Commit FS#12150 - Fully-functional audio mixer - and finally whip old limitations about playback of voice and other sounds when paused. Channels are independent in state and amplitude. Fade on stop/pause is handled by the channel's volume control rather than global volume which means it now works from anywhere. Opens up the possibility of plugin sounds during music playback by merely adding an additional channel enum. If any PCM drivers were not properly modified, see one of the last comments in the task for a description of the simple change that is expected. Some params are tunable in firmware/export/pcm-mixer.h as well.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30097 a1c6a512-1295-4272-9138-f99709370657

1 files changed, 81 insertions, 0 deletions

diff --git a/firmware/export/pcm-internal.h b/firmware/export/pcm-internal.h
new file mode 100644
index 0000000000..d69138f534
--- /dev/null
+++ b/firmware/export/pcm-internal.h
@@ -0,0 +1,81 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2005 by Linus Nielsen Feltzing
+ * Copyright (C) 2011 by Michael Sevakis
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+ * KIND, either express or implied.
+ *
+ ****************************************************************************/
+#ifndef PCM_INTERNAL_H
+#define PCM_INTERNAL_H
+
+/** The following are for internal use between pcm.c and target-
+    specific portion **/
+
+/* Called by the bottom layer ISR when more data is needed. Returns non-
+ * zero size if more data is to be played. Setting start to NULL
+ * forces stop. */
+void pcm_play_get_more_callback(void **start, size_t *size);
+
+/* Called by the bottom layer ISR after next transfer has begun in order
+   to fill more data for next "get more" callback to implement double-buffered
+   callbacks - except for a couple ASM handlers, help drivers to implement
+   this functionality with minimal overhead */
+static FORCE_INLINE void pcm_play_dma_started_callback(void)
+{
+    extern void (* pcm_play_dma_started)(void);
+    void (* callback)(void) = pcm_play_dma_started;
+    if (callback)
+        callback();
+}
+
+extern unsigned long pcm_curr_sampr;
+extern unsigned long pcm_sampr;
+extern int pcm_fsel;
+
+#ifdef HAVE_PCM_DMA_ADDRESS
+void * pcm_dma_addr(void *addr);
+#endif
+
+extern volatile bool pcm_playing;
+extern volatile bool pcm_paused;
+
+void pcm_play_dma_lock(void);
+void pcm_play_dma_unlock(void);
+void pcm_play_dma_init(void) INIT_ATTR;
+void pcm_play_dma_start(const void *addr, size_t size);
+void pcm_play_dma_stop(void);
+void pcm_play_dma_pause(bool pause);
+const void * pcm_play_dma_get_peak_buffer(int *count);
+
+void pcm_dma_apply_settings(void);
+
+#ifdef HAVE_RECORDING
+
+/* DMA transfer in is currently active */
+extern volatile bool pcm_recording;
+
+/* APIs implemented in the target-specific portion */
+void pcm_rec_dma_init(void);
+void pcm_rec_dma_close(void);
+void pcm_rec_dma_start(void *addr, size_t size);
+void pcm_rec_dma_record_more(void *start, size_t size);
+void pcm_rec_dma_stop(void);
+const void * pcm_rec_dma_get_peak_buffer(void);
+
+#endif /* HAVE_RECORDING */
+
+#endif /* PCM_INTERNAL_H */