Re: [PATCH v7 6/7] platform/chrome: cros_ec: add EC host command support using rpmsg.

[Enric Balletbo Serra <eballetbo@gmail.com>]

Hi,

Missatge de Pi-Hsun Shih <pihsun@chromium.org> del dia dc., 10 d’abr.
2019 a les 9:13:
>
> Hi,
>
> On Thu, Mar 28, 2019 at 7:16 PM Enric Balletbo Serra
> <eballetbo@gmail.com> wrote:
> >
> > Hi
> >
> > Thanks for sending this upstream, Some few comments and questions
> > below. Apart from these LGTM.
> >
> > Missatge de Peter Shih <pihsun@chromium.org> del dia dc., 27 de març
> > 2019 a les 6:17:
> > >
> > > From: Pi-Hsun Shih <pihsun@chromium.org>
> > >
> > > Add EC host command support through rpmsg.
> > >
> > > Signed-off-by: Pi-Hsun Shih <pihsun@chromium.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.
>

Ok, fine with me.

> >
> > > +                       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.
>

Will wait for v7.

Thanks,
 Enric

> >
> > > +}
> > > +
> > > +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
> > >