Re: [PATCH v4 08/79] media: atmel: properly get pm_runtime

[Jonathan Cameron]

On Wed, 28 Apr 2021 16:51:29 +0200
Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> wrote:

> There are several issues in the way the atmel driver handles
> pm_runtime_get_sync():
> 
> - it doesn't check return codes;
> - it doesn't properly decrement the usage_count on all places;
> - it starts streaming even if pm_runtime_get_sync() fails.
> - while it tries to get pm_runtime at the clock enable logic,
>   it doesn't check if the operation was suceeded.
> 
> Replace all occurrences of it to use the new kAPI:
> pm_runtime_resume_and_get(), which ensures that, if the
> return code is not negative, the usage_count was incremented.
> 
> With that, add additional checks when this is called, in order
> to ensure that errors will be properly addressed.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
> ---
>  drivers/media/platform/atmel/atmel-isc-base.c | 27 ++++++++++++++-----
>  drivers/media/platform/atmel/atmel-isi.c      | 19 ++++++++++---
>  2 files changed, 35 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/media/platform/atmel/atmel-isc-base.c b/drivers/media/platform/atmel/atmel-isc-base.c
> index fe3ec8d0eaee..02543fe42e9d 100644
> --- a/drivers/media/platform/atmel/atmel-isc-base.c
> +++ b/drivers/media/platform/atmel/atmel-isc-base.c
> @@ -294,9 +294,13 @@ static int isc_wait_clk_stable(struct clk_hw *hw)
>  static int isc_clk_prepare(struct clk_hw *hw)
>  {
>  	struct isc_clk *isc_clk = to_isc_clk(hw);
> +	int ret;
>  
> -	if (isc_clk->id == ISC_ISPCK)
> -		pm_runtime_get_sync(isc_clk->dev);
> +	if (isc_clk->id == ISC_ISPCK) {
> +		ret = pm_runtime_resume_and_get(isc_clk->dev);
> +		if (ret < 0)
> +			return 0;

Why not the error?  isc_wait_clk_stable() is happy to return -ETIMEDOUT so I
assume the callers should fine with errors.

> +	}
>  
>  	return isc_wait_clk_stable(hw);
>  }
> @@ -353,9 +357,13 @@ static int isc_clk_is_enabled(struct clk_hw *hw)
>  {
>  	struct isc_clk *isc_clk = to_isc_clk(hw);
>  	u32 status;
> +	int ret;
>  
> -	if (isc_clk->id == ISC_ISPCK)
> -		pm_runtime_get_sync(isc_clk->dev);
> +	if (isc_clk->id == ISC_ISPCK) {
> +		ret = pm_runtime_resume_and_get(isc_clk->dev);
> +		if (ret < 0)
> +			return 0;
> +	}
>  
>  	regmap_read(isc_clk->regmap, ISC_CLKSR, &status);
>  
> @@ -807,7 +815,9 @@ static int isc_start_streaming(struct vb2_queue *vq, unsigned int count)
>  		goto err_start_stream;
>  	}
>  
> -	pm_runtime_get_sync(isc->dev);
> +	ret = pm_runtime_resume_and_get(isc->dev);
> +	if (ret < 0)
> +		goto err_pm_get;
>  
>  	ret = isc_configure(isc);
>  	if (unlikely(ret))
> @@ -838,7 +848,7 @@ static int isc_start_streaming(struct vb2_queue *vq, unsigned int count)
>  
>  err_configure:
>  	pm_runtime_put_sync(isc->dev);
> -
> +err_pm_get:
>  	v4l2_subdev_call(isc->current_subdev->sd, video, s_stream, 0);
>  
>  err_start_stream:
> @@ -1809,6 +1819,7 @@ static void isc_awb_work(struct work_struct *w)
>  	u32 baysel;
>  	unsigned long flags;
>  	u32 min, max;
> +	int ret;
>  
>  	/* streaming is not active anymore */
>  	if (isc->stop)
> @@ -1831,7 +1842,9 @@ static void isc_awb_work(struct work_struct *w)
>  	ctrls->hist_id = hist_id;
>  	baysel = isc->config.sd_format->cfa_baycfg << ISC_HIS_CFG_BAYSEL_SHIFT;
>  
> -	pm_runtime_get_sync(isc->dev);
> +	ret = pm_runtime_resume_and_get(isc->dev);
> +	if (ret < 0)

Maybe warn or similar?

> +		return;
>  
>  	/*
>  	 * only update if we have all the required histograms and controls
> diff --git a/drivers/media/platform/atmel/atmel-isi.c b/drivers/media/platform/atmel/atmel-isi.c
> index 0514be6153df..6a433926726d 100644
> --- a/drivers/media/platform/atmel/atmel-isi.c
> +++ b/drivers/media/platform/atmel/atmel-isi.c
> @@ -422,7 +422,9 @@ static int start_streaming(struct vb2_queue *vq, unsigned int count)
>  	struct frame_buffer *buf, *node;
>  	int ret;
>  
> -	pm_runtime_get_sync(isi->dev);
> +	ret = pm_runtime_resume_and_get(isi->dev);
> +	if (ret < 0)
> +		return ret;
>  
>  	/* Enable stream on the sub device */
>  	ret = v4l2_subdev_call(isi->entity.subdev, video, s_stream, 1);
> @@ -782,9 +784,10 @@ static int isi_enum_frameintervals(struct file *file, void *fh,
>  	return 0;
>  }
>  
> -static void isi_camera_set_bus_param(struct atmel_isi *isi)
> +static int isi_camera_set_bus_param(struct atmel_isi *isi)
>  {
>  	u32 cfg1 = 0;
> +	int ret;
>  
>  	/* set bus param for ISI */
>  	if (isi->pdata.hsync_act_low)
> @@ -801,12 +804,16 @@ static void isi_camera_set_bus_param(struct atmel_isi *isi)
>  	cfg1 |= ISI_CFG1_THMASK_BEATS_16;
>  
>  	/* Enable PM and peripheral clock before operate isi registers */
> -	pm_runtime_get_sync(isi->dev);
> +	ret = pm_runtime_resume_and_get(isi->dev);
> +	if (ret < 0)
> +		return ret;
>  
>  	isi_writel(isi, ISI_CTRL, ISI_CTRL_DIS);
>  	isi_writel(isi, ISI_CFG1, cfg1);
>  
>  	pm_runtime_put(isi->dev);
> +
> +	return 0;
>  }
>  
>  /* -----------------------------------------------------------------------*/
> @@ -1085,7 +1092,11 @@ static int isi_graph_notify_complete(struct v4l2_async_notifier *notifier)
>  		dev_err(isi->dev, "No supported mediabus format found\n");
>  		return ret;
>  	}
> -	isi_camera_set_bus_param(isi);
> +	ret = isi_camera_set_bus_param(isi);
> +	if (ret) {
> +		dev_err(isi->dev, "Can't wake up device\n");
> +		return ret;
> +	}
>  
>  	ret = isi_set_default_fmt(isi);
>  	if (ret) {