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authorTakashi Sakamoto <o-takashi@sakamocchi.jp>2017-04-11 20:33:18 +0900
committerTakashi Iwai <tiwai@suse.de>2017-04-12 15:34:21 +0200
commitf91c9d7610a2fe306273a83e2fd5351bceb85d28 (patch)
tree83e477ea0a5ccdaa6f6e57e5ccbd83882c7a2d45 /sound
parent12ee4022f67f8854061b46e5c0a7ad6258ab66c2 (diff)
downloadlinux-f91c9d7610a2fe306273a83e2fd5351bceb85d28.tar.bz2
ALSA: firewire-lib: cache maximum length of payload to reduce function calls
During packet streaming, maximum length of payload for isochronous packet is invariable, therefore no need to recalculate. Current ALSA IEC 61883-1/6 engine calls a function to calculate it 8,000 or more times per second for incoming packet processing. This commit adds a member to have maximum length of payload into 'struct amdtp_stream', to reduces the function calls. At first callback from isochronous context, the length is calculated and stored for later processing. Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
-rw-r--r--sound/firewire/amdtp-stream.c9
-rw-r--r--sound/firewire/amdtp-stream.h1
2 files changed, 6 insertions, 4 deletions
diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index f6af8e64c2cd..9e6f54f8c45d 100644
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -412,8 +412,7 @@ static inline int queue_out_packet(struct amdtp_stream *s,
static inline int queue_in_packet(struct amdtp_stream *s)
{
- return queue_packet(s, IN_PACKET_HEADER_SIZE,
- amdtp_stream_get_max_payload(s));
+ return queue_packet(s, IN_PACKET_HEADER_SIZE, s->max_payload_length);
}
static int handle_out_packet(struct amdtp_stream *s,
@@ -713,12 +712,12 @@ static void in_stream_callback(struct fw_iso_context *context, u32 tstamp,
cycle = decrement_cycle_count(cycle, packets);
/* For buffer-over-run prevention. */
- max_payload_length = amdtp_stream_get_max_payload(s);
+ max_payload_length = s->max_payload_length;
for (i = 0; i < packets; i++) {
cycle = increment_cycle_count(cycle, 1);
- /* The number of quadlets in this packet */
+ /* The number of bytes in this packet */
payload_length =
(be32_to_cpu(headers[i]) >> ISO_DATA_LENGTH_SHIFT);
if (payload_length > max_payload_length) {
@@ -751,6 +750,8 @@ static void amdtp_stream_first_callback(struct fw_iso_context *context,
u32 cycle;
unsigned int packets;
+ s->max_payload_length = amdtp_stream_get_max_payload(s);
+
/*
* For in-stream, first packet has come.
* For out-stream, prepared to transmit first packet
diff --git a/sound/firewire/amdtp-stream.h b/sound/firewire/amdtp-stream.h
index 2bd4de4c7bb7..7e8831722821 100644
--- a/sound/firewire/amdtp-stream.h
+++ b/sound/firewire/amdtp-stream.h
@@ -110,6 +110,7 @@ struct amdtp_stream {
int (*handle_packet)(struct amdtp_stream *s,
unsigned int payload_quadlets, unsigned int cycle,
unsigned int index);
+ unsigned int max_payload_length;
/* For CIP headers. */
unsigned int source_node_id_field;