diff options
Diffstat (limited to 'drivers/staging/ccg/u_serial.c')
| -rw-r--r-- | drivers/staging/ccg/u_serial.c | 1339 |
1 files changed, 0 insertions, 1339 deletions
diff --git a/drivers/staging/ccg/u_serial.c b/drivers/staging/ccg/u_serial.c deleted file mode 100644 index b10947ae0ac..00000000000 --- a/drivers/staging/ccg/u_serial.c +++ /dev/null @@ -1,1339 +0,0 @@ -/* - * u_serial.c - utilities for USB gadget "serial port"/TTY support - * - * Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com) - * Copyright (C) 2008 David Brownell - * Copyright (C) 2008 by Nokia Corporation - * - * This code also borrows from usbserial.c, which is - * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com) - * Copyright (C) 2000 Peter Berger (pberger@brimson.com) - * Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com) - * - * This software is distributed under the terms of the GNU General - * Public License ("GPL") as published by the Free Software Foundation, - * either version 2 of that License or (at your option) any later version. - */ - -/* #define VERBOSE_DEBUG */ - -#include <linux/kernel.h> -#include <linux/sched.h> -#include <linux/interrupt.h> -#include <linux/device.h> -#include <linux/delay.h> -#include <linux/tty.h> -#include <linux/tty_flip.h> -#include <linux/slab.h> -#include <linux/export.h> - -#include "u_serial.h" - - -/* - * This component encapsulates the TTY layer glue needed to provide basic - * "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. - * - * A given TTY port can be made available in multiple configurations. - * For example, each one might expose a ttyGS0 node which provides a - * login application. In one case that might use CDC ACM interface 0, - * while another configuration might use interface 3 for that. The - * work to handle that (including descriptor management) is not part - * of this component. - * - * Configurations may expose more than one TTY port. For example, if - * ttyGS0 provides login service, then ttyGS1 might provide dialer access - * for a telephone or fax link. And ttyGS2 might be something that just - * needs a simple byte stream interface for some messaging protocol that - * is managed in userspace ... OBEX, PTP, and MTP have been mentioned. - */ - -#define PREFIX "ttyGS" - -/* - * gserial is the lifecycle interface, used by USB functions - * gs_port is the I/O nexus, used by the tty driver - * tty_struct links to the tty/filesystem framework - * - * gserial <---> gs_port ... links will be null when the USB link is - * inactive; managed by gserial_{connect,disconnect}(). each gserial - * instance can wrap its own USB control protocol. - * gserial->ioport == usb_ep->driver_data ... gs_port - * gs_port->port_usb ... gserial - * - * gs_port <---> tty_struct ... links will be null when the TTY file - * isn't opened; managed by gs_open()/gs_close() - * gserial->port_tty ... tty_struct - * tty_struct->driver_data ... gserial - */ - -/* RX and TX queues can buffer QUEUE_SIZE packets before they hit the - * next layer of buffering. For TX that's a circular buffer; for RX - * consider it a NOP. A third layer is provided by the TTY code. - */ -#define QUEUE_SIZE 16 -#define WRITE_BUF_SIZE 8192 /* TX only */ - -/* circular buffer */ -struct gs_buf { - unsigned buf_size; - char *buf_buf; - char *buf_get; - char *buf_put; -}; - -/* - * The port structure holds info for each port, one for each minor number - * (and thus for each /dev/ node). - */ -struct gs_port { - struct tty_port port; - spinlock_t port_lock; /* guard port_* access */ - - struct gserial *port_usb; - - bool openclose; /* open/close in progress */ - u8 port_num; - - struct list_head read_pool; - int read_started; - int read_allocated; - struct list_head read_queue; - unsigned n_read; - struct tasklet_struct push; - - struct list_head write_pool; - int write_started; - int write_allocated; - struct gs_buf port_write_buf; - wait_queue_head_t drain_wait; /* wait while writes drain */ - - /* REVISIT this state ... */ - 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; - -#define GS_CLOSE_TIMEOUT 15 /* seconds */ - - - -#ifdef VERBOSE_DEBUG -#define pr_vdebug(fmt, arg...) \ - pr_debug(fmt, ##arg) -#else -#define pr_vdebug(fmt, arg...) \ - ({ if (0) pr_debug(fmt, ##arg); }) -#endif - -/*-------------------------------------------------------------------------*/ - -/* Circular Buffer */ - -/* - * gs_buf_alloc - * - * Allocate a circular buffer and all associated memory. - */ -static int gs_buf_alloc(struct gs_buf *gb, unsigned size) -{ - gb->buf_buf = kmalloc(size, GFP_KERNEL); - if (gb->buf_buf == NULL) - return -ENOMEM; - - gb->buf_size = size; - gb->buf_put = gb->buf_buf; - gb->buf_get = gb->buf_buf; - - return 0; -} - -/* - * gs_buf_free - * - * Free the buffer and all associated memory. - */ -static void gs_buf_free(struct gs_buf *gb) -{ - kfree(gb->buf_buf); - gb->buf_buf = NULL; -} - -/* - * gs_buf_clear - * - * Clear out all data in the circular buffer. - */ -static void gs_buf_clear(struct gs_buf *gb) -{ - gb->buf_get = gb->buf_put; - /* equivalent to a get of all data available */ -} - -/* - * gs_buf_data_avail - * - * Return the number of bytes of data written into the circular - * buffer. - */ -static unsigned gs_buf_data_avail(struct gs_buf *gb) -{ - return (gb->buf_size + gb->buf_put - gb->buf_get) % gb->buf_size; -} - -/* - * gs_buf_space_avail - * - * Return the number of bytes of space available in the circular - * buffer. - */ -static unsigned gs_buf_space_avail(struct gs_buf *gb) -{ - return (gb->buf_size + gb->buf_get - gb->buf_put - 1) % gb->buf_size; -} - -/* - * gs_buf_put - * - * Copy data data from a user buffer and put it into the circular buffer. - * Restrict to the amount of space available. - * - * Return the number of bytes copied. - */ -static unsigned -gs_buf_put(struct gs_buf *gb, const char *buf, unsigned count) -{ - unsigned len; - - len = gs_buf_space_avail(gb); - if (count > len) - count = len; - - if (count == 0) - return 0; - - len = gb->buf_buf + gb->buf_size - gb->buf_put; - if (count > len) { - memcpy(gb->buf_put, buf, len); - memcpy(gb->buf_buf, buf+len, count - len); - gb->buf_put = gb->buf_buf + count - len; - } else { - memcpy(gb->buf_put, buf, count); - if (count < len) - gb->buf_put += count; - else /* count == len */ - gb->buf_put = gb->buf_buf; - } - - return count; -} - -/* - * gs_buf_get - * - * Get data from the circular buffer and copy to the given buffer. - * Restrict to the amount of data available. - * - * Return the number of bytes copied. - */ -static unsigned -gs_buf_get(struct gs_buf *gb, char *buf, unsigned count) -{ - unsigned len; - - len = gs_buf_data_avail(gb); - if (count > len) - count = len; - - if (count == 0) - return 0; - - len = gb->buf_buf + gb->buf_size - gb->buf_get; - if (count > len) { - memcpy(buf, gb->buf_get, len); - memcpy(buf+len, gb->buf_buf, count - len); - gb->buf_get = gb->buf_buf + count - len; - } else { - memcpy(buf, gb->buf_get, count); - if (count < len) - gb->buf_get += count; - else /* count == len */ - gb->buf_get = gb->buf_buf; - } - - return count; -} - -/*-------------------------------------------------------------------------*/ - -/* I/O glue between TTY (upper) and USB function (lower) driver layers */ - -/* - * gs_alloc_req - * - * Allocate a usb_request and its buffer. Returns a pointer to the - * usb_request or NULL if there is an error. - */ -struct usb_request * -gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags) -{ - struct usb_request *req; - - req = usb_ep_alloc_request(ep, kmalloc_flags); - - if (req != NULL) { - req->length = len; - req->buf = kmalloc(len, kmalloc_flags); - if (req->buf == NULL) { - usb_ep_free_request(ep, req); - return NULL; - } - } - - return req; -} - -/* - * gs_free_req - * - * Free a usb_request and its buffer. - */ -void gs_free_req(struct usb_ep *ep, struct usb_request *req) -{ - kfree(req->buf); - usb_ep_free_request(ep, req); -} - -/* - * gs_send_packet - * - * If there is data to send, a packet is built in the given - * buffer and the size is returned. If there is no data to - * send, 0 is returned. - * - * Called with port_lock held. - */ -static unsigned -gs_send_packet(struct gs_port *port, char *packet, unsigned size) -{ - unsigned len; - - len = gs_buf_data_avail(&port->port_write_buf); - if (len < size) - size = len; - if (size != 0) - size = gs_buf_get(&port->port_write_buf, packet, size); - return size; -} - -/* - * gs_start_tx - * - * This function finds available write requests, calls - * gs_send_packet to fill these packets with data, and - * continues until either there are no more write requests - * available or no more data to send. This function is - * run whenever data arrives or write requests are available. - * - * Context: caller owns port_lock; port_usb is non-null. - */ -static int gs_start_tx(struct gs_port *port) -/* -__releases(&port->port_lock) -__acquires(&port->port_lock) -*/ -{ - struct list_head *pool = &port->write_pool; - struct usb_ep *in = port->port_usb->in; - int status = 0; - bool do_tty_wake = false; - - while (!list_empty(pool)) { - struct usb_request *req; - int len; - - if (port->write_started >= QUEUE_SIZE) - break; - - req = list_entry(pool->next, struct usb_request, list); - len = gs_send_packet(port, req->buf, in->maxpacket); - if (len == 0) { - wake_up_interruptible(&port->drain_wait); - break; - } - do_tty_wake = true; - - req->length = len; - list_del(&req->list); - req->zero = (gs_buf_data_avail(&port->port_write_buf) == 0); - - pr_vdebug(PREFIX "%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n", - port->port_num, len, *((u8 *)req->buf), - *((u8 *)req->buf+1), *((u8 *)req->buf+2)); - - /* Drop lock while we call out of driver; completions - * could be issued while we do so. Disconnection may - * happen too; maybe immediately before we queue this! - * - * NOTE that we may keep sending data for a while after - * the TTY closed (dev->ioport->port_tty is NULL). - */ - spin_unlock(&port->port_lock); - status = usb_ep_queue(in, req, GFP_ATOMIC); - spin_lock(&port->port_lock); - - if (status) { - pr_debug("%s: %s %s err %d\n", - __func__, "queue", in->name, status); - list_add(&req->list, pool); - break; - } - - port->write_started++; - - /* abort immediately after disconnect */ - if (!port->port_usb) - break; - } - - if (do_tty_wake && port->port.tty) - tty_wakeup(port->port.tty); - return status; -} - -/* - * Context: caller owns port_lock, and port_usb is set - */ -static unsigned gs_start_rx(struct gs_port *port) -/* -__releases(&port->port_lock) -__acquires(&port->port_lock) -*/ -{ - struct list_head *pool = &port->read_pool; - struct usb_ep *out = port->port_usb->out; - - while (!list_empty(pool)) { - struct usb_request *req; - int status; - struct tty_struct *tty; - - /* no more rx if closed */ - tty = port->port.tty; - if (!tty) - break; - - if (port->read_started >= QUEUE_SIZE) - break; - - req = list_entry(pool->next, struct usb_request, list); - list_del(&req->list); - req->length = out->maxpacket; - - /* drop lock while we call out; the controller driver - * may need to call us back (e.g. for disconnect) - */ - spin_unlock(&port->port_lock); - status = usb_ep_queue(out, req, GFP_ATOMIC); - spin_lock(&port->port_lock); - - if (status) { - pr_debug("%s: %s %s err %d\n", - __func__, "queue", out->name, status); - list_add(&req->list, pool); - break; - } - port->read_started++; - - /* abort immediately after disconnect */ - if (!port->port_usb) - break; - } - return port->read_started; -} - -/* - * RX tasklet takes data out of the RX queue and hands it up to the TTY - * layer until it refuses to take any more data (or is throttled back). - * Then it issues reads for any further data. - * - * If the RX queue becomes full enough that no usb_request is queued, - * the OUT endpoint may begin NAKing as soon as its FIFO fills up. - * So QUEUE_SIZE packets plus however many the FIFO holds (usually two) - * can be buffered before the TTY layer's buffers (currently 64 KB). - */ -static void gs_rx_push(unsigned long _port) -{ - struct gs_port *port = (void *)_port; - struct tty_struct *tty; - struct list_head *queue = &port->read_queue; - bool disconnect = false; - bool do_push = false; - - /* hand any queued data to the tty */ - spin_lock_irq(&port->port_lock); - tty = port->port.tty; - while (!list_empty(queue)) { - struct usb_request *req; - - req = list_first_entry(queue, struct usb_request, list); - - /* leave data queued if tty was rx throttled */ - if (tty && test_bit(TTY_THROTTLED, &tty->flags)) - break; - - switch (req->status) { - case -ESHUTDOWN: - disconnect = true; - pr_vdebug(PREFIX "%d: shutdown\n", port->port_num); - break; - - default: - /* presumably a transient fault */ - pr_warning(PREFIX "%d: unexpected RX status %d\n", - port->port_num, req->status); - /* FALLTHROUGH */ - case 0: - /* normal completion */ - break; - } - - /* push data to (open) tty */ - if (req->actual) { - char *packet = req->buf; - unsigned size = req->actual; - unsigned n; - int count; - - /* we may have pushed part of this packet already... */ - n = port->n_read; - if (n) { - packet += n; - size -= n; - } - - count = tty_insert_flip_string(&port->port, packet, size); - if (count) - do_push = true; - if (count != size) { - /* stop pushing; TTY layer can't handle more */ - port->n_read += count; - pr_vdebug(PREFIX "%d: rx block %d/%d\n", - port->port_num, - count, req->actual); - break; - } - port->n_read = 0; - } - list_move(&req->list, &port->read_pool); - port->read_started--; - } - - /* Push from tty to ldisc; without low_latency set this is handled by - * a workqueue, so we won't get callbacks and can hold port_lock - */ - if (do_push) - tty_flip_buffer_push(&port->port); - - - /* We want our data queue to become empty ASAP, keeping data - * in the tty and ldisc (not here). If we couldn't push any - * this time around, there may be trouble unless there's an - * implicit tty_unthrottle() call on its way... - * - * REVISIT we should probably add a timer to keep the tasklet - * from starving ... but it's not clear that case ever happens. - */ - if (!list_empty(queue) && tty) { - if (!test_bit(TTY_THROTTLED, &tty->flags)) { - if (do_push) - tasklet_schedule(&port->push); - else - pr_warning(PREFIX "%d: RX not scheduled?\n", - port->port_num); - } - } - - /* If we're still connected, refill the USB RX queue. */ - if (!disconnect && port->port_usb) - gs_start_rx(port); - - spin_unlock_irq(&port->port_lock); -} - -static void gs_read_complete(struct usb_ep *ep, struct usb_request *req) -{ - struct gs_port *port = ep->driver_data; - - /* Queue all received data until the tty layer is ready for it. */ - spin_lock(&port->port_lock); - list_add_tail(&req->list, &port->read_queue); - tasklet_schedule(&port->push); - spin_unlock(&port->port_lock); -} - -static void gs_write_complete(struct usb_ep *ep, struct usb_request *req) -{ - struct gs_port *port = ep->driver_data; - - spin_lock(&port->port_lock); - list_add(&req->list, &port->write_pool); - port->write_started--; - - switch (req->status) { - default: - /* presumably a transient fault */ - pr_warning("%s: unexpected %s status %d\n", - __func__, ep->name, req->status); - /* FALL THROUGH */ - case 0: - /* normal completion */ - gs_start_tx(port); - break; - - case -ESHUTDOWN: - /* disconnect */ - pr_vdebug("%s: %s shutdown\n", __func__, ep->name); - break; - } - - spin_unlock(&port->port_lock); -} - -static void gs_free_requests(struct usb_ep *ep, struct list_head *head, - int *allocated) -{ - struct usb_request *req; - - while (!list_empty(head)) { - req = list_entry(head->next, struct usb_request, list); - list_del(&req->list); - gs_free_req(ep, req); - if (allocated) - (*allocated)--; - } -} - -static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head, - void (*fn)(struct usb_ep *, struct usb_request *), - int *allocated) -{ - int i; - struct usb_request *req; - int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE; - - /* Pre-allocate up to QUEUE_SIZE transfers, but if we can't - * do quite that many this time, don't fail ... we just won't - * be as speedy as we might otherwise be. - */ - for (i = 0; i < n; i++) { - req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC); - if (!req) - return list_empty(head) ? -ENOMEM : 0; - req->complete = fn; - list_add_tail(&req->list, head); - if (allocated) - (*allocated)++; - } - return 0; -} - -/** - * gs_start_io - start USB I/O streams - * @dev: encapsulates endpoints to use - * Context: holding port_lock; port_tty and port_usb are non-null - * - * We only start I/O when something is connected to both sides of - * this port. If nothing is listening on the host side, we may - * be pointlessly filling up our TX buffers and FIFO. - */ -static int gs_start_io(struct gs_port *port) -{ - struct list_head *head = &port->read_pool; - struct usb_ep *ep = port->port_usb->out; - int status; - unsigned started; - - /* Allocate RX and TX I/O buffers. We can't easily do this much - * earlier (with GFP_KERNEL) because the requests are coupled to - * endpoints, as are the packet sizes we'll be using. Different - * configurations may use different endpoints with a given port; - * and high speed vs full speed changes packet sizes too. - */ - status = gs_alloc_requests(ep, head, gs_read_complete, - &port->read_allocated); - if (status) - return status; - - status = gs_alloc_requests(port->port_usb->in, &port->write_pool, - gs_write_complete, &port->write_allocated); - if (status) { - gs_free_requests(ep, head, &port->read_allocated); - return status; - } - - /* queue read requests */ - port->n_read = 0; - started = gs_start_rx(port); - - /* unblock any pending writes into our circular buffer */ - if (started) { - tty_wakeup(port->port.tty); - } else { - gs_free_requests(ep, head, &port->read_allocated); - gs_free_requests(port->port_usb->in, &port->write_pool, - &port->write_allocated); - status = -EIO; - } - - return status; -} - -/*-------------------------------------------------------------------------*/ - -/* TTY Driver */ - -/* - * gs_open sets up the link between a gs_port and its associated TTY. - * That link is broken *only* by TTY close(), and all driver methods - * know that. - */ -static int gs_open(struct tty_struct *tty, struct file *file) -{ - int port_num = tty->index; - struct gs_port *port; - int status; - - do { - mutex_lock(&ports[port_num].lock); - port = ports[port_num].port; - if (!port) - status = -ENODEV; - else { - spin_lock_irq(&port->port_lock); - - /* already open? Great. */ - if (port->port.count) { - status = 0; - port->port.count++; - - /* currently opening/closing? wait ... */ - } else if (port->openclose) { - status = -EBUSY; - - /* ... else we do the work */ - } else { - status = -EAGAIN; - port->openclose = true; - } - spin_unlock_irq(&port->port_lock); - } - mutex_unlock(&ports[port_num].lock); - - switch (status) { - default: - /* fully handled */ - return status; - case -EAGAIN: - /* must do the work */ - break; - case -EBUSY: - /* wait for EAGAIN task to finish */ - msleep(1); - /* REVISIT could have a waitchannel here, if - * concurrent open performance is important - */ - break; - } - } while (status != -EAGAIN); - - /* Do the "real open" */ - spin_lock_irq(&port->port_lock); - - /* allocate circular buffer on first open */ - if (port->port_write_buf.buf_buf == NULL) { - - spin_unlock_irq(&port->port_lock); - status = gs_buf_alloc(&port->port_write_buf, WRITE_BUF_SIZE); - spin_lock_irq(&port->port_lock); - - if (status) { - pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n", - port->port_num, tty, file); - port->openclose = false; - goto exit_unlock_port; - } - } - - /* REVISIT if REMOVED (ports[].port NULL), abort the open - * to let rmmod work faster (but this way isn't wrong). - */ - - /* REVISIT maybe wait for "carrier detect" */ - - tty->driver_data = port; - port->port.tty = tty; - - port->port.count = 1; - port->openclose = false; - - /* if connected, start the I/O stream */ - if (port->port_usb) { - struct gserial *gser = port->port_usb; - - pr_debug("gs_open: start ttyGS%d\n", port->port_num); - gs_start_io(port); - - if (gser->connect) - gser->connect(gser); - } - - pr_debug("gs_open: ttyGS%d (%p,%p)\n", port->port_num, tty, file); - - status = 0; - -exit_unlock_port: - spin_unlock_irq(&port->port_lock); - return status; -} - -static int gs_writes_finished(struct gs_port *p) -{ - int cond; - - /* return true on disconnect or empty buffer */ - spin_lock_irq(&p->port_lock); - cond = (p->port_usb == NULL) || !gs_buf_data_avail(&p->port_write_buf); - spin_unlock_irq(&p->port_lock); - - return cond; -} - -static void gs_close(struct tty_struct *tty, struct file *file) -{ - struct gs_port *port = tty->driver_data; - struct gserial *gser; - - spin_lock_irq(&port->port_lock); - - if (port->port.count != 1) { - if (port->port.count == 0) - WARN_ON(1); - else - --port->port.count; - goto exit; - } - - pr_debug("gs_close: ttyGS%d (%p,%p) ...\n", port->port_num, tty, file); - - /* mark port as closing but in use; we can drop port lock - * and sleep if necessary - */ - port->openclose = true; - port->port.count = 0; - - gser = port->port_usb; - if (gser && gser->disconnect) - gser->disconnect(gser); - - /* wait for circular write buffer to drain, disconnect, or at - * most GS_CLOSE_TIMEOUT seconds; then discard the rest - */ - if (gs_buf_data_avail(&port->port_write_buf) > 0 && gser) { - spin_unlock_irq(&port->port_lock); - wait_event_interruptible_timeout(port->drain_wait, - gs_writes_finished(port), - GS_CLOSE_TIMEOUT * HZ); - spin_lock_irq(&port->port_lock); - gser = port->port_usb; - } - - /* Iff we're disconnected, there can be no I/O in flight so it's - * ok to free the circular buffer; else just scrub it. And don't - * let the push tasklet fire again until we're re-opened. - */ - if (gser == NULL) - gs_buf_free(&port->port_write_buf); - else - gs_buf_clear(&port->port_write_buf); - - tty->driver_data = NULL; - port->port.tty = NULL; - - port->openclose = false; - - pr_debug("gs_close: ttyGS%d (%p,%p) done!\n", - port->port_num, tty, file); - - wake_up_interruptible(&port->port.close_wait); -exit: - spin_unlock_irq(&port->port_lock); -} - -static int gs_write(struct tty_struct *tty, const unsigned char *buf, int count) -{ - struct gs_port *port = tty->driver_data; - unsigned long flags; - int status; - - pr_vdebug("gs_write: ttyGS%d (%p) writing %d bytes\n", - port->port_num, tty, count); - - spin_lock_irqsave(&port->port_lock, flags); - if (count) - count = gs_buf_put(&port->port_write_buf, buf, count); - /* treat count == 0 as flush_chars() */ - if (port->port_usb) - status = gs_start_tx(port); - spin_unlock_irqrestore(&port->port_lock, flags); - - return count; -} - -static int gs_put_char(struct tty_struct *tty, unsigned char ch) -{ - struct gs_port *port = tty->driver_data; - unsigned long flags; - int status; - - pr_vdebug("gs_put_char: (%d,%p) char=0x%x, called from %pf\n", - port->port_num, tty, ch, __builtin_return_address(0)); - - spin_lock_irqsave(&port->port_lock, flags); - status = gs_buf_put(&port->port_write_buf, &ch, 1); - spin_unlock_irqrestore(&port->port_lock, flags); - - return status; -} - -static void gs_flush_chars(struct tty_struct *tty) -{ - struct gs_port *port = tty->driver_data; - unsigned long flags; - - pr_vdebug("gs_flush_chars: (%d,%p)\n", port->port_num, tty); - - spin_lock_irqsave(&port->port_lock, flags); - if (port->port_usb) - gs_start_tx(port); - spin_unlock_irqrestore(&port->port_lock, flags); -} - -static int gs_write_room(struct tty_struct *tty) -{ - struct gs_port *port = tty->driver_data; - unsigned long flags; - int room = 0; - - spin_lock_irqsave(&port->port_lock, flags); - if (port->port_usb) - room = gs_buf_space_avail(&port->port_write_buf); - spin_unlock_irqrestore(&port->port_lock, flags); - - pr_vdebug("gs_write_room: (%d,%p) room=%d\n", - port->port_num, tty, room); - - return room; -} - -static int gs_chars_in_buffer(struct tty_struct *tty) -{ - struct gs_port *port = tty->driver_data; - unsigned long flags; - int chars = 0; - - spin_lock_irqsave(&port->port_lock, flags); - chars = gs_buf_data_avail(&port->port_write_buf); - spin_unlock_irqrestore(&port->port_lock, flags); - - pr_vdebug("gs_chars_in_buffer: (%d,%p) chars=%d\n", - port->port_num, tty, chars); - - return chars; -} - -/* undo side effects of setting TTY_THROTTLED */ -static void gs_unthrottle(struct tty_struct *tty) -{ - struct gs_port *port = tty->driver_data; - unsigned long flags; - - spin_lock_irqsave(&port->port_lock, flags); - if (port->port_usb) { - /* Kickstart read queue processing. We don't do xon/xoff, - * rts/cts, or other handshaking with the host, but if the - * read queue backs up enough we'll be NAKing OUT packets. - */ - tasklet_schedule(&port->push); - pr_vdebug(PREFIX "%d: unthrottle\n", port->port_num); - } - spin_unlock_irqrestore(&port->port_lock, flags); -} - -static int gs_break_ctl(struct tty_struct *tty, int duration) -{ - struct gs_port *port = tty->driver_data; - int status = 0; - struct gserial *gser; - - pr_vdebug("gs_break_ctl: ttyGS%d, send break (%d) \n", - port->port_num, duration); - - spin_lock_irq(&port->port_lock); - gser = port->port_usb; - if (gser && gser->send_break) - status = gser->send_break(gser, duration); - spin_unlock_irq(&port->port_lock); - - return status; -} - -static const struct tty_operations gs_tty_ops = { - .open = gs_open, - .close = gs_close, - .write = gs_write, - .put_char = gs_put_char, - .flush_chars = gs_flush_chars, - .write_room = gs_write_room, - .chars_in_buffer = gs_chars_in_buffer, - .unthrottle = gs_unthrottle, - .break_ctl = gs_break_ctl, -}; - -/*-------------------------------------------------------------------------*/ - -static struct tty_driver *gs_tty_driver; - -static int -gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding) -{ - struct gs_port *port; - - port = kzalloc(sizeof(struct gs_port), GFP_KERNEL); - if (port == NULL) - return -ENOMEM; - - tty_port_init(&port->port); - spin_lock_init(&port->port_lock); - init_waitqueue_head(&port->drain_wait); - - tasklet_init(&port->push, gs_rx_push, (unsigned long) port); - - INIT_LIST_HEAD(&port->read_pool); - INIT_LIST_HEAD(&port->read_queue); - INIT_LIST_HEAD(&port->write_pool); - - port->port_num = port_num; - 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_register_device(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; -} - -static int gs_closed(struct gs_port *port) -{ - int cond; - - spin_lock_irq(&port->port_lock); - cond = (port->port.count == 0) && !port->openclose; - spin_unlock_irq(&port->port_lock); - 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) -{ - unsigned i; - struct gs_port *port; - - if (!gs_tty_driver) - return; - - /* 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); - - /* 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); - } - n_ports = 0; - - tty_unregister_driver(gs_tty_driver); - put_tty_driver(gs_tty_driver); - gs_tty_driver = NULL; - - pr_debug("%s: cleaned up ttyGS* support\n", __func__); -} - -/** - * gserial_connect - notify TTY I/O glue that USB link is active - * @gser: the function, set up with endpoints and descriptors - * @port_num: which port is active - * Context: any (usually from irq) - * - * This is called activate endpoints and let the TTY layer know that - * the connection is active ... not unlike "carrier detect". It won't - * necessarily start I/O queues; unless the TTY is held open by any - * task, there would be no point. However, the endpoints will be - * activated so the USB host can perform I/O, subject to basic USB - * hardware flow control. - * - * 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(). - * - * Returns negative errno or zero. - * On success, ep->driver_data will be overwritten. - */ -int gserial_connect(struct gserial *gser, u8 port_num) -{ - struct gs_port *port; - unsigned long flags; - int status; - - if (!gs_tty_driver || port_num >= n_ports) - return -ENXIO; - - /* we "know" gserial_cleanup() hasn't been called */ - port = ports[port_num].port; - - /* activate the endpoints */ - status = usb_ep_enable(gser->in); - if (status < 0) - return status; - gser->in->driver_data = port; - - status = usb_ep_enable(gser->out); - if (status < 0) - goto fail_out; - gser->out->driver_data = port; - - /* then tell the tty glue that I/O can work */ - spin_lock_irqsave(&port->port_lock, flags); - gser->ioport = port; - port->port_usb = gser; - - /* REVISIT unclear how best to handle this state... - * we don't really couple it with the Linux TTY. - */ - gser->port_line_coding = port->port_line_coding; - - /* REVISIT if waiting on "carrier detect", signal. */ - - /* if it's already open, start I/O ... and notify the serial - * protocol about open/close status (connect/disconnect). - */ - if (port->port.count) { - pr_debug("gserial_connect: start ttyGS%d\n", port->port_num); - gs_start_io(port); - if (gser->connect) - gser->connect(gser); - } else { - if (gser->disconnect) - gser->disconnect(gser); - } - - spin_unlock_irqrestore(&port->port_lock, flags); - - return status; - -fail_out: - usb_ep_disable(gser->in); - gser->in->driver_data = NULL; - return status; -} - -/** - * gserial_disconnect - notify TTY I/O glue that USB link is inactive - * @gser: the function, on which gserial_connect() was called - * Context: any (usually from irq) - * - * This is called to deactivate endpoints and let the TTY layer know - * that the connection went inactive ... not unlike "hangup". - * - * On return, the state is as if gserial_connect() had never been called; - * there is no active USB I/O on these endpoints. - */ -void gserial_disconnect(struct gserial *gser) -{ - struct gs_port *port = gser->ioport; - unsigned long flags; - - if (!port) - return; - - /* tell the TTY glue not to do I/O here any more */ - spin_lock_irqsave(&port->port_lock, flags); - - /* REVISIT as above: how best to track this? */ - port->port_line_coding = gser->port_line_coding; - - port->port_usb = NULL; - gser->ioport = NULL; - if (port->port.count > 0 || port->openclose) { - wake_up_interruptible(&port->drain_wait); - if (port->port.tty) - tty_hangup(port->port.tty); - } - spin_unlock_irqrestore(&port->port_lock, flags); - - /* disable endpoints, aborting down any active I/O */ - usb_ep_disable(gser->out); - gser->out->driver_data = NULL; - - usb_ep_disable(gser->in); - gser->in->driver_data = NULL; - - /* finally, free any unused/unusable I/O buffers */ - spin_lock_irqsave(&port->port_lock, flags); - if (port->port.count == 0 && !port->openclose) - gs_buf_free(&port->port_write_buf); - gs_free_requests(gser->out, &port->read_pool, NULL); - gs_free_requests(gser->out, &port->read_queue, NULL); - gs_free_requests(gser->in, &port->write_pool, NULL); - - port->read_allocated = port->read_started = - port->write_allocated = port->write_started = 0; - - spin_unlock_irqrestore(&port->port_lock, flags); -} |