ALSA: firewire-lib: flush completed packets when reading PCM position

[firefly-linux-kernel-4.4.55.git] / sound / firewire / amdtp.c

diff --git a/sound/firewire/amdtp.c b/sound/firewire/amdtp.c
index 87657dd7714ccccb59f4922f12a880680b7838c8..c2685fbd73666635e579e3a5d5bc58fbc68795f0 100644 (file)
--- a/sound/firewire/amdtp.c
+++ b/sound/firewire/amdtp.c
@@ -31,6 +31,8 @@
 #define INTERRUPT_INTERVAL     16
 #define QUEUE_LENGTH           48
 
+static void pcm_period_tasklet(unsigned long data);
+
 /**
  * amdtp_out_stream_init - initialize an AMDTP output stream structure
  * @s: the AMDTP output stream to initialize
@@ -47,6 +49,7 @@ int amdtp_out_stream_init(struct amdtp_out_stream *s, struct fw_unit *unit,
        s->flags = flags;
        s->context = ERR_PTR(-1);
        mutex_init(&s->mutex);
+       tasklet_init(&s->period_tasklet, pcm_period_tasklet, (unsigned long)s);
        s->packet_index = 0;
 
        return 0;
@@ -164,6 +167,20 @@ void amdtp_out_stream_set_pcm_format(struct amdtp_out_stream *s,
 }
 EXPORT_SYMBOL(amdtp_out_stream_set_pcm_format);
 
+/**
+ * amdtp_out_stream_pcm_prepare - prepare PCM device for running
+ * @s: the AMDTP output stream
+ *
+ * This function should be called from the PCM device's .prepare callback.
+ */
+void amdtp_out_stream_pcm_prepare(struct amdtp_out_stream *s)
+{
+       tasklet_kill(&s->period_tasklet);
+       s->pcm_buffer_pointer = 0;
+       s->pcm_period_pointer = 0;
+}
+EXPORT_SYMBOL(amdtp_out_stream_pcm_prepare);
+
 static unsigned int calculate_data_blocks(struct amdtp_out_stream *s)
 {
        unsigned int phase, data_blocks;
@@ -376,11 +393,20 @@ static void queue_out_packet(struct amdtp_out_stream *s, unsigned int cycle)
                s->pcm_period_pointer += data_blocks;
                if (s->pcm_period_pointer >= pcm->runtime->period_size) {
                        s->pcm_period_pointer -= pcm->runtime->period_size;
-                       snd_pcm_period_elapsed(pcm);
+                       tasklet_hi_schedule(&s->period_tasklet);
                }
        }
 }
 
+static void pcm_period_tasklet(unsigned long data)
+{
+       struct amdtp_out_stream *s = (void *)data;
+       struct snd_pcm_substream *pcm = ACCESS_ONCE(s->pcm);
+
+       if (pcm)
+               snd_pcm_period_elapsed(pcm);
+}
+
 static void out_packet_callback(struct fw_iso_context *context, u32 cycle,
                                size_t header_length, void *header, void *data)
 {
@@ -505,6 +531,20 @@ err_unlock:
 }
 EXPORT_SYMBOL(amdtp_out_stream_start);
 
+/**
+ * amdtp_out_stream_pcm_pointer - get the PCM buffer position
+ * @s: the AMDTP output stream that transports the PCM data
+ *
+ * Returns the current buffer position, in frames.
+ */
+unsigned long amdtp_out_stream_pcm_pointer(struct amdtp_out_stream *s)
+{
+       fw_iso_context_flush_completions(s->context);
+
+       return ACCESS_ONCE(s->pcm_buffer_pointer);
+}
+EXPORT_SYMBOL(amdtp_out_stream_pcm_pointer);
+
 /**
  * amdtp_out_stream_update - update the stream after a bus reset
  * @s: the AMDTP output stream
@@ -532,6 +572,7 @@ void amdtp_out_stream_stop(struct amdtp_out_stream *s)
                return;
        }
 
+       tasklet_kill(&s->period_tasklet);
        fw_iso_context_stop(s->context);
        fw_iso_context_destroy(s->context);
        s->context = ERR_PTR(-1);