1 files changed, 264 insertions, 0 deletions

diff --git a/firmware/pcm_sw_volume.c b/firmware/pcm_sw_volume.c
new file mode 100644
index 0000000000..bcd498fe46
--- /dev/null
+++ b/firmware/pcm_sw_volume.c
@@ -0,0 +1,264 @@
+/***************************************************************************
+ *             __________               __   ___.
+ *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
+ *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
+ *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
+ *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
+ *                     \/            \/     \/    \/            \/
+ * $Id$
+ *
+ * Copyright (C) 2013 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.
+ *
+ ****************************************************************************/
+#include "config.h"
+#include "system.h"
+#include "pcm.h"
+#include "pcm-internal.h"
+#include "dsp-util.h"
+#include "fixedpoint.h"
+#include "pcm_sw_volume.h"
+
+/* source buffer from client */
+static const void * volatile src_buf_addr = NULL;
+static size_t volatile src_buf_rem = 0;
+
+#define PCM_PLAY_DBL_BUF_SIZE (PCM_PLAY_DBL_BUF_SAMPLE*PCM_SAMPLE_SIZE)
+
+/* double buffer and frame length control */
+static int16_t pcm_dbl_buf[2][PCM_PLAY_DBL_BUF_SAMPLES*2]
+        PCM_DBL_BUF_BSS MEM_ALIGN_ATTR;
+static size_t pcm_dbl_buf_size[2];
+static int pcm_dbl_buf_num = 0;
+static size_t frame_size;
+static unsigned int frame_count, frame_err, frame_frac;
+
+#ifdef AUDIOHW_HAVE_PRESCALER
+static int32_t prescale_factor = PCM_FACTOR_UNITY;
+static int32_t vol_factor_l = 0, vol_factor_r = 0;
+#endif /* AUDIOHW_HAVE_PRESCALER */
+
+/* pcm scaling factors */
+static int32_t pcm_factor_l = 0, pcm_factor_r = 0;
+
+#define PCM_FACTOR_CLIP(f) \
+    MAX(MIN((f), PCM_FACTOR_MAX), PCM_FACTOR_MIN)
+#define PCM_SCALE_SAMPLE(f, s) \
+    (((f) * (s) + PCM_FACTOR_UNITY/2) >> PCM_FACTOR_BITS)
+
+
+/* TODO: #include CPU-optimized routines and move this to /firmware/asm */
+static inline void pcm_copy_buffer(int16_t *dst, const int16_t *src,
+                                   size_t size)
+{
+    int32_t factor_l = pcm_factor_l;
+    int32_t factor_r = pcm_factor_r;
+
+    if (LIKELY(factor_l <= PCM_FACTOR_UNITY && factor_r <= PCM_FACTOR_UNITY))
+    {
+        /* All cut or unity */
+        while (size)
+        {
+            *dst++ = PCM_SCALE_SAMPLE(factor_l, *src++);
+            *dst++ = PCM_SCALE_SAMPLE(factor_r, *src++);
+            size -= PCM_SAMPLE_SIZE;
+        }
+    }
+    else
+    {
+        /* Any positive gain requires clipping */
+        while (size)
+        {
+            *dst++ = clip_sample_16(PCM_SCALE_SAMPLE(factor_l, *src++));
+            *dst++ = clip_sample_16(PCM_SCALE_SAMPLE(factor_r, *src++));
+            size -= PCM_SAMPLE_SIZE;
+        }
+    }
+}
+
+bool pcm_play_dma_complete_callback(enum pcm_dma_status status,
+                                    const void **addr, size_t *size)
+{
+    /* Check status callback first if error */
+    if (status < PCM_DMAST_OK)
+        status = pcm_play_call_status_cb(status);
+
+    size_t sz = pcm_dbl_buf_size[pcm_dbl_buf_num];
+
+    if (status >= PCM_DMAST_OK && sz)
+    {
+        /* Do next chunk */
+        *addr = pcm_dbl_buf[pcm_dbl_buf_num];
+        *size = sz;
+        return true;
+    }
+    else
+    {
+        /* This is a stop chunk or error */
+        pcm_play_stop_int();
+        return false;
+    }
+}
+
+/* Equitably divide large source buffers amongst double buffer frames;
+   frames smaller than or equal to the double buffer chunk size will play
+   in one chunk */
+static void update_frame_params(size_t size)
+{
+    int count    = size / PCM_SAMPLE_SIZE;
+    frame_count  = (count + PCM_PLAY_DBL_BUF_SAMPLES - 1) /
+                   PCM_PLAY_DBL_BUF_SAMPLES;
+    int perframe = count / frame_count;
+    frame_size   = perframe * PCM_SAMPLE_SIZE;
+    frame_frac   = count - perframe * frame_count;
+    frame_err    = 0;
+}
+
+/* Obtain the next buffer and prepare it for pcm driver playback */
+enum pcm_dma_status
+pcm_play_dma_status_callback_int(enum pcm_dma_status status)
+{
+    if (status != PCM_DMAST_STARTED)
+        return status;
+
+    size_t size = pcm_dbl_buf_size[pcm_dbl_buf_num];
+    const void *addr = src_buf_addr + size;
+
+    size = src_buf_rem - size;
+
+    if (size == 0 && pcm_get_more_int(&addr, &size))
+    {
+        update_frame_params(size);
+        pcm_play_call_status_cb(PCM_DMAST_STARTED);
+    }
+
+    src_buf_addr = addr;
+    src_buf_rem = size;
+
+    if (size != 0)
+    {
+        size = frame_size;
+
+        if ((frame_err += frame_frac) >= frame_count)
+        {
+            frame_err -= frame_count;
+            size += PCM_SAMPLE_SIZE;
+        }
+    }
+
+    pcm_dbl_buf_num ^= 1;
+    pcm_dbl_buf_size[pcm_dbl_buf_num] = size;
+    pcm_copy_buffer(pcm_dbl_buf[pcm_dbl_buf_num], addr, size);
+
+    return PCM_DMAST_OK;
+}
+
+/* Prefill double buffer and start pcm driver */
+static void start_pcm(bool reframe)
+{
+    pcm_dbl_buf_num = 0;
+    pcm_dbl_buf_size[0] = 0;
+
+    if (reframe)
+        update_frame_params(src_buf_rem);
+
+    pcm_play_dma_status_callback(PCM_DMAST_STARTED);
+    pcm_play_dma_status_callback(PCM_DMAST_STARTED);
+
+    pcm_play_dma_start(pcm_dbl_buf[1], pcm_dbl_buf_size[1]);
+}
+
+void pcm_play_dma_start_int(const void *addr, size_t size)
+{
+    src_buf_addr = addr;
+    src_buf_rem = size;
+    start_pcm(true);
+}
+
+void pcm_play_dma_pause_int(bool pause)
+{
+    if (pause)
+        pcm_play_dma_pause(true);
+    else if (src_buf_rem)
+        start_pcm(false);    /* Reprocess in case volume level changed */
+    else
+        pcm_play_stop_int(); /* Playing frame was last frame */
+}
+
+void pcm_play_dma_stop_int(void)
+{
+    pcm_play_dma_stop();
+    src_buf_addr = NULL;
+    src_buf_rem = 0;
+}
+
+/* Return playing buffer from the source buffer */
+const void * pcm_play_dma_get_peak_buffer_int(int *count)
+{
+    const void *addr = src_buf_addr;
+    size_t size = src_buf_rem;
+    const void *addr2 = src_buf_addr;
+
+    if (addr == addr2 && size)
+    {
+        *count = size / PCM_SAMPLE_SIZE;
+        return addr;
+    }
+
+    *count = 0;
+    return NULL;
+}
+
+/* Return the scale factor corresponding to the centibel level */
+static int32_t pcm_centibels_to_factor(int volume)
+{
+    if (volume == PCM_MUTE_LEVEL)
+        return 0; /* mute */
+
+    /* Centibels -> fixedpoint */
+    return fp_factor(PCM_FACTOR_UNITY*volume / 10, PCM_FACTOR_BITS);
+}
+
+#ifdef AUDIOHW_HAVE_PRESCALER
+/* Produce final pcm scale factor */
+static void pcm_sync_prescaler(void)
+{
+    int32_t factor_l = fp_mul(prescale_factor, vol_factor_l, PCM_FACTOR_BITS);
+    int32_t factor_r = fp_mul(prescale_factor, vol_factor_r, PCM_FACTOR_BITS);
+    pcm_factor_l = PCM_FACTOR_CLIP(factor_l);
+    pcm_factor_r = PCM_FACTOR_CLIP(factor_r);
+}
+
+/* Set the prescaler value for all PCM playback */
+void pcm_set_prescaler(int prescale)
+{
+    prescale_factor = pcm_centibels_to_factor(-prescale);
+    pcm_sync_prescaler();
+}
+
+/* Set the per-channel volume cut/gain for all PCM playback */
+void pcm_set_master_volume(int vol_l, int vol_r)
+{
+    vol_factor_l = pcm_centibels_to_factor(vol_l);
+    vol_factor_r = pcm_centibels_to_factor(vol_r);
+    pcm_sync_prescaler();
+}
+
+#else /* ndef AUDIOHW_HAVE_PRESCALER */
+
+/* Set the per-channel volume cut/gain for all PCM playback */
+void pcm_set_master_volume(int vol_l, int vol_r)
+{
+    int32_t factor_l = pcm_centibels_to_factor(vol_l);
+    int32_t factor_r = pcm_centibels_to_factor(vol_r);
+    pcm_factor_l = PCM_FACTOR_CLIP(factor_l);
+    pcm_factor_r = PCM_FACTOR_CLIP(factor_r);
+}
+#endif /* AUDIOHW_HAVE_PRESCALER */