From 55bb9159aa8c7f88a7abb6a6ecc772e8f4e51c41 Mon Sep 17 00:00:00 2001
From: Philippe Gerum <rpm@xenomai.org>
Date: Wed, 22 Apr 2020 11:11:39 +0200
Subject: [PATCH] lib/sched: add evl_yield() for manual round-robin

An equivalent of sched_yield().

Signed-off-by: Philippe Gerum <rpm@xenomai.org>
---
 include/evl/evl.h            | 2 +-
 include/evl/sched.h          | 2 ++
 lib/sched.c                  | 9 +++++++++
 tests/compile-tests/sched.cc | 1 +
 4 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/include/evl/evl.h b/include/evl/evl.h
index 116049c..160e5b4 100644
--- a/include/evl/evl.h
+++ b/include/evl/evl.h
@@ -20,7 +20,7 @@
 #include <evl/poll.h>
 #include <evl/proxy.h>
 
-#define __EVL__  12	/* API version */
+#define __EVL__  13	/* API version */
 
 #define EVL_ABI_PREREQ  21
 
diff --git a/include/evl/sched.h b/include/evl/sched.h
index 76c4559..448c001 100644
--- a/include/evl/sched.h
+++ b/include/evl/sched.h
@@ -26,6 +26,8 @@ int evl_control_sched(int policy,
 
 int evl_get_cpustate(int cpu, int *state_r);
 
+int evl_yield(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/sched.c b/lib/sched.c
index f2ffd22..7f0ec6a 100644
--- a/lib/sched.c
+++ b/lib/sched.c
@@ -71,3 +71,12 @@ int evl_get_cpustate(int cpu, int *state_r)
 
 	return 0;
 }
+
+int evl_yield(void)
+{
+	if (evl_current == EVL_NO_HANDLE)
+		return -EPERM;
+
+	/* This is our sched_yield(). */
+	return oob_ioctl(evl_efd, EVL_THRIOC_YIELD) ? -errno : 0;
+}
diff --git a/tests/compile-tests/sched.cc b/tests/compile-tests/sched.cc
index ffb59f7..abb2c89 100644
--- a/tests/compile-tests/sched.cc
+++ b/tests/compile-tests/sched.cc
@@ -22,6 +22,7 @@ int main(int argc, char *argv[])
 	param.quota.op = evl_quota_add;
 	evl_control_sched(SCHED_QUOTA, &param, &info, 0);
 	evl_get_cpustate(0, &cpu_state);
+	evl_yield();
 
 	return 0;
 }