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

Pi-Hsun Shih
2019-04-10T07:13:52Z

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.

>
> > + 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
> >