Re: [PATCH 4/4] soundwire: stream: Move remaining register accesses over to no_pm

[Pierre-Louis Bossart]

On 11/14/22 04:29, Charles Keepax wrote:
> There is no need to play with the runtime reference everytime a register
> is accessed. All the remaining "pm" style register accesses trace back
> to 4 functions:
> 
> sdw_prepare_stream
> sdw_deprepare_stream
> sdw_enable_stream
> sdw_disable_stream
> 
> Any sensible implementation will need to hold a runtime reference
> across all those functions, it makes no sense to be allowing the
> device/bus to suspend whilst streams are being prepared/enabled. And
> certainly in the case of the all existing users, they all call these
> functions from hw_params/prepare/trigger/hw_free callbacks in ALSA,
> which will have already runtime resumed all the audio devices
> associated during the open callback.
> 
> Signed-off-by: Charles Keepax <ckeepax@xxxxxxxxxxxxxxxxxxxxx>

I tend to agree with this one, and if this ever fails that would point
to a miss at a higher-level we'd need to address.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>

> ---
>  drivers/soundwire/bus.c    |  2 +-
>  drivers/soundwire/stream.c | 30 +++++++++++++++---------------
>  2 files changed, 16 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
> index ef4878258afad..d87a188fcce1e 100644
> --- a/drivers/soundwire/bus.c
> +++ b/drivers/soundwire/bus.c
> @@ -1214,7 +1214,7 @@ int sdw_configure_dpn_intr(struct sdw_slave *slave,
>  		val &= ~SDW_DPN_INT_PORT_READY;
>  	}
>  
> -	ret = sdw_update(slave, addr, (mask | SDW_DPN_INT_PORT_READY), val);
> +	ret = sdw_update_no_pm(slave, addr, (mask | SDW_DPN_INT_PORT_READY), val);
>  	if (ret < 0)
>  		dev_err(&slave->dev,
>  			"SDW_DPN_INTMASK write failed:%d\n", val);
> diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
> index bd502368339e5..df3b36670df4c 100644
> --- a/drivers/soundwire/stream.c
> +++ b/drivers/soundwire/stream.c
> @@ -81,14 +81,14 @@ static int _sdw_program_slave_port_params(struct sdw_bus *bus,
>  	}
>  
>  	/* Program DPN_OffsetCtrl2 registers */
> -	ret = sdw_write(slave, addr1, t_params->offset2);
> +	ret = sdw_write_no_pm(slave, addr1, t_params->offset2);
>  	if (ret < 0) {
>  		dev_err(bus->dev, "DPN_OffsetCtrl2 register write failed\n");
>  		return ret;
>  	}
>  
>  	/* Program DPN_BlockCtrl3 register */
> -	ret = sdw_write(slave, addr2, t_params->blk_pkg_mode);
> +	ret = sdw_write_no_pm(slave, addr2, t_params->blk_pkg_mode);
>  	if (ret < 0) {
>  		dev_err(bus->dev, "DPN_BlockCtrl3 register write failed\n");
>  		return ret;
> @@ -105,7 +105,7 @@ static int _sdw_program_slave_port_params(struct sdw_bus *bus,
>  	/* Program DPN_SampleCtrl2 register */
>  	wbuf = FIELD_GET(SDW_DPN_SAMPLECTRL_HIGH, t_params->sample_interval - 1);
>  
> -	ret = sdw_write(slave, addr3, wbuf);
> +	ret = sdw_write_no_pm(slave, addr3, wbuf);
>  	if (ret < 0) {
>  		dev_err(bus->dev, "DPN_SampleCtrl2 register write failed\n");
>  		return ret;
> @@ -115,7 +115,7 @@ static int _sdw_program_slave_port_params(struct sdw_bus *bus,
>  	wbuf = FIELD_PREP(SDW_DPN_HCTRL_HSTART, t_params->hstart);
>  	wbuf |= FIELD_PREP(SDW_DPN_HCTRL_HSTOP, t_params->hstop);
>  
> -	ret = sdw_write(slave, addr4, wbuf);
> +	ret = sdw_write_no_pm(slave, addr4, wbuf);
>  	if (ret < 0)
>  		dev_err(bus->dev, "DPN_HCtrl register write failed\n");
>  
> @@ -163,7 +163,7 @@ static int sdw_program_slave_port_params(struct sdw_bus *bus,
>  	wbuf = FIELD_PREP(SDW_DPN_PORTCTRL_DATAMODE, p_params->data_mode);
>  	wbuf |= FIELD_PREP(SDW_DPN_PORTCTRL_FLOWMODE, p_params->flow_mode);
>  
> -	ret = sdw_update(s_rt->slave, addr1, 0xF, wbuf);
> +	ret = sdw_update_no_pm(s_rt->slave, addr1, 0xF, wbuf);
>  	if (ret < 0) {
>  		dev_err(&s_rt->slave->dev,
>  			"DPN_PortCtrl register write failed for port %d\n",
> @@ -173,7 +173,7 @@ static int sdw_program_slave_port_params(struct sdw_bus *bus,
>  
>  	if (!dpn_prop->read_only_wordlength) {
>  		/* Program DPN_BlockCtrl1 register */
> -		ret = sdw_write(s_rt->slave, addr2, (p_params->bps - 1));
> +		ret = sdw_write_no_pm(s_rt->slave, addr2, (p_params->bps - 1));
>  		if (ret < 0) {
>  			dev_err(&s_rt->slave->dev,
>  				"DPN_BlockCtrl1 register write failed for port %d\n",
> @@ -184,7 +184,7 @@ static int sdw_program_slave_port_params(struct sdw_bus *bus,
>  
>  	/* Program DPN_SampleCtrl1 register */
>  	wbuf = (t_params->sample_interval - 1) & SDW_DPN_SAMPLECTRL_LOW;
> -	ret = sdw_write(s_rt->slave, addr3, wbuf);
> +	ret = sdw_write_no_pm(s_rt->slave, addr3, wbuf);
>  	if (ret < 0) {
>  		dev_err(&s_rt->slave->dev,
>  			"DPN_SampleCtrl1 register write failed for port %d\n",
> @@ -193,7 +193,7 @@ static int sdw_program_slave_port_params(struct sdw_bus *bus,
>  	}
>  
>  	/* Program DPN_OffsetCtrl1 registers */
> -	ret = sdw_write(s_rt->slave, addr4, t_params->offset1);
> +	ret = sdw_write_no_pm(s_rt->slave, addr4, t_params->offset1);
>  	if (ret < 0) {
>  		dev_err(&s_rt->slave->dev,
>  			"DPN_OffsetCtrl1 register write failed for port %d\n",
> @@ -203,7 +203,7 @@ static int sdw_program_slave_port_params(struct sdw_bus *bus,
>  
>  	/* Program DPN_BlockCtrl2 register*/
>  	if (t_params->blk_grp_ctrl_valid) {
> -		ret = sdw_write(s_rt->slave, addr5, t_params->blk_grp_ctrl);
> +		ret = sdw_write_no_pm(s_rt->slave, addr5, t_params->blk_grp_ctrl);
>  		if (ret < 0) {
>  			dev_err(&s_rt->slave->dev,
>  				"DPN_BlockCtrl2 reg write failed for port %d\n",
> @@ -214,7 +214,7 @@ static int sdw_program_slave_port_params(struct sdw_bus *bus,
>  
>  	/* program DPN_LaneCtrl register */
>  	if (slave_prop->lane_control_support) {
> -		ret = sdw_write(s_rt->slave, addr6, t_params->lane_ctrl);
> +		ret = sdw_write_no_pm(s_rt->slave, addr6, t_params->lane_ctrl);
>  		if (ret < 0) {
>  			dev_err(&s_rt->slave->dev,
>  				"DPN_LaneCtrl register write failed for port %d\n",
> @@ -319,9 +319,9 @@ static int sdw_enable_disable_slave_ports(struct sdw_bus *bus,
>  	 * it is safe to reset this register
>  	 */
>  	if (en)
> -		ret = sdw_write(s_rt->slave, addr, p_rt->ch_mask);
> +		ret = sdw_write_no_pm(s_rt->slave, addr, p_rt->ch_mask);
>  	else
> -		ret = sdw_write(s_rt->slave, addr, 0x0);
> +		ret = sdw_write_no_pm(s_rt->slave, addr, 0x0);
>  
>  	if (ret < 0)
>  		dev_err(&s_rt->slave->dev,
> @@ -476,9 +476,9 @@ static int sdw_prep_deprep_slave_ports(struct sdw_bus *bus,
>  		addr = SDW_DPN_PREPARECTRL(p_rt->num);
>  
>  		if (prep)
> -			ret = sdw_write(s_rt->slave, addr, p_rt->ch_mask);
> +			ret = sdw_write_no_pm(s_rt->slave, addr, p_rt->ch_mask);
>  		else
> -			ret = sdw_write(s_rt->slave, addr, 0x0);
> +			ret = sdw_write_no_pm(s_rt->slave, addr, 0x0);
>  
>  		if (ret < 0) {
>  			dev_err(&s_rt->slave->dev,
> @@ -491,7 +491,7 @@ static int sdw_prep_deprep_slave_ports(struct sdw_bus *bus,
>  		wait_for_completion_timeout(port_ready,
>  			msecs_to_jiffies(dpn_prop->ch_prep_timeout));
>  
> -		val = sdw_read(s_rt->slave, SDW_DPN_PREPARESTATUS(p_rt->num));
> +		val = sdw_read_no_pm(s_rt->slave, SDW_DPN_PREPARESTATUS(p_rt->num));
>  		if ((val < 0) || (val & p_rt->ch_mask)) {
>  			ret = (val < 0) ? val : -ETIMEDOUT;
>  			dev_err(&s_rt->slave->dev,