Commit 345e9f5c authored by Pierre-Louis Bossart's avatar Pierre-Louis Bossart Committed by Vinod Koul
Browse files

soundwire: bus: only use CLOCK_STOP_MODE0 and fix confusions 



Existing devices and implementations only support the required
CLOCK_STOP_MODE0. All the code related to CLOCK_STOP_MODE1 has not
been tested and is highly questionable, with a clear confusion between
CLOCK_STOP_MODE1 and the simple clock stop state machine.

This patch removes all usages of CLOCK_STOP_MODE1 - which has no
impact on any solution - and fixes the use of the simple clock stop
state machine. The resulting code should be a lot more symmetrical and
easier to maintain.

Note that CLOCK_STOP_MODE1 is not supported in the SoundWire Device
Class specification so it's rather unlikely that we need to re-add
this mode later.

Signed-off-by: default avatarPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Reviewed-by: default avatarGuennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Reviewed-by: default avatarRander Wang <rander.wang@intel.com>
Signed-off-by: default avatarBard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210511030048.25622-2-yung-chuan.liao@linux.intel.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 0531e6b6

drivers/soundwire/bus.c

+40 −60
Original line number Diff line number Diff line
@@ -821,26 +821,6 @@ static void sdw_modify_slave_status(struct sdw_slave *slave, 
	mutex_unlock(&bus->bus_lock);

}



static enum sdw_clk_stop_mode sdw_get_clk_stop_mode(struct sdw_slave *slave)

{

	enum sdw_clk_stop_mode mode;



	/*

	 * Query for clock stop mode if Slave implements

	 * ops->get_clk_stop_mode, else read from property.

	 */

	if (slave->ops && slave->ops->get_clk_stop_mode) {

		mode = slave->ops->get_clk_stop_mode(slave);

	} else {

		if (slave->prop.clk_stop_mode1)

			mode = SDW_CLK_STOP_MODE1;

		else

			mode = SDW_CLK_STOP_MODE0;

	}



	return mode;

}



static int sdw_slave_clk_stop_callback(struct sdw_slave *slave,

				       enum sdw_clk_stop_mode mode,

				       enum sdw_clk_stop_type type)
@@ -933,7 +913,6 @@ static int sdw_bus_wait_for_clk_prep_deprep(struct sdw_bus *bus, u16 dev_num) 
 */

int sdw_bus_prep_clk_stop(struct sdw_bus *bus)

{

	enum sdw_clk_stop_mode slave_mode;

	bool simple_clk_stop = true;

	struct sdw_slave *slave;

	bool is_slave = false;
@@ -955,10 +934,8 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus) 
		/* Identify if Slave(s) are available on Bus */

		is_slave = true;



		slave_mode = sdw_get_clk_stop_mode(slave);

		slave->curr_clk_stop_mode = slave_mode;



		ret = sdw_slave_clk_stop_callback(slave, slave_mode,

		ret = sdw_slave_clk_stop_callback(slave,

						  SDW_CLK_STOP_MODE0,

						  SDW_CLK_PRE_PREPARE);

		if (ret < 0) {

			dev_err(&slave->dev,
@@ -966,22 +943,29 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus) 
			return ret;

		}



		/* Only prepare a Slave device if needed */

		if (!slave->prop.simple_clk_stop_capable) {

			simple_clk_stop = false;



			ret = sdw_slave_clk_stop_prepare(slave,

						 slave_mode, true);

							 SDW_CLK_STOP_MODE0,

							 true);

			if (ret < 0) {

				dev_err(&slave->dev,

					"pre-prepare failed:%d", ret);

				return ret;

			}



		if (slave_mode == SDW_CLK_STOP_MODE1)

			simple_clk_stop = false;

		}

	}



	/* Skip remaining clock stop preparation if no Slave is attached */

	if (!is_slave)

		return ret;



	/*

	 * Don't wait for all Slaves to be ready if they follow the simple

	 * state machine

	 */

	if (!simple_clk_stop) {

		ret = sdw_bus_wait_for_clk_prep_deprep(bus,

						       SDW_BROADCAST_DEV_NUM);
@@ -998,11 +982,8 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus) 
		    slave->status != SDW_SLAVE_ALERT)

			continue;



		slave_mode = slave->curr_clk_stop_mode;



		if (slave_mode == SDW_CLK_STOP_MODE1) {

		ret = sdw_slave_clk_stop_callback(slave,

							  slave_mode,

						  SDW_CLK_STOP_MODE0,

						  SDW_CLK_POST_PREPARE);



		if (ret < 0) {
@@ -1010,7 +991,6 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus) 
				"post-prepare failed:%d", ret);

		}

	}

	}



	return ret;

}
@@ -1059,7 +1039,6 @@ EXPORT_SYMBOL(sdw_bus_clk_stop); 
 */

int sdw_bus_exit_clk_stop(struct sdw_bus *bus)

{

	enum sdw_clk_stop_mode mode;

	bool simple_clk_stop = true;

	struct sdw_slave *slave;

	bool is_slave = false;
@@ -1081,31 +1060,33 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus) 
		/* Identify if Slave(s) are available on Bus */

		is_slave = true;



		mode = slave->curr_clk_stop_mode;



		if (mode == SDW_CLK_STOP_MODE1) {

			simple_clk_stop = false;

			continue;

		}



		ret = sdw_slave_clk_stop_callback(slave, mode,

		ret = sdw_slave_clk_stop_callback(slave, SDW_CLK_STOP_MODE0,

						  SDW_CLK_PRE_DEPREPARE);

		if (ret < 0)

			dev_warn(&slave->dev,

				 "clk stop deprep failed:%d", ret);



		ret = sdw_slave_clk_stop_prepare(slave, mode,

		/* Only de-prepare a Slave device if needed */

		if (!slave->prop.simple_clk_stop_capable) {

			simple_clk_stop = false;



			ret = sdw_slave_clk_stop_prepare(slave, SDW_CLK_STOP_MODE0,

							 false);



			if (ret < 0)

				dev_warn(&slave->dev,

					 "clk stop deprep failed:%d", ret);

		}

	}



	/* Skip remaining clock stop de-preparation if no Slave is attached */

	if (!is_slave)

		return 0;



	/*

	 * Don't wait for all Slaves to be ready if they follow the simple

	 * state machine

	 */

	if (!simple_clk_stop)

		sdw_bus_wait_for_clk_prep_deprep(bus, SDW_BROADCAST_DEV_NUM);
@@ -1117,8 +1098,7 @@ int sdw_bus_exit_clk_stop(struct sdw_bus *bus) 
		    slave->status != SDW_SLAVE_ALERT)

			continue;



		mode = slave->curr_clk_stop_mode;

		sdw_slave_clk_stop_callback(slave, mode,

		sdw_slave_clk_stop_callback(slave, SDW_CLK_STOP_MODE0,

					    SDW_CLK_POST_DEPREPARE);

	}

include/linux/soundwire/sdw.h

+0 −2
Original line number Diff line number Diff line
@@ -624,7 +624,6 @@ struct sdw_slave_ops { 
	int (*port_prep)(struct sdw_slave *slave,

			 struct sdw_prepare_ch *prepare_ch,

			 enum sdw_port_prep_ops pre_ops);

	int (*get_clk_stop_mode)(struct sdw_slave *slave);

	int (*clk_stop)(struct sdw_slave *slave,

			enum sdw_clk_stop_mode mode,

			enum sdw_clk_stop_type type);
@@ -675,7 +674,6 @@ struct sdw_slave { 
	struct list_head node;

	struct completion port_ready[SDW_MAX_PORTS];

	unsigned int m_port_map[SDW_MAX_PORTS];

	enum sdw_clk_stop_mode curr_clk_stop_mode;

	u16 dev_num;

	u16 dev_num_sticky;

	bool probed;