maa: add maa_set_priority call

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>

api/maa.h

@@ -195,6 +195,17 @@ maa_result_t maa_init() __attribute__((constructor));
 maa_result_t maa_init();
 #endif
 
+/**
+ * This function attempts to set the maa process to a given priority and the
+ * scheduler to SCHED_RR. Highest * priority is typically 99 and minimum is 0.
+ * This function * will set to MAX if * priority is > MAX. Function will return
+ * -1 on failure.
+
+ * @param priority Value from typically 0 to 99
+ * @return The priority value set
+ */
+int maa_set_priority(const unsigned int priority);
+
 /** Get the version string of maa autogenerated from git tag
  *
  * The version returned may not be what is expected however it is a reliable

src/maa.c

@@ -25,6 +25,8 @@
 
 #include <stddef.h>
 #include <stdlib.h>
+#include <sched.h>
+#include <string.h>
 
 #include "maa.h"
 #include "maa_internal.h"
@@ -65,6 +67,22 @@ maa_init()
     return MAA_SUCCESS;
 }
 
+int
+maa_set_priority(const unsigned int priority)
+{
+    struct sched_param sched_s;
+
+    memset(&sched_s, 0, sizeof(struct sched_param));
+    if (priority > sched_get_priority_max(SCHED_RR)) {
+        sched_s.sched_priority = sched_get_priority_max(SCHED_RR);
+    }
+    else {
+        sched_s.sched_priority = priority;
+    }
+
+    return sched_setscheduler(0, SCHED_RR, &sched_s);
+}
+
 static maa_result_t
 maa_setup_mux_mapped(maa_pin_t meta)
 {

src/maa.i

@@ -24,6 +24,9 @@
 %rename(getVersion) maa_get_version();
 const char * maa_get_version();
 
+%rename(setPriority) maa_set_priority;
+int maa_set_priority(const unsigned int);
+
 %rename(printError) maa_result_print(maa_result_t error);
 void maa_result_print(maa_result_t error);