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soundwire: bus: add stream refcount

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The notion of stream is by construction based on a multi-bus
capability, to allow for aggregation of Peripheral devices or
functions located on different segments. We currently count how many
master_rt contexts are used by a stream, but we don't have the dual
refcount of how many streams are allocated on a given bus. This
refcount will be useful to check if BTP/BRA streams can be allocated.

Note that the stream_refcount is modified in sdw_master_rt_alloc() and
sdw_master_rt_free() which are both called with the bus_lock mutex
held, so there's no need for refcount_ primitives for additional
protection.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: Rander Wang <rander.wang@intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20240603065841.4860-2-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Pierre-Louis Bossart 2024-06-03 14:58:41 +08:00 committed by Vinod Koul
parent fe46d2a430
commit a5b7365f28
2 changed files with 7 additions and 0 deletions
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5
drivers/soundwire/stream.c
View File

@ -1181,6 +1181,8 @@ static struct sdw_master_runtime
m_rt->bus = bus;
m_rt->stream = stream;
bus->stream_refcount++;
return m_rt;
}
@ -1217,6 +1219,7 @@ static void sdw_master_rt_free(struct sdw_master_runtime *m_rt,
struct sdw_stream_runtime *stream)
{
struct sdw_slave_runtime *s_rt, *_s_rt;
struct sdw_bus *bus = m_rt->bus;
list_for_each_entry_safe(s_rt, _s_rt, &m_rt->slave_rt_list, m_rt_node) {
sdw_slave_port_free(s_rt->slave, stream);
@ -1226,6 +1229,8 @@ static void sdw_master_rt_free(struct sdw_master_runtime *m_rt,
list_del(&m_rt->stream_node);
list_del(&m_rt->bus_node);
kfree(m_rt);
bus->stream_refcount--;
}
/**

2
include/linux/soundwire/sdw.h
View File

@ -903,6 +903,7 @@ struct sdw_master_ops {
* meaningful if multi_link is set. If set to 1, hardware-based
* synchronization will be used even if a stream only uses a single
* SoundWire segment.
* @stream_refcount: number of streams currently using this bus
*/
struct sdw_bus {
struct device *dev;
@ -933,6 +934,7 @@ struct sdw_bus {
u32 bank_switch_timeout;
bool multi_link;
int hw_sync_min_links;
int stream_refcount;
};
int sdw_bus_master_add(struct sdw_bus *bus, struct device *parent,