From: Takashi Iwai <tiwai@suse.de>
To: alsa-devel@alsa-project.org
Subject: [PATCH 2/5] ALSA: usb-audio: Pre-calculate buffer byte size
Date: Tue, 1 Jun 2021 18:24:54 +0200 [thread overview]
Message-ID: <20210601162457.4877-3-tiwai@suse.de> (raw)
In-Reply-To: <20210601162457.4877-1-tiwai@suse.de>
There are a bunch of lines calculating the buffer size in bytes at
each time. Keep the value in subs->buffer_bytes and use it
consistently for the code simplicity.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
sound/usb/card.h | 1 +
sound/usb/pcm.c | 48 ++++++++++++++++++++++++------------------------
2 files changed, 25 insertions(+), 24 deletions(-)
diff --git a/sound/usb/card.h b/sound/usb/card.h
index a741e7da83a2..b346653d4b76 100644
--- a/sound/usb/card.h
+++ b/sound/usb/card.h
@@ -158,6 +158,7 @@ struct snd_usb_substream {
unsigned int running: 1; /* running status */
+ unsigned int buffer_bytes; /* buffer size in bytes */
unsigned int hwptr_done; /* processed byte position in the buffer */
unsigned int transfer_done; /* processed frames since last period update */
unsigned int frame_limit; /* limits number of packets in URB */
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 359c759a7023..e8121af8e1d5 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -600,6 +600,7 @@ static int snd_usb_pcm_prepare(struct snd_pcm_substream *substream)
goto unlock;
/* reset the pointer */
+ subs->buffer_bytes = frames_to_bytes(runtime, runtime->buffer_size);
subs->hwptr_done = 0;
subs->transfer_done = 0;
subs->last_delay = 0;
@@ -1147,8 +1148,8 @@ static void retire_capture_urb(struct snd_usb_substream *subs,
spin_lock_irqsave(&subs->lock, flags);
oldptr = subs->hwptr_done;
subs->hwptr_done += bytes;
- if (subs->hwptr_done >= runtime->buffer_size * stride)
- subs->hwptr_done -= runtime->buffer_size * stride;
+ if (subs->hwptr_done >= subs->buffer_bytes)
+ subs->hwptr_done -= subs->buffer_bytes;
frames = (bytes + (oldptr % stride)) / stride;
subs->transfer_done += frames;
if (subs->transfer_done >= runtime->period_size) {
@@ -1166,9 +1167,9 @@ static void retire_capture_urb(struct snd_usb_substream *subs,
spin_unlock_irqrestore(&subs->lock, flags);
/* copy a data chunk */
- if (oldptr + bytes > runtime->buffer_size * stride) {
- unsigned int bytes1 =
- runtime->buffer_size * stride - oldptr;
+ if (oldptr + bytes > subs->buffer_bytes) {
+ unsigned int bytes1 = subs->buffer_bytes - oldptr;
+
memcpy(runtime->dma_area + oldptr, cp, bytes1);
memcpy(runtime->dma_area, cp + bytes1, bytes - bytes1);
} else {
@@ -1184,10 +1185,9 @@ static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
struct urb *urb, unsigned int bytes)
{
struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
- unsigned int stride = runtime->frame_bits >> 3;
unsigned int dst_idx = 0;
unsigned int src_idx = subs->hwptr_done;
- unsigned int wrap = runtime->buffer_size * stride;
+ unsigned int wrap = subs->buffer_bytes;
u8 *dst = urb->transfer_buffer;
u8 *src = runtime->dma_area;
u8 marker[] = { 0x05, 0xfa };
@@ -1233,8 +1233,8 @@ static inline void fill_playback_urb_dsd_dop(struct snd_usb_substream *subs,
subs->hwptr_done++;
}
}
- if (subs->hwptr_done >= runtime->buffer_size * stride)
- subs->hwptr_done -= runtime->buffer_size * stride;
+ if (subs->hwptr_done >= subs->buffer_bytes)
+ subs->hwptr_done -= subs->buffer_bytes;
}
static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
@@ -1242,10 +1242,10 @@ static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
{
struct snd_pcm_runtime *runtime = subs->pcm_substream->runtime;
- if (subs->hwptr_done + bytes > runtime->buffer_size * stride) {
+ if (subs->hwptr_done + bytes > subs->buffer_bytes) {
/* err, the transferred area goes over buffer boundary. */
- unsigned int bytes1 =
- runtime->buffer_size * stride - subs->hwptr_done;
+ unsigned int bytes1 = subs->buffer_bytes - subs->hwptr_done;
+
memcpy(urb->transfer_buffer + offset,
runtime->dma_area + subs->hwptr_done, bytes1);
memcpy(urb->transfer_buffer + offset + bytes1,
@@ -1255,8 +1255,8 @@ static void copy_to_urb(struct snd_usb_substream *subs, struct urb *urb,
runtime->dma_area + subs->hwptr_done, bytes);
}
subs->hwptr_done += bytes;
- if (subs->hwptr_done >= runtime->buffer_size * stride)
- subs->hwptr_done -= runtime->buffer_size * stride;
+ if (subs->hwptr_done >= subs->buffer_bytes)
+ subs->hwptr_done -= subs->buffer_bytes;
}
static unsigned int copy_to_urb_quirk(struct snd_usb_substream *subs,
@@ -1295,7 +1295,7 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
int i, stride, period_elapsed = 0;
unsigned long flags;
- stride = runtime->frame_bits >> 3;
+ stride = ep->stride;
frames = 0;
urb->number_of_packets = 0;
@@ -1304,8 +1304,8 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
for (i = 0; i < ctx->packets; i++) {
counts = snd_usb_endpoint_next_packet_size(ep, ctx, i);
/* set up descriptor */
- urb->iso_frame_desc[i].offset = frames * ep->stride;
- urb->iso_frame_desc[i].length = counts * ep->stride;
+ urb->iso_frame_desc[i].offset = frames * stride;
+ urb->iso_frame_desc[i].length = counts * stride;
frames += counts;
urb->number_of_packets++;
subs->transfer_done += counts;
@@ -1320,14 +1320,14 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
frames -= subs->transfer_done;
counts -= subs->transfer_done;
urb->iso_frame_desc[i].length =
- counts * ep->stride;
+ counts * stride;
subs->transfer_done = 0;
}
i++;
if (i < ctx->packets) {
/* add a transfer delimiter */
urb->iso_frame_desc[i].offset =
- frames * ep->stride;
+ frames * stride;
urb->iso_frame_desc[i].length = 0;
urb->number_of_packets++;
}
@@ -1340,7 +1340,7 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
!snd_usb_endpoint_implicit_feedback_sink(ep))
break;
}
- bytes = frames * ep->stride;
+ bytes = frames * stride;
if (unlikely(ep->cur_format == SNDRV_PCM_FORMAT_DSD_U16_LE &&
subs->cur_audiofmt->dsd_dop)) {
@@ -1350,14 +1350,14 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
/* bit-reverse the bytes */
u8 *buf = urb->transfer_buffer;
for (i = 0; i < bytes; i++) {
- int idx = (subs->hwptr_done + i)
- % (runtime->buffer_size * stride);
+ int idx = (subs->hwptr_done + i) % subs->buffer_bytes;
+
buf[i] = bitrev8(runtime->dma_area[idx]);
}
subs->hwptr_done += bytes;
- if (subs->hwptr_done >= runtime->buffer_size * stride)
- subs->hwptr_done -= runtime->buffer_size * stride;
+ if (subs->hwptr_done >= subs->buffer_bytes)
+ subs->hwptr_done -= subs->buffer_bytes;
} else {
/* usual PCM */
if (!subs->tx_length_quirk)
--
2.26.2
next prev parent reply other threads:[~2021-06-01 16:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-01 16:24 [PATCH 0/5] ALSA: usb-audio: Delay account cleanup and latency reduction Takashi Iwai
2021-06-01 16:24 ` [PATCH 1/5] ALSA: usb-audio: Make snd_usb_pcm_delay() static Takashi Iwai
2021-06-01 16:24 ` Takashi Iwai [this message]
2021-06-01 16:24 ` [PATCH 3/5] ALSA: usb-audio: Refactoring delay account code Takashi Iwai
2021-06-01 16:24 ` [PATCH 4/5] ALSA: usb-audio: Factor out DSD bitrev copy function Takashi Iwai
2021-06-01 16:24 ` [PATCH 5/5] ALSA: usb-audio: Reduce latency at playback start Takashi Iwai
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