Date:   Thu, 14 Sep 2017 17:56:16 +0800
From:   Wu Hao <hao.wu@...el.com>
To:     Alan Tull <atull@...nel.org>
Cc:     Moritz Fischer <mdf@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-fpga@...r.kernel.org" <linux-fpga@...r.kernel.org>
Subject: Re: [PATCH v4 13/18] fpga: region: add register/unregister functions

On Thu, Sep 14, 2017 at 04:48:36AM +0800, Alan Tull wrote:
> Another step in separating common code from device tree specific
> code for FPGA regions.
> 
> * add FPGA region register/unregister functions.
> * add the register/unregister functions to the header
> * use devm_kzalloc to alloc the region.
> * add a method for getting bridges to the region struct
> * add priv to the region struct
> * use region->info in of_fpga_region_get_bridges
> 
> Signed-off-by: Alan Tull <atull@...nel.org>
> ---
> v2: split out from another patch
> v3: use region->info, remove info param where applicable
> v4: no change to this patch in this version of patchset
> ---
>  drivers/fpga/fpga-region.c       | 106 ++++++++++++++++++++++++---------------
>  include/linux/fpga/fpga-region.h |   7 +++
>  2 files changed, 72 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index 92ab216..ce57383 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -143,7 +143,6 @@ static struct fpga_manager *of_fpga_region_get_mgr(struct device_node *np)
>  /**
>   * of_fpga_region_get_bridges - create a list of bridges
>   * @region: FPGA region
> - * @info: FPGA image info
>   *
>   * Create a list of bridges including the parent bridge and the bridges
>   * specified by "fpga-bridges" property.  Note that the
> @@ -156,11 +155,11 @@ static struct fpga_manager *of_fpga_region_get_mgr(struct device_node *np)
>   * Return 0 for success (even if there are no bridges specified)
>   * or -EBUSY if any of the bridges are in use.
>   */
> -static int of_fpga_region_get_bridges(struct fpga_region *region,
> -				      struct fpga_image_info *info)
> +static int of_fpga_region_get_bridges(struct fpga_region *region)
>  {
>  	struct device *dev = &region->dev;
>  	struct device_node *region_np = dev->of_node;
> +	struct fpga_image_info *info = region->info;
>  	struct device_node *br, *np, *parent_br = NULL;
>  	int i, ret;
>  
> @@ -192,7 +191,7 @@ static int of_fpga_region_get_bridges(struct fpga_region *region,
>  			continue;
>  
>  		/* If node is a bridge, get it and add to list */
> -		ret = of_fpga_bridge_get_to_list(br, region->info,
> +		ret = of_fpga_bridge_get_to_list(br, info,
>  						 &region->bridge_list);
>  
>  		/* If any of the bridges are in use, give up */
> @@ -229,10 +228,16 @@ int fpga_region_program_fpga(struct fpga_region *region)
>  		goto err_put_region;
>  	}
>  
> -	ret = of_fpga_region_get_bridges(region, info);
> -	if (ret) {
> -		dev_err(dev, "failed to get FPGA bridges\n");
> -		goto err_unlock_mgr;
> +	/*
> +	 * In some cases, we already have a list of bridges in the
> +	 * fpga region struct.  Or we don't have any bridges.
> +	 */
> +	if (region->get_bridges) {
> +		ret = region->get_bridges(region);
> +		if (ret) {
> +			dev_err(dev, "failed to get fpga region bridges\n");
> +			goto err_unlock_mgr;
> +		}
>  	}
>  
>  	ret = fpga_bridges_disable(&region->bridge_list);
> @@ -259,7 +264,8 @@ int fpga_region_program_fpga(struct fpga_region *region)
>  	return 0;
>  
>  err_put_br:
> -	fpga_bridges_put(&region->bridge_list);
> +	if (region->get_bridges)
> +		fpga_bridges_put(&region->bridge_list);
>  err_unlock_mgr:
>  	fpga_mgr_unlock(region->mgr);
>  err_put_region:
> @@ -522,39 +528,20 @@ static struct notifier_block fpga_region_of_nb = {
>  	.notifier_call = of_fpga_region_notify,
>  };
>  
> -static int of_fpga_region_probe(struct platform_device *pdev)
> +int fpga_region_register(struct device *dev, struct fpga_region *region)
>  {
> -	struct device *dev = &pdev->dev;
> -	struct device_node *np = dev->of_node;
> -	struct fpga_region *region;
> -	struct fpga_manager *mgr;
>  	int id, ret = 0;
>  
> -	mgr = of_fpga_region_get_mgr(np);
> -	if (IS_ERR(mgr))
> -		return -EPROBE_DEFER;
> -
> -	region = kzalloc(sizeof(*region), GFP_KERNEL);
> -	if (!region) {
> -		ret = -ENOMEM;
> -		goto err_put_mgr;
> -	}
> -
> -	region->mgr = mgr;
> -
>  	id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
> -	if (id < 0) {
> -		ret = id;
> -		goto err_kfree;
> -	}
> +	if (id < 0)
> +		return id;
>  
>  	mutex_init(&region->mutex);
>  	INIT_LIST_HEAD(&region->bridge_list);
> -
>  	device_initialize(&region->dev);
>  	region->dev.class = fpga_region_class;
>  	region->dev.parent = dev;
> -	region->dev.of_node = np;
> +	region->dev.of_node = dev->of_node;
>  	region->dev.id = id;
>  	dev_set_drvdata(dev, region);
>  
> @@ -566,19 +553,58 @@ static int of_fpga_region_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto err_remove;
>  
> +	return 0;
> +
> +err_remove:
> +	ida_simple_remove(&fpga_region_ida, id);
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(fpga_region_register);
> +
> +int fpga_region_unregister(struct fpga_region *region)
> +{
> +	device_unregister(&region->dev);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(fpga_region_unregister);
> +
> +static int of_fpga_region_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct fpga_region *region;
> +	struct fpga_manager *mgr;
> +	int ret;
> +
> +	/* Find the FPGA mgr specified by region or parent region. */
> +	mgr = of_fpga_region_get_mgr(np);
> +	if (IS_ERR(mgr))
> +		return -EPROBE_DEFER;
> +
> +	region = devm_kzalloc(dev, sizeof(*region), GFP_KERNEL);
> +	if (!region) {
> +		ret = -ENOMEM;
> +		goto eprobe_mgr_put;
> +	}
> +
> +	region->mgr = mgr;
> +
> +	/* Specify how to get bridges for this type of region. */
> +	region->get_bridges = of_fpga_region_get_bridges;
> +
> +	ret = fpga_region_register(dev, region);
> +	if (ret)
> +		goto eprobe_mgr_put;
> +
>  	of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
>  
>  	dev_info(dev, "FPGA Region probed\n");
>  
>  	return 0;
>  
> -err_remove:
> -	ida_simple_remove(&fpga_region_ida, id);
> -err_kfree:
> -	kfree(region);
> -err_put_mgr:
> +eprobe_mgr_put:
>  	fpga_mgr_put(mgr);
> -
>  	return ret;
>  }
>  
> @@ -586,8 +612,7 @@ static int of_fpga_region_remove(struct platform_device *pdev)
>  {
>  	struct fpga_region *region = platform_get_drvdata(pdev);
>  
> -	device_unregister(&region->dev);
> -	fpga_mgr_put(region->mgr);
> +	fpga_region_unregister(region);

Hi Alan

Do you think if we need to keep fpga_mgr_put(region->mgr) in this remove
function? :)

Thanks
Hao

>  
>  	return 0;
>  }
> @@ -606,7 +631,6 @@ static void fpga_region_dev_release(struct device *dev)
>  	struct fpga_region *region = to_fpga_region(dev);
>  
>  	ida_simple_remove(&fpga_region_ida, region->dev.id);
> -	kfree(region);
>  }
>  
>  /**
> diff --git a/include/linux/fpga/fpga-region.h b/include/linux/fpga/fpga-region.h
> index f84a2e1..76dda68 100644
> --- a/include/linux/fpga/fpga-region.h
> +++ b/include/linux/fpga/fpga-region.h
> @@ -12,6 +12,8 @@
>   * @bridge_list: list of FPGA bridges specified in region
>   * @mgr: FPGA manager
>   * @info: FPGA image info
> + * @priv: private data
> + * @get_bridges: optional function to get bridges to a list
>   */
>  struct fpga_region {
>  	struct device dev;
> @@ -19,10 +21,15 @@ struct fpga_region {
>  	struct list_head bridge_list;
>  	struct fpga_manager *mgr;
>  	struct fpga_image_info *info;
> +	void *priv;
> +	int (*get_bridges)(struct fpga_region *region);
>  };
>  
>  #define to_fpga_region(d) container_of(d, struct fpga_region, dev)
>  
>  int fpga_region_program_fpga(struct fpga_region *region);
>  
> +int fpga_region_register(struct device *dev, struct fpga_region *region);
> +int fpga_region_unregister(struct fpga_region *region);
> +
>  #endif /* _FPGA_REGION_H */
> -- 
> 2.7.4
> 
> --
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