Hey Andry,
Long time no seeing :-)
On Tue, Jun 04, 2019 at 08:16:11PM +0300, Andy Shevchenko wrote:
> On Thu, May 30, 2019 at 09:33:46PM -0700, Eduardo Valentin wrote:
> > From: Haiyue Wang <haiyue.wang@xxxxxxxxxxxxxxx>
> >
> > Some protocols over I2C are designed for bi-directional transferring
> > messages by using I2C Master Write protocol. Like the MCTP (Management
> > Component Transport Protocol) and IPMB (Intelligent Platform Management
> > Bus), they both require that the userspace can receive messages from
> > I2C dirvers under slave mode.
> >
> > This new slave mqueue backend is used to receive and queue messages, it
> > will exposes these messages to userspace by sysfs bin file.
> >
> > Note: DT interface and a couple of minor fixes here and there
> > by Eduardo, so I kept the original authorship here.
>
> > +#define MQ_MSGBUF_SIZE CONFIG_I2C_SLAVE_MQUEUE_MESSAGE_SIZE
> > +#define MQ_QUEUE_SIZE CONFIG_I2C_SLAVE_MQUEUE_QUEUE_SIZE
>
> > +#define MQ_QUEUE_NEXT(x) (((x) + 1) & (MQ_QUEUE_SIZE - 1))
>
> Also possible ((x + 1) % ..._SIZE)
Right.. but I suppose the original idea is to avoid divisions on the hotpath.
So, I am actually fine with the limitation of only using power of 2.
>
> > + mq = dev_get_drvdata(container_of(kobj, struct device, kobj));
>
> kobj_to_dev()
Well, yeah, I guess this is a nit, but I can add that in case of a real need for a v7.
>
> > +static int i2c_slave_mqueue_probe(struct i2c_client *client,
> > + const struct i2c_device_id *id)
> > +{
> > + struct device *dev = &client->dev;
> > + struct mq_queue *mq;
> > + int ret, i;
> > + void *buf;
> > +
> > + mq = devm_kzalloc(dev, sizeof(*mq), GFP_KERNEL);
> > + if (!mq)
> > + return -ENOMEM;
> > +
>
> > + BUILD_BUG_ON(!is_power_of_2(MQ_QUEUE_SIZE));
>
> Perhaps start function with this kind of assertions?
>
same here, in case I see a huge ask for a v7, I can move this up.
> > +
> > + buf = devm_kmalloc_array(dev, MQ_QUEUE_SIZE, MQ_MSGBUF_SIZE,
> > + GFP_KERNEL);
> > + if (!buf)
> > + return -ENOMEM;
> > +
> > + for (i = 0; i < MQ_QUEUE_SIZE; i++)
> > + mq->queue[i].buf = buf + i * MQ_MSGBUF_SIZE;
>
>
> Just wondering if kfifo API can bring an advantage here?
>
Well, then again, I suppose the idea is simplify here, not if we need to go
kfifo as the Protocol on top of this is perfectly fine with the current
discipline of just having a simple drop of older messages.
> > + return 0;
> > +}
>
> > +static const struct of_device_id i2c_slave_mqueue_of_match[] = {
> > + {
> > + .compatible = "i2c-slave-mqueue",
> > + },
>
> > + { },
>
> No need for comma here.
It does not hurt to have it either :-)
>
> > +};
>
> > +
> > +static struct i2c_driver i2c_slave_mqueue_driver = {
> > + .driver = {
> > + .name = "i2c-slave-mqueue",
>
> > + .of_match_table = of_match_ptr(i2c_slave_mqueue_of_match),
>
> Wouldn't compiler warn you due to unused data?
> Perhaps drop of_match_ptr() for good...
Not sure what you meant here. I dont see any compiler warning.
Also, of_match_ptr seams to be well spread in the kernel.
>
> > + },
> > + .probe = i2c_slave_mqueue_probe,
> > + .remove = i2c_slave_mqueue_remove,
> > + .id_table = i2c_slave_mqueue_id,
> > +};
>
> --
> With Best Regards,
> Andy Shevchenko
>
>
--
All the best,
Eduardo Valentin
