Message-ID: <CANdKZ0ec_aux+tWatB563LJEmOt=RVJb5wH5eknQh6u1NraAqg@mail.gmail.com>
Date:   Wed, 10 Apr 2019 15:13:10 +0800
From:   Pi-Hsun Shih <pihsun@...omium.org>
To:     Enric Balletbo Serra <eballetbo@...il.com>
Cc:     Benson Leung <bleung@...omium.org>,
        Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        Guenter Roeck <groeck@...omium.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 6/7] platform/chrome: cros_ec: add EC host command
 support using rpmsg.

Hi,

On Thu, Mar 28, 2019 at 7:16 PM Enric Balletbo Serra
<eballetbo@...il.com> wrote:
>
> Hi
>
> Thanks for sending this upstream, Some few comments and questions
> below. Apart from these LGTM.
>
> Missatge de Peter Shih <pihsun@...omium.org> del dia dc., 27 de març
> 2019 a les 6:17:
> >
> > From: Pi-Hsun Shih <pihsun@...omium.org>
> >
> > Add EC host command support through rpmsg.
> >
> > Signed-off-by: Pi-Hsun Shih <pihsun@...omium.org>
> > ---
> > ...
> > diff --git a/drivers/platform/chrome/cros_ec_rpmsg.c b/drivers/platform/chrome/cros_ec_rpmsg.c
> > new file mode 100644
> > index 000000000000..2ecae806cfc5
> > --- /dev/null
> > +++ b/drivers/platform/chrome/cros_ec_rpmsg.c
> > ...
> > +static int cros_ec_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
> > +                                 int len, void *priv, u32 src)
> > +{
> > +       struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
> > +       struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
> > +       struct cros_ec_rpmsg_response *resp;
> > +
> > +       if (!len) {
> > +               dev_warn(ec_dev->dev, "rpmsg received empty response");
>
> Is this is unlikely to happen?

Yes this should not happen unless the firmware is broken. Should I
change this to `if(unlikely(!len))`, or use dev_err instead ?

>
> > +               return -EINVAL;
> > +       }
> > +
> > +       resp = data;
> > +       len -= offsetof(struct cros_ec_rpmsg_response, data);
> > +       if (resp->type == HOST_COMMAND_MARK) {
> > +               if (len > ec_dev->din_size) {
> > +                       dev_warn(
> > +                               ec_dev->dev,
> > +                               "received length %d > din_size %d, truncating",
> > +                               len, ec_dev->din_size);
>
> How often this warning appears? Should be this a dev_dbg?

This also should not happen unless the firmware is broken, so I think
it's better to have a warning here when there's something wrong.

>
> > +                       len = ec_dev->din_size;
> > +               }
> > +
> > +               memcpy(ec_dev->din, resp->data, len);
> > +               complete(&ec_rpmsg->xfer_ack);
> > +       } else if (resp->type == HOST_EVENT_MARK) {
> > +               schedule_work(&ec_rpmsg->host_event_work);
> > +       } else {
> > +               dev_warn(ec_dev->dev, "rpmsg received invalid type = %d",
> > +                        resp->type);
>
> Is this is unlikely to happen?

Same as above, this should not happen unless the firmware is broken.

>
> > +               return -EINVAL;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static int cros_ec_rpmsg_probe(struct rpmsg_device *rpdev)
> > +{
> > +       struct device *dev = &rpdev->dev;
> > +       struct cros_ec_device *ec_dev;
> > +       struct cros_ec_rpmsg *ec_rpmsg;
> > +       int ret;
> > +
> > +       ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
> > +       if (!ec_dev)
> > +               return -ENOMEM;
> > +
> > +       ec_rpmsg = devm_kzalloc(dev, sizeof(*ec_rpmsg), GFP_KERNEL);
> > +       if (!ec_rpmsg)
> > +               return -ENOMEM;
> > +
> > +       ec_dev->dev = dev;
> > +       ec_dev->priv = ec_rpmsg;
> > +       ec_dev->cmd_xfer = cros_ec_cmd_xfer_rpmsg;
> > +       ec_dev->pkt_xfer = cros_ec_pkt_xfer_rpmsg;
> > +       ec_dev->phys_name = dev_name(&rpdev->dev);
> > +       ec_dev->din_size = sizeof(struct ec_host_response) +
> > +                          sizeof(struct ec_response_get_protocol_info);
> > +       ec_dev->dout_size = sizeof(struct ec_host_request);
> > +       dev_set_drvdata(dev, ec_dev);
> > +
> > +       ec_rpmsg->rpdev = rpdev;
> > +       init_completion(&ec_rpmsg->xfer_ack);
> > +       INIT_WORK(&ec_rpmsg->host_event_work,
> > +                 cros_ec_rpmsg_host_event_function);
> > +
> > +       ret = cros_ec_register(ec_dev);
> > +       if (ret) {
> > +               dev_err(dev, "cannot register EC\n");
> > +               return ret;
> > +       }
> > +
> > +       return 0;
>
> cros_ec_register returns 0 on success and prints an error message if
> something went wrong. Remove the above and just do:
>
> return cros_ec_register(ec_dev);
>

Ack, would change this in v7.

>
> > +}
> > +
> > +static void cros_ec_rpmsg_remove(struct rpmsg_device *rpdev)
> > +{
> > +       struct cros_ec_device *ec_dev = dev_get_drvdata(&rpdev->dev);
> > +       struct cros_ec_rpmsg *ec_rpmsg = ec_dev->priv;
> > +
> > +       cancel_work_sync(&ec_rpmsg->host_event_work);
> > +}
> > +
> > +static const struct of_device_id cros_ec_rpmsg_of_match[] = {
> > +       { .compatible = "google,cros-ec-rpmsg", },
> > +       { }
> > +};
> > +MODULE_DEVICE_TABLE(of, cros_ec_rpmsg_of_match);
> > +
> > +static struct rpmsg_driver cros_ec_driver_rpmsg = {
> > +       .drv = {
> > +               .name   = KBUILD_MODNAME,
> > +               .of_match_table = cros_ec_rpmsg_of_match,
> > +       },
> > +       .probe          = cros_ec_rpmsg_probe,
> > +       .remove         = cros_ec_rpmsg_remove,
> > +       .callback       = cros_ec_rpmsg_callback,
> > +};
> > +
> > +module_rpmsg_driver(cros_ec_driver_rpmsg);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_DESCRIPTION("ChromeOS EC multi function device (rpmsg)");
> > --
> > 2.21.0.392.gf8f6787159e-goog
> >

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