Re: [PATCH v7 5/7] mtk-mdp: make mdp driver to be loadable by platform_device_register*()

[houlong wei <houlong.wei@mediatek.com>]

Hi Eizan,
I have inline comment below.

Regards,
Houlong

On Wed, 2021-08-25 at 14:33 +0800, Eizan Miyamoto wrote:
> Rather than hanging the MDP master component driver off of the rdma0
> device, make it possible too create a "virtual" device by registering
> it with platform_device_register_*() to be probed by the mtk_mdp_core
> driver.
> 
> Broadly, three interdependent things are done by this change:
> - Make it is possible to search for MDP devices in the device tree
>   through the grandparent device's of_node.
> - v4l-related setup is moved into from the mtk_mdp_core driver to the
>   mtk_mdp_comp driver.
> - Presence of a mediatek,vpu property in an MDP component device node
>   is used to determine what device to use when dispatching DMA ops from
>   the relevant ioctl, and also do V4L2 initialization in this case.
> 
> Signed-off-by: Eizan Miyamoto <eizan@chromium.org>
> Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
> Reviewed-by: Houlong Wei <houlong.wei@mediatek.com>
> ---
> 
> Changes in v7:
> - Drop last two changes from this series related to removing the vpu
>   property from the mdp_rdma0 device node
> 
> Changes in v6:
> - Don't propagate errors from clock_on/off as an afterthought.
> - Split apart modifying mdp driver to be loadable from mmsys from
>   actually loading it from mmsys into two changs to make review easier.
> - Update devicetree bindings to reflect no longer needing the
>   mediatek,vpu property in the mdp_rdma0 device node.
> - Some stylistic cleanups.
> 
> Changes in v5:
> - rebase and test on 5.13-next @ e2f74b13dbe6
> 
> Changes in v4:
> - rebase and test on 5.13
> - don't depend on https://patchwork.kernel.org/project/linux-mediatek/list/?series=464873
> 
> Changes in v3:
> - get mdp master from aliases instead of strcmp against of_node->name
> 
> Changes in v2:
> - rebased onto Linux 5.12
> - 100 char line length allowance was utilized in a few places
> - Removal of a redundant dev_err() print at the end of
>   mtk_mdp_comp_init()
> - Instead of printing errors and ignoring them, I've added a patch to
>   correctly propagate them.
> - Use of C style comments.
> - Three additional patches were added to eliminate dependency on the
>   mediatek,vpu property inside the mdp_rdma0 device node.
> 
>  drivers/media/platform/mtk-mdp/mtk_mdp_comp.c | 51 ++++++++++-----
>  drivers/media/platform/mtk-mdp/mtk_mdp_core.c | 62 ++++++-------------
>  drivers/media/platform/mtk-mdp/mtk_mdp_core.h |  2 +
>  drivers/media/platform/mtk-mdp/mtk_mdp_m2m.c  |  4 +-
>  4 files changed, 60 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> index 7b6c8a3f3455..85ef274841a3 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_comp.c
> @@ -155,8 +155,45 @@ static int mtk_mdp_comp_bind(struct device *dev, struct device *master, void *da
>  {
>  	struct mtk_mdp_comp *comp = dev_get_drvdata(dev);
>  	struct mtk_mdp_dev *mdp = data;
> +	struct device_node *vpu_node;
>  
>  	mtk_mdp_register_component(mdp, comp);
> +
> +	/*
> +	 * If this component has a "mediatek-vpu" property, it is responsible for
> +	 * notifying the mdp master driver about it so it can be further initialized
> +	 * later.
> +	 */
> +	vpu_node = of_parse_phandle(dev->of_node, "mediatek,vpu", 0);
> +	if (vpu_node) {
> +		int ret;
> +
> +		mdp->vpu_dev = of_find_device_by_node(vpu_node);
> +		if (WARN_ON(!mdp->vpu_dev)) {
> +			dev_err(dev, "vpu pdev failed\n");
> +			of_node_put(vpu_node);
> +		}

The 'vpu_node' should be put when 'mdp->vpu_dev' is valid.

		mdp->vpu_dev = of_find_device_by_node(vpu_node);
		of_node_put(vpu_node);
		if (WARN_ON(!mdp->vpu_dev))
			dev_err(dev, "vpu pdev failed\n");

I commented it before, refer to
http://lists.infradead.org/pipermail/linux-mediatek/2021-August/028370.html

> +		ret = v4l2_device_register(dev, &mdp->v4l2_dev);
> +		if (ret) {
> +			dev_err(dev, "Failed to register v4l2 device\n");
> +			return -EINVAL;
> +		}
> +
> +		ret = vb2_dma_contig_set_max_seg_size(dev, DMA_BIT_MASK(32));
> +		if (ret) {
> +			dev_err(dev, "Failed to set vb2 dma mag seg size\n");
> +			return -EINVAL;
> +		}
> +
> +		/*
> +		 * presence of the "mediatek,vpu" property in a device node
> +		 * indicates that it is the primary MDP rdma device and MDP DMA
> +		 * ops should be handled by its DMA callbacks.
> +		 */
> +		mdp->rdma_dev = dev;
> +	}
> +
>  	pm_runtime_enable(dev);
>  
>  	return 0;
> @@ -237,23 +274,9 @@ int mtk_mdp_comp_init(struct mtk_mdp_comp *comp, struct device *dev)
>  static int mtk_mdp_comp_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> -	struct device_node *vpu_node;
>  	int status;
>  	struct mtk_mdp_comp *comp;
>  
> -	vpu_node = of_parse_phandle(dev->of_node, "mediatek,vpu", 0);
> -	if (vpu_node) {
> -		of_node_put(vpu_node);
> -		/*
> -		 * The device tree node with a mediatek,vpu property is deemed
> -		 * the MDP "master" device, we don't want to add a component
> -		 * for it in this function because the initialization for the
> -		 * master is done elsewhere.
> -		 */
> -		dev_info(dev, "vpu node found, not probing\n");
> -		return -ENODEV;
> -	}
> -
>  	comp = devm_kzalloc(dev, sizeof(*comp), GFP_KERNEL);
>  	if (!comp)
>  		return -ENOMEM;
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> index a72a9ba41ea6..50eafcc9993d 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.c
> @@ -159,6 +159,17 @@ static int mtk_mdp_master_bind(struct device *dev)
>  		goto err_component_bind_all;
>  	}
>  
> +	if (mdp->vpu_dev) {
> +		int ret = vpu_wdt_reg_handler(mdp->vpu_dev, mtk_mdp_reset_handler, mdp,
> +					  VPU_RST_MDP);
> +		if (ret) {
> +			dev_err(dev, "Failed to register reset handler\n");
> +			goto err_wdt_reg;
> +		}
> +	} else {
> +		dev_err(dev, "no vpu_dev found\n");
> +	}
> +
>  	status = mtk_mdp_register_m2m_device(mdp);
>  	if (status) {
>  		dev_err(dev, "Failed to register m2m device: %d\n", status);
> @@ -170,6 +181,8 @@ static int mtk_mdp_master_bind(struct device *dev)
>  	return 0;
>  
>  err_mtk_mdp_register_m2m_device:
> +
> +err_wdt_reg:
>  	component_unbind_all(dev, mdp);
>  
>  err_component_bind_all:
> @@ -228,8 +241,13 @@ static int mtk_mdp_probe(struct platform_device *pdev)
>  		of_node_put(node);
>  		parent = dev->of_node;
>  		dev_warn(dev, "device tree is out of date\n");
> -	} else {
> +	} else if (dev->of_node) {
>  		parent = dev->of_node->parent;
> +	} else if (dev->parent) {
> +		/* maybe we were created from a call to platform_device_register_data() */
> +		parent = dev->parent->parent->of_node;
> +	} else {
> +		return -ENODEV;
>  	}
>  
>  	/* Iterate over sibling MDP function blocks */
> @@ -262,16 +280,6 @@ static int mtk_mdp_probe(struct platform_device *pdev)
>  		}
>  	}
>  
> -	/*
> -	 * Create a component for myself so that clocks can be toggled in
> -	 * clock_on().
> -	 */
> -	ret = mtk_mdp_comp_init(&mdp->comp_self, dev);
> -	if (ret) {
> -		dev_err(dev, "Failed to initialize component\n");
> -		goto err_comp;
> -	}
> -
>  	mdp->job_wq = create_singlethread_workqueue(MTK_MDP_MODULE_NAME);
>  	if (!mdp->job_wq) {
>  		dev_err(&pdev->dev, "unable to alloc job workqueue\n");
> @@ -287,29 +295,8 @@ static int mtk_mdp_probe(struct platform_device *pdev)
>  	}
>  	INIT_WORK(&mdp->wdt_work, mtk_mdp_wdt_worker);
>  
> -	ret = v4l2_device_register(dev, &mdp->v4l2_dev);
> -	if (ret) {
> -		dev_err(&pdev->dev, "Failed to register v4l2 device\n");
> -		ret = -EINVAL;
> -		goto err_dev_register;
> -	}
> -
> -	mdp->vpu_dev = vpu_get_plat_device(pdev);
> -	ret = vpu_wdt_reg_handler(mdp->vpu_dev, mtk_mdp_reset_handler, mdp,
> -				  VPU_RST_MDP);
> -	if (ret) {
> -		dev_err(&pdev->dev, "Failed to register reset handler\n");
> -		goto err_wdt_reg;
> -	}
> -
>  	platform_set_drvdata(pdev, mdp);
>  
> -	ret = vb2_dma_contig_set_max_seg_size(&pdev->dev, DMA_BIT_MASK(32));
> -	if (ret) {
> -		dev_err(&pdev->dev, "Failed to set vb2 dma mag seg size\n");
> -		goto err_set_max_seg_size;
> -	}
> -
>  	ret = component_master_add_with_match(dev, &mtk_mdp_com_ops, match);
>  	if (ret) {
>  		dev_err(dev, "Component master add failed\n");
> @@ -321,22 +308,12 @@ static int mtk_mdp_probe(struct platform_device *pdev)
>  	return 0;
>  
>  err_component_master_add:
> -	vb2_dma_contig_clear_max_seg_size(&pdev->dev);
> -
> -err_set_max_seg_size:
> -
> -err_wdt_reg:
> -	v4l2_device_unregister(&mdp->v4l2_dev);
> -
> -err_dev_register:
>  	destroy_workqueue(mdp->wdt_wq);
>  
>  err_alloc_wdt_wq:
>  	destroy_workqueue(mdp->job_wq);
>  
>  err_alloc_job_wq:
> -
> -err_comp:
>  	dev_dbg(dev, "err %d\n", ret);
>  	return ret;
>  }
> @@ -404,7 +381,6 @@ static struct platform_driver mtk_mdp_driver = {
>  	.driver = {
>  		.name	= MTK_MDP_MODULE_NAME,
>  		.pm	= &mtk_mdp_pm_ops,
> -		.of_match_table = mtk_mdp_of_ids,
>  	}
>  };
>  
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_core.h b/drivers/media/platform/mtk-mdp/mtk_mdp_core.h
> index 8a52539b15d4..9fcd8b8e7c25 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_core.h
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_core.h
> @@ -133,6 +133,7 @@ struct mtk_mdp_variant {
>   * struct mtk_mdp_dev - abstraction for image processor entity
>   * @lock:	the mutex protecting this data structure
>   * @vpulock:	the mutex protecting the communication with VPU
> + * @rdma_dev:  device pointer to rdma device for MDP
>   * @pdev:	pointer to the image processor platform device
>   * @variant:	the IP variant information
>   * @id:		image processor device index (0..MTK_MDP_MAX_DEVS)
> @@ -151,6 +152,7 @@ struct mtk_mdp_variant {
>  struct mtk_mdp_dev {
>  	struct mutex			lock;
>  	struct mutex			vpulock;
> +	struct device			*rdma_dev;
>  	struct platform_device		*pdev;
>  	struct mtk_mdp_variant		*variant;
>  	u16				id;
> diff --git a/drivers/media/platform/mtk-mdp/mtk_mdp_m2m.c b/drivers/media/platform/mtk-mdp/mtk_mdp_m2m.c
> index f14779e7596e..9834d3bbe851 100644
> --- a/drivers/media/platform/mtk-mdp/mtk_mdp_m2m.c
> +++ b/drivers/media/platform/mtk-mdp/mtk_mdp_m2m.c
> @@ -929,7 +929,7 @@ static int mtk_mdp_m2m_queue_init(void *priv, struct vb2_queue *src_vq,
>  	src_vq->mem_ops = &vb2_dma_contig_memops;
>  	src_vq->buf_struct_size = sizeof(struct v4l2_m2m_buffer);
>  	src_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
> -	src_vq->dev = &ctx->mdp_dev->pdev->dev;
> +	src_vq->dev = ctx->mdp_dev->rdma_dev;
>  	src_vq->lock = &ctx->mdp_dev->lock;
>  
>  	ret = vb2_queue_init(src_vq);
> @@ -944,7 +944,7 @@ static int mtk_mdp_m2m_queue_init(void *priv, struct vb2_queue *src_vq,
>  	dst_vq->mem_ops = &vb2_dma_contig_memops;
>  	dst_vq->buf_struct_size = sizeof(struct v4l2_m2m_buffer);
>  	dst_vq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_COPY;
> -	dst_vq->dev = &ctx->mdp_dev->pdev->dev;
> +	dst_vq->dev = ctx->mdp_dev->rdma_dev;
>  	dst_vq->lock = &ctx->mdp_dev->lock;
>  
>  	return vb2_queue_init(dst_vq);