define clockid_t              zap_clockid_t
 #define sched_param	       zap_sched_param
-
+#define itimerspe	       zap_sched_param
+#define timer_t                zap_timer_t
+#define sigval		       zap_sigval
+#define sigevent	       zap_sigevent
 /* Condition variables */
 #define pthread_cond_init(...)        zap_pthread_cond_init(__VA_ARGS__)
 #define pthread_cond_destroy(...)     zap_pthread_cond_destroy(__VA_ARGS__)
@@ -105,6 +108,12 @@
 #define clock_gettime(...)		zap_clock_gettime(__VA_ARGS__)
 #define clock_settime(...)		zap_clock_settime(__VA_ARGS__)
 
+/* Timer */
+#define timer_create(...)	zap_timer_create(__VA_ARGS__)
+#define timer_delete(...)	zap_timer_delete(__VA_ARGS__)
+#define timer_gettime(...)	zap_timer_gettime(__VA_ARGS__)
+#define timer_settime(...)	zap_timer_settime(__VA_ARGS__)
+
 #endif /* CONFIG_ARCH_POSIX */
 
 #endif

include/posix/signal.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2018 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef __POSIX_SIGNAL_H__
+#define __POSIX_SIGNAL_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "sys/types.h"
+
+#ifndef SIGEV_NONE
+#define SIGEV_NONE 1
+#endif
+
+#ifndef SIGEV_SIGNAL
+#define SIGEV_SIGNAL 2
+#endif
+
+#ifndef SIGEV_THREAD
+#define SIGEV_THREAD 3
+#endif
+
+typedef union sigval {
+	int sival_int;
+	void *sival_ptr;
+} sigval;
+
+typedef struct sigevent {
+	int sigev_notify;
+	int sigev_signo;
+	sigval sigev_value;
+	void (*sigev_notify_function)(sigval val);
+	pthread_attr_t *sigev_notify_attributes;
+} sigevent;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __POSIX_TIME_H__ */

include/posix/sys/types.h

@@ -60,6 +60,7 @@ typedef struct pthread_barrierattr {
 #ifndef CONFIG_NEWLIB_LIBC
 typedef u32_t clockid_t;
 #endif /*CONFIG_NEWLIB_LIBC */
+typedef unsigned long timer_t;
 typedef unsigned long useconds_t;
 
 #endif /* CONFIG_PTHREAD_IPC */

include/posix/time.h

@@ -14,19 +14,38 @@ extern "C" {
 #include_next <time.h>
 #else
 struct timespec {
-	s32_t tv_sec;
-	s32_t tv_nsec;
+	signed int  tv_sec;
+	signed int  tv_nsec;
+};
+
+struct itimerspec {
+	struct timespec it_interval;  /* Timer interval */
+	struct timespec it_value;     /* Timer expiration */
 };
 #endif /* CONFIG_NEWLIB_LIBC */
+
 #include <kernel.h>
 #include <errno.h>
 #include "sys/types.h"
+#include "signal.h"
 
+#ifndef CLOCK_REALTIME
+#define CLOCK_REALTIME 0
+#endif
+
+#ifndef CLOCK_MONOTONIC
 #define CLOCK_MONOTONIC 1
+#endif
+
+#define NSEC_PER_MSEC (NSEC_PER_USEC * USEC_PER_MSEC)
+
+#ifndef TIMER_ABSTIME
+#define TIMER_ABSTIME 4
+#endif
 
 static inline s32_t _ts_to_ms(const struct timespec *to)
 {
-	return (to->tv_sec * 1000) + (to->tv_nsec / 1000000);
+	return (to->tv_sec * MSEC_PER_SEC) + (to->tv_nsec / NSEC_PER_MSEC);
 }
 
 /**
@@ -41,6 +60,12 @@ static inline int clock_settime(clockid_t clock_id, const struct timespec *ts)
 }
 
 int clock_gettime(clockid_t clock_id, struct timespec *ts);
+/* Timer APIs */
+int timer_create(clockid_t clockId, struct sigevent *evp, timer_t *timerid);
+int timer_delete(timer_t timerid);
+int timer_gettime(timer_t timerid, struct itimerspec *its);
+int timer_settime(timer_t timerid, int flags, const struct itimerspec *value,
+		  struct itimerspec *ovalue);
 
 #ifdef __cplusplus
 }

kernel/Kconfig

@@ -512,6 +512,14 @@ config MAX_PTHREAD_COUNT
 	range 0 255
 	help
 	  Mention maximum number of threads in POSIX compliant application.
+
+config MAX_TIMER_COUNT
+	int
+	prompt "Maximum timer count in POSIX application"
+	default 5
+	range 0 255
+	help
+	  Mention maximum number of timers in POSIX compliant application.
 endif
 endmenu
 

kernel/posix/CMakeLists.txt

@@ -5,3 +5,4 @@ target_sources(kernel PRIVATE posix/pthread_barrier.c)
 target_sources(kernel PRIVATE posix/pthread.c)
 target_sources(kernel PRIVATE posix/pthread_sched.c)
 target_sources(kernel PRIVATE posix/clock.c)
+target_sources(kernel PRIVATE posix/timer.c)

kernel/posix/timer.c

@@ -0,0 +1,204 @@
+/*
+ * Copyright (c) 2018 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include <kernel.h>
+#include <time.h>
+#include <errno.h>
+#include <string.h>
+#include <misc/printk.h>
+
+#define ACTIVE 1
+#define NOT_ACTIVE 0
+
+static void zephyr_timer_wrapper(struct k_timer *timer);
+
+struct timer_obj {
+	struct k_timer ztimer;
+	void (*sigev_notify_function)(sigval val);
+	sigval val;
+	struct timespec interval;	/* Reload value */
+	u32_t reload;			/* Reload value in ms */
+	u32_t status;
+};
+
+K_MEM_SLAB_DEFINE(posix_timer_slab, sizeof(struct timer_obj),
+		  CONFIG_MAX_TIMER_COUNT, 4);
+
+static void zephyr_timer_wrapper(struct k_timer *ztimer)
+{
+	struct timer_obj *timer;
+
+	timer = (struct timer_obj *)ztimer;
+
+	if (timer->reload == 0) {
+		timer->status = NOT_ACTIVE;
+	}
+
+	(timer->sigev_notify_function)(timer->val);
+}
+
+/**
+ * @brief Create a per-process timer.
+ *
+ * This API does not accept SIGEV_THREAD as valid signal event notification
+ * type.
+ *
+ * See IEEE 1003.1
+ */
+int timer_create(clockid_t clockid, struct sigevent *evp, timer_t *timerid)
+{
+	struct timer_obj *timer;
+
+	if (clockid != CLOCK_MONOTONIC || evp == NULL ||
+	    (evp->sigev_notify != SIGEV_NONE &&
+	     evp->sigev_notify != SIGEV_SIGNAL)) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (k_mem_slab_alloc(&posix_timer_slab, (void **)&timer, 100) == 0) {
+		memset(timer, 0, sizeof(struct timer_obj));
+	} else {
+		errno = ENOMEM;
+		return -1;
+	}
+
+	timer->sigev_notify_function = evp->sigev_notify_function;
+	timer->val = evp->sigev_value;
+	timer->interval.tv_sec = 0;
+	timer->interval.tv_nsec = 0;
+	timer->reload = 0;
+	timer->status = NOT_ACTIVE;
+
+	if (evp->sigev_notify == SIGEV_NONE) {
+		k_timer_init(&timer->ztimer, NULL, NULL);
+	} else {
+		k_timer_init(&timer->ztimer, zephyr_timer_wrapper, NULL);
+	}
+
+	*timerid = (timer_t)timer;
+
+	return 0;
+}
+
+/**
+ * @brief Get amount of time left for expiration on a per-process timer.
+ *
+ * See IEEE 1003.1
+ */
+int timer_gettime(timer_t timerid, struct itimerspec *its)
+{
+	struct timer_obj *timer = (struct timer_obj *)timerid;
+	s32_t remaining, leftover;
+	s64_t   nsecs, secs;
+
+	if (timer == NULL) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (timer->status == ACTIVE) {
+		remaining = k_timer_remaining_get(&timer->ztimer);
+		secs =  remaining / sys_clock_ticks_per_sec;
+		leftover = remaining - (secs * sys_clock_ticks_per_sec);
+		nsecs = leftover * NSEC_PER_SEC / sys_clock_ticks_per_sec;
+		its->it_value.tv_sec = (s32_t) secs;
+		its->it_value.tv_nsec = (s32_t) nsecs;
+	} else {
+		/* Timer is disarmed */
+		its->it_value.tv_sec = 0;
+		its->it_value.tv_nsec = 0;
+	}
+
+	/* The interval last set by timer_settime() */
+	its->it_interval = timer->interval;
+	return 0;
+}
+
+/**
+ * @brief Sets expiration time of per-process timer.
+ *
+ * See IEEE 1003.1
+ */
+int timer_settime(timer_t timerid, int flags, const struct itimerspec *value,
+		  struct itimerspec *ovalue)
+{
+	struct timer_obj *timer = (struct timer_obj *) timerid;
+	u32_t duration, current;
+
+	if (timer == NULL ||
+	    value->it_interval.tv_nsec < 0 ||
+	    value->it_interval.tv_nsec >= NSEC_PER_SEC ||
+	    value->it_value.tv_nsec < 0 ||
+	    value->it_value.tv_nsec >= NSEC_PER_SEC) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	/*  Save time to expire and old reload value. */
+	if (ovalue) {
+		timer_gettime(timerid, ovalue);
+	}
+
+	/* Stop the timer if the value is 0 */
+	if ((value->it_value.tv_sec == 0) && (value->it_value.tv_nsec == 0)) {
+		if (timer->status == ACTIVE) {
+			k_timer_stop(&timer->ztimer);
+		}
+
+		timer->status = NOT_ACTIVE;
+		return 0;
+	}
+
+	/* Calculate timer period */
+	timer->reload = _ts_to_ms(&value->it_interval);
+	timer->interval.tv_sec = value->it_interval.tv_sec;
+	timer->interval.tv_nsec = value->it_interval.tv_nsec;
+
+	/* Calcaulte timer duration */
+	duration = _ts_to_ms(&(value->it_value));
+	if (flags & TIMER_ABSTIME) {
+		current = k_timer_remaining_get(&timer->ztimer);
+
+		if (current >= duration) {
+			duration = 0;
+		} else {
+			duration -= current;
+		}
+	}
+
+	if (timer->status == ACTIVE) {
+		k_timer_stop(&timer->ztimer);
+	}
+
+	timer->status = ACTIVE;
+	k_timer_start(&timer->ztimer, duration, timer->reload);
+	return 0;
+}
+
+/**
+ * @brief Delete a per-process timer.
+ *
+ * See IEEE 1003.1
+ */
+int timer_delete(timer_t timerid)
+{
+	struct timer_obj *timer = (struct timer_obj *) timerid;
+
+	if (timer == NULL) {
+		errno = EINVAL;
+		return -1;
+	}
+
+	if (timer->status == ACTIVE) {
+		timer->status = NOT_ACTIVE;
+		k_timer_stop(&timer->ztimer);
+	}
+
+	k_mem_slab_free(&posix_timer_slab, (void *) &timer);
+
+	return 0;
+}
+