linux-kernel - Re: [PATCH V2 6/8] soundwire: amd: add runtime pm ops for AMD soundwire manager driver

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Date:   Mon, 13 Feb 2023 12:20:14 -0600
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Vijendar Mukunda <Vijendar.Mukunda@....com>, vkoul@...nel.org
Cc:     amadeuszx.slawinski@...ux.intel.com, Mario.Limonciello@....com,
        Sunil-kumar.Dommati@....com, Basavaraj.Hiregoudar@....com,
        Mastan.Katragadda@....com, Arungopal.kondaveeti@....com,
        Bard Liao <yung-chuan.liao@...ux.intel.com>,
        Sanyog Kale <sanyog.r.kale@...el.com>,
        "moderated list:SOUNDWIRE SUBSYSTEM" <alsa-devel@...a-project.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2 6/8] soundwire: amd: add runtime pm ops for AMD
 soundwire manager driver



On 2/13/23 03:40, Vijendar Mukunda wrote:
> Add support for runtime pm ops for AMD soundwire manager driver.
> 
> Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@....com>
> Signed-off-by: Mastan Katragadda <Mastan.Katragadda@....com>
> ---
>  drivers/soundwire/amd_manager.c   | 163 ++++++++++++++++++++++++++++++
>  drivers/soundwire/amd_manager.h   |   3 +
>  include/linux/soundwire/sdw_amd.h |  16 +++
>  3 files changed, 182 insertions(+)
> 
> diff --git a/drivers/soundwire/amd_manager.c b/drivers/soundwire/amd_manager.c
> index 87f9a987d93a..eced189ba6e0 100644
> --- a/drivers/soundwire/amd_manager.c
> +++ b/drivers/soundwire/amd_manager.c
> @@ -14,6 +14,7 @@
>  #include <linux/slab.h>
>  #include <linux/soundwire/sdw.h>
>  #include <linux/soundwire/sdw_registers.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/wait.h>
>  #include <sound/pcm_params.h>
>  #include <sound/soc.h>
> @@ -185,6 +186,15 @@ static void amd_disable_sdw_interrupts(struct amd_sdw_manager *amd_manager)
>  	acp_reg_writel(0x00, amd_manager->mmio + ACP_SW_ERROR_INTR_MASK);
>  }
>  
> +static int amd_deinit_sdw_manager(struct amd_sdw_manager *amd_manager)
> +{
> +	int ret;
> +
> +	amd_disable_sdw_interrupts(amd_manager);
> +	ret = amd_disable_sdw_manager(amd_manager);
> +	return ret;
> +}
> +
>  static void amd_sdw_set_frameshape(struct amd_sdw_manager *amd_manager)
>  {
>  	u32 frame_size;
> @@ -1043,6 +1053,12 @@ static int amd_sdw_manager_probe(struct platform_device *pdev)
>  	INIT_WORK(&amd_manager->amd_sdw_work, amd_sdw_update_slave_status_work);
>  	INIT_WORK(&amd_manager->probe_work, amd_sdw_probe_work);
>  	schedule_work(&amd_manager->probe_work);
> +	/* Enable runtime PM */
> +	pm_runtime_set_autosuspend_delay(dev, AMD_SDW_MASTER_SUSPEND_DELAY_MS);
> +	pm_runtime_use_autosuspend(dev);
> +	pm_runtime_mark_last_busy(dev);
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);

that doesn't sound good to me, why do this here and not in the work
function? That creates a racy case where the device might suspend before
being initialized.

>  	return 0;
>  }
>  
> @@ -1057,14 +1073,161 @@ static int amd_sdw_manager_remove(struct platform_device *pdev)
>  	amd_disable_sdw_interrupts(amd_manager);
>  	sdw_bus_master_delete(&amd_manager->bus);
>  	ret = amd_disable_sdw_manager(amd_manager);
> +	pm_runtime_disable(&pdev->dev);

shouldn't you do the pm_runtime_disable first?

>  	return ret;
>  }

> +/* AMD pm_runtime quirk definitions */
> +
> +/*
> + * Force the clock to stop(ClockStopMode0) when suspend callback
> + * is invoked.
> + */
> +#define AMD_SDW_CLK_STOP_MODE		1
> +
> +/*
> + * Stop the bus when runtime suspend/system level suspend callback
> + * is invoked. If set, a complete bus reset and re-enumeration will
> + * be performed when the bus restarts.
> + */
> +#define AMD_SDW_POWER_OFF_MODE		2

You need to clarify this mode, can you deal with device in-band wakes if
the power is off?

>  #define ACP_SDW0	0
>  #define ACP_SDW1	1
>  
> @@ -57,6 +71,7 @@ struct sdw_amd_dai_runtime {
>   * @instance: soundwire manager instance
>   * @quirks: soundwire manager quirks
>   * @wake_en_mask: wake enable mask per soundwire manager
> + * @clk_stopped: flag set to true when clock is stopped
>   * @power_mode_mask: flag interprets amd soundwire manager power mode
>   * @dai_runtime_array: dai runtime array
>   */
> @@ -86,6 +101,7 @@ struct amd_sdw_manager {
>  	u32 quirks;
>  	u32 wake_en_mask;
>  	u32 power_mode_mask;
> +	bool clk_stopped;
>  
>  	struct sdw_amd_dai_runtime **dai_runtime_array;
>  };