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path: root/drivers/usb/gadget/u_serial.c
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* usb gadget: issue notifications from ACM functionDavid Brownell2008-08-131-14/+42
| | | | | | | | | | | | | | | | | Update the CDC-ACM gadget code to support the peripheral-to-host notifications when the tty is opened or closed, or issues a BREAK. The serial framework code calls new generic hooks; right now only CDC-ACM uses those hooks. This resolves several REVISIT comments in the code. (Based on a patch from Felipe Balbi.) Note that this doesn't expose USB_CDC_CAP_BRK to the host, since this code still rejects USB_CDC_REQ_SEND_BREAK control requests for host-to-peripheral BREAK signaling (received via /dev/ttyGS*). Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Cc: Felipe Balbi <felipe.balbi@nokia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* USB: serial gadget: rx path data loss fixesDavid Brownell2008-08-131-90/+146
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Update RX path handling in new serial gadget code to cope better with RX blockage: queue every RX packet until its contents can safely be passed up to the ldisc. Most of the RX path work is now done in the RX tasklet, instead of just the final "push to ldisc" step. This addresses some cases of data loss: - A longstanding serial gadget bug: when tty_insert_flip_string() didn't copy the entire buffer, the rest of the characters were dropped! Now that packet stays queued until the rest of its data is pushed to the ldisc. - Another longstanding issue: in the unlikely case that an RX transfer returns data and also reports a fault, that data is no longer discarded. - In the recently added RX throttling logic: it needs to stop pushing data into the TTY layer, instead of just not submitting new USB read requests. When the TTY is throttled long enough, backpressure will eventually make the OUT endpoint NAK. Also: an #ifdef is removed (no longer necessary); and start switching to a better convention for debug messages (prefix them with tty name). Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* usb_gadget: composite cdc gadget fault handlingDavid Brownell2008-07-211-0/+3
| | | | | | | | | | These two fixes ensure the new "CDC Composite Device" gadget fails cleanly when it's loaded on hardware that can't support this particular gadget driver. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* usb gadget: split out serial coreDavid Brownell2008-07-211-0/+1243
This abstracts the "gadget serial" driver TTY glue into a separate component, cleaning it up and disentangling it from connection state. It also changed some behaviors for the better: - Stops using "experimental" major #127, and switches over to having the TTY layer allocate the dev_t numbers. - Provides /sys/class/tty/ttyGS* nodes, thus mdev/udev support. (Note "mdev" hotplug bug in Busybox v1.7.2: /dev/ttyGS0 will be a *block* device without CONFIG_SYSFS_DEPRECATED_V2.) - The tty nodes no longer reject opens when there's no host. Now they can support normal getty configs in /etc/inttab... - Now implements RX throttling. When the line discipline says it doesn't want any more data, only packets in flight will be delivered (currently, max 1K/8K at full/high speeds) until it unthrottles the data. - Supports low_latency. This is a good policy for all USB serial adapters, since it eliminates scheduler overhead on RX paths. This also includes much cleanup including better comments, fixing memory leaks and other bugs (including some locking fixes), messaging cleanup, and an interface audit and tightening. This added up to a significant object code shrinkage, on the order of 20% (!) depending on CPU and compiler. A separate patch actually kicks in this new code, using the functions declared in this new header, and removes the previous glue. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>