Re: [PATCH v4 1/5] mfd: Add support for Intel LJCA device

Ye, Xiang
2023-03-10T04:20:18Z

Hi Oliver,

Thanks for your review.
On Thu, Mar 09, 2023 at 01:53:28PM +0100, Oliver Neukum wrote:
>
>
> On 09.03.23 08:10, Ye Xiang wrote:
>
> > +static int ljca_stub_write(struct ljca_stub *stub, u8 cmd, const void *obuf, unsigned int obuf_len,
> > + void *ibuf, unsigned int *ibuf_len, bool wait_ack, unsigned long timeout)
>
> Why do you make ibuf_len a pointer?
Because ibuf_len is also used as output of this function here.
It stores the actual length of ibuf receive from LJCA device.
>
> > +{
> > + struct ljca_dev *dev = usb_get_intfdata(stub->intf);
> > + u8 flags = LJCA_CMPL_FLAG;
> > + struct ljca_msg *header;
> > + unsigned int msg_len = sizeof(*header) + obuf_len;
> > + int actual;
> > + int ret;
> > +
> > + if (msg_len > LJCA_MAX_PACKET_SIZE)
> > + return -EINVAL;
> > +
> > + if (wait_ack)
> > + flags |= LJCA_ACK_FLAG;
> > +
> > + header = kmalloc(msg_len, GFP_KERNEL);
> > + if (!header)
> > + return -ENOMEM;
> > +
> > + header->type = stub->type;
> > + header->cmd = cmd;
> > + header->flags = flags;
> > + header->len = obuf_len;
> > +
> > + if (obuf)
> > + memcpy(header->data, obuf, obuf_len);
> > +
> > + dev_dbg(&dev->intf->dev, "send: type:%d cmd:%d flags:%d len:%d\n", header->type,
> > + header->cmd, header->flags, header->len);
> > +
> > + usb_autopm_get_interface(dev->intf);
> > + if (!dev->started) {
>
> Memory leak in error case. You must free header.
Good catch. Thanks. Will address it.
>
> > + ret = -ENODEV;
> > + goto error_put;
> > + }
> > +
> > + mutex_lock(&dev->mutex);
> > + stub->cur_cmd = cmd;
> > + stub->ipacket.ibuf = ibuf;
> > + stub->ipacket.ibuf_len = ibuf_len;
> > + stub->acked = false;
> > + ret = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, dev->out_ep), header, msg_len,
> > + &actual, LJCA_USB_WRITE_TIMEOUT_MS);
> > + kfree(header);
> > + if (ret) {
> > + dev_err(&dev->intf->dev, "bridge write failed ret:%d\n", ret);
> > + goto error_unlock;
> > + }
> > +
> > + if (actual != msg_len) {
> > + dev_err(&dev->intf->dev, "bridge write length mismatch (%d vs %d)\n", msg_len,
> > + actual);
> > + ret = -EINVAL;
> > + goto error_unlock;
> > + }
> > +
> > + if (wait_ack) {
> > + ret = wait_event_timeout(dev->ack_wq, stub->acked, msecs_to_jiffies(timeout));
> > + if (!ret) {
> > + dev_err(&dev->intf->dev, "acked wait timeout\n");
> > + ret = -ETIMEDOUT;
>
> If that triggers, you may have a pending URB.
> You must kill it.
which URB? I guess what you mean is dev->in_urb?
But the in_urb should always be up to waiting for message from firmware,
even through this timeout happen.

>
> > + goto error_unlock;
> > + }
> > + }
> > +
> > + stub->ipacket.ibuf = NULL;
> > + stub->ipacket.ibuf_len = NULL;
> > + ret = 0;
> > +error_unlock:
> > + mutex_unlock(&dev->mutex);
> > +error_put:
> > + usb_autopm_put_interface(dev->intf);
> > + return ret;
> > +}
>
>
> > +static int ljca_i2c_stub_init(struct ljca_dev *dev, struct ljca_i2c_descriptor *desc)
> > +{
> > + struct ljca_i2c_info *i2c_info;
> > + struct ljca_stub *stub;
> > + int ret;
> > + int i;
> > +
> > + stub = ljca_stub_alloc(dev, LJCA_I2C_STUB, size_mul(desc->num, sizeof(*i2c_info)));
> > + if (IS_ERR(stub))
> > + return PTR_ERR(stub);
> > +
> > + i2c_info = ljca_priv(stub);
> > +
> > + for (i = 0; i < desc->num; i++) {
> > + struct mfd_cell cell = {};
> > +
> > + i2c_info[i].ljca = &stub->ljca;
> > + i2c_info[i].id = desc->info[i].id;
> > + i2c_info[i].capacity = desc->info[i].capacity;
> > + i2c_info[i].intr_pin = desc->info[i].intr_pin;
> > +
> > + cell.name = "ljca-i2c";
> > + cell.platform_data = &i2c_info[i];
> > + cell.pdata_size = sizeof(i2c_info[i]);
> > +
> > + if (i < ARRAY_SIZE(ljca_acpi_match_i2cs))
> > + cell.acpi_match = &ljca_acpi_match_i2cs[i];
> > +
> > + ret = ljca_add_mfd_cell(dev, &cell);
> > + if (ret)
> > + return ret;
>
> What happens to stub in the error case?
ljca_add_mfd_cell only failed when krealloc_array failing. When
ljca_add_mfd_cell fails, the related stub just be left alone here.

Maybe I should free the stub here when fails? what is your advice?
>
> > + }
> > +
> > + return 0;
> > +}
>
>
> > +
> > +static void ljca_disconnect(struct usb_interface *intf)
> > +{
> > + struct ljca_dev *dev = usb_get_intfdata(intf);
> > +
> > + ljca_stop(dev);
>
> What prevents restarting the device here?
Why need to restart the device here?
The ljca_disconnect function should be called when the LJCA device is
unplugged.
>
> > + mfd_remove_devices(&intf->dev);
> > + ljca_stub_cleanup(dev);
> > + ljca_delete(dev);
> > +}
> > +
> > +static int ljca_suspend(struct usb_interface *intf, pm_message_t message)
> > +{
> > + struct ljca_dev *dev = usb_get_intfdata(intf);
> > +
> > + ljca_stop(dev);
> > + return 0;
> > +}
> > +
> > +static int ljca_resume(struct usb_interface *intf)
> > +{
> > + struct ljca_dev *dev = usb_get_intfdata(intf);
> > +
> > + return ljca_start(dev);
>
> So here you report errors, but at the same time you set "started"
> even if errors occur.
Thanks, Got it. Will address it on next version.

--
Thanks
Ye Xiang