drivers/usb/serial/usb_wwan.c

Source file repositories/reference/linux-study-clean/drivers/usb/serial/usb_wwan.c

File Facts

System
Linux kernel
Corpus path
drivers/usb/serial/usb_wwan.c
Extension
.c
Size
16313 bytes
Lines
659
Domain
Driver Families
Bucket
drivers/usb
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (test_and_set_bit(i, &portdata->out_busy)) {
			if (time_before(jiffies,
					portdata->tx_start_time[i] + 10 * HZ))
				continue;
			usb_unlink_urb(this_urb);
			continue;
		}
		dev_dbg(&port->dev, "%s: endpoint %d buf %d\n", __func__,
			usb_pipeendpoint(this_urb->pipe), i);

		err = usb_autopm_get_interface_async(port->serial->interface);
		if (err < 0) {
			clear_bit(i, &portdata->out_busy);
			break;
		}

		/* send the data */
		memcpy(this_urb->transfer_buffer, buf, todo);
		this_urb->transfer_buffer_length = todo;

		spin_lock_irqsave(&intfdata->susp_lock, flags);
		if (intfdata->suspended) {
			usb_anchor_urb(this_urb, &portdata->delayed);
			spin_unlock_irqrestore(&intfdata->susp_lock, flags);
		} else {
			intfdata->in_flight++;
			spin_unlock_irqrestore(&intfdata->susp_lock, flags);
			err = usb_submit_urb(this_urb, GFP_ATOMIC);
			if (err) {
				dev_err(&port->dev,
					"%s: submit urb %d failed: %d\n",
					__func__, i, err);
				clear_bit(i, &portdata->out_busy);
				spin_lock_irqsave(&intfdata->susp_lock, flags);
				intfdata->in_flight--;
				spin_unlock_irqrestore(&intfdata->susp_lock,
						       flags);
				usb_autopm_put_interface_async(port->serial->interface);
				break;
			}
		}

		portdata->tx_start_time[i] = jiffies;
		buf += todo;
		left -= todo;
	}

	count -= left;
	dev_dbg(&port->dev, "%s: wrote (did %d)\n", __func__, count);
	return count;
}
EXPORT_SYMBOL(usb_wwan_write);

static void usb_wwan_indat_callback(struct urb *urb)
{
	int err;
	int endpoint;
	struct usb_serial_port *port;
	struct device *dev;
	unsigned char *data = urb->transfer_buffer;
	int status = urb->status;

	endpoint = usb_pipeendpoint(urb->pipe);
	port = urb->context;
	dev = &port->dev;

	if (status) {
		dev_dbg(dev, "%s: nonzero status: %d on endpoint %02x.\n",
			__func__, status, endpoint);

		/* don't resubmit on fatal errors */
		if (status == -ESHUTDOWN || status == -ENOENT)
			return;
	} else {
		if (urb->actual_length) {
			tty_insert_flip_string(&port->port, data,
					urb->actual_length);
			tty_flip_buffer_push(&port->port);
		} else
			dev_dbg(dev, "%s: empty read urb received\n", __func__);
	}
	/* Resubmit urb so we continue receiving */
	err = usb_submit_urb(urb, GFP_ATOMIC);
	if (err) {
		if (err != -EPERM && err != -ENODEV) {
			dev_err(dev, "%s: resubmit read urb failed. (%d)\n",
				__func__, err);
			/* busy also in error unless we are killed */
			usb_mark_last_busy(port->serial->dev);
		}

Annotation

Implementation Notes