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@@ -36,11 +36,12 @@
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* "serial port" functionality through the USB gadget stack. Each such
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* port is exposed through a /dev/ttyGS* node.
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*
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- * After initialization (gserial_setup), these TTY port devices stay
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- * available until they are removed (gserial_cleanup). Each one may be
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- * connected to a USB function (gserial_connect), or disconnected (with
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- * gserial_disconnect) when the USB host issues a config change event.
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- * Data can only flow when the port is connected to the host.
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+ * After this module has been loaded, the individual TTY port can be requested
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+ * (gserial_alloc_line()) and it will stay available until they are removed
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+ * (gserial_free_line()). Each one may be connected to a USB function
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+ * (gserial_connect), or disconnected (with gserial_disconnect) when the USB
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+ * host issues a config change event. Data can only flow when the port is
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+ * connected to the host.
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*
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* A given TTY port can be made available in multiple configurations.
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* For example, each one might expose a ttyGS0 node which provides a
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@@ -120,13 +121,10 @@ struct gs_port {
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struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */
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};
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-/* increase N_PORTS if you need more */
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-#define N_PORTS 4
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static struct portmaster {
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struct mutex lock; /* protect open/close */
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struct gs_port *port;
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-} ports[N_PORTS];
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-static unsigned n_ports;
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+} ports[MAX_U_SERIAL_PORTS];
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#define GS_CLOSE_TIMEOUT 15 /* seconds */
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@@ -1033,10 +1031,19 @@ static int
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gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
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{
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struct gs_port *port;
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+ int ret = 0;
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+
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+ mutex_lock(&ports[port_num].lock);
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+ if (ports[port_num].port) {
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+ ret = -EBUSY;
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+ goto out;
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+ }
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port = kzalloc(sizeof(struct gs_port), GFP_KERNEL);
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- if (port == NULL)
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- return -ENOMEM;
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+ if (port == NULL) {
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+ ret = -ENOMEM;
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+ goto out;
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+ }
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tty_port_init(&port->port);
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spin_lock_init(&port->port_lock);
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@@ -1052,114 +1059,10 @@ gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
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port->port_line_coding = *coding;
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ports[port_num].port = port;
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-
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- return 0;
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-}
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-
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-/**
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- * gserial_setup - initialize TTY driver for one or more ports
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- * @g: gadget to associate with these ports
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- * @count: how many ports to support
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- * Context: may sleep
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- *
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- * The TTY stack needs to know in advance how many devices it should
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- * plan to manage. Use this call to set up the ports you will be
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- * exporting through USB. Later, connect them to functions based
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- * on what configuration is activated by the USB host; and disconnect
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- * them as appropriate.
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- *
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- * An example would be a two-configuration device in which both
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- * configurations expose port 0, but through different functions.
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- * One configuration could even expose port 1 while the other
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- * one doesn't.
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- *
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- * Returns negative errno or zero.
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- */
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-int gserial_setup(struct usb_gadget *g, unsigned count)
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-{
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- unsigned i;
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- struct usb_cdc_line_coding coding;
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- int status;
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-
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- if (count == 0 || count > N_PORTS)
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- return -EINVAL;
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-
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- if (gs_tty_driver)
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- return -EBUSY;
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-
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- gs_tty_driver = alloc_tty_driver(count);
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- if (!gs_tty_driver)
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- return -ENOMEM;
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-
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- gs_tty_driver->driver_name = "g_serial";
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- gs_tty_driver->name = PREFIX;
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- /* uses dynamically assigned dev_t values */
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-
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- gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
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- gs_tty_driver->subtype = SERIAL_TYPE_NORMAL;
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- gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
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- gs_tty_driver->init_termios = tty_std_termios;
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-
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- /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on
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- * MS-Windows. Otherwise, most of these flags shouldn't affect
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- * anything unless we were to actually hook up to a serial line.
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- */
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- gs_tty_driver->init_termios.c_cflag =
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- B9600 | CS8 | CREAD | HUPCL | CLOCAL;
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- gs_tty_driver->init_termios.c_ispeed = 9600;
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- gs_tty_driver->init_termios.c_ospeed = 9600;
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-
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- coding.dwDTERate = cpu_to_le32(9600);
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- coding.bCharFormat = 8;
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- coding.bParityType = USB_CDC_NO_PARITY;
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- coding.bDataBits = USB_CDC_1_STOP_BITS;
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-
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- tty_set_operations(gs_tty_driver, &gs_tty_ops);
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-
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- /* make devices be openable */
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- for (i = 0; i < count; i++) {
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- mutex_init(&ports[i].lock);
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- status = gs_port_alloc(i, &coding);
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- if (status) {
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- count = i;
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- goto fail;
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- }
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- }
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- n_ports = count;
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-
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- /* export the driver ... */
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- status = tty_register_driver(gs_tty_driver);
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- if (status) {
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- pr_err("%s: cannot register, err %d\n",
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- __func__, status);
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- goto fail;
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- }
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-
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- /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */
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- for (i = 0; i < count; i++) {
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- struct device *tty_dev;
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-
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- tty_dev = tty_port_register_device(&ports[i].port->port,
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- gs_tty_driver, i, &g->dev);
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- if (IS_ERR(tty_dev))
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- pr_warning("%s: no classdev for port %d, err %ld\n",
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- __func__, i, PTR_ERR(tty_dev));
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- }
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-
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- pr_debug("%s: registered %d ttyGS* device%s\n", __func__,
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- count, (count == 1) ? "" : "s");
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-
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- return status;
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-fail:
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- while (count--) {
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- tty_port_destroy(&ports[count].port->port);
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- kfree(ports[count].port);
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- }
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- put_tty_driver(gs_tty_driver);
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- gs_tty_driver = NULL;
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- return status;
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+out:
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+ mutex_unlock(&ports[port_num].lock);
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+ return ret;
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}
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-EXPORT_SYMBOL_GPL(gserial_setup);
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static int gs_closed(struct gs_port *port)
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{
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@@ -1171,56 +1074,77 @@ static int gs_closed(struct gs_port *port)
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return cond;
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}
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-/**
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- * gserial_cleanup - remove TTY-over-USB driver and devices
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- * Context: may sleep
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- *
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- * This is called to free all resources allocated by @gserial_setup().
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- * Accordingly, it may need to wait until some open /dev/ files have
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- * closed.
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- *
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- * The caller must have issued @gserial_disconnect() for any ports
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- * that had previously been connected, so that there is never any
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- * I/O pending when it's called.
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- */
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-void gserial_cleanup(void)
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+static void gserial_free_port(struct gs_port *port)
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+{
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+ tasklet_kill(&port->push);
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+ /* wait for old opens to finish */
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+ wait_event(port->port.close_wait, gs_closed(port));
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+ WARN_ON(port->port_usb != NULL);
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+ tty_port_destroy(&port->port);
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+ kfree(port);
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+}
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+
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+void gserial_free_line(unsigned char port_num)
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{
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- unsigned i;
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struct gs_port *port;
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- if (!gs_tty_driver)
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+ mutex_lock(&ports[port_num].lock);
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+ if (WARN_ON(!ports[port_num].port)) {
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+ mutex_unlock(&ports[port_num].lock);
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return;
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+ }
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+ port = ports[port_num].port;
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+ ports[port_num].port = NULL;
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+ mutex_unlock(&ports[port_num].lock);
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- /* start sysfs and /dev/ttyGS* node removal */
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- for (i = 0; i < n_ports; i++)
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- tty_unregister_device(gs_tty_driver, i);
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-
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- for (i = 0; i < n_ports; i++) {
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- /* prevent new opens */
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- mutex_lock(&ports[i].lock);
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- port = ports[i].port;
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- ports[i].port = NULL;
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- mutex_unlock(&ports[i].lock);
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-
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- tasklet_kill(&port->push);
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+ gserial_free_port(port);
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+ tty_unregister_device(gs_tty_driver, port_num);
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+}
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+EXPORT_SYMBOL_GPL(gserial_free_line);
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- /* wait for old opens to finish */
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- wait_event(port->port.close_wait, gs_closed(port));
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+int gserial_alloc_line(unsigned char *line_num)
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+{
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+ struct usb_cdc_line_coding coding;
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+ struct device *tty_dev;
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+ int ret;
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+ int port_num;
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- WARN_ON(port->port_usb != NULL);
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+ coding.dwDTERate = cpu_to_le32(9600);
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+ coding.bCharFormat = 8;
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+ coding.bParityType = USB_CDC_NO_PARITY;
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+ coding.bDataBits = USB_CDC_1_STOP_BITS;
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- tty_port_destroy(&port->port);
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- kfree(port);
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+ for (port_num = 0; port_num < MAX_U_SERIAL_PORTS; port_num++) {
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+ ret = gs_port_alloc(port_num, &coding);
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+ if (ret == -EBUSY)
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+ continue;
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+ if (ret)
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+ return ret;
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+ break;
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}
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- n_ports = 0;
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+ if (ret)
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+ return ret;
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- tty_unregister_driver(gs_tty_driver);
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- put_tty_driver(gs_tty_driver);
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- gs_tty_driver = NULL;
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+ /* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */
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- pr_debug("%s: cleaned up ttyGS* support\n", __func__);
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+ tty_dev = tty_port_register_device(&ports[port_num].port->port,
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+ gs_tty_driver, port_num, NULL);
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+ if (IS_ERR(tty_dev)) {
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+ struct gs_port *port;
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+ pr_err("%s: failed to register tty for port %d, err %ld\n",
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+ __func__, port_num, PTR_ERR(tty_dev));
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+
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+ ret = PTR_ERR(tty_dev);
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+ port = ports[port_num].port;
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+ ports[port_num].port = NULL;
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+ gserial_free_port(port);
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+ goto err;
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+ }
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+ *line_num = port_num;
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+err:
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+ return ret;
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}
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-EXPORT_SYMBOL_GPL(gserial_cleanup);
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+EXPORT_SYMBOL_GPL(gserial_alloc_line);
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/**
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* gserial_connect - notify TTY I/O glue that USB link is active
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@@ -1237,8 +1161,8 @@ EXPORT_SYMBOL_GPL(gserial_cleanup);
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*
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* Caller needs to have set up the endpoints and USB function in @dev
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* before calling this, as well as the appropriate (speed-specific)
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- * endpoint descriptors, and also have set up the TTY driver by calling
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- * @gserial_setup().
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+ * endpoint descriptors, and also have allocate @port_num by calling
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+ * @gserial_alloc_line().
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*
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* Returns negative errno or zero.
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* On success, ep->driver_data will be overwritten.
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@@ -1249,11 +1173,18 @@ int gserial_connect(struct gserial *gser, u8 port_num)
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unsigned long flags;
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int status;
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- if (!gs_tty_driver || port_num >= n_ports)
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+ if (port_num >= MAX_U_SERIAL_PORTS)
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return -ENXIO;
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- /* we "know" gserial_cleanup() hasn't been called */
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port = ports[port_num].port;
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+ if (!port) {
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+ pr_err("serial line %d not allocated.\n", port_num);
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+ return -EINVAL;
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+ }
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+ if (port->port_usb) {
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+ pr_err("serial line %d is in use.\n", port_num);
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+ return -EBUSY;
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+ }
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/* activate the endpoints */
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status = usb_ep_enable(gser->in);
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@@ -1357,4 +1288,63 @@ void gserial_disconnect(struct gserial *gser)
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}
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EXPORT_SYMBOL_GPL(gserial_disconnect);
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+int userial_init(void)
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+{
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+ unsigned i;
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+ int status;
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+
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+ gs_tty_driver = alloc_tty_driver(MAX_U_SERIAL_PORTS);
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+ if (!gs_tty_driver)
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+ return -ENOMEM;
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+
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+ gs_tty_driver->driver_name = "g_serial";
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+ gs_tty_driver->name = PREFIX;
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+ /* uses dynamically assigned dev_t values */
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+
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+ gs_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
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+ gs_tty_driver->subtype = SERIAL_TYPE_NORMAL;
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+ gs_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
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+ gs_tty_driver->init_termios = tty_std_termios;
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+
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+ /* 9600-8-N-1 ... matches defaults expected by "usbser.sys" on
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+ * MS-Windows. Otherwise, most of these flags shouldn't affect
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+ * anything unless we were to actually hook up to a serial line.
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+ */
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+ gs_tty_driver->init_termios.c_cflag =
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+ B9600 | CS8 | CREAD | HUPCL | CLOCAL;
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+ gs_tty_driver->init_termios.c_ispeed = 9600;
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+ gs_tty_driver->init_termios.c_ospeed = 9600;
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+
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+ tty_set_operations(gs_tty_driver, &gs_tty_ops);
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+ for (i = 0; i < MAX_U_SERIAL_PORTS; i++)
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+ mutex_init(&ports[i].lock);
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+
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+ /* export the driver ... */
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+ status = tty_register_driver(gs_tty_driver);
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+ if (status) {
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+ pr_err("%s: cannot register, err %d\n",
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+ __func__, status);
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+ goto fail;
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+ }
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+
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+ pr_debug("%s: registered %d ttyGS* device%s\n", __func__,
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+ MAX_U_SERIAL_PORTS,
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+ (MAX_U_SERIAL_PORTS == 1) ? "" : "s");
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+
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+ return status;
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+fail:
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+ put_tty_driver(gs_tty_driver);
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+ gs_tty_driver = NULL;
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+ return status;
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+}
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+module_init(userial_init);
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+
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+static void userial_cleanup(void)
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+{
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+ tty_unregister_driver(gs_tty_driver);
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+ put_tty_driver(gs_tty_driver);
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+ gs_tty_driver = NULL;
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+}
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+module_exit(userial_cleanup);
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+
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MODULE_LICENSE("GPL");
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Sebastian Andrzej Siewior