ALSA: firewire-lib: postpone to start IR context

[linux-2.6-block.git] / sound / firewire / amdtp-stream.c

diff --git a/sound/firewire/amdtp-stream.c b/sound/firewire/amdtp-stream.c
index 48be31eae9a5be08947514937f2c40f866ccae05..37d38efb4c877f8084400b92a4c9e87599fc007c 100644 (file)
--- a/sound/firewire/amdtp-stream.c
+++ b/sound/firewire/amdtp-stream.c
@@ -9,6 +9,7 @@
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/firewire.h>
+#include <linux/firewire-constants.h>
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <sound/pcm.h>
@@ -983,13 +984,16 @@ static void amdtp_stream_master_first_callback(struct fw_iso_context *context,
  * @d: the AMDTP domain to which the AMDTP stream belongs
  * @is_irq_target: whether isoc context for the AMDTP stream is used to generate
  *                hardware IRQ.
+ * @start_cycle: the isochronous cycle to start the context. Start immediately
+ *              if negative value is given.
  *
  * The stream cannot be started until it has been configured with
  * amdtp_stream_set_parameters() and it must be started before any PCM or MIDI
  * device can be started.
  */
 static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed,
-                             struct amdtp_domain *d, bool is_irq_target)
+                             struct amdtp_domain *d, bool is_irq_target,
+                             int start_cycle)
 {
        static const struct {
                unsigned int data_block;
@@ -1146,7 +1150,7 @@ static int amdtp_stream_start(struct amdtp_stream *s, int channel, int speed,
                tag |= FW_ISO_CONTEXT_MATCH_TAG0;
 
        s->callbacked = false;
-       err = fw_iso_context_start(s->context, -1, 0, tag);
+       err = fw_iso_context_start(s->context, start_cycle, 0, tag);
        if (err < 0)
                goto err_pkt_descs;
 
@@ -1339,14 +1343,40 @@ int amdtp_domain_add_stream(struct amdtp_domain *d, struct amdtp_stream *s,
 }
 EXPORT_SYMBOL_GPL(amdtp_domain_add_stream);
 
+static int get_current_cycle_time(struct fw_card *fw_card, int *cur_cycle)
+{
+       int generation;
+       int rcode;
+       __be32 reg;
+       u32 data;
+
+       // This is a request to local 1394 OHCI controller and expected to
+       // complete without any event waiting.
+       generation = fw_card->generation;
+       smp_rmb();      // node_id vs. generation.
+       rcode = fw_run_transaction(fw_card, TCODE_READ_QUADLET_REQUEST,
+                                  fw_card->node_id, generation, SCODE_100,
+                                  CSR_REGISTER_BASE + CSR_CYCLE_TIME,
+                                  &reg, sizeof(reg));
+       if (rcode != RCODE_COMPLETE)
+               return -EIO;
+
+       data = be32_to_cpu(reg);
+       *cur_cycle = data >> 12;
+
+       return 0;
+}
+
 /**
  * amdtp_domain_start - start sending packets for isoc context in the domain.
  * @d: the AMDTP domain.
+ * @ir_delay_cycle: the cycle delay to start all IR contexts.
  */
-int amdtp_domain_start(struct amdtp_domain *d)
+int amdtp_domain_start(struct amdtp_domain *d, unsigned int ir_delay_cycle)
 {
        struct amdtp_stream *s;
-       int err = 0;
+       int cycle;
+       int err;
 
        // Select an IT context as IRQ target.
        list_for_each_entry(s, &d->streams, list) {
@@ -1357,17 +1387,54 @@ int amdtp_domain_start(struct amdtp_domain *d)
                return -ENXIO;
        d->irq_target = s;
 
+       if (ir_delay_cycle > 0) {
+               struct fw_card *fw_card = fw_parent_device(s->unit)->card;
+
+               err = get_current_cycle_time(fw_card, &cycle);
+               if (err < 0)
+                       return err;
+
+               // No need to care overflow in cycle field because of enough
+               // width.
+               cycle += ir_delay_cycle;
+
+               // Round up to sec field.
+               if ((cycle & 0x00001fff) >= CYCLES_PER_SECOND) {
+                       unsigned int sec;
+
+                       // The sec field can overflow.
+                       sec = (cycle & 0xffffe000) >> 13;
+                       cycle = (++sec << 13) |
+                               ((cycle & 0x00001fff) / CYCLES_PER_SECOND);
+               }
+
+               // In OHCI 1394 specification, lower 2 bits are available for
+               // sec field.
+               cycle &= 0x00007fff;
+       } else {
+               cycle = -1;
+       }
+
        list_for_each_entry(s, &d->streams, list) {
+               int cycle_match;
+
+               if (s->direction == AMDTP_IN_STREAM) {
+                       cycle_match = cycle;
+               } else {
+                       // IT context starts immediately.
+                       cycle_match = -1;
+               }
+
                if (s != d->irq_target) {
                        err = amdtp_stream_start(s, s->channel, s->speed, d,
-                                                false);
+                                                false, cycle_match);
                        if (err < 0)
                                goto error;
                }
        }
 
        s = d->irq_target;
-       err = amdtp_stream_start(s, s->channel, s->speed, d, true);
+       err = amdtp_stream_start(s, s->channel, s->speed, d, true, -1);
        if (err < 0)
                goto error;