hikey960: HiFi3 DSP firmware and documentation

HiFi3 DSP firmware source code, documentation to build and understand DSP

Change-Id: I752416536cc2165868c56d2a2ba2d60b71c2b9a4
Signed-off-by: Niranjan Yadla <nyadla@cadence.com>
diff --git a/hifi/xaf/hifi-dpf/audio/xa-class-mixer.c b/hifi/xaf/hifi-dpf/audio/xa-class-mixer.c
new file mode 100644
index 0000000..ac2ff9a
--- /dev/null
+++ b/hifi/xaf/hifi-dpf/audio/xa-class-mixer.c
@@ -0,0 +1,870 @@
+/*******************************************************************************
+* Copyright (C) 2018 Cadence Design Systems, Inc.
+* 
+* Permission is hereby granted, free of charge, to any person obtaining
+* a copy of this software and associated documentation files (the
+* "Software"), to use this Software with Cadence processor cores only and 
+* not with any other processors and platforms, subject to
+* the following conditions:
+* 
+* The above copyright notice and this permission notice shall be included
+* in all copies or substantial portions of the Software.
+* 
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+******************************************************************************/
+
+/*******************************************************************************
+ * xa-class-mixer.c
+ *
+ * Generic mixer component class
+ *
+ ******************************************************************************/
+
+#define MODULE_TAG                      MIXER
+
+/*******************************************************************************
+ * Includes
+ ******************************************************************************/
+
+#include "xf.h"
+#include "xa-class-base.h"
+#include "audio/xa-mixer-api.h"
+
+/*******************************************************************************
+ * Tracing tags
+ ******************************************************************************/
+
+TRACE_TAG(INIT, 1);
+TRACE_TAG(WARNING, 1);
+TRACE_TAG(INFO, 1);
+TRACE_TAG(INPUT, 1);
+TRACE_TAG(OUTPUT, 1);
+
+/*******************************************************************************
+ * Data structures
+ ******************************************************************************/
+
+/* ...mixed source - input data */
+typedef struct XATrack
+{
+    /* ...input port data */
+    xf_input_port_t     input;
+
+    /* ...current presentation timestamp (in samples; local to a mixer state) */
+    u32                 pts;
+
+    /* ...total amount of decoded frames since last synchronization point */
+    u32                 decoded;
+
+    /* ...total amount of rendered frames (consumed) since last synchronization point */
+    u32                 rendered;
+
+}   XATrack;
+
+/*******************************************************************************
+ * Helpers
+ ******************************************************************************/
+
+static inline u32 xa_track_test_flags(XATrack *track, u32 flags)
+{
+    return (track->input.flags & flags);
+}
+
+static inline u32 xa_track_set_flags(XATrack *track, u32 flags)
+{
+    return (track->input.flags |= flags);
+}
+
+static inline u32 xa_track_clear_flags(XATrack *track, u32 flags)
+{
+    return (track->input.flags &= ~flags);
+}
+
+static inline u32 xa_track_toggle_flags(XATrack *track, u32 flags)
+{
+    return (track->input.flags ^= flags);
+}
+
+/*******************************************************************************
+ * Mixer data definitions
+ ******************************************************************************/
+
+/* ...mixer data */
+typedef struct XAMixer
+{
+    /***************************************************************************
+     * Control data
+     **************************************************************************/
+
+    /* ...generic audio codec data */
+    XACodecBase         base;
+
+    /* ...input tracks */
+    XATrack             track[XA_MIXER_MAX_TRACK_NUMBER];
+    
+    /* ...output port */
+    xf_output_port_t    output;
+
+    /***************************************************************************
+     * Run-time configuration parameters
+     **************************************************************************/
+
+    /* ...audio frame size in samples */
+    u32                 frame_size;
+
+    /* ...audio frame duration */
+    u32                 frame_duration;
+    
+    /* ...presentation timestamp (in samples; local mixer scope) */
+    u32                 pts;
+    
+}   XAMixer;
+
+/*******************************************************************************
+ * Mixer flags
+ ******************************************************************************/
+
+/* ...output port setup completed */
+#define XA_MIXER_FLAG_OUTPUT_SETUP      __XA_BASE_FLAG(1 << 0)
+
+/*******************************************************************************
+ * Track state flags
+ ******************************************************************************/
+
+/* ...track is idle (will autostart as soon as input data received) */
+#define XA_TRACK_FLAG_IDLE              __XF_INPUT_FLAG(1 << 0)
+
+/* ...track is rendered */
+#define XA_TRACK_FLAG_ACTIVE            __XF_INPUT_FLAG(1 << 1)
+
+/* ...track is paused */
+#define XA_TRACK_FLAG_PAUSED            __XF_INPUT_FLAG(1 << 2)
+
+/* ...track input port is setup */
+#define XA_TRACK_FLAG_INPUT_SETUP       __XF_INPUT_FLAG(1 << 3)
+
+/* ...track has received data */
+#define XA_TRACK_FLAG_RECVD_DATA        __XF_INPUT_FLAG(1 << 4)
+
+/*******************************************************************************
+ * Helper functions
+ ******************************************************************************/
+/* ...Count the tracks that have received data or are active*/
+static inline UWORD32 xa_mixer_check_active(XAMixer *mixer)
+{
+    XATrack        *track;
+    UWORD32            i;
+    UWORD32            cnt = 0;
+    
+    for (track = &mixer->track[i = 0]; i < XA_MIXER_MAX_TRACK_NUMBER; i++, track++)
+    {
+        if (xa_track_test_flags(track, XA_TRACK_FLAG_RECVD_DATA | XA_TRACK_FLAG_ACTIVE))
+            cnt++;
+    }
+    return cnt;
+}
+
+/* ...prepare mixer for steady operation */
+static inline XA_ERRORCODE xa_mixer_prepare_runtime(XAMixer *mixer)
+{
+    XACodecBase    *base = (XACodecBase *) mixer;
+    xf_message_t   *m = xf_msg_dequeue(&mixer->output.queue);
+    xf_start_msg_t *msg = m->buffer;
+    u32             frame_size;
+    u32             factor;
+    
+    /* ...query mixer parameters */
+    XA_API(base, XA_API_CMD_GET_CONFIG_PARAM, XA_MIXER_CONFIG_PARAM_SAMPLE_RATE, &msg->sample_rate);
+    XA_API(base, XA_API_CMD_GET_CONFIG_PARAM, XA_MIXER_CONFIG_PARAM_CHANNELS, &msg->channels);
+    XA_API(base, XA_API_CMD_GET_CONFIG_PARAM, XA_MIXER_CONFIG_PARAM_PCM_WIDTH, &msg->pcm_width);
+    XA_API(base, XA_API_CMD_GET_MEM_INFO_SIZE, 0, &msg->input_length);
+    XA_API(base, XA_API_CMD_GET_MEM_INFO_SIZE, XA_MIXER_MAX_TRACK_NUMBER, &msg->output_length);
+    XA_API(base, XA_API_CMD_GET_CONFIG_PARAM, XA_MIXER_CONFIG_PARAM_FRAME_SIZE, &frame_size);
+
+    /* ...calculate mixer frame duration; get upsample factor */
+    XF_CHK_ERR(factor = xf_timebase_factor(msg->sample_rate), XA_MIXER_CONFIG_FATAL_RANGE);
+
+    /* ...set mixer frame duration */
+    mixer->frame_duration = frame_size * factor;
+    
+    /* ...pass response to caller */
+    xf_response_data(m, sizeof(*msg));
+
+    return XA_NO_ERROR;
+}
+
+/*******************************************************************************
+ * Commands handlers
+ ******************************************************************************/
+
+/* ...EMPTY-THIS-BUFFER command processing */
+static XA_ERRORCODE xa_mixer_empty_this_buffer(XACodecBase *base, xf_message_t *m)
+{
+    XAMixer    *mixer = (XAMixer *) base;
+    u32         i = XF_MSG_DST_PORT(m->id);
+    XATrack    *track = &mixer->track[i];
+
+    /* ...make sure the port is valid */
+    XF_CHK_ERR(i < XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
+    
+    /* ...command is allowed only in "postinit" state */
+    XF_CHK_ERR(base->state & XA_BASE_FLAG_POSTINIT, XA_API_FATAL_INVALID_CMD);
+
+    TRACE(INPUT, _b("track-%u: received buffer [%p]:%u"), i, m->buffer, m->length);
+
+    /* ...update received data for the track */
+    if (m->length)
+        xa_track_set_flags(track, XA_TRACK_FLAG_RECVD_DATA);
+    else
+        xa_track_clear_flags(track, XA_TRACK_FLAG_RECVD_DATA);
+    
+    /* ...place received message into track input port */
+    if (xf_input_port_put(&track->input, m))
+    {
+        /* ...process track autostart if needed */
+        if (xa_track_test_flags(track, XA_TRACK_FLAG_IDLE))
+        {
+            /* ...put track into active state */
+            xa_track_toggle_flags(track, XA_TRACK_FLAG_IDLE | XA_TRACK_FLAG_ACTIVE);
+            
+            /* ...save track presentation timestamp */
+            track->pts = mixer->pts;
+
+            TRACE(INFO, _b("track-%u started (pts=%x)"), i, track->pts);
+        }
+        
+        /* ...schedule data processing if there is output port available */
+        if (xf_output_port_ready(&mixer->output))
+        {
+            /* ...force data processing */
+            xa_base_schedule(base, 0);
+        }
+    }
+    
+    return XA_NO_ERROR;
+}
+
+/* ...FILL-THIS-BUFFER command processing */
+static XA_ERRORCODE xa_mixer_fill_this_buffer(XACodecBase *base, xf_message_t *m)
+{
+    XAMixer    *mixer = (XAMixer *) base;
+    u32         i = XF_MSG_DST_PORT(m->id);
+    
+    /* ...make sure the port is valid */
+    XF_CHK_ERR(i == XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
+    
+    /* ...command is allowed only in "postinit" state */
+    XF_CHK_ERR(base->state & XA_BASE_FLAG_POSTINIT, XA_API_FATAL_INVALID_CMD);
+
+    /* ...process runtime initialization explicitly */
+    if (base->state & XA_BASE_FLAG_RUNTIME_INIT)
+    {
+        /* ...message must be zero-length */
+        XF_CHK_ERR(m->length == 0, XA_MIXER_EXEC_FATAL_STATE);
+    }
+    else if (m->length != 0) /* ...EOS response */
+    {
+        /* ...message must have exactly expected size (there is no ordered abortion) */
+        XF_CHK_ERR(m->length == mixer->output.length, XA_MIXER_EXEC_FATAL_STATE);
+    }
+
+    TRACE(OUTPUT, _b("received output buffer [%p]:%u"), m->buffer, m->length);
+    
+    /* ...put message into output port */
+    if (xf_output_port_put(&mixer->output, m))
+    {
+        /* ...force data processing */
+        xa_base_schedule(base, 0);
+    }
+
+    return XA_NO_ERROR;
+}
+
+/* ...output port routing */
+static XA_ERRORCODE xa_mixer_port_route(XACodecBase *base, xf_message_t *m)
+{
+    XAMixer                *mixer = (XAMixer *) base;
+    xf_route_port_msg_t    *cmd = m->buffer;
+    xf_output_port_t       *port = &mixer->output;
+    u32                     src = XF_MSG_DST(m->id);
+    u32                     dst = cmd->dst;
+    
+    /* ...command is allowed only in "postinit" state */
+    XF_CHK_ERR(base->state & XA_BASE_FLAG_POSTINIT, XA_API_FATAL_INVALID_CMD);
+
+    /* ...make sure output port is addressed */
+    XF_CHK_ERR(XF_MSG_DST_PORT(m->id) == XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
+
+    /* ...make sure port is not routed yet */
+    XF_CHK_ERR(!xf_output_port_routed(port), XA_API_FATAL_INVALID_CMD_TYPE);
+
+    /* ...route output port - allocate queue */
+    XF_CHK_ERR(xf_output_port_route(port, __XF_MSG_ID(dst, src), cmd->alloc_number, cmd->alloc_size, cmd->alloc_align) == 0, XA_API_FATAL_MEM_ALLOC);
+
+    /* ...schedule processing instantly - tbd - check if we have anything pending on input */
+    xa_base_schedule(base, 0);
+    
+    /* ...pass success result to caller */
+    xf_response_ok(m);
+    
+    return XA_NO_ERROR;
+}
+
+/* ...port unroute command */
+static XA_ERRORCODE xa_mixer_port_unroute(XACodecBase *base, xf_message_t *m)
+{
+    XAMixer            *mixer = (XAMixer *) base;
+    xf_output_port_t   *port = &mixer->output;
+    
+    /* ...command is allowed only in "postinit" state */
+    XF_CHK_ERR(base->state & XA_BASE_FLAG_POSTINIT, XA_API_FATAL_INVALID_CMD);
+
+    /* ...make sure output port is addressed */
+    XF_CHK_ERR(XF_MSG_DST_PORT(m->id) == XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
+
+    /* ...cancel any pending processing */
+    xa_base_cancel(base);
+
+    /* ...clear output-port-setup condition */
+    base->state &= ~XA_MIXER_FLAG_OUTPUT_SETUP;
+
+    /* ...pass flush command down the graph */
+    if (xf_output_port_flush(port, XF_FLUSH))
+    {
+        TRACE(INFO, _b("port is idle; instantly unroute"));
+
+        /* ...flushing sequence is not needed; command may be satisfied instantly */
+        xf_output_port_unroute(port);
+
+        /* ...pass response to the proxy */
+        xf_response_ok(m);
+    }
+    else
+    {
+        TRACE(INFO, _b("port is busy; propagate unroute command"));
+
+        /* ...flushing sequence is started; save flow-control message */
+        xf_output_port_unroute_start(port, m);
+    }
+
+    return XA_NO_ERROR;
+}
+
+/* ...PAUSE message processing */
+static XA_ERRORCODE xa_mixer_pause(XACodecBase *base, xf_message_t *m)
+{
+    XAMixer    *mixer = (XAMixer *) base;
+    u32         i = XF_MSG_DST_PORT(m->id);
+    XATrack    *track = &mixer->track[i];
+    
+    /* ...make sure the buffer is empty */
+    XF_CHK_ERR(m->length == 0, XA_API_FATAL_INVALID_CMD_TYPE);
+    
+    /* ...check destination port is valid */
+    XF_CHK_ERR(i < XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
+
+    /* ...check for actual track flags */
+    if (xa_track_test_flags(track, XA_TRACK_FLAG_ACTIVE))
+    {
+        /* ...switch to paused state */
+        xa_track_toggle_flags(track, XA_TRACK_FLAG_ACTIVE | XA_TRACK_FLAG_PAUSED);
+
+        /* ...other tracks may be waiting for this one, so force data processing */
+        if (xf_output_port_ready(&mixer->output))
+        {
+            xa_base_schedule(base, 0);
+        }
+
+        TRACE(INFO, _b("mixer[%p]::track[%u] paused"), mixer, i);
+    }
+    else
+    {
+        /* ...track is in idle state and pausing here means suspending */
+        TRACE(INFO, _b("mixer[%p]::track[%u] is not active"), mixer, i);
+    }
+
+    /* ...complete message immediately */
+    xf_response(m);
+    
+    return XA_NO_ERROR;
+}
+
+/* ...RESUME command processing */
+static XA_ERRORCODE xa_mixer_resume(XACodecBase *base, xf_message_t *m)
+{
+    XAMixer    *mixer = (XAMixer *) base;
+    u32         i = XF_MSG_DST_PORT(m->id);
+    XATrack    *track = &mixer->track[i];
+    
+    /* ...make sure the buffer is empty */
+    XF_CHK_ERR(m->length == 0, XA_API_FATAL_INVALID_CMD_TYPE);
+    
+    /* ...check destination port is valid */
+    XF_CHK_ERR(i < XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
+    
+    /* ...check for actual track state */
+    if (xa_track_test_flags(track, XA_TRACK_FLAG_PAUSED))
+    {
+        /* ...switch track to active state */
+        xa_track_toggle_flags(track, XA_TRACK_FLAG_ACTIVE | XA_TRACK_FLAG_PAUSED);
+
+        /* ...reset track presentation timestamp - tbd */
+        track->pts = mixer->pts;
+
+        /* ...force data processing if there is an output buffer */
+        if (xf_output_port_ready(&mixer->output))
+        {
+            xa_base_schedule(base, 0);
+        }
+
+        TRACE(INFO, _b("mixer[%p]::track[%u] resumed"), mixer, i);
+    }
+    else
+    {
+        /* ...track is in idle state; do nothing */
+        TRACE(INFO, _b("mixer[%p]::track[%u] is not paused"), mixer, i);
+    }
+    
+    /* ...complete message */
+    xf_response(m);
+    
+    return XA_NO_ERROR;
+}
+
+/* ...FLUSH command processing */
+static XA_ERRORCODE xa_mixer_flush(XACodecBase *base, xf_message_t *m)
+{
+    XAMixer    *mixer = (XAMixer *) base;
+    u32         i = XF_MSG_DST_PORT(m->id);
+    XATrack    *track = &mixer->track[i];
+
+    /* ...make sure the buffer is empty */
+    XF_CHK_ERR(m->length == 0, XA_API_FATAL_INVALID_CMD_TYPE);
+
+    /* ...check destination port index */
+    if (i == XA_MIXER_MAX_TRACK_NUMBER)
+    {
+        /* ...flushing response received; that is a port unrouting sequence */
+        XF_CHK_ERR(xf_output_port_unrouting(&mixer->output), XA_API_FATAL_INVALID_CMD_TYPE);
+        
+        /* ...complete unroute sequence */
+        xf_output_port_unroute_done(&mixer->output);
+
+        TRACE(INFO, _b("port is unrouted"));
+
+        return XA_NO_ERROR;
+    }
+
+    /* ...check destination port index is valid */
+    XF_CHK_ERR(i < XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
+
+    /* ...input port flushing; check the track state is valid */
+    if (xa_track_test_flags(track, XA_TRACK_FLAG_ACTIVE | XA_TRACK_FLAG_PAUSED))
+    {
+        /* ...purge input port */
+        xf_input_port_purge(&track->input);
+
+        /* ...force clearing of ACTIVE and INPUT_SETUP condition */
+        xa_track_clear_flags(track, XA_TRACK_FLAG_ACTIVE | XA_TRACK_FLAG_PAUSED | XA_TRACK_FLAG_INPUT_SETUP);
+
+        /* ...and enter into idle state */
+        xa_track_set_flags(track, XA_TRACK_FLAG_IDLE);
+
+        /* ...other tracks may be waiting for this track, so force data processing */
+        if (xf_output_port_ready(&mixer->output))
+        {
+            xa_base_schedule(base, 0);
+        }
+
+        TRACE(INFO, _b("mixer[%p]::track[%u] flushed"), mixer, i);
+    }
+
+    /* ...complete message instantly (no propagation to output port) */
+    xf_response(m);
+
+    return XA_NO_ERROR;
+}
+
+/*******************************************************************************
+ * Codec API implementation
+ ******************************************************************************/
+
+/* ...buffers handling */
+static XA_ERRORCODE xa_mixer_memtab(XACodecBase *base, WORD32 idx, WORD32 type, WORD32 size, WORD32 align, u32 core)
+{
+    XAMixer    *mixer = (XAMixer *)base;
+    
+    if (type == XA_MEMTYPE_INPUT)
+    {
+        XATrack    *track = &mixer->track[idx];
+
+        /* ...input buffer allocation; check track number is sane */
+        XF_CHK_ERR(idx < XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
+
+        /* ...create input port for a track */
+        XF_CHK_ERR(xf_input_port_init(&track->input, size, align, core) == 0, XA_API_FATAL_MEM_ALLOC);
+
+        /* ...set input port buffer */
+        XA_API(base, XA_API_CMD_SET_MEM_PTR, idx, track->input.buffer);
+
+        /* ...put track into idle state (will start as soon as we receive data) */
+        xa_track_set_flags(track, XA_TRACK_FLAG_IDLE);
+        
+        TRACE(INIT, _b("mixer[%p]::track[%u] input port created - size=%u"), mixer, idx, size);
+    }
+    else
+    {
+        /* ...output buffer allocation */
+        XF_CHK_ERR(type == XA_MEMTYPE_OUTPUT, XA_API_FATAL_INVALID_CMD_TYPE);
+
+        /* ...check port number is what we expect */
+        XF_CHK_ERR(idx == XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
+
+        /* ...set mixer frame-size (in samples - for timestamp tracking) */
+        XA_API(base, XA_API_CMD_GET_CONFIG_PARAM, XA_MIXER_CONFIG_PARAM_FRAME_SIZE, &mixer->frame_size);
+        
+        /* ...create output port for a track */
+        XF_CHK_ERR(xf_output_port_init(&mixer->output, size) == 0, XA_API_FATAL_MEM_ALLOC);
+        
+        TRACE(INIT, _b("mixer[%p] output port created; size=%u"), mixer, size);
+    }
+
+    return XA_NO_ERROR;
+}
+
+/* ...preprocessing function */
+static XA_ERRORCODE xa_mixer_preprocess(XACodecBase *base)
+{
+    XAMixer        *mixer = (XAMixer *) base;
+    XATrack        *track;
+    u8              i;
+    XA_ERRORCODE    e = XA_MIXER_EXEC_NONFATAL_NO_DATA;
+
+    /* ...prepare output buffer */
+    if (!(base->state & XA_MIXER_FLAG_OUTPUT_SETUP))
+    {
+        void   *output;
+
+        /* ...set output buffer pointer */
+        if (base->state & XA_BASE_FLAG_RUNTIME_INIT)
+        {
+            /* ...no actual data processing during initialization */
+            return XA_NO_ERROR;
+        }
+        else if ((output = xf_output_port_data(&mixer->output)) == NULL)
+        {
+            /* ...no output buffer available */
+            return e;
+        }
+            
+        /* ...set output buffer pointer */
+        XA_API(base, XA_API_CMD_SET_MEM_PTR, XA_MIXER_MAX_TRACK_NUMBER, output);
+
+        /* ...mark output port is setup */
+        base->state ^= XA_MIXER_FLAG_OUTPUT_SETUP;
+    }
+    
+    /* ...check EOS */
+    if (!xa_mixer_check_active(mixer))
+    {
+        /* ...push EOS to output port */
+        xf_output_port_produce(&mixer->output, 0);
+        TRACE(INFO, _b("mixer[%p]::EOS generated"), mixer);
+    }
+
+    /* ...setup input buffer pointers and length */
+    for (track = &mixer->track[i = 0]; i < XA_MIXER_MAX_TRACK_NUMBER; i++, track++)
+    {
+        /* ...skip tracks that are not played */
+        if (!xa_track_test_flags(track, XA_TRACK_FLAG_ACTIVE))  continue;
+
+        /* ...set temporary mixing request */
+        e = XA_NO_ERROR;
+
+        /* ...skip the tracks that has been setup already */
+        if (xa_track_test_flags(track, XA_TRACK_FLAG_INPUT_SETUP))  continue;
+
+        /* ...found active track that hasn't been setup yet */
+        TRACE(INPUT, _b("track-%u: ts=%x vs mts=%x"), i, track->pts, mixer->pts);
+
+        /* ...if track presentation timestamp is in the future, do nothing yet really */
+        if (!xf_time_after(track->pts, mixer->pts))
+        {
+            u32     filled;
+            
+            /* ...take actual data from input port (mixer is always using internal buffer) */
+            if (!xf_input_port_fill(&track->input))
+            {
+                /* ...failed to prefill input buffer - no sufficient data yet */
+                return XA_MIXER_EXEC_NONFATAL_NO_DATA;
+            }
+            else
+            {
+                /* ...retrieve number of bytes available */
+                filled = xf_input_port_level(&track->input);
+            }
+
+            /* ...set total number of bytes we have in buffer */
+            XA_API(base, XA_API_CMD_SET_INPUT_BYTES, i, &filled);
+
+            /* ...actual data is to be played */
+            TRACE(INPUT, _b("track-%u: filled %u bytes"), i, filled);
+        }
+        
+        /* ...mark the track input is setup (emit silence or actual data) */
+        xa_track_set_flags(track, XA_TRACK_FLAG_INPUT_SETUP);
+    }
+
+    /* ...do mixing operation only when all active tracks are setup */
+    return e;
+}
+
+/* ...postprocessing function */
+static XA_ERRORCODE xa_mixer_postprocess(XACodecBase *base, int done)
+{
+    XAMixer        *mixer = (XAMixer *) base;
+    XATrack        *track;
+    u32             produced;
+    u32             consumed;
+    u8              i;
+
+    /* ...process execution stage transitions */
+    if (done)
+    {
+        if (base->state & XA_BASE_FLAG_RUNTIME_INIT)
+        {
+            /* ...failed to initialize runtime (can't be? - tbd)*/
+            BUG(1, _x("breakpoint"));
+        }
+        else if (base->state & XA_BASE_FLAG_EXECUTION)
+        {
+            /* ...enter into execution state; initialize runtime */
+            return XA_CHK(xa_mixer_prepare_runtime(mixer));
+        }
+        else
+        {
+            /* ...mixer operation is over (can't be? - tbd) */
+            BUG(1, _x("breakpoint"));
+        }
+    }
+
+    /* ...input ports maintenance; process all tracks */
+    for (track = &mixer->track[i = 0]; i < XA_MIXER_MAX_TRACK_NUMBER; i++, track++)
+    {
+        /* ...skip the tracks that are not runing */
+        if (!xa_track_test_flags(track, XA_TRACK_FLAG_ACTIVE))  continue;
+
+        /* ...clear input setup flag */
+        xa_track_clear_flags(track, XA_TRACK_FLAG_INPUT_SETUP);
+        
+        /* ...advance track presentation timestamp */
+        track->pts += mixer->frame_size;
+        
+        /* ...get total amount of consumed bytes */
+        XA_API(base, XA_API_CMD_GET_CURIDX_INPUT_BUF, i, &consumed);
+
+        TRACE(INPUT, _b("track-%u::postprocess(c=%u, ts=%x)"), i, consumed, track->pts);
+
+        /* ...consume that amount from input port (may be zero) */
+        xf_input_port_consume(&track->input, consumed);
+        
+        /* ...check if input port is done */
+        if (xf_input_port_done(&track->input))
+        {
+            /* ...input stream is over; return zero-length input back to caller */
+            xf_input_port_purge(&track->input);
+
+            /* ...switch to idle state */
+            xa_track_toggle_flags(track, XA_TRACK_FLAG_ACTIVE | XA_TRACK_FLAG_IDLE);
+
+            TRACE(INFO, _b("mixer[%p]::track[%u] completed"), mixer, i);
+        }
+    }
+
+    /* ...check if we have produced anything */
+    XA_API(base, XA_API_CMD_GET_OUTPUT_BYTES, XA_MIXER_MAX_TRACK_NUMBER, &produced);
+
+    TRACE(OUTPUT, _b("mixer[%p]::postprocess(p=%u, ts=%x, done=%u)"), mixer, produced, mixer->pts, done);
+
+    /* ...output port maintenance */
+    if (produced)
+    {
+        /* ...make sure we have produced exactly single frame */
+        BUG(produced != mixer->output.length, _x("Invalid length: %u != %u"), produced, mixer->output.length);
+        
+        /* ...steady mixing process; advance mixer presentation timestamp */
+        mixer->pts += mixer->frame_size;
+
+        /* ...push data from output port */
+        xf_output_port_produce(&mixer->output, produced);
+
+        /* ...clear output-setup condition */
+        base->state &= ~XA_MIXER_FLAG_OUTPUT_SETUP;
+    }    
+    
+    /* ...reschedule data processing if there is a pending output message */
+    if (xf_output_port_ready(&mixer->output))
+    {
+        /* ...schedule execution with respect to urgency */
+        xa_base_schedule(base, (produced ? mixer->frame_duration : 0));
+    }
+
+    return XA_NO_ERROR;
+}
+
+/*******************************************************************************
+ * Command-processing function
+ ******************************************************************************/
+
+/* ...command hooks */
+static XA_ERRORCODE (* const xa_mixer_cmd[])(XACodecBase *, xf_message_t *) =
+{
+    /* ...set-parameter - actually, same as in generic case */
+    [XF_OPCODE_TYPE(XF_SET_PARAM)] = xa_base_set_param,
+    [XF_OPCODE_TYPE(XF_GET_PARAM)] = xa_base_get_param,
+
+    /* ...output port routing/unrouting */
+    [XF_OPCODE_TYPE(XF_ROUTE)] = xa_mixer_port_route,
+    [XF_OPCODE_TYPE(XF_UNROUTE)] = xa_mixer_port_unroute,
+
+    /* ...input/output buffers processing */
+    [XF_OPCODE_TYPE(XF_EMPTY_THIS_BUFFER)] = xa_mixer_empty_this_buffer,
+    [XF_OPCODE_TYPE(XF_FILL_THIS_BUFFER)] = xa_mixer_fill_this_buffer,
+    [XF_OPCODE_TYPE(XF_FLUSH)] = xa_mixer_flush,
+
+    /* ...track control */
+    [XF_OPCODE_TYPE(XF_PAUSE)] = xa_mixer_pause,
+    [XF_OPCODE_TYPE(XF_RESUME)] = xa_mixer_resume,
+};
+
+/* ...total number of commands supported */
+#define XA_MIXER_CMD_NUM        (sizeof(xa_mixer_cmd) / sizeof(xa_mixer_cmd[0]))
+
+/*******************************************************************************
+ * Entry points
+ ******************************************************************************/
+
+/* ...mixer termination-state command processor */
+static int xa_mixer_terminate(xf_component_t *component, xf_message_t *m)
+{
+    XAMixer    *mixer = (XAMixer *) component;
+    u32         opcode = m->opcode;
+    
+    if (m == xf_output_port_control_msg(&mixer->output))
+    {
+        /* ...output port flushing complete; mark port is idle and terminate */
+        xf_output_port_flush_done(&mixer->output);
+        return -1;
+    }
+    else if (opcode == XF_FILL_THIS_BUFFER && xf_output_port_routed(&mixer->output))
+    {
+        /* ...output buffer returned by the sink component; ignore and keep waiting */
+        TRACE(OUTPUT, _b("collect output buffer"));
+        return 0;
+    }
+    else if (opcode == XF_UNREGISTER)
+    {
+        /* ...ignore subsequent unregister command/response */
+        return 0;
+    }
+    else
+    {
+        /* ...everything else is responded with generic failure */
+        xf_response_err(m);
+        return 0;
+    }
+}
+
+/* ...mixer class destructor */
+static int xa_mixer_destroy(xf_component_t *component, xf_message_t *m)
+{
+    XAMixer    *mixer = (XAMixer *) component;
+    u32         core = xf_component_core(component);
+    u32         i;
+    
+    /* ...destroy all inputs */
+    for (i = 0; i < XA_MIXER_MAX_TRACK_NUMBER; i++)
+    {
+        xf_input_port_destroy(&mixer->track[i].input, core);
+    }
+
+    /* ...destroy output port */
+    xf_output_port_destroy(&mixer->output, core);
+
+    /* ...destroy base object */
+    xa_base_destroy(&mixer->base, XF_MM(sizeof(*mixer)), core);
+
+    TRACE(INIT, _b("mixer[%p] destroyed"), mixer);
+
+    return 0;
+}
+
+/* ...mixer class first-stage destructor */
+static int xa_mixer_cleanup(xf_component_t *component, xf_message_t *m)
+{
+    XAMixer    *mixer = (XAMixer *) component;
+    u32         i;
+
+    /* ...complete message with error result code */
+    xf_response_err(m);
+    
+    /* ...cancel internal scheduling message if needed */
+    xa_base_cancel(&mixer->base);    
+    
+    /* ...purge all input ports (specify "unregister"? - don't know yet - tbd) */
+    for (i = 0; i < XA_MIXER_MAX_TRACK_NUMBER; i++)
+    {
+        xf_input_port_purge(&mixer->track[i].input);
+    }
+
+    /* ...flush output port */
+    if (xf_output_port_flush(&mixer->output, XF_FLUSH))
+    {
+        /* ...flushing sequence is not needed; destroy mixer */
+        return xa_mixer_destroy(component, NULL);
+    }
+    else
+    {
+        /* ...wait until output port is cleaned; adjust component hooks */
+        component->entry = xa_mixer_terminate;
+        component->exit = xa_mixer_destroy;
+        
+        TRACE(INIT, _b("mixer[%p] cleanup sequence started"), mixer);
+
+        /* ...indicate that second stage is required */
+        return 1;
+    }
+}
+
+/* ...mixer class factory */
+xf_component_t * xa_mixer_factory(u32 core, xa_codec_func_t process)
+{
+    XAMixer    *mixer;
+
+    /* ...construct generic audio component */
+    XF_CHK_ERR(mixer = (XAMixer *)xa_base_factory(core, XF_MM(sizeof(*mixer)), process), NULL);
+
+    /* ...set generic codec API */
+    mixer->base.memtab = xa_mixer_memtab;
+    mixer->base.preprocess = xa_mixer_preprocess;
+    mixer->base.postprocess = xa_mixer_postprocess;
+
+    /* ...set message-processing table */
+    mixer->base.command = xa_mixer_cmd;
+    mixer->base.command_num = XA_MIXER_CMD_NUM;
+
+    /* ...set component destructor hook */
+    mixer->base.component.exit = xa_mixer_cleanup;
+    
+    TRACE(INIT, _b("Mixer[%p] created"), mixer);
+
+    /* ...return handle to component */
+    return (xf_component_t *) mixer;
+}