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Commit ce6e74d0 authored by Shreyas NC's avatar Shreyas NC Committed by Vinod Koul
Browse files

soundwire: Add support for multi link bank switch 



In cases of multiple Masters in a stream, synchronization
between multiple Master(s) is achieved by performing bank switch
together and using Master methods.

Add sdw_ml_bank_switch() to wait for completion of bank switch.

Signed-off-by: default avatarSanyog Kale <sanyog.r.kale@intel.com>
Signed-off-by: default avatarShreyas NC <shreyas.nc@intel.com>
Acked-by: default avatarPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 48949722

drivers/soundwire/bus.c

+5 −0
Original line number Diff line number Diff line
@@ -35,6 +35,11 @@ int sdw_add_bus_master(struct sdw_bus *bus) 
	INIT_LIST_HEAD(&bus->slaves);

	INIT_LIST_HEAD(&bus->m_rt_list);



	/*

	 * Initialize multi_link flag

	 * TODO: populate this flag by reading property from FW node

	 */

	bus->multi_link = false;

	if (bus->ops->read_prop) {

		ret = bus->ops->read_prop(bus);

		if (ret < 0) {

drivers/soundwire/bus.h

+2 −0
Original line number Diff line number Diff line
@@ -4,6 +4,8 @@ 
#ifndef __SDW_BUS_H

#define __SDW_BUS_H



#define DEFAULT_BANK_SWITCH_TIMEOUT 3000



#if IS_ENABLED(CONFIG_ACPI)

int sdw_acpi_find_slaves(struct sdw_bus *bus);

#else

drivers/soundwire/stream.c

+133 −12
Original line number Diff line number Diff line
@@ -626,9 +626,10 @@ static int sdw_program_params(struct sdw_bus *bus) 
	return ret;

}



static int sdw_bank_switch(struct sdw_bus *bus)

static int sdw_bank_switch(struct sdw_bus *bus, int m_rt_count)

{

	int col_index, row_index;

	bool multi_link;

	struct sdw_msg *wr_msg;

	u8 *wbuf = NULL;

	int ret = 0;
@@ -638,6 +639,8 @@ static int sdw_bank_switch(struct sdw_bus *bus) 
	if (!wr_msg)

		return -ENOMEM;



	bus->defer_msg.msg = wr_msg;



	wbuf = kzalloc(sizeof(*wbuf), GFP_KERNEL);

	if (!wbuf) {

		ret = -ENOMEM;
@@ -658,17 +661,29 @@ static int sdw_bank_switch(struct sdw_bus *bus) 
					SDW_MSG_FLAG_WRITE, wbuf);

	wr_msg->ssp_sync = true;



	/*

	 * Set the multi_link flag only when both the hardware supports

	 * and there is a stream handled by multiple masters

	 */

	multi_link = bus->multi_link && (m_rt_count > 1);



	if (multi_link)

		ret = sdw_transfer_defer(bus, wr_msg, &bus->defer_msg);

	else

		ret = sdw_transfer(bus, wr_msg);



	if (ret < 0) {

		dev_err(bus->dev, "Slave frame_ctrl reg write failed");

		goto error;

	}



	if (!multi_link) {

		kfree(wr_msg);

		kfree(wbuf);

		bus->defer_msg.msg = NULL;

		bus->params.curr_bank = !bus->params.curr_bank;

		bus->params.next_bank = !bus->params.next_bank;

	}



	return 0;
@@ -679,36 +694,87 @@ static int sdw_bank_switch(struct sdw_bus *bus) 
	return ret;

}



/**

 * sdw_ml_sync_bank_switch: Multilink register bank switch

 *

 * @bus: SDW bus instance

 *

 * Caller function should free the buffers on error

 */

static int sdw_ml_sync_bank_switch(struct sdw_bus *bus)

{

	unsigned long time_left;



	if (!bus->multi_link)

		return 0;



	/* Wait for completion of transfer */

	time_left = wait_for_completion_timeout(&bus->defer_msg.complete,

						bus->bank_switch_timeout);



	if (!time_left) {

		dev_err(bus->dev, "Controller Timed out on bank switch");

		return -ETIMEDOUT;

	}



	bus->params.curr_bank = !bus->params.curr_bank;

	bus->params.next_bank = !bus->params.next_bank;



	if (bus->defer_msg.msg) {

		kfree(bus->defer_msg.msg->buf);

		kfree(bus->defer_msg.msg);

	}



	return 0;

}



static int do_bank_switch(struct sdw_stream_runtime *stream)

{

	struct sdw_master_runtime *m_rt = NULL;

	const struct sdw_master_ops *ops;

	struct sdw_bus *bus = NULL;

	bool multi_link = false;

	int ret = 0;





	list_for_each_entry(m_rt, &stream->master_list, stream_node) {

		bus = m_rt->bus;

		ops = bus->ops;



		if (bus->multi_link) {

			multi_link = true;

			mutex_lock(&bus->msg_lock);

		}



		/* Pre-bank switch */

		if (ops->pre_bank_switch) {

			ret = ops->pre_bank_switch(bus);

			if (ret < 0) {

				dev_err(bus->dev,

					"Pre bank switch op failed: %d", ret);

				return ret;

				goto msg_unlock;

			}

		}



		/* Bank switch */

		ret = sdw_bank_switch(bus);

		/*

		 * Perform Bank switch operation.

		 * For multi link cases, the actual bank switch is

		 * synchronized across all Masters and happens later as a

		 * part of post_bank_switch ops.

		 */

		ret = sdw_bank_switch(bus, stream->m_rt_count);

		if (ret < 0) {

			dev_err(bus->dev, "Bank switch failed: %d", ret);

			return ret;

			goto error;



		}

	}



	/*

	 * For multi link cases, it is expected that the bank switch is

	 * triggered by the post_bank_switch for the first Master in the list

	 * and for the other Masters the post_bank_switch() should return doing

	 * nothing.

	 */

	list_for_each_entry(m_rt, &stream->master_list, stream_node) {

		bus = m_rt->bus;

		ops = bus->ops;
@@ -719,7 +785,47 @@ static int do_bank_switch(struct sdw_stream_runtime *stream) 
			if (ret < 0) {

				dev_err(bus->dev,

					"Post bank switch op failed: %d", ret);

				goto error;

			}

		} else if (bus->multi_link && stream->m_rt_count > 1) {

			dev_err(bus->dev,

				"Post bank switch ops not implemented");

			goto error;

		}



		/* Set the bank switch timeout to default, if not set */

		if (!bus->bank_switch_timeout)

			bus->bank_switch_timeout = DEFAULT_BANK_SWITCH_TIMEOUT;



		/* Check if bank switch was successful */

		ret = sdw_ml_sync_bank_switch(bus);

		if (ret < 0) {

			dev_err(bus->dev,

				"multi link bank switch failed: %d", ret);

			goto error;

		}



		mutex_unlock(&bus->msg_lock);

	}



	return ret;



error:

	list_for_each_entry(m_rt, &stream->master_list, stream_node) {



		bus = m_rt->bus;



		kfree(bus->defer_msg.msg->buf);

		kfree(bus->defer_msg.msg);

	}



msg_unlock:



	if (multi_link) {

		list_for_each_entry(m_rt, &stream->master_list, stream_node) {

			bus = m_rt->bus;

			if (mutex_is_locked(&bus->msg_lock))

				mutex_unlock(&bus->msg_lock);

		}

	}
@@ -964,6 +1070,7 @@ int sdw_stream_remove_master(struct sdw_bus *bus, 


		sdw_master_port_release(bus, m_rt);

		sdw_release_master_stream(m_rt, stream);

		stream->m_rt_count--;

	}



	if (list_empty(&stream->master_list))
@@ -1150,6 +1257,18 @@ int sdw_stream_add_master(struct sdw_bus *bus, 


	mutex_lock(&bus->bus_lock);



	/*

	 * For multi link streams, add the second master only if

	 * the bus supports it.

	 * Check if bus->multi_link is set

	 */

	if (!bus->multi_link && stream->m_rt_count > 0) {

		dev_err(bus->dev,

			"Multilink not supported, link %d", bus->link_id);

		ret = -EINVAL;

		goto unlock;

	}



	m_rt = sdw_alloc_master_rt(bus, stream_config, stream);

	if (!m_rt) {

		dev_err(bus->dev,
@@ -1167,6 +1286,8 @@ int sdw_stream_add_master(struct sdw_bus *bus, 
	if (ret)

		goto stream_error;



	stream->m_rt_count++;



	goto unlock;



stream_error:

include/linux/soundwire/sdw.h

+4 −0
Original line number Diff line number Diff line
@@ -678,6 +678,9 @@ struct sdw_master_ops { 
 * @defer_msg: Defer message

 * @clk_stop_timeout: Clock stop timeout computed

 * @bank_switch_timeout: Bank switch timeout computed

 * @multi_link: Store bus property that indicates if multi links

 * are supported. This flag is populated by drivers after reading

 * appropriate firmware (ACPI/DT).

 */

struct sdw_bus {

	struct device *dev;
@@ -694,6 +697,7 @@ struct sdw_bus { 
	struct sdw_defer defer_msg;

	unsigned int clk_stop_timeout;

	u32 bank_switch_timeout;

	bool multi_link;

};



int sdw_add_bus_master(struct sdw_bus *bus);