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usb/gadget: make serial gadget resistant to cable unplug 

As USB can have its cable plugged out anytime, make the
serial gadget reliable in case of unplugging :
 - unregister the gadget_serial provided console
 - don't stay forever in the read loop if connection was cut

This behaviour relies on correct implementation of
usb_gadget_poll(), which should return an error if the USB
cable was removed.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Robert Jarzmik 2011-11-24 04:01:30 +01:00 committed by Sascha Hauer
parent 8173427d8d
commit 699a4a1eca
1 changed files with 18 additions and 6 deletions
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24
drivers/usb/gadget/u_serial.c
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@ -367,12 +367,13 @@ static void serial_putc(struct console_device *cdev, char c)
struct gs_port *port = container_of(cdev,
struct gs_port, cdev);
struct list_head *pool = &port->write_pool;
struct usb_ep *in = port->port_usb->in;
struct usb_ep *in;
struct usb_request *req;
int status;
if (list_empty(pool))
return;
in = port->port_usb->in;
req = list_entry(pool->next, struct usb_request, list);
req->length = 1;
@ -381,8 +382,8 @@ static void serial_putc(struct console_device *cdev, char c)
*(unsigned char *)req->buf = c;
status = usb_ep_queue(in, req);
while (list_empty(pool))
usb_gadget_poll();
while (status >= 0 && list_empty(pool))
status = usb_gadget_poll();
}
static int serial_tstc(struct console_device *cdev)
@ -399,7 +400,10 @@ static int serial_getc(struct console_device *cdev)
struct gs_port, cdev);
unsigned char ch;
while (kfifo_getc(port->recv_fifo, &ch));
if (!port->port_usb)
return -EIO;
while (kfifo_getc(port->recv_fifo, &ch))
usb_gadget_poll();
return ch;
}
@ -421,6 +425,10 @@ int gserial_connect(struct gserial *gser, u8 port_num)
/* we "know" gserial_cleanup() hasn't been called */
port = ports[port_num].port;
/* In case of multiple activation (ie. multiple SET_INTERFACE) */
if (port->port_usb)
return 0;
/* activate the endpoints */
status = usb_ep_enable(gser->in, gser->in_desc);
if (status < 0)
@ -498,7 +506,9 @@ BAREBOX_CMD_END
void gserial_disconnect(struct gserial *gser)
{
struct gs_port *port = gser->ioport;
printf("%s\n", __func__);
struct console_device *cdev;
printf("%s\n", __func__);
if (!port)
return;
@ -518,7 +528,9 @@ printf("%s\n", __func__);
gser->in->driver_data = NULL;
/* finally, free any unused/unusable I/O buffers */
gs_free_requests(gser->out, &port->read_pool);
gs_free_requests(gser->in, &port->write_pool);
cdev = &port->cdev;
console_unregister(cdev);
}