7 files changed, 42 insertions, 39 deletions

diff --git a/firmware/target/hosted/android/button-android.c b/firmware/target/hosted/android/button-android.c
index e7a3d00a65..ed1e125223 100644
--- a/firmware/target/hosted/android/button-android.c
+++ b/firmware/target/hosted/android/button-android.c
@@ -29,6 +29,7 @@
 #include "system.h"
 #include "touchscreen.h"
 
+extern JNIEnv *env_ptr;
 static int last_y, last_x;
 static int last_btns;
 
diff --git a/firmware/target/hosted/android/lcd-android.c b/firmware/target/hosted/android/lcd-android.c
index 19f077010f..abde72155d 100644
--- a/firmware/target/hosted/android/lcd-android.c
+++ b/firmware/target/hosted/android/lcd-android.c
@@ -28,6 +28,7 @@
 #include "lcd.h"
 #include "button.h"
 
+extern JNIEnv *env_ptr;
 extern jobject RockboxService_instance;
 
 static jobject RockboxFramebuffer_instance;
@@ -90,8 +91,6 @@ void lcd_init_device(void)
 
 void lcd_update(void)
 {
-    JNIEnv *env_ptr = getJavaEnvironment();
-
     if (display_on)
         (*env_ptr)->CallVoidMethod(env_ptr, RockboxFramebuffer_instance,
                                    java_lcd_update);
@@ -99,8 +98,6 @@ void lcd_update(void)
 
 void lcd_update_rect(int x, int y, int width, int height)
 {
-    JNIEnv *env_ptr = getJavaEnvironment();
-
     if (display_on)
         (*env_ptr)->CallVoidMethod(env_ptr, RockboxFramebuffer_instance,
                                    java_lcd_update_rect, x, y, width, height);
diff --git a/firmware/target/hosted/android/pcm-android.c b/firmware/target/hosted/android/pcm-android.c
index 24881bd3df..edb3503262 100644
--- a/firmware/target/hosted/android/pcm-android.c
+++ b/firmware/target/hosted/android/pcm-android.c
@@ -21,10 +21,13 @@
 
 #include <jni.h>
 #include <stdbool.h>
+#define _SYSTEM_WITH_JNI /* for getJavaEnvironment */
 #include <system.h>
 #include "debug.h"
 #include "pcm.h"
 
+extern JNIEnv *env_ptr;
+
 /* infos about our pcm chunks */
 static size_t  pcm_data_size;
 static char   *pcm_data_start;
@@ -115,17 +118,17 @@ void pcm_play_dma_start(const void *addr, size_t size)
 
 void pcm_play_dma_stop(void)
 {
-    JNIEnv *env_ptr = getJavaEnvironment();
-
-    (*env_ptr)->CallVoidMethod(env_ptr,
-                               RockboxPCM_instance,
-                               stop_method);
+    /* NOTE: due to how pcm_play_get_more_callback() works, this is
+     * possibly called from pcmSamplesToByteArray(), i.e. another thread.
+     * => We need to discover the env_ptr */
+    JNIEnv* env = getJavaEnvironment();
+    (*env)->CallVoidMethod(env,
+                           RockboxPCM_instance,
+                           stop_method);
 }
 
 void pcm_play_dma_pause(bool pause)
 {
-    JNIEnv *env_ptr = getJavaEnvironment();
-
     (*env_ptr)->CallVoidMethod(env_ptr,
                                RockboxPCM_instance,
                                play_pause_method,
@@ -154,7 +157,6 @@ void pcm_play_dma_init(void)
      * Luckily we only reference the PCM object from here, so it's safe (and
      * clean) to allocate it here
      **/
-    JNIEnv *env_ptr = getJavaEnvironment();
     JNIEnv e = *env_ptr;
     /* get the class and its constructor */
     jclass RockboxPCM_class = e->FindClass(env_ptr, "org/rockbox/RockboxPCM");
@@ -175,8 +177,6 @@ void pcm_postinit(void)
 
 void pcm_set_mixer_volume(int volume)
 {
-    JNIEnv *env_ptr = getJavaEnvironment();
-
     (*env_ptr)->CallVoidMethod(env_ptr, RockboxPCM_instance, set_volume_method, volume);
 }
 
diff --git a/firmware/target/hosted/android/powermgmt-android.c b/firmware/target/hosted/android/powermgmt-android.c
index 222212f9c8..d23fece39a 100644
--- a/firmware/target/hosted/android/powermgmt-android.c
+++ b/firmware/target/hosted/android/powermgmt-android.c
@@ -23,8 +23,8 @@
 #include <jni.h>
 #include <stdbool.h>
 #include "config.h"
-#include "system.h"
 
+extern JNIEnv *env_ptr;
 extern jclass  RockboxService_class;
 extern jobject RockboxService_instance;
 
@@ -32,8 +32,6 @@ static jfieldID _battery_level;
 
 void powermgmt_init_target(void)
 {
-    JNIEnv *env_ptr = getJavaEnvironment();
-
     jmethodID initBatteryMonitor = (*env_ptr)->GetMethodID(env_ptr,
                                                            RockboxService_class,
                                                            "initBatteryMonitor",
@@ -52,8 +50,6 @@ void powermgmt_init_target(void)
 
 int battery_level(void)
 {
-    JNIEnv *env_ptr = getJavaEnvironment();
-
     return (*env_ptr)->GetIntField(env_ptr, RockboxService_instance, _battery_level);
 }
 
diff --git a/firmware/target/hosted/android/system-android.c b/firmware/target/hosted/android/system-android.c
index 8d36198c61..686453cfbb 100644
--- a/firmware/target/hosted/android/system-android.c
+++ b/firmware/target/hosted/android/system-android.c
@@ -27,7 +27,8 @@
 
 
 /* global fields for use with various JNI calls */
-JavaVM *vm_ptr;
+static JavaVM *vm_ptr;
+JNIEnv *env_ptr;
 jobject RockboxService_instance;
 jclass  RockboxService_class;
 
@@ -47,6 +48,22 @@ void system_init(void)
     telephony_init_device();
 }
 
+JNIEXPORT jint JNICALL
+JNI_OnLoad(JavaVM *vm, void* reserved)
+{
+    (void)reserved;
+    vm_ptr = vm;
+
+    return JNI_VERSION_1_2;
+}
+
+JNIEnv* getJavaEnvironment(void)
+{
+    JNIEnv* env;
+    (*vm_ptr)->GetEnv(vm_ptr, (void**) &env, JNI_VERSION_1_2);
+    return env;
+}
+
 /* this is the entry point of the android app initially called by jni */
 JNIEXPORT void JNICALL
 Java_org_rockbox_RockboxService_main(JNIEnv *env, jobject this)
@@ -58,8 +75,8 @@ Java_org_rockbox_RockboxService_main(JNIEnv *env, jobject this)
 
     volatile uintptr_t stack = 0;
     stackbegin = stackend = (uintptr_t*) &stack;
+    env_ptr = env;
 
-    (*env)->GetJavaVM(env, &vm_ptr);
     RockboxService_instance = this;
     RockboxService_class = (*env)->GetObjectClass(env, this);
 
diff --git a/firmware/target/hosted/android/system-target.h b/firmware/target/hosted/android/system-target.h
index 9145ab1e84..325c1012af 100644
--- a/firmware/target/hosted/android/system-target.h
+++ b/firmware/target/hosted/android/system-target.h
@@ -21,8 +21,6 @@
 #ifndef __SYSTEM_TARGET_H__
 #define __SYSTEM_TARGET_H__
 
-#include <jni.h>
-
 #define disable_irq()
 #define enable_irq()
 #define disable_irq_save() 0
@@ -32,19 +30,15 @@ void power_off(void);
 void wait_for_interrupt(void);
 void interrupt(void);
 
-/* A JNI environment is specific to its thread, so use the correct way to
- * obtain it: share a pointer to the JavaVM structure and ask that the JNI
- * environment attached to the current thread. */
-static inline JNIEnv* getJavaEnvironment(void)
-{
-    extern JavaVM *vm_ptr;
-    JNIEnv *env = NULL;
-
-    if (vm_ptr)
-        (*vm_ptr)->GetEnv(vm_ptr, (void**) &env, JNI_VERSION_1_2);
-
-    return env;
-}
+ /* don't pull in jni.h for every user of this file, it should be only needed
+  * within the target tree (if at all)
+  * define this before #including system.h or system-target.h */
+#ifdef _SYSTEM_WITH_JNI
+#include <jni.h>
+/*
+ * discover the JNIEnv for this the calling thread in case it's not known */
+extern JNIEnv* getJavaEnvironment(void);
+#endif /* _SYSTEM_WITH_JNI */
 
 #endif /* __SYSTEM_TARGET_H__ */
 
diff --git a/firmware/target/hosted/android/telephony-android.c b/firmware/target/hosted/android/telephony-android.c
index fb2dc37623..64ad436ca7 100644
--- a/firmware/target/hosted/android/telephony-android.c
+++ b/firmware/target/hosted/android/telephony-android.c
@@ -22,16 +22,14 @@
 
 #include <jni.h>
 #include "kernel.h"
-#include "system.h"
 
+extern JNIEnv *env_ptr;
 extern jobject RockboxService_instance;
 
 
 void telephony_init_device(void)
 {
-    JNIEnv *env_ptr = getJavaEnvironment();
     JNIEnv e = *env_ptr;
-
     jclass class = e->FindClass(env_ptr, "org/rockbox/RockboxTelephony");
     jmethodID constructor = e->GetMethodID(env_ptr, class, "<init>", "(Landroid/content/Context;)V");