RE: [PATCH v2 4/4] fpga: remove compat_id from fpga_manager and fpga_region

["Wu, Hao" <hao.wu@intel.com>]

> -----Original Message-----
> From: trix@redhat.com <trix@redhat.com>
> Sent: Friday, July 9, 2021 9:42 PM
> To: mdf@kernel.org; corbet@lwn.net; Wu, Hao <hao.wu@intel.com>
> Cc: linux-fpga@vger.kernel.org; linux-doc@vger.kernel.org; linux-
> kernel@vger.kernel.org; Tom Rix <trix@redhat.com>
> Subject: [PATCH v2 4/4] fpga: remove compat_id from fpga_manager and
> fpga_region
> 
> From: Tom Rix <trix@redhat.com>
> 
> compat_id is implementation specific.  So the data should be
> stored at the implemeation layer, not the infrastructure layer.
> Remove the compat_id elements and supporting code.

I think current compat_id format can meet the checking requirement.
Actually I hope other hardware which needs compatible checking
to expose the same format compat_id. Then we can have more 
unified/common code, e.g. userspace application/lib handling.

Currently I didn't see any other usage or requirement on this part
now, only DFL uses it.  So should we leave it here at this moment?
I feel we don't have to change it for now to move it to a
Per-fpga-mgr format. : )

Thanks
Hao

> 
> Printing out the compat_id is done with the fpga_region
> compat_id_show() op.
> 
> Signed-off-by: Tom Rix <trix@redhat.com>
> ---
>  drivers/fpga/dfl-fme-mgr.c       |  7 -------
>  drivers/fpga/dfl-fme-region.c    |  1 -
>  drivers/fpga/fpga-region.c       |  7 +------
>  include/linux/fpga/fpga-mgr.h    | 13 -------------
>  include/linux/fpga/fpga-region.h |  2 --
>  5 files changed, 1 insertion(+), 29 deletions(-)
> 
> diff --git a/drivers/fpga/dfl-fme-mgr.c b/drivers/fpga/dfl-fme-mgr.c
> index cd0b9157ea6e5..8c5423eeffe75 100644
> --- a/drivers/fpga/dfl-fme-mgr.c
> +++ b/drivers/fpga/dfl-fme-mgr.c
> @@ -292,7 +292,6 @@ EXPORT_SYMBOL_GPL(fme_mgr_get_compat_id);
>  static int fme_mgr_probe(struct platform_device *pdev)
>  {
>  	struct dfl_fme_mgr_pdata *pdata = dev_get_platdata(&pdev->dev);
> -	struct fpga_compat_id *compat_id;
>  	struct device *dev = &pdev->dev;
>  	struct fme_mgr_priv *priv;
>  	struct fpga_manager *mgr;
> @@ -312,10 +311,6 @@ static int fme_mgr_probe(struct platform_device
> *pdev)
>  			return PTR_ERR(priv->ioaddr);
>  	}
> 
> -	compat_id = devm_kzalloc(dev, sizeof(*compat_id), GFP_KERNEL);
> -	if (!compat_id)
> -		return -ENOMEM;
> -
>  	_fme_mgr_get_compat_id(priv->ioaddr, &priv->compat_id);
> 
>  	mgr = devm_fpga_mgr_create(dev, "DFL FME FPGA Manager",
> @@ -323,8 +318,6 @@ static int fme_mgr_probe(struct platform_device *pdev)
>  	if (!mgr)
>  		return -ENOMEM;
> 
> -	mgr->compat_id = compat_id;
> -
>  	return devm_fpga_mgr_register(dev, mgr);
>  }
> 
> diff --git a/drivers/fpga/dfl-fme-region.c b/drivers/fpga/dfl-fme-region.c
> index d21eacbf2469f..be1d57ee37666 100644
> --- a/drivers/fpga/dfl-fme-region.c
> +++ b/drivers/fpga/dfl-fme-region.c
> @@ -64,7 +64,6 @@ static int fme_region_probe(struct platform_device *pdev)
>  	}
> 
>  	region->priv = pdata;
> -	region->compat_id = mgr->compat_id;
>  	platform_set_drvdata(pdev, region);
> 
>  	ret = fpga_region_register(region);
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index 864dd4f290e3b..b08d3914716f0 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -172,12 +172,7 @@ static ssize_t compat_id_show(struct device *dev,
>  	if (region->rops && region->rops->compat_id_show)
>  		return region->rops->compat_id_show(region, buf);
> 
> -	if (!region->compat_id)
> -		return -ENOENT;
> -
> -	return sprintf(buf, "%016llx%016llx\n",
> -		       (unsigned long long)region->compat_id->id_h,
> -		       (unsigned long long)region->compat_id->id_l);
> +	return -ENOENT;
>  }
> 
>  static DEVICE_ATTR_RO(compat_id);
> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
> index ec2cd8bfceb00..ebdea215a8643 100644
> --- a/include/linux/fpga/fpga-mgr.h
> +++ b/include/linux/fpga/fpga-mgr.h
> @@ -143,24 +143,12 @@ struct fpga_manager_ops {
>  #define FPGA_MGR_STATUS_IP_PROTOCOL_ERR		BIT(3)
>  #define FPGA_MGR_STATUS_FIFO_OVERFLOW_ERR	BIT(4)
> 
> -/**
> - * struct fpga_compat_id - id for compatibility check
> - *
> - * @id_h: high 64bit of the compat_id
> - * @id_l: low 64bit of the compat_id
> - */
> -struct fpga_compat_id {
> -	u64 id_h;
> -	u64 id_l;
> -};
> -
>  /**
>   * struct fpga_manager - fpga manager structure
>   * @name: name of low level fpga manager
>   * @dev: fpga manager device
>   * @ref_mutex: only allows one reference to fpga manager
>   * @state: state of fpga manager
> - * @compat_id: FPGA manager id for compatibility check.
>   * @mops: pointer to struct of fpga manager ops
>   * @priv: low level driver private date
>   */
> @@ -169,7 +157,6 @@ struct fpga_manager {
>  	struct device dev;
>  	struct mutex ref_mutex;
>  	enum fpga_mgr_states state;
> -	struct fpga_compat_id *compat_id;
>  	const struct fpga_manager_ops *mops;
>  	void *priv;
>  };
> diff --git a/include/linux/fpga/fpga-region.h b/include/linux/fpga/fpga-region.h
> index 236d3819f1c13..afc79784b2823 100644
> --- a/include/linux/fpga/fpga-region.h
> +++ b/include/linux/fpga/fpga-region.h
> @@ -30,7 +30,6 @@ struct fpga_region_ops {
>   * @bridge_list: list of FPGA bridges specified in region
>   * @mgr: FPGA manager
>   * @info: FPGA image info
> - * @compat_id: FPGA region id for compatibility check.
>   * @priv: private data
>   * @rops: optional pointer to struct for fpga region ops
>   */
> @@ -40,7 +39,6 @@ struct fpga_region {
>  	struct list_head bridge_list;
>  	struct fpga_manager *mgr;
>  	struct fpga_image_info *info;
> -	struct fpga_compat_id *compat_id;
>  	void *priv;
>  	const struct fpga_region_ops *rops;
>  };
> --
> 2.26.3