Re: [PATCH v1] firmware: microchip: auto-update: fix poll_complete() to not report spurious timeout errors

[Jamie.Gibbons]

On Wed, 2024-10-16 at 17:35 +0100, Conor Dooley wrote:
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> 
> From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> 
> fw_upload's poll_complete() is really intended for use with
> asynchronous write() implementations - or at least those where the
> write() loop may terminate without the kernel yet being aware of
> whether
> or not the firmware upload has succeeded. For auto-update, write() is
> only ever called once and will only return when uploading has
> completed,
> be that by passing or failing. The core fw_upload code only calls
> poll_complete() after the final call to write() has returned.
> 
> However, the poll_complete() implementation in the auto-update driver
> was written to expect poll_complete() to be called from another
> context,
> and it waits for a completion signalled from write(). Since
> poll_complete() is actually called from the same context, after the
> write() loop has terminated, wait_for_completion() never sees the
> completion get signalled and always times out, causing programming to
> always report a failing.
> 
> Since write() is full synchronous, and its return value will indicate
> whether or not programming passed or failed, poll_complete() serves
> no
> purpose and can be cut down to simply return FW_UPLOAD_ERR_NONE.
> 
> Fixes: ec5b0f1193ad4 ("firmware: microchip: add PolarFire SoC Auto
> Update support")
> Reported-by: Jamie Gibbons <jamie.gibbons@xxxxxxxxxxxxx>
> Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
Tested-by: Jamie Gibbons <jamie.gibbons@xxxxxxxxxxxxx
> ---
> CC: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
> CC: Daire McNamara <daire.mcnamara@xxxxxxxxxxxxx>
> CC: linux-riscv@xxxxxxxxxxxxxxxxxxx
> CC: linux-kernel@xxxxxxxxxxxxxxx
> ---
>  drivers/firmware/microchip/mpfs-auto-update.c | 42 ++++-------------
> --
>  1 file changed, 7 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/firmware/microchip/mpfs-auto-update.c
> b/drivers/firmware/microchip/mpfs-auto-update.c
> index 9ca5ee58edbdf..0f7ec88482022 100644
> --- a/drivers/firmware/microchip/mpfs-auto-update.c
> +++ b/drivers/firmware/microchip/mpfs-auto-update.c
> @@ -76,14 +76,11 @@
>  #define AUTO_UPDATE_INFO_SIZE          SZ_1M
>  #define AUTO_UPDATE_BITSTREAM_BASE     (AUTO_UPDATE_DIRECTORY_SIZE +
> AUTO_UPDATE_INFO_SIZE)
> 
> -#define AUTO_UPDATE_TIMEOUT_MS         60000
> -
>  struct mpfs_auto_update_priv {
>         struct mpfs_sys_controller *sys_controller;
>         struct device *dev;
>         struct mtd_info *flash;
>         struct fw_upload *fw_uploader;
> -       struct completion programming_complete;
>         size_t size_per_bitstream;
>         bool cancel_request;
>  };
> @@ -156,19 +153,6 @@ static void mpfs_auto_update_cancel(struct
> fw_upload *fw_uploader)
> 
>  static enum fw_upload_err mpfs_auto_update_poll_complete(struct
> fw_upload *fw_uploader)
>  {
> -       struct mpfs_auto_update_priv *priv = fw_uploader->dd_handle;
> -       int ret;
> -
> -       /*
> -        * There is no meaningful way to get the status of the
> programming while
> -        * it is in progress, so attempting anything other than
> waiting for it
> -        * to complete would be misplaced.
> -        */
> -       ret = wait_for_completion_timeout(&priv-
> >programming_complete,
> -                                        
> msecs_to_jiffies(AUTO_UPDATE_TIMEOUT_MS));
> -       if (!ret)
> -               return FW_UPLOAD_ERR_TIMEOUT;
> -
>         return FW_UPLOAD_ERR_NONE;
>  }
> 
> @@ -349,33 +333,23 @@ static enum fw_upload_err
> mpfs_auto_update_write(struct fw_upload *fw_uploader,
>                                                  u32 offset, u32
> size, u32 *written)
>  {
>         struct mpfs_auto_update_priv *priv = fw_uploader->dd_handle;
> -       enum fw_upload_err err = FW_UPLOAD_ERR_NONE;
>         int ret;
> 
> -       reinit_completion(&priv->programming_complete);
> -
>         ret = mpfs_auto_update_write_bitstream(fw_uploader, data,
> offset, size, written);
> -       if (ret) {
> -               err = FW_UPLOAD_ERR_RW_ERROR;
> -               goto out;
> -       }
> +       if (ret)
> +               return FW_UPLOAD_ERR_RW_ERROR;
> 
> -       if (priv->cancel_request) {
> -               err = FW_UPLOAD_ERR_CANCELED;
> -               goto out;
> -       }
> +       if (priv->cancel_request)
> +               return FW_UPLOAD_ERR_CANCELED;
> 
>         if (mpfs_auto_update_is_bitstream_info(data, size))
> -               goto out;
> +               return FW_UPLOAD_ERR_NONE;
> 
>         ret = mpfs_auto_update_verify_image(fw_uploader);
>         if (ret)
> -               err = FW_UPLOAD_ERR_FW_INVALID;
> +               return FW_UPLOAD_ERR_FW_INVALID;
> 
> -out:
> -       complete(&priv->programming_complete);
> -
> -       return err;
> +       return FW_UPLOAD_ERR_NONE;
>  }
> 
>  static const struct fw_upload_ops mpfs_auto_update_ops = {
> @@ -461,8 +435,6 @@ static int mpfs_auto_update_probe(struct
> platform_device *pdev)
>                 return dev_err_probe(dev, ret,
>                                      "The current bitstream does not
> support auto-update\n");
> 
> -       init_completion(&priv->programming_complete);
> -
>         fw_uploader = firmware_upload_register(THIS_MODULE, dev,
> "mpfs-auto-update",
>                                                &mpfs_auto_update_ops,
> priv);
>         if (IS_ERR(fw_uploader))
> --
> 2.45.2
>