* "serial port" functionality through the USB gadget stack. Each such
* port is exposed through a /dev/ttyGS* node.
*
- * After initialization (gserial_setup), these TTY port devices stay
- * available until they are removed (gserial_cleanup). Each one may be
- * connected to a USB function (gserial_connect), or disconnected (with
- * gserial_disconnect) when the USB host issues a config change event.
- * Data can only flow when the port is connected to the host.
+ * After this module has been loaded, the individual TTY port can be requested
+ * (gserial_alloc_line()) and it will stay available until they are removed
+ * (gserial_free_line()). Each one may be connected to a USB function
+ * (gserial_connect), or disconnected (with gserial_disconnect) when the USB
+ * host issues a config change event. Data can only flow when the port is
+ * connected to the host.
*
* A given TTY port can be made available in multiple configurations.
* For example, each one might expose a ttyGS0 node which provides a
struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */
};
-/* increase N_PORTS if you need more */
-#define N_PORTS 4
static struct portmaster {
struct mutex lock; /* protect open/close */
struct gs_port *port;
-} ports[N_PORTS];
-static unsigned n_ports;
+} ports[MAX_U_SERIAL_PORTS];
#define GS_CLOSE_TIMEOUT 15 /* seconds */
gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
{
struct gs_port *port;
+ int ret = 0;
+
+ mutex_lock(&ports[port_num].lock);
+ if (ports[port_num].port) {
+ ret = -EBUSY;
+ goto out;
+ }
port = kzalloc(sizeof(struct gs_port), GFP_KERNEL);
- if (port == NULL)
- return -ENOMEM;
+ if (port == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
tty_port_init(&port->port);
spin_lock_init(&port->port_lock);
port->port_line_coding = *coding;
ports[port_num].port = port;
-
- return 0;
-}
-
-/**
- * gserial_setup - initialize TTY driver for one or more ports
- * @g: gadget to associate with these ports
- * @count: how many ports to support
- * Context: may sleep
- *
- * The TTY stack needs to know in advance how many devices it should
- * plan to manage. Use this call to set up the ports you will be
- * exporting through USB. Later, connect them to functions based
- * on what configuration is activated by the USB host; and disconnect
- * them as appropriate.
- *
- * An example would be a two-configuration device in which both
- * configurations expose port 0, but through different functions.
- * One configuration could even expose port 1 while the other
- * one doesn't.
- *
- * Returns negative errno or zero.
- */
-int gserial_setup(struct usb_gadget *g, unsigned count)
-{
- unsigned i;
- struct usb_cdc_line_coding coding;
- int status;
-
- if (count == 0 || count > N_PORTS)
- return -EINVAL;
-
- if (gs_tty_driver)
- return -EBUSY;
-
- gs_tty_driver = alloc_tty_driver(count);
- if (!gs_tty_driver)
- return -ENOMEM;
-
- gs_tty_driver->driver_name = "g_serial";
- gs_tty_driver->name = PREFIX;
- /* uses dynamically assigned dev_t values */
-
- gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
- gs_tty_driver->subtype = SERIAL_TYPE_NORMAL;
- gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
- gs_tty_driver->init_termios = tty_std_termios;
-
- /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on
- * MS-Windows. Otherwise, most of these flags shouldn't affect
- * anything unless we were to actually hook up to a serial line.
- */
- gs_tty_driver->init_termios.c_cflag =
- B9600 | CS8 | CREAD | HUPCL | CLOCAL;
- gs_tty_driver->init_termios.c_ispeed = 9600;
- gs_tty_driver->init_termios.c_ospeed = 9600;
-
- coding.dwDTERate = cpu_to_le32(9600);
- coding.bCharFormat = 8;
- coding.bParityType = USB_CDC_NO_PARITY;
- coding.bDataBits = USB_CDC_1_STOP_BITS;
-
- tty_set_operations(gs_tty_driver, &gs_tty_ops);
-
- /* make devices be openable */
- for (i = 0; i < count; i++) {
- mutex_init(&ports[i].lock);
- status = gs_port_alloc(i, &coding);
- if (status) {
- count = i;
- goto fail;
- }
- }
- n_ports = count;
-
- /* export the driver ... */
- status = tty_register_driver(gs_tty_driver);
- if (status) {
- pr_err("%s: cannot register, err %d\n",
- __func__, status);
- goto fail;
- }
-
- /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */
- for (i = 0; i < count; i++) {
- struct device *tty_dev;
-
- tty_dev = tty_port_register_device(&ports[i].port->port,
- gs_tty_driver, i, &g->dev);
- if (IS_ERR(tty_dev))
- pr_warning("%s: no classdev for port %d, err %ld\n",
- __func__, i, PTR_ERR(tty_dev));
- }
-
- pr_debug("%s: registered %d ttyGS* device%s\n", __func__,
- count, (count == 1) ? "" : "s");
-
- return status;
-fail:
- while (count--) {
- tty_port_destroy(&ports[count].port->port);
- kfree(ports[count].port);
- }
- put_tty_driver(gs_tty_driver);
- gs_tty_driver = NULL;
- return status;
+out:
+ mutex_unlock(&ports[port_num].lock);
+ return ret;
}
-EXPORT_SYMBOL_GPL(gserial_setup);
static int gs_closed(struct gs_port *port)
{
return cond;
}
-/**
- * gserial_cleanup - remove TTY-over-USB driver and devices
- * Context: may sleep
- *
- * This is called to free all resources allocated by @gserial_setup().
- * Accordingly, it may need to wait until some open /dev/ files have
- * closed.
- *
- * The caller must have issued @gserial_disconnect() for any ports
- * that had previously been connected, so that there is never any
- * I/O pending when it's called.
- */
-void gserial_cleanup(void)
+static void gserial_free_port(struct gs_port *port)
+{
+ tasklet_kill(&port->push);
+ /* wait for old opens to finish */
+ wait_event(port->port.close_wait, gs_closed(port));
+ WARN_ON(port->port_usb != NULL);
+ tty_port_destroy(&port->port);
+ kfree(port);
+}
+
+void gserial_free_line(unsigned char port_num)
{
- unsigned i;
struct gs_port *port;
- if (!gs_tty_driver)
+ mutex_lock(&ports[port_num].lock);
+ if (WARN_ON(!ports[port_num].port)) {
+ mutex_unlock(&ports[port_num].lock);
return;
+ }
+ port = ports[port_num].port;
+ ports[port_num].port = NULL;
+ mutex_unlock(&ports[port_num].lock);
- /* start sysfs and /dev/ttyGS* node removal */
- for (i = 0; i < n_ports; i++)
- tty_unregister_device(gs_tty_driver, i);
-
- for (i = 0; i < n_ports; i++) {
- /* prevent new opens */
- mutex_lock(&ports[i].lock);
- port = ports[i].port;
- ports[i].port = NULL;
- mutex_unlock(&ports[i].lock);
-
- tasklet_kill(&port->push);
+ gserial_free_port(port);
+ tty_unregister_device(gs_tty_driver, port_num);
+}
+EXPORT_SYMBOL_GPL(gserial_free_line);
- /* wait for old opens to finish */
- wait_event(port->port.close_wait, gs_closed(port));
+int gserial_alloc_line(unsigned char *line_num)
+{
+ struct usb_cdc_line_coding coding;
+ struct device *tty_dev;
+ int ret;
+ int port_num;
- WARN_ON(port->port_usb != NULL);
+ coding.dwDTERate = cpu_to_le32(9600);
+ coding.bCharFormat = 8;
+ coding.bParityType = USB_CDC_NO_PARITY;
+ coding.bDataBits = USB_CDC_1_STOP_BITS;
- tty_port_destroy(&port->port);
- kfree(port);
+ for (port_num = 0; port_num < MAX_U_SERIAL_PORTS; port_num++) {
+ ret = gs_port_alloc(port_num, &coding);
+ if (ret == -EBUSY)
+ continue;
+ if (ret)
+ return ret;
+ break;
}
- n_ports = 0;
+ if (ret)
+ return ret;
- tty_unregister_driver(gs_tty_driver);
- put_tty_driver(gs_tty_driver);
- gs_tty_driver = NULL;
+ /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */
- pr_debug("%s: cleaned up ttyGS* support\n", __func__);
+ tty_dev = tty_port_register_device(&ports[port_num].port->port,
+ gs_tty_driver, port_num, NULL);
+ if (IS_ERR(tty_dev)) {
+ struct gs_port *port;
+ pr_err("%s: failed to register tty for port %d, err %ld\n",
+ __func__, port_num, PTR_ERR(tty_dev));
+
+ ret = PTR_ERR(tty_dev);
+ port = ports[port_num].port;
+ ports[port_num].port = NULL;
+ gserial_free_port(port);
+ goto err;
+ }
+ *line_num = port_num;
+err:
+ return ret;
}
-EXPORT_SYMBOL_GPL(gserial_cleanup);
+EXPORT_SYMBOL_GPL(gserial_alloc_line);
/**
* gserial_connect - notify TTY I/O glue that USB link is active
*
* Caller needs to have set up the endpoints and USB function in @dev
* before calling this, as well as the appropriate (speed-specific)
- * endpoint descriptors, and also have set up the TTY driver by calling
- * @gserial_setup().
+ * endpoint descriptors, and also have allocate @port_num by calling
+ * @gserial_alloc_line().
*
* Returns negative errno or zero.
* On success, ep->driver_data will be overwritten.
unsigned long flags;
int status;
- if (!gs_tty_driver || port_num >= n_ports)
+ if (port_num >= MAX_U_SERIAL_PORTS)
return -ENXIO;
- /* we "know" gserial_cleanup() hasn't been called */
port = ports[port_num].port;
+ if (!port) {
+ pr_err("serial line %d not allocated.\n", port_num);
+ return -EINVAL;
+ }
+ if (port->port_usb) {
+ pr_err("serial line %d is in use.\n", port_num);
+ return -EBUSY;
+ }
/* activate the endpoints */
status = usb_ep_enable(gser->in);
}
EXPORT_SYMBOL_GPL(gserial_disconnect);
+int userial_init(void)
+{
+ unsigned i;
+ int status;
+
+ gs_tty_driver = alloc_tty_driver(MAX_U_SERIAL_PORTS);
+ if (!gs_tty_driver)
+ return -ENOMEM;
+
+ gs_tty_driver->driver_name = "g_serial";
+ gs_tty_driver->name = PREFIX;
+ /* uses dynamically assigned dev_t values */
+
+ gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
+ gs_tty_driver->subtype = SERIAL_TYPE_NORMAL;
+ gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
+ gs_tty_driver->init_termios = tty_std_termios;
+
+ /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on
+ * MS-Windows. Otherwise, most of these flags shouldn't affect
+ * anything unless we were to actually hook up to a serial line.
+ */
+ gs_tty_driver->init_termios.c_cflag =
+ B9600 | CS8 | CREAD | HUPCL | CLOCAL;
+ gs_tty_driver->init_termios.c_ispeed = 9600;
+ gs_tty_driver->init_termios.c_ospeed = 9600;
+
+ tty_set_operations(gs_tty_driver, &gs_tty_ops);
+ for (i = 0; i < MAX_U_SERIAL_PORTS; i++)
+ mutex_init(&ports[i].lock);
+
+ /* export the driver ... */
+ status = tty_register_driver(gs_tty_driver);
+ if (status) {
+ pr_err("%s: cannot register, err %d\n",
+ __func__, status);
+ goto fail;
+ }
+
+ pr_debug("%s: registered %d ttyGS* device%s\n", __func__,
+ MAX_U_SERIAL_PORTS,
+ (MAX_U_SERIAL_PORTS == 1) ? "" : "s");
+
+ return status;
+fail:
+ put_tty_driver(gs_tty_driver);
+ gs_tty_driver = NULL;
+ return status;
+}
+module_init(userial_init);
+
+static void userial_cleanup(void)
+{
+ tty_unregister_driver(gs_tty_driver);
+ put_tty_driver(gs_tty_driver);
+ gs_tty_driver = NULL;
+}
+module_exit(userial_cleanup);
+
MODULE_LICENSE("GPL");
projects / users / hch / uuid.git / commitdiff