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authorTakashi Iwai <tiwai@suse.de>2021-06-01 18:24:56 +0200
committerTakashi Iwai <tiwai@suse.de>2021-06-02 09:01:55 +0200
commit4f083917994fdde40a86e51c4ee0af5a61182117 (patch)
treedbb2467219623a19fa4548f80749dd2b94e364f9 /sound/usb/pcm.c
parentALSA: usb-audio: Refactoring delay account code (diff)
downloadlinux-4f083917994fdde40a86e51c4ee0af5a61182117.tar.xz
linux-4f083917994fdde40a86e51c4ee0af5a61182117.zip
ALSA: usb-audio: Factor out DSD bitrev copy function
Just minor code refactoring. Like DOP DSD code, it can be better in a separate function for code readability. Link: https://lore.kernel.org/r/20210601162457.4877-5-tiwai@suse.de Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/pcm.c')
-rw-r--r--sound/usb/pcm.c28
1 files changed, 19 insertions, 9 deletions
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 8ee45f2e8dce..e26d37365f02 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1250,6 +1250,24 @@ static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
urb_ctx_queue_advance(subs, urb, queued);
}
+/* copy bit-reversed bytes onto transfer buffer */
+static void fill_playback_urb_dsd_bitrev(struct snd_usb_substream *subs,
+ struct urb *urb, unsigned int bytes)
+{
+ struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
+ const u8 *src = runtime->dma_area;
+ u8 *buf = urb->transfer_buffer;
+ int i, ofs = subs->hwptr_done;
+
+ for (i = 0; i < bytes; i++) {
+ *buf++ = bitrev8(src[ofs]);
+ if (++ofs >= subs->buffer_bytes)
+ ofs = 0;
+ }
+
+ urb_ctx_queue_advance(subs, urb, bytes);
+}
+
static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
int offset, int stride, unsigned int bytes)
{
@@ -1360,15 +1378,7 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
fill_playback_urb_dsd_dop(subs, urb, bytes);
} else if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U8 &&
subs->cur_audiofmt->dsd_bitrev)) {
- /* bit-reverse the bytes */
- u8 *buf = urb->transfer_buffer;
- for (i = 0; i < bytes; i++) {
- int idx = (subs->hwptr_done + i) % subs->buffer_bytes;
-
- buf[i] = bitrev8(runtime->dma_area[idx]);
- }
-
- urb_ctx_queue_advance(subs, urb, bytes);
+ fill_playback_urb_dsd_bitrev(subs, urb, bytes);
} else {
/* usual PCM */
if (!subs->tx_length_quirk)