linux-kernel - Re: [PATCH v2 10/16] fpga: region: use image info as parameter for programming region

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Message-ID: <CANk1AXS02dKP6PbRevxvdBF8DvsT00EGQb5d-200VOwjbzBarg@mail.gmail.com>
Date:   Tue, 9 May 2017 10:25:12 -0500
From:   Alan Tull <atull@...nel.org>
To:     Moritz Fischer <moritz.fischer@...us.com>
Cc:     Alan Tull <atull@...nel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-fpga@...r.kernel.org
Subject: Re: [PATCH v2 10/16] fpga: region: use image info as parameter for
 programming region

On Thu, Apr 20, 2017 at 9:09 AM, Alan Tull <atull@...nel.org> wrote:
> Use FPGA image info as a parameter when region code is
> programming the FPGA.
>
> This is a baby step in refactoring the FPGA region code to
> separate out common FPGA region code from FPGA region
> Device Tree overlay support.
>
> Signed-off-by: Alan Tull <atull@...nel.org>
> ---
> v2: split out from another patch
> ---
>  drivers/fpga/fpga-region.c    | 26 ++++++++++++++++----------
>  include/linux/fpga/fpga-mgr.h |  4 ++++
>  2 files changed, 20 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index d6f2313..1892126 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -223,16 +223,21 @@ static int fpga_region_get_bridges(struct fpga_region *region,
>  /**
>   * fpga_region_program_fpga - program FPGA
>   * @region: FPGA region
> - * @overlay: device node of the overlay
> - * Program an FPGA using information in the region's fpga image info.
> + * @info: FPGA image info
> + * Program an FPGA using fpga image info.
>   * Return 0 for success or negative error code.
>   */
>  static int fpga_region_program_fpga(struct fpga_region *region,
> -                                   struct device_node *overlay)
> +                                   struct fpga_image_info *info)
>  {
>         struct device *dev = &region->dev;
>         int ret;
>
> +       if (region->info) {
> +               dev_err(dev, "region already programmed\n");
> +               return PTR_ERR(region);
> +       }
> +

Currently if region has info, that is supposed to mean that the region
is programmed.  I can already see how that could be limiting.  I'm
think that in v3, I'm going to change this to add a region->state or
region->status that can indicate whether the region has been
programmed.  Having done that, the second parameter of this functon
can go away and region->info is used.

Alan

>         region = fpga_region_get(region);
>         if (IS_ERR(region)) {
>                 dev_err(dev, "failed to get FPGA region\n");
> @@ -245,7 +250,7 @@ static int fpga_region_program_fpga(struct fpga_region *region,
>                 goto err_put_region;
>         }
>
> -       ret = fpga_region_get_bridges(region, overlay);
> +       ret = fpga_region_get_bridges(region, info->overlay);
>         if (ret) {
>                 dev_err(dev, "failed to get FPGA bridges\n");
>                 goto err_unlock_mgr;
> @@ -257,7 +262,7 @@ static int fpga_region_program_fpga(struct fpga_region *region,
>                 goto err_put_br;
>         }
>
> -       ret = fpga_mgr_load(region->mgr, region->info);
> +       ret = fpga_mgr_load(region->mgr, info);
>         if (ret) {
>                 dev_err(dev, "failed to load FPGA image\n");
>                 goto err_put_br;
> @@ -269,6 +274,8 @@ static int fpga_region_program_fpga(struct fpga_region *region,
>                 goto err_put_br;
>         }
>
> +       region->info = info;
> +
>         fpga_mgr_unlock(region->mgr);
>         fpga_region_put(region);
>
> @@ -373,6 +380,8 @@ static int fpga_region_notify_pre_apply(struct fpga_region *region,
>         if (!info)
>                 return -ENOMEM;
>
> +       info->overlay = nd->overlay;
> +
>         /* Read FPGA region properties from the overlay */
>         if (of_property_read_bool(nd->overlay, "partial-fpga-config"))
>                 info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
> @@ -420,12 +429,9 @@ static int fpga_region_notify_pre_apply(struct fpga_region *region,
>                 return -EINVAL;
>         }
>
> -       region->info = info;
> -       ret = fpga_region_program_fpga(region, nd->overlay);
> -       if (ret) {
> +       ret = fpga_region_program_fpga(region, info);
> +       if (ret)
>                 fpga_image_info_free(&region->dev, info);
> -               region->info = NULL;
> -       }
>
>         return ret;
>  }
> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
> index 4e14bdb..66d0e32 100644
> --- a/include/linux/fpga/fpga-mgr.h
> +++ b/include/linux/fpga/fpga-mgr.h
> @@ -84,6 +84,7 @@ enum fpga_mgr_states {
>   * @sgt: scatter/gather table containing FPGA image
>   * @buf: contiguous buffer containing FPGA image
>   * @count: size of buf
> + * @overlay: Device Tree overlay
>   */
>  struct fpga_image_info {
>         u32 flags;
> @@ -94,6 +95,9 @@ struct fpga_image_info {
>         struct sg_table *sgt;
>         const char *buf;
>         size_t count;
> +#ifdef CONFIG_OF
> +       struct device_node *overlay;
> +#endif
>  };
>
>  /**
> --
> 2.7.4
>