linux-kernel - Re: [PATCH 3/3] mfd: cros_ec: Add support for dumping panic information

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Date:   Tue, 23 Aug 2016 14:19:16 -0700
From:   Guenter Roeck <groeck@...gle.com>
To:     Nicolas Boichat <drinkcat@...omium.org>
Cc:     Lee Jones <lee.jones@...aro.org>,
        Gwendal Grignou <gwendal@...omium.org>, ejcaruso@...omium.org,
        Olof Johansson <olof@...om.net>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Guenter Roeck <groeck@...omium.org>
Subject: Re: [PATCH 3/3] mfd: cros_ec: Add support for dumping panic information

On Mon, Aug 22, 2016 at 9:34 PM, Nicolas Boichat <drinkcat@...omium.org> wrote:
> This dumps the EC panic information from the previous reboot.
>
> Similar to the information presented by ectool panicinfo, except
> that we do not bother doing any parsing (we should write a small
> offline tool for that).
>
> Signed-off-by: Nicolas Boichat <drinkcat@...omium.org>

Reviewed-by: Guenter Roeck <groeck@...omium.org>

> ---
>  drivers/platform/chrome/cros_ec_debugfs.c | 54 +++++++++++++++++++++++++++++++
>  1 file changed, 54 insertions(+)
>
> diff --git a/drivers/platform/chrome/cros_ec_debugfs.c b/drivers/platform/chrome/cros_ec_debugfs.c
> index 225f936..f4b6a29 100644
> --- a/drivers/platform/chrome/cros_ec_debugfs.c
> +++ b/drivers/platform/chrome/cros_ec_debugfs.c
> @@ -47,15 +47,19 @@
>   * @log_mutex: mutex to protect circular buffer
>   * @log_wq: waitqueue for log readers
>   * @log_poll_work: recurring task to poll EC for new console log data
> + * @panicinfo_blob: panicinfo debugfs blob
>   */
>  struct cros_ec_debugfs {
>         struct cros_ec_dev *ec;
>         struct dentry *dir;
> +       /* EC log */
>         struct circ_buf log_buffer;
>         struct cros_ec_command *read_msg;
>         struct mutex log_mutex;
>         wait_queue_head_t log_wq;
>         struct delayed_work log_poll_work;
> +       /* EC panicinfo */
> +       struct debugfs_blob_wrapper panicinfo_blob;
>  };
>
>  /*
> @@ -308,6 +312,52 @@ static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
>         }
>  }
>
> +static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
> +{
> +       struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
> +       int ret;
> +       struct cros_ec_command *msg;
> +       int insize;
> +
> +       insize = ec_dev->max_response;
> +
> +       msg = devm_kzalloc(debug_info->ec->dev,
> +                       sizeof(*msg) + insize, GFP_KERNEL);
> +       if (!msg)
> +               return -ENOMEM;
> +
> +       msg->command = EC_CMD_GET_PANIC_INFO;
> +       msg->insize = insize;
> +
> +       ret = cros_ec_cmd_xfer(ec_dev, msg);
> +       if (ret < 0) {
> +               dev_warn(debug_info->ec->dev, "Cannot read panicinfo.\n");
> +               ret = 0;
> +               goto free;
> +       }
> +
> +       /* No panic data */
> +       if (ret == 0)
> +               goto free;
> +
> +       debug_info->panicinfo_blob.data = msg->data;
> +       debug_info->panicinfo_blob.size = ret;
> +
> +       if (!debugfs_create_blob("panicinfo",
> +                                S_IFREG | S_IRUGO,
> +                                debug_info->dir,
> +                                &debug_info->panicinfo_blob)) {
> +               ret = -ENOMEM;
> +               goto free;
> +       }
> +
> +       return 0;
> +
> +free:
> +       devm_kfree(debug_info->ec->dev, msg);
> +       return ret;
> +}
> +
>  int cros_ec_debugfs_init(struct cros_ec_dev *ec)
>  {
>         struct cros_ec_platform *ec_platform = dev_get_platdata(ec->dev);
> @@ -324,6 +374,10 @@ int cros_ec_debugfs_init(struct cros_ec_dev *ec)
>         if (!debug_info->dir)
>                 return -ENOMEM;
>
> +       ret = cros_ec_create_panicinfo(debug_info);
> +       if (ret)
> +               goto remove_debugfs;
> +
>         ret = cros_ec_create_console_log(debug_info);
>         if (ret)
>                 goto remove_debugfs;
> --
> 2.8.0.rc3.226.g39d4020
>