linux-kernel - Re: [PATCH 1/7] soundwire: bus: use sdw_update_no

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Date:   Sat, 5 Dec 2020 13:15:08 +0530
From:   Vinod Koul <vkoul@...nel.org>
To:     Bard Liao <yung-chuan.liao@...ux.intel.com>
Cc:     alsa-devel@...a-project.org, linux-kernel@...r.kernel.org,
        tiwai@...e.de, broonie@...nel.org, gregkh@...uxfoundation.org,
        jank@...ence.com, srinivas.kandagatla@...aro.org,
        rander.wang@...ux.intel.com, ranjani.sridharan@...ux.intel.com,
        hui.wang@...onical.com, pierre-louis.bossart@...ux.intel.com,
        sanyog.r.kale@...el.com, bard.liao@...el.com
Subject: Re: [PATCH 1/7] soundwire: bus: use sdw_update_no_pm when
 initializing a device

On 03-12-20, 04:46, Bard Liao wrote:
> From: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
> 
> When a Slave device is resumed, it may resume the bus and restart the
> enumeration. During that process, we absolutely don't want to call
> regular read/write routines which will wait for the resume to
> complete, otherwise a deadlock occurs.
> 
> Fixes: 60ee9be25571 ('soundwire: bus: add PM/no-PM versions of read/write functions')

Change looks okay, but not sure why this is a fix for adding no pm
version?

> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
> Reviewed-by: Rander Wang <rander.wang@...ux.intel.com>
> Signed-off-by: Bard Liao <yung-chuan.liao@...ux.intel.com>
> ---
>  drivers/soundwire/bus.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
> index d1e8c3a54976..60c42508c6c6 100644
> --- a/drivers/soundwire/bus.c
> +++ b/drivers/soundwire/bus.c
> @@ -489,6 +489,18 @@ sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
>  		return buf;
>  }
>  
> +static int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
> +{
> +	int tmp;
> +
> +	tmp = sdw_read_no_pm(slave, addr);
> +	if (tmp < 0)
> +		return tmp;
> +
> +	tmp = (tmp & ~mask) | val;
> +	return sdw_write_no_pm(slave, addr, tmp);
> +}
> +
>  /**
>   * sdw_nread() - Read "n" contiguous SDW Slave registers
>   * @slave: SDW Slave
> @@ -1256,7 +1268,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
>  	val = slave->prop.scp_int1_mask;
>  
>  	/* Enable SCP interrupts */
> -	ret = sdw_update(slave, SDW_SCP_INTMASK1, val, val);
> +	ret = sdw_update_no_pm(slave, SDW_SCP_INTMASK1, val, val);
>  	if (ret < 0) {
>  		dev_err(slave->bus->dev,
>  			"SDW_SCP_INTMASK1 write failed:%d\n", ret);
> @@ -1271,7 +1283,7 @@ static int sdw_initialize_slave(struct sdw_slave *slave)
>  	val = prop->dp0_prop->imp_def_interrupts;
>  	val |= SDW_DP0_INT_PORT_READY | SDW_DP0_INT_BRA_FAILURE;
>  
> -	ret = sdw_update(slave, SDW_DP0_INTMASK, val, val);
> +	ret = sdw_update_no_pm(slave, SDW_DP0_INTMASK, val, val);
>  	if (ret < 0)
>  		dev_err(slave->bus->dev,
>  			"SDW_DP0_INTMASK read failed:%d\n", ret);
> -- 
> 2.17.1

-- 
~Vinod