pcm: softvol: add support for S24_LE

Tested with the Wolfson WM8524 DAC on a i.MX6UL board and the following
ALSA configuration file using the pcm test utility from alsa-lib:

"""
$ cat /etc/asound.conf
pcm.!default {
    type plug
    slave.pcm "softvol"
}
pcm.softvol {
    type softvol
    slave {
        pcm "hw:0"
    }
    control {
        name "Master"
        card 0
    }
}
ctl.!default {
    type hw
    card 0
}
ctl.softvol {
    type hw
    card 0
}

$ pcm -D softvol -o S24_LE -c 2 -r 48000
"""

The data in the Synchronous Audio Interface (SAI) of the i.MX6UL is
aligned the following way:

"""
31 30 29 28 | 27 26 25 24 | 23 22 21 20 | .. | 3 2 1 0
## ## ## ##   ## ## ## ## [           DATA[23:0]       ]
"""

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/src/pcm/pcm_softvol.c b/src/pcm/pcm_softvol.c
index 1fe5784..68a35b5 100644 (file)
--- a/src/pcm/pcm_softvol.c
+++ b/src/pcm/pcm_softvol.c
@@ -251,6 +251,44 @@ static inline short MULTI_DIV_short(short a, unsigned int b, int swap)
                }                                                       \
        }                                                               \
 } while (0)
+
+#define CONVERT_AREA_S24_LE() do {                                     \
+       unsigned int ch, fr;                                            \
+       int *src, *dst;                                                 \
+       int tmp;                                                        \
+       for (ch = 0; ch < channels; ch++) {                             \
+               src_area = &src_areas[ch];                              \
+               dst_area = &dst_areas[ch];                              \
+               src = snd_pcm_channel_area_addr(src_area, src_offset);  \
+               dst = snd_pcm_channel_area_addr(dst_area, dst_offset);  \
+               src_step = snd_pcm_channel_area_step(src_area)          \
+                               / sizeof(int);                          \
+               dst_step = snd_pcm_channel_area_step(dst_area)          \
+                               / sizeof(int);                          \
+               GET_VOL_SCALE;                                          \
+               fr = frames;                                            \
+               if (! vol_scale) {                                      \
+                       while (fr--) {                                  \
+                               *dst = 0;                               \
+                               dst += dst_step;                        \
+                       }                                               \
+               } else if (vol_scale == 0xffff) {                       \
+                       while (fr--) {                                  \
+                               *dst = *src;                            \
+                               src += dst_step;                        \
+                               dst += src_step;                        \
+                       }                                               \
+               } else {                                                \
+                       while (fr--) {                                  \
+                               tmp = *src << 8;                        \
+                               tmp = (signed int) tmp >> 8;            \
+                               *dst = MULTI_DIV_24(tmp, vol_scale);    \
+                               src += dst_step;                        \
+                               dst += src_step;                        \
+                       }                                               \
+               }                                                       \
+       }                                                               \
+} while (0)
                
 #define GET_VOL_SCALE \
        switch (ch) { \
@@ -315,6 +353,10 @@ static void softvol_convert_stereo_vol(snd_pcm_softvol_t *svol,
                CONVERT_AREA(int,
                             !snd_pcm_format_cpu_endian(svol->sformat));
                break;
+       case SND_PCM_FORMAT_S24_LE:
+               /* 24bit samples */
+               CONVERT_AREA_S24_LE();
+               break;
        case SND_PCM_FORMAT_S24_3LE:
                CONVERT_AREA_S24_3LE();
                break;
@@ -366,6 +408,10 @@ static void softvol_convert_mono_vol(snd_pcm_softvol_t *svol,
                CONVERT_AREA(int,
                             !snd_pcm_format_cpu_endian(svol->sformat));
                break;
+       case SND_PCM_FORMAT_S24_LE:
+               /* 24bit samples */
+               CONVERT_AREA_S24_LE();
+               break;
        case SND_PCM_FORMAT_S24_3LE:
                CONVERT_AREA_S24_3LE();
                break;
@@ -422,6 +468,7 @@ static int snd_pcm_softvol_hw_refine_cprepare(snd_pcm_t *pcm,
                {
                        (1ULL << SND_PCM_FORMAT_S16_LE) |
                        (1ULL << SND_PCM_FORMAT_S16_BE) |
+                       (1ULL << SND_PCM_FORMAT_S24_LE) |
                        (1ULL << SND_PCM_FORMAT_S32_LE) |
                        (1ULL << SND_PCM_FORMAT_S32_BE),
                        (1ULL << (SND_PCM_FORMAT_S24_3LE - 32))
@@ -577,10 +624,11 @@ static int snd_pcm_softvol_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * param
        if (slave->format != SND_PCM_FORMAT_S16_LE &&
            slave->format != SND_PCM_FORMAT_S16_BE &&
            slave->format != SND_PCM_FORMAT_S24_3LE && 
+           slave->format != SND_PCM_FORMAT_S24_LE &&
            slave->format != SND_PCM_FORMAT_S32_LE &&
            slave->format != SND_PCM_FORMAT_S32_BE) {
-               SNDERR("softvol supports only S16_LE, S16_BE, S24_3LE, S32_LE "
-                      " or S32_BE");
+               SNDERR("softvol supports only S16_LE, S16_BE, S24_LE, S24_3LE, "
+                      "S32_LE or S32_BE");
                return -EINVAL;
        }
        svol->sformat = slave->format;
@@ -863,6 +911,7 @@ int snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name,
            sformat != SND_PCM_FORMAT_S16_LE &&
            sformat != SND_PCM_FORMAT_S16_BE &&
            sformat != SND_PCM_FORMAT_S24_3LE && 
+           sformat != SND_PCM_FORMAT_S24_LE &&
            sformat != SND_PCM_FORMAT_S32_LE &&
            sformat != SND_PCM_FORMAT_S32_BE)
                return -EINVAL;
@@ -1082,9 +1131,10 @@ int _snd_pcm_softvol_open(snd_pcm_t **pcmp, const char *name,
                    sformat != SND_PCM_FORMAT_S16_LE &&
                    sformat != SND_PCM_FORMAT_S16_BE &&
                    sformat != SND_PCM_FORMAT_S24_3LE && 
+                   sformat != SND_PCM_FORMAT_S24_LE &&
                    sformat != SND_PCM_FORMAT_S32_LE &&
                    sformat != SND_PCM_FORMAT_S32_BE) {
-                       SNDERR("only S16_LE, S16_BE, S24_3LE, S32_LE or S32_BE format is supported");
+                       SNDERR("only S16_LE, S16_BE, S24_LE, S24_3LE, S32_LE or S32_BE format is supported");
                        snd_config_delete(sconf);
                        return -EINVAL;
                }