Re: [PATCH v6 07/11] bus: mhi: core: Introduce counters to track MHI device state transitions

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Mon, Jul 27, 2020 at 07:02:16PM -0700, Bhaumik Bhatt wrote:
> Use counters to track MHI device state transitions such as those
> to M0, M2, or M3 states. This can help in better debug, allowing
> the user to see the number of transitions to a certain MHI state
> when queried using debugfs entries or via other mechanisms.
> 
> Signed-off-by: Bhaumik Bhatt <bbhatt@codeaurora.org>

Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

A minor nit below...

> ---
>  drivers/bus/mhi/core/pm.c | 4 ++++
>  include/linux/mhi.h       | 2 ++
>  2 files changed, 6 insertions(+)
> 
> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
> index 27bb471..ce4d969 100644
> --- a/drivers/bus/mhi/core/pm.c
> +++ b/drivers/bus/mhi/core/pm.c
> @@ -256,6 +256,7 @@ int mhi_pm_m0_transition(struct mhi_controller *mhi_cntrl)
>  		dev_err(dev, "Unable to transition to M0 state\n");
>  		return -EIO;
>  	}
> +	mhi_cntrl->M0++;
>  
>  	/* Wake up the device */
>  	read_lock_bh(&mhi_cntrl->pm_lock);
> @@ -326,6 +327,8 @@ void mhi_pm_m1_transition(struct mhi_controller *mhi_cntrl)
>  		mhi_cntrl->dev_state = MHI_STATE_M2;
>  
>  		write_unlock_irq(&mhi_cntrl->pm_lock);
> +
> +		mhi_cntrl->M2++;
>  		wake_up_all(&mhi_cntrl->state_event);
>  
>  		/* If there are any pending resources, exit M2 immediately */
> @@ -362,6 +365,7 @@ int mhi_pm_m3_transition(struct mhi_controller *mhi_cntrl)
>  		return -EIO;
>  	}
>  
> +	mhi_cntrl->M3++;
>  	wake_up_all(&mhi_cntrl->state_event);
>  
>  	return 0;
> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
> index a8379b3..e38de6d 100644
> --- a/include/linux/mhi.h
> +++ b/include/linux/mhi.h
> @@ -328,6 +328,7 @@ struct mhi_controller_config {
>   * @dev_state: MHI device state
>   * @dev_wake: Device wakeup count
>   * @pending_pkts: Pending packets for the controller
> + * @M0, M2, M3, M3_fast: Counters to track number of device MHI state changes
>   * @transition_list: List of MHI state transitions
>   * @transition_lock: Lock for protecting MHI state transition list
>   * @wlock: Lock for protecting device wakeup
> @@ -407,6 +408,7 @@ struct mhi_controller {
>  	enum mhi_state dev_state;
>  	atomic_t dev_wake;
>  	atomic_t pending_pkts;
> +	u32 M0, M2, M3, M3_fast;

Are you using M3_fast anywhere in current series? If not, please drop it for
now.

Thanks,
Mani

>  	struct list_head transition_list;
>  	spinlock_t transition_lock;
>  	spinlock_t wlock;
> -- 
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