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Date:   Mon, 10 Jul 2017 10:36:50 -0700
From:   Moritz Fischer <moritz.fischer@...us.com>
To:     Alan Tull <atull@...nel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-fpga@...r.kernel.org
Subject: Re: [PATCH v3 03/16] fpga: mgr: API change to replace fpga load
 functions with single function

Hi Alan,

On Thu, Jul 6, 2017 at 11:47 AM, Alan Tull <atull@...nel.org> wrote:
> fpga-mgr has three methods for programming FPGAs, depending on
> whether the image is in a scatter gather list, a contiguous
> buffer, or a firmware file. This makes it difficult to write
> upper layers as the caller has to assume whether the FPGA image
> is in a sg table, as a single buffer, or a firmware file.
> This commit moves these parameters to struct fpga_image_info
> and adds a single function for programming fpgas.
>
> New functions:
> * fpga_mgr_load - given fpga manager and struct fpga_image_info,
>    program the fpga.
>
> * fpga_image_info_alloc - alloc a struct fpga_image_info.
>
> * fpga_image_info_free - free a struct fpga_image_info.
>
> These three functions are unexported:
> * fpga_mgr_buf_load_sg
> * fpga_mgr_buf_load
> * fpga_mgr_firmware_load
>
> Also use devm_kstrdup to copy firmware_name so we aren't making
> assumptions about where it comes from when allocing/freeing the
> struct fpga_image_info.
>
> Signed-off-by: Alan Tull <atull@...nel.org>
> ---
>  drivers/fpga/fpga-mgr.c       | 59 +++++++++++++++++++++++++++++++++++--------
>  drivers/fpga/fpga-region.c    | 43 ++++++++++++++++++++-----------
>  include/linux/fpga/fpga-mgr.h | 22 ++++++++++------
>  3 files changed, 90 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
> index 188ffef..3478aab 100644
> --- a/drivers/fpga/fpga-mgr.c
> +++ b/drivers/fpga/fpga-mgr.c
> @@ -2,6 +2,7 @@
>   * FPGA Manager Core
>   *
>   *  Copyright (C) 2013-2015 Altera Corporation
> + *  Copyright (C) 2017 Intel Corporation
>   *
>   * With code from the mailing list:
>   * Copyright (C) 2013 Xilinx, Inc.
> @@ -31,6 +32,31 @@
>  static DEFINE_IDA(fpga_mgr_ida);
>  static struct class *fpga_mgr_class;
>
> +struct fpga_image_info *fpga_image_info_alloc(struct device *dev)
> +{
> +       struct fpga_image_info *info;
> +
> +       info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
> +       if (!info)
> +               return ERR_PTR(-ENOMEM);

Doesn't this make it more complex? If in the end you'll anyway have to check
if IS_ERR_OR_NULL()? As opposed to just checking if (!info) on the returned
value.

Just a thought.

> +
> +       return info;
> +}
> +EXPORT_SYMBOL_GPL(fpga_image_info_alloc);
> +
> +void fpga_image_info_free(struct device *dev,
> +                         struct fpga_image_info *info)
> +{
> +       if (!info)
> +               return;
> +
> +       if (info->firmware_name)
> +               devm_kfree(dev, info->firmware_name);
> +
> +       devm_kfree(dev, info);
> +}
> +EXPORT_SYMBOL_GPL(fpga_image_info_free);
> +
>  /*
>   * Call the low level driver's write_init function.  This will do the
>   * device-specific things to get the FPGA into the state where it is ready to
> @@ -137,8 +163,9 @@ static int fpga_mgr_write_complete(struct fpga_manager *mgr,
>   *
>   * Return: 0 on success, negative error code otherwise.
>   */
> -int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, struct fpga_image_info *info,
> -                        struct sg_table *sgt)
> +static int fpga_mgr_buf_load_sg(struct fpga_manager *mgr,
> +                               struct fpga_image_info *info,
> +                               struct sg_table *sgt)
>  {
>         int ret;
>
> @@ -170,7 +197,6 @@ int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, struct fpga_image_info *info,
>
>         return fpga_mgr_write_complete(mgr, info);
>  }
> -EXPORT_SYMBOL_GPL(fpga_mgr_buf_load_sg);
>
>  static int fpga_mgr_buf_load_mapped(struct fpga_manager *mgr,
>                                     struct fpga_image_info *info,
> @@ -210,8 +236,9 @@ static int fpga_mgr_buf_load_mapped(struct fpga_manager *mgr,
>   *
>   * Return: 0 on success, negative error code otherwise.
>   */
> -int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info,
> -                     const char *buf, size_t count)
> +static int fpga_mgr_buf_load(struct fpga_manager *mgr,
> +                            struct fpga_image_info *info,
> +                            const char *buf, size_t count)
>  {
>         struct page **pages;
>         struct sg_table sgt;
> @@ -266,7 +293,6 @@ int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info,
>
>         return rc;
>  }
> -EXPORT_SYMBOL_GPL(fpga_mgr_buf_load);
>
>  /**
>   * fpga_mgr_firmware_load - request firmware and load to fpga
> @@ -282,9 +308,9 @@ EXPORT_SYMBOL_GPL(fpga_mgr_buf_load);
>   *
>   * Return: 0 on success, negative error code otherwise.
>   */
> -int fpga_mgr_firmware_load(struct fpga_manager *mgr,
> -                          struct fpga_image_info *info,
> -                          const char *image_name)
> +static int fpga_mgr_firmware_load(struct fpga_manager *mgr,
> +                                 struct fpga_image_info *info,
> +                                 const char *image_name)
>  {
>         struct device *dev = &mgr->dev;
>         const struct firmware *fw;
> @@ -307,7 +333,18 @@ int fpga_mgr_firmware_load(struct fpga_manager *mgr,
>
>         return ret;
>  }
> -EXPORT_SYMBOL_GPL(fpga_mgr_firmware_load);
> +
> +int fpga_mgr_load(struct fpga_manager *mgr, struct fpga_image_info *info)
> +{
> +       if (info->sgt)
> +               return fpga_mgr_buf_load_sg(mgr, info, info->sgt);
> +       if (info->buf && info->count)
> +               return fpga_mgr_buf_load(mgr, info, info->buf, info->count);
> +       if (info->firmware_name)
> +               return fpga_mgr_firmware_load(mgr, info, info->firmware_name);
> +       return -EINVAL;
> +}
> +EXPORT_SYMBOL_GPL(fpga_mgr_load);
>
>  static const char * const state_str[] = {
>         [FPGA_MGR_STATE_UNKNOWN] =              "unknown",
> @@ -578,7 +615,7 @@ static void __exit fpga_mgr_class_exit(void)
>         ida_destroy(&fpga_mgr_ida);
>  }
>
> -MODULE_AUTHOR("Alan Tull <atull@...nsource.altera.com>");
> +MODULE_AUTHOR("Alan Tull <atull@...nel.org>");
>  MODULE_DESCRIPTION("FPGA manager framework");
>  MODULE_LICENSE("GPL v2");
>
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index 655940f..c71c9cb 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -226,14 +226,11 @@ static int fpga_region_get_bridges(struct fpga_region *region,
>  /**
>   * fpga_region_program_fpga - program FPGA
>   * @region: FPGA region
> - * @firmware_name: name of FPGA image firmware file
>   * @overlay: device node of the overlay
> - * Program an FPGA using information in the device tree.
> - * Function assumes that there is a firmware-name property.
> + * Program an FPGA using information in the region's fpga image info.
>   * Return 0 for success or negative error code.
>   */
>  static int fpga_region_program_fpga(struct fpga_region *region,
> -                                   const char *firmware_name,
>                                     struct device_node *overlay)
>  {
>         struct fpga_manager *mgr;
> @@ -264,7 +261,7 @@ static int fpga_region_program_fpga(struct fpga_region *region,
>                 goto err_put_br;
>         }
>
> -       ret = fpga_mgr_firmware_load(mgr, region->info, firmware_name);
> +       ret = fpga_mgr_load(mgr, region->info);
>         if (ret) {
>                 pr_err("failed to load fpga image\n");
>                 goto err_put_br;
> @@ -357,16 +354,15 @@ static int child_regions_with_firmware(struct device_node *overlay)
>  static int fpga_region_notify_pre_apply(struct fpga_region *region,
>                                         struct of_overlay_notify_data *nd)
>  {
> -       const char *firmware_name = NULL;
> +       struct device *dev = &region->dev;
>         struct fpga_image_info *info;
> +       const char *firmware_name;
>         int ret;
>
> -       info = devm_kzalloc(&region->dev, sizeof(*info), GFP_KERNEL);
> +       info = fpga_image_info_alloc(dev);
>         if (!info)
>                 return -ENOMEM;

Can't you return PTR_ERR(info) here (If you don't follow my suggestion above),
or keep it the same here and follow my suggestion ;-)
>
> -       region->info = info;
> -
>         /* Reject overlay if child FPGA Regions have firmware-name property */
>         ret = child_regions_with_firmware(nd->overlay);
>         if (ret)
> @@ -382,7 +378,13 @@ static int fpga_region_notify_pre_apply(struct fpga_region *region,
>         if (of_property_read_bool(nd->overlay, "encrypted-fpga-config"))
>                 info->flags |= FPGA_MGR_ENCRYPTED_BITSTREAM;
>
> -       of_property_read_string(nd->overlay, "firmware-name", &firmware_name);
> +       if (!of_property_read_string(nd->overlay, "firmware-name",
> +                                    &firmware_name)) {
> +               info->firmware_name = devm_kstrdup(dev, firmware_name,
> +                                                  GFP_KERNEL);
> +               if (!info->firmware_name)
> +                       return -ENOMEM;
> +       }
>
>         of_property_read_u32(nd->overlay, "region-unfreeze-timeout-us",
>                              &info->enable_timeout_us);
> @@ -394,22 +396,33 @@ static int fpga_region_notify_pre_apply(struct fpga_region *region,
>                              &info->config_complete_timeout_us);
>
>         /* If FPGA was externally programmed, don't specify firmware */
> -       if ((info->flags & FPGA_MGR_EXTERNAL_CONFIG) && firmware_name) {
> +       if ((info->flags & FPGA_MGR_EXTERNAL_CONFIG) && info->firmware_name) {
>                 pr_err("error: specified firmware and external-fpga-config");
> +               fpga_image_info_free(dev, info);
>                 return -EINVAL;
>         }
>
>         /* FPGA is already configured externally.  We're done. */
> -       if (info->flags & FPGA_MGR_EXTERNAL_CONFIG)
> +       if (info->flags & FPGA_MGR_EXTERNAL_CONFIG) {
> +               fpga_image_info_free(dev, info);
>                 return 0;
> +       }
>
>         /* If we got this far, we should be programming the FPGA */
> -       if (!firmware_name) {
> +       if (!info->firmware_name) {
>                 pr_err("should specify firmware-name or external-fpga-config\n");
> +               fpga_image_info_free(dev, info);
>                 return -EINVAL;
>         }
>
> -       return fpga_region_program_fpga(region, firmware_name, nd->overlay);
> +       region->info = info;
> +       ret = fpga_region_program_fpga(region, nd->overlay);
> +       if (ret) {
> +               fpga_image_info_free(dev, info);
> +               region->info = NULL;
> +       }
> +
> +       return ret;
>  }
>
>  /**
> @@ -426,7 +439,7 @@ static void fpga_region_notify_post_remove(struct fpga_region *region,
>  {
>         fpga_bridges_disable(&region->bridge_list);
>         fpga_bridges_put(&region->bridge_list);
> -       devm_kfree(&region->dev, region->info);
> +       fpga_image_info_free(&region->dev, region->info);
>         region->info = NULL;
>  }
>
> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
> index b4ac24c..1c53aa3 100644
> --- a/include/linux/fpga/fpga-mgr.h
> +++ b/include/linux/fpga/fpga-mgr.h
> @@ -1,7 +1,8 @@
>  /*
>   * FPGA Framework
>   *
> - *  Copyright (C) 2013-2015 Altera Corporation
> + *  Copyright (C) 2013-2016 Altera Corporation
> + *  Copyright (C) 2017 Intel Corporation
>   *
>   * This program is free software; you can redistribute it and/or modify it
>   * under the terms and conditions of the GNU General Public License,
> @@ -79,12 +80,20 @@ enum fpga_mgr_states {
>   * @disable_timeout_us: maximum time to disable traffic through bridge (uSec)
>   * @config_complete_timeout_us: maximum time for FPGA to switch to operating
>   *        status in the write_complete op.
> + * @firmware_name: name of FPGA image firmware file
> + * @sgt: scatter/gather table containing FPGA image
> + * @buf: contiguous buffer containing FPGA image
> + * @count: size of buf
>   */
>  struct fpga_image_info {
>         u32 flags;
>         u32 enable_timeout_us;
>         u32 disable_timeout_us;
>         u32 config_complete_timeout_us;
> +       char *firmware_name;
> +       struct sg_table *sgt;
> +       const char *buf;
> +       size_t count;
>  };
>
>  /**
> @@ -134,14 +143,11 @@ struct fpga_manager {
>
>  #define to_fpga_manager(d) container_of(d, struct fpga_manager, dev)
>
> -int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info,
> -                     const char *buf, size_t count);
> -int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, struct fpga_image_info *info,
> -                        struct sg_table *sgt);
> +struct fpga_image_info *fpga_image_info_alloc(struct device *dev);
>
> -int fpga_mgr_firmware_load(struct fpga_manager *mgr,
> -                          struct fpga_image_info *info,
> -                          const char *image_name);
> +void fpga_image_info_free(struct device *dev, struct fpga_image_info *info);
> +
> +int fpga_mgr_load(struct fpga_manager *mgr, struct fpga_image_info *info);
>
>  struct fpga_manager *of_fpga_mgr_get(struct device_node *node);
>
> --
> 2.7.4
>

Cheers,
Moritz

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