diff options
Diffstat (limited to 'drivers/usb/gadget/u_serial.c')
| -rw-r--r-- | drivers/usb/gadget/u_serial.c | 313 |
1 files changed, 157 insertions, 156 deletions
diff --git a/drivers/usb/gadget/u_serial.c b/drivers/usb/gadget/u_serial.c index 598dcc1212f..588a9be18ef 100644 --- a/drivers/usb/gadget/u_serial.c +++ b/drivers/usb/gadget/u_serial.c @@ -26,6 +26,7 @@ #include <linux/tty_flip.h> #include <linux/slab.h> #include <linux/export.h> +#include <linux/module.h> #include "u_serial.h" @@ -35,11 +36,12 @@ * "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 @@ -119,13 +121,10 @@ struct gs_port { 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 */ @@ -309,6 +308,7 @@ gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags) return req; } +EXPORT_SYMBOL_GPL(gs_alloc_req); /* * gs_free_req @@ -320,6 +320,7 @@ void gs_free_req(struct usb_ep *ep, struct usb_request *req) kfree(req->buf); usb_ep_free_request(ep, req); } +EXPORT_SYMBOL_GPL(gs_free_req); /* * gs_send_packet @@ -1030,10 +1031,19 @@ static int 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); @@ -1049,109 +1059,9 @@ gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding) 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; - - 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; } static int gs_closed(struct gs_port *port) @@ -1164,55 +1074,77 @@ 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* */ + + 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)); - pr_debug("%s: cleaned up ttyGS* support\n", __func__); + 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_alloc_line); /** * gserial_connect - notify TTY I/O glue that USB link is active @@ -1229,8 +1161,8 @@ void gserial_cleanup(void) * * 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. @@ -1241,11 +1173,18 @@ int gserial_connect(struct gserial *gser, u8 port_num) 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); @@ -1292,7 +1231,7 @@ fail_out: gser->in->driver_data = NULL; return status; } - +EXPORT_SYMBOL_GPL(gserial_connect); /** * gserial_disconnect - notify TTY I/O glue that USB link is inactive * @gser: the function, on which gserial_connect() was called @@ -1347,3 +1286,65 @@ void gserial_disconnect(struct gserial *gser) spin_unlock_irqrestore(&port->port_lock, flags); } +EXPORT_SYMBOL_GPL(gserial_disconnect); + +static 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"); |