On 06/05/2018 06:01 AM, Shreyas NC wrote:
From: Sanyog Kale <sanyog.r.kale@xxxxxxxxx>
Currently, the stream concept is limited to a Master and one or
more Codecs.
This patch extends the concept to support multiple Master(s)
sharing the same reference clock and synchronized in the hardware.
Modify sdw_stream_runtime to support a list of sdw_master_runtime
for the same. The existing reference to a single m_rt is removed
in the next patch.
Typically to lock, one would acquire a global lock and then lock
bus instances. In this case, the caller framework(ASoC DPCM)
guarentees that stream operations on a card are always serialised.
guarantees
So, there is no race condition and hence no need for global lock.
Bus lock(s) are acquired to reconfigure the bus while the stream
is set-up.
So, we add sdw_acquire_bus_lock()/sdw_release_bus_lock() for the same.
We should add a precision that this lock is only needed for the
reconfiguration parts. It is my understanding that we can still do a
synchronized bank switch between two or more streams handled by multiple
masters, right?
Signed-off-by: Sanyog Kale <sanyog.r.kale@xxxxxxxxx>
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Shreyas NC <shreyas.nc@xxxxxxxxx>
---
drivers/soundwire/bus.h | 2 ++
drivers/soundwire/stream.c | 26 ++++++++++++++++++++++++++
include/linux/soundwire/sdw.h | 2 ++
3 files changed, 30 insertions(+)
diff --git a/drivers/soundwire/bus.h b/drivers/soundwire/bus.h
index 3b15c4e..b6cfbdf 100644
--- a/drivers/soundwire/bus.h
+++ b/drivers/soundwire/bus.h
@@ -99,6 +99,7 @@ struct sdw_slave_runtime {
* this stream, can be zero.
* @slave_rt_list: Slave runtime list
* @port_list: List of Master Ports configured for this stream, can be zero.
+ * @stream_node: sdw_stream_runtime master_list node
Should we clarify that there is an expectation that the master_list can
only handle one node per master?
* @bus_node: sdw_bus m_rt_list node
*/
struct sdw_master_runtime {
@@ -108,6 +109,7 @@ struct sdw_master_runtime {
unsigned int ch_count;
struct list_head slave_rt_list;
struct list_head port_list;
+ struct list_head stream_node;
struct list_head bus_node;
};
diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index 68252f2..604fe93 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -749,6 +749,7 @@ struct sdw_stream_runtime *sdw_alloc_stream(char *stream_name)
return NULL;
stream->name = stream_name;
+ INIT_LIST_HEAD(&stream->master_list);
stream->state = SDW_STREAM_ALLOCATED;
return stream;
@@ -1243,6 +1244,31 @@ struct sdw_dpn_prop *sdw_get_slave_dpn_prop(struct sdw_slave *slave,
return NULL;
}
+static void sdw_acquire_bus_lock(struct sdw_stream_runtime *stream)
+{
+ struct sdw_master_runtime *m_rt = NULL;
+ struct sdw_bus *bus = NULL;
+
+ /* Iterate for all Master(s) in Master list */
+ list_for_each_entry(m_rt, &stream->master_list, stream_node) {
+ bus = m_rt->bus;
+
+ mutex_lock(&bus->bus_lock);
+ }
+}
+
+static void sdw_release_bus_lock(struct sdw_stream_runtime *stream)
+{
+ struct sdw_master_runtime *m_rt = NULL;
+ struct sdw_bus *bus = NULL;
+
+ /* Iterate for all Master(s) in Master list */
+ list_for_each_entry(m_rt, &stream->master_list, stream_node) {
+ bus = m_rt->bus;
+ mutex_unlock(&bus->bus_lock);
+ }
+}
+
static int _sdw_prepare_stream(struct sdw_stream_runtime *stream)
{
struct sdw_master_runtime *m_rt = stream->m_rt;
diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index 322baf4..5692de0 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -769,6 +769,7 @@ struct sdw_stream_params {
* @state: Current state of the stream
* @type: Stream type PCM or PDM
* @m_rt: Master runtime
+ * @master_list: List of Master runtime(s) in this stream
*/
struct sdw_stream_runtime {
char *name;
@@ -776,6 +777,7 @@ struct sdw_stream_runtime {
enum sdw_stream_state state;
enum sdw_stream_type type;
struct sdw_master_runtime *m_rt;
+ struct list_head master_list;
};
struct sdw_stream_runtime *sdw_alloc_stream(char *stream_name);
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