Re: [PATCH] media: nxp: imx8-isi: Add suspend/resume support for ISI mem2mem

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Guoniu,

Thank you for the patch.

On Thu, Jul 17, 2025 at 10:43:54AM +0800, guoniu.zhou@oss.nxp.com wrote:
> From: Guoniu Zhou <guoniu.zhou@nxp.com>
> 
> Add suspend/resume support for ISI when work at memory to memory mode.
> 
> Signed-off-by: Guoniu Zhou <guoniu.zhou@nxp.com>
> ---
>  .../platform/nxp/imx8-isi/imx8-isi-core.c     |  8 ++++
>  .../platform/nxp/imx8-isi/imx8-isi-core.h     | 11 +++++
>  .../platform/nxp/imx8-isi/imx8-isi-m2m.c      | 48 +++++++++++++++++++
>  3 files changed, 67 insertions(+)
> 
> diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c
> index 981648a03113..6eef45302e6c 100644
> --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c
> +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c
> @@ -372,6 +372,7 @@ static int mxc_isi_pm_suspend(struct device *dev)
>  		struct mxc_isi_pipe *pipe = &isi->pipes[i];
>  
>  		mxc_isi_video_suspend(pipe);
> +		mxc_isi_m2m_suspend(pipe);
>  	}

Given that only the first pipe can be used for M2M, I would move the
mxc_isi_m2m_suspend() call after the loop, and pass it a &isi->m2m
argument.

>  
>  	return pm_runtime_force_suspend(dev);
> @@ -401,6 +402,13 @@ static int mxc_isi_pm_resume(struct device *dev)
>  			 */
>  			err = ret;
>  		}
> +
> +		ret = mxc_isi_m2m_resume(pipe);
> +		if (ret) {
> +			dev_err(dev, "Failed to resume ISI%u (%d) for m2m\n", i,
> +				ret);
> +			err = ret;
> +		}

Same here, that can be moved after the loop.

>  	}
>  
>  	return err;
> diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.h b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.h
> index 206995bedca4..b979b79b5525 100644
> --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.h
> +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-core.h
> @@ -343,6 +343,8 @@ int mxc_isi_video_buffer_prepare(struct mxc_isi_dev *isi, struct vb2_buffer *vb2
>  #ifdef CONFIG_VIDEO_IMX8_ISI_M2M
>  int mxc_isi_m2m_register(struct mxc_isi_dev *isi, struct v4l2_device *v4l2_dev);
>  int mxc_isi_m2m_unregister(struct mxc_isi_dev *isi);
> +void mxc_isi_m2m_suspend(struct mxc_isi_pipe *pipe);
> +int mxc_isi_m2m_resume(struct mxc_isi_pipe *pipe);
>  #else
>  static inline int mxc_isi_m2m_register(struct mxc_isi_dev *isi,
>  				       struct v4l2_device *v4l2_dev)
> @@ -353,6 +355,15 @@ static inline int mxc_isi_m2m_unregister(struct mxc_isi_dev *isi)
>  {
>  	return 0;
>  }
> +
> +static inline void mxc_isi_m2m_suspend(struct mxc_isi_pipe *pipe)
> +{
> +}
> +
> +static inline int mxc_isi_m2m_resume(struct mxc_isi_pipe *pipe)
> +{
> +	return 0;
> +}
>  #endif
>  
>  int mxc_isi_channel_acquire(struct mxc_isi_pipe *pipe,
> diff --git a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c
> index 22e49d3a1287..fe9d85335b6c 100644
> --- a/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c
> +++ b/drivers/media/platform/nxp/imx8-isi/imx8-isi-m2m.c
> @@ -732,6 +732,54 @@ static const struct v4l2_file_operations mxc_isi_m2m_fops = {
>  	.mmap		= v4l2_m2m_fop_mmap,
>  };
>  
> +/* -----------------------------------------------------------------------------
> + * Suspend & resume
> + */
> +
> +void mxc_isi_m2m_suspend(struct mxc_isi_pipe *pipe)
> +{
> +	struct mxc_isi_m2m *m2m = &pipe->isi->m2m;
> +	struct mxc_isi_m2m_ctx *ctx = m2m->last_ctx;
> +
> +	/*
> +	 * Check pipe for ISI memory to memory since only
> +	 * channel 0 support this feature.
> +	 */
> +	if (m2m->pipe != pipe || m2m->usage_count == 0)

If we pass the mxc_isi_m2m pointer to the function, you can drop the
comment and the first part of the condition. Same in
mxc_isi_m2m_resume().

> +		return;
> +
> +	v4l2_m2m_suspend(m2m->m2m_dev);
> +
> +	if (ctx->chained)

Shouldn't you check m2m->chained_count instead ? Same in
mxc_isi_m2m_resume().

> +		mxc_isi_channel_unchain(pipe);
> +
> +	mxc_isi_channel_disable(pipe);
> +	mxc_isi_channel_put(pipe);
> +}
> +
> +int mxc_isi_m2m_resume(struct mxc_isi_pipe *pipe)
> +{
> +	struct mxc_isi_m2m *m2m = &pipe->isi->m2m;
> +	struct mxc_isi_m2m_ctx *ctx = m2m->last_ctx;
> +
> +	/*
> +	 * Check pipe for ISI memory to memory since only
> +	 * channel 0 support this feature.
> +	 */
> +	if (m2m->pipe != pipe || m2m->usage_count == 0)
> +		return 0;
> +
> +	mxc_isi_channel_get(pipe);
> +
> +	if (ctx->chained)
> +		mxc_isi_channel_chain(pipe, false);
> +
> +	m2m->last_ctx = NULL;
> +	v4l2_m2m_resume(m2m->m2m_dev);
> +
> +	return 0;
> +}
> +
>  /* -----------------------------------------------------------------------------
>   * Registration
>   */

-- 
Regards,

Laurent Pinchart