1 files changed, 102 insertions, 0 deletions

diff --git a/firmware/export/pcm_mixer.h b/firmware/export/pcm_mixer.h
new file mode 100644
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+++ b/firmware/export/pcm_mixer.h
@@ -0,0 +1,102 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * 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_MIXER_H
+#define PCM_MIXER_H
+
+/** Simple config **/
+
+/* Length of PCM frames (always) */
+#if CONFIG_CPU == PP5002
+/* There's far less time to do mixing because HW FIFOs are short */
+#define MIX_FRAME_SAMPLES 64
+#else
+/* Assume HW DMA engine is available or sufficient latency exists in the
+   PCM pathway */
+#define MIX_FRAME_SAMPLES 256
+#endif
+
+#if defined(CPU_COLDFIRE) || defined(CPU_PP)
+/* For Coldfire, it's just faster
+   For PortalPlayer, this also avoids more expensive cache coherency */
+#define DOWNMIX_BUF_IBSS    IBSS_ATTR
+#else
+/* Otherwise can't DMA from IRAM, IRAM is pointless or worse */
+#define DOWNMIX_BUF_IBSS
+#endif
+
+
+/** Definitions **/
+
+/* Channels are preassigned for simplicity */
+enum pcm_mixer_channel
+{
+    PCM_MIXER_CHAN_PLAYBACK = 0,
+    PCM_MIXER_CHAN_VOICE,
+#ifndef HAVE_HARDWARE_BEEP
+    PCM_MIXER_CHAN_BEEP,
+#endif
+    /* Add new channel indexes above this line */
+    PCM_MIXER_NUM_CHANNELS,
+};
+
+/* Channel playback states */
+enum channel_status
+{
+    CHANNEL_STOPPED = 0,
+    CHANNEL_PLAYING,
+    CHANNEL_PAUSED,
+};
+
+#define MIX_AMP_UNITY    0x00010000
+#define MIX_AMP_MUTE     0x00000000
+
+
+/** Public interfaces **/
+
+/* Start playback on a channel */
+void mixer_channel_play_data(enum pcm_mixer_channel channel,
+                             pcm_play_callback_type get_more,
+                             unsigned char *start, size_t size);
+
+/* Pause or resume a channel (when started) */
+void mixer_channel_play_pause(enum pcm_mixer_channel channel, bool play);
+
+/* Stop playback on a channel */
+void mixer_channel_stop(enum pcm_mixer_channel channel);
+
+/* Set channel's amplitude factor */
+void mixer_channel_set_amplitude(enum pcm_mixer_channel channel,
+                                 unsigned int amplitude);
+
+/* Return channel's playback status */
+enum channel_status mixer_channel_status(enum pcm_mixer_channel channel);
+
+/* Returns amount data remaining in channel before next callback */
+size_t mixer_channel_get_bytes_waiting(enum pcm_mixer_channel channel);
+
+/* Return pointer to channel's playing audio data and the size remaining */
+void * mixer_channel_get_buffer(enum pcm_mixer_channel channel, int *count);
+
+/* Stop ALL channels and PCM and reset state */
+void mixer_reset(void);
+
+#endif /* PCM_MIXER_H */