linux-kernel - Re: [PATCH v4 3/9] bus: mhi: core: Use helper API to trigger a non-blocking host resume

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Date:   Sat, 4 Jul 2020 20:17:14 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To:     Bhaumik Bhatt <bbhatt@...eaurora.org>
Cc:     linux-arm-msm@...r.kernel.org, hemantk@...eaurora.org,
        jhugo@...eaurora.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/9] bus: mhi: core: Use helper API to trigger a
 non-blocking host resume

On Mon, Jun 29, 2020 at 09:39:36AM -0700, Bhaumik Bhatt wrote:
> Autonomous low power mode support requires the MHI host to resume from
> multiple places and post a wakeup source to exit system suspend. This
> needs to be done in a non-blocking manner. Introduce a helper API to
> trigger the host resume for data transfers and other non-blocking use
> cases while supporting implementation of autonomous low power modes.
> 

Why can't you use pm_wakeup_event() as done in __mhi_device_get_sync()?

Thanks,
Mani

> Signed-off-by: Bhaumik Bhatt <bbhatt@...eaurora.org>
> ---
>  drivers/bus/mhi/core/internal.h |  8 ++++++++
>  drivers/bus/mhi/core/main.c     | 21 +++++++--------------
>  drivers/bus/mhi/core/pm.c       |  6 ++----
>  3 files changed, 17 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/bus/mhi/core/internal.h b/drivers/bus/mhi/core/internal.h
> index bcfa7b6..cb32eaf 100644
> --- a/drivers/bus/mhi/core/internal.h
> +++ b/drivers/bus/mhi/core/internal.h
> @@ -599,6 +599,14 @@ int mhi_queue_state_transition(struct mhi_controller *mhi_cntrl,
>  int mhi_send_cmd(struct mhi_controller *mhi_cntrl, struct mhi_chan *mhi_chan,
>  		 enum mhi_cmd_type cmd);
>  
> +static inline void mhi_trigger_resume(struct mhi_controller *mhi_cntrl,
> +				      bool hard_wakeup)
> +{
> +	pm_wakeup_dev_event(&mhi_cntrl->mhi_dev->dev, 0, hard_wakeup);
> +	mhi_cntrl->runtime_get(mhi_cntrl);
> +	mhi_cntrl->runtime_put(mhi_cntrl);
> +}
> +
>  /* Register access methods */
>  void mhi_db_brstmode(struct mhi_controller *mhi_cntrl, struct db_cfg *db_cfg,
>  		     void __iomem *db_addr, dma_addr_t db_val);
> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
> index 1f622ce..8d6ec34 100644
> --- a/drivers/bus/mhi/core/main.c
> +++ b/drivers/bus/mhi/core/main.c
> @@ -909,8 +909,7 @@ void mhi_ctrl_ev_task(unsigned long data)
>  		 * process it since we are probably in a suspended state,
>  		 * so trigger a resume.
>  		 */
> -		mhi_cntrl->runtime_get(mhi_cntrl);
> -		mhi_cntrl->runtime_put(mhi_cntrl);
> +		mhi_trigger_resume(mhi_cntrl, false);
>  
>  		return;
>  	}
> @@ -971,10 +970,8 @@ int mhi_queue_skb(struct mhi_device *mhi_dev, enum dma_data_direction dir,
>  	}
>  
>  	/* we're in M3 or transitioning to M3 */
> -	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
> -		mhi_cntrl->runtime_get(mhi_cntrl);
> -		mhi_cntrl->runtime_put(mhi_cntrl);
> -	}
> +	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
> +		mhi_trigger_resume(mhi_cntrl, false);
>  
>  	/* Toggle wake to exit out of M2 */
>  	mhi_cntrl->wake_toggle(mhi_cntrl);
> @@ -1032,10 +1029,8 @@ int mhi_queue_dma(struct mhi_device *mhi_dev, enum dma_data_direction dir,
>  	}
>  
>  	/* we're in M3 or transitioning to M3 */
> -	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
> -		mhi_cntrl->runtime_get(mhi_cntrl);
> -		mhi_cntrl->runtime_put(mhi_cntrl);
> -	}
> +	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
> +		mhi_trigger_resume(mhi_cntrl, false);
>  
>  	/* Toggle wake to exit out of M2 */
>  	mhi_cntrl->wake_toggle(mhi_cntrl);
> @@ -1147,10 +1142,8 @@ int mhi_queue_buf(struct mhi_device *mhi_dev, enum dma_data_direction dir,
>  	read_lock_irqsave(&mhi_cntrl->pm_lock, flags);
>  
>  	/* we're in M3 or transitioning to M3 */
> -	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
> -		mhi_cntrl->runtime_get(mhi_cntrl);
> -		mhi_cntrl->runtime_put(mhi_cntrl);
> -	}
> +	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
> +		mhi_trigger_resume(mhi_cntrl, false);
>  
>  	/* Toggle wake to exit out of M2 */
>  	mhi_cntrl->wake_toggle(mhi_cntrl);
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index 661d704..5e3994e 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -1139,10 +1139,8 @@ void mhi_device_put(struct mhi_device *mhi_dev)
>  
>  	mhi_dev->dev_wake--;
>  	read_lock_bh(&mhi_cntrl->pm_lock);
> -	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state)) {
> -		mhi_cntrl->runtime_get(mhi_cntrl);
> -		mhi_cntrl->runtime_put(mhi_cntrl);
> -	}
> +	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
> +		mhi_trigger_resume(mhi_cntrl, false);
>  
>  	mhi_cntrl->wake_put(mhi_cntrl, false);
>  	read_unlock_bh(&mhi_cntrl->pm_lock);
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
>