1466 строки
35 KiB
C
1466 строки
35 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* u_serial.c - utilities for USB gadget "serial port"/TTY support
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*
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* Copyright (C) 2003 Al Borchers (alborchers@steinerpoint.com)
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* Copyright (C) 2008 David Brownell
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* Copyright (C) 2008 by Nokia Corporation
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*
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* This code also borrows from usbserial.c, which is
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* Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
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* Copyright (C) 2000 Peter Berger (pberger@brimson.com)
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* Copyright (C) 2000 Al Borchers (alborchers@steinerpoint.com)
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*/
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/* #define VERBOSE_DEBUG */
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/device.h>
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#include <linux/delay.h>
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#include <linux/tty.h>
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#include <linux/tty_flip.h>
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#include <linux/slab.h>
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#include <linux/export.h>
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#include <linux/module.h>
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#include <linux/console.h>
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#include <linux/kthread.h>
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#include <linux/workqueue.h>
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#include <linux/kfifo.h>
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#include "u_serial.h"
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/*
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* This component encapsulates the TTY layer glue needed to provide basic
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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 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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* login application. In one case that might use CDC ACM interface 0,
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* while another configuration might use interface 3 for that. The
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* work to handle that (including descriptor management) is not part
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* of this component.
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*
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* Configurations may expose more than one TTY port. For example, if
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* ttyGS0 provides login service, then ttyGS1 might provide dialer access
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* for a telephone or fax link. And ttyGS2 might be something that just
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* needs a simple byte stream interface for some messaging protocol that
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* is managed in userspace ... OBEX, PTP, and MTP have been mentioned.
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*
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*
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* gserial is the lifecycle interface, used by USB functions
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* gs_port is the I/O nexus, used by the tty driver
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* tty_struct links to the tty/filesystem framework
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*
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* gserial <---> gs_port ... links will be null when the USB link is
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* inactive; managed by gserial_{connect,disconnect}(). each gserial
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* instance can wrap its own USB control protocol.
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* gserial->ioport == usb_ep->driver_data ... gs_port
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* gs_port->port_usb ... gserial
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*
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* gs_port <---> tty_struct ... links will be null when the TTY file
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* isn't opened; managed by gs_open()/gs_close()
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* gserial->port_tty ... tty_struct
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* tty_struct->driver_data ... gserial
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*/
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/* RX and TX queues can buffer QUEUE_SIZE packets before they hit the
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* next layer of buffering. For TX that's a circular buffer; for RX
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* consider it a NOP. A third layer is provided by the TTY code.
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*/
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#define QUEUE_SIZE 16
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#define WRITE_BUF_SIZE 8192 /* TX only */
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#define GS_CONSOLE_BUF_SIZE 8192
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/* console info */
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struct gs_console {
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struct console console;
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struct work_struct work;
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spinlock_t lock;
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struct usb_request *req;
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struct kfifo buf;
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size_t missed;
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};
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/*
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* The port structure holds info for each port, one for each minor number
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* (and thus for each /dev/ node).
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*/
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struct gs_port {
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struct tty_port port;
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spinlock_t port_lock; /* guard port_* access */
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struct gserial *port_usb;
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#ifdef CONFIG_U_SERIAL_CONSOLE
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struct gs_console *console;
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#endif
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u8 port_num;
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struct list_head read_pool;
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int read_started;
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int read_allocated;
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struct list_head read_queue;
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unsigned n_read;
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struct delayed_work push;
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struct list_head write_pool;
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int write_started;
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int write_allocated;
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struct kfifo port_write_buf;
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wait_queue_head_t drain_wait; /* wait while writes drain */
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bool write_busy;
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wait_queue_head_t close_wait;
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/* REVISIT this state ... */
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struct usb_cdc_line_coding port_line_coding; /* 8-N-1 etc */
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};
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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[MAX_U_SERIAL_PORTS];
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#define GS_CLOSE_TIMEOUT 15 /* seconds */
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#ifdef VERBOSE_DEBUG
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#ifndef pr_vdebug
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#define pr_vdebug(fmt, arg...) \
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pr_debug(fmt, ##arg)
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#endif /* pr_vdebug */
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#else
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#ifndef pr_vdebug
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#define pr_vdebug(fmt, arg...) \
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({ if (0) pr_debug(fmt, ##arg); })
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#endif /* pr_vdebug */
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#endif
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/*-------------------------------------------------------------------------*/
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/* I/O glue between TTY (upper) and USB function (lower) driver layers */
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/*
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* gs_alloc_req
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*
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* Allocate a usb_request and its buffer. Returns a pointer to the
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* usb_request or NULL if there is an error.
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*/
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struct usb_request *
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gs_alloc_req(struct usb_ep *ep, unsigned len, gfp_t kmalloc_flags)
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{
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struct usb_request *req;
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req = usb_ep_alloc_request(ep, kmalloc_flags);
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if (req != NULL) {
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req->length = len;
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req->buf = kmalloc(len, kmalloc_flags);
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if (req->buf == NULL) {
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usb_ep_free_request(ep, req);
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return NULL;
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}
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}
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return req;
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}
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EXPORT_SYMBOL_GPL(gs_alloc_req);
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/*
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* gs_free_req
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*
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* Free a usb_request and its buffer.
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*/
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void gs_free_req(struct usb_ep *ep, struct usb_request *req)
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{
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kfree(req->buf);
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usb_ep_free_request(ep, req);
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}
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EXPORT_SYMBOL_GPL(gs_free_req);
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/*
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* gs_send_packet
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*
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* If there is data to send, a packet is built in the given
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* buffer and the size is returned. If there is no data to
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* send, 0 is returned.
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*
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* Called with port_lock held.
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*/
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static unsigned
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gs_send_packet(struct gs_port *port, char *packet, unsigned size)
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{
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unsigned len;
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len = kfifo_len(&port->port_write_buf);
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if (len < size)
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size = len;
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if (size != 0)
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size = kfifo_out(&port->port_write_buf, packet, size);
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return size;
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}
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/*
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* gs_start_tx
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*
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* This function finds available write requests, calls
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* gs_send_packet to fill these packets with data, and
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* continues until either there are no more write requests
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* available or no more data to send. This function is
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* run whenever data arrives or write requests are available.
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*
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* Context: caller owns port_lock; port_usb is non-null.
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*/
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static int gs_start_tx(struct gs_port *port)
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/*
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__releases(&port->port_lock)
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__acquires(&port->port_lock)
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*/
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{
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struct list_head *pool = &port->write_pool;
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struct usb_ep *in;
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int status = 0;
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bool do_tty_wake = false;
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if (!port->port_usb)
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return status;
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in = port->port_usb->in;
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while (!port->write_busy && !list_empty(pool)) {
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struct usb_request *req;
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int len;
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if (port->write_started >= QUEUE_SIZE)
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break;
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req = list_entry(pool->next, struct usb_request, list);
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len = gs_send_packet(port, req->buf, in->maxpacket);
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if (len == 0) {
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wake_up_interruptible(&port->drain_wait);
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break;
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}
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do_tty_wake = true;
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req->length = len;
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list_del(&req->list);
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req->zero = kfifo_is_empty(&port->port_write_buf);
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pr_vdebug("ttyGS%d: tx len=%d, 0x%02x 0x%02x 0x%02x ...\n",
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port->port_num, len, *((u8 *)req->buf),
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*((u8 *)req->buf+1), *((u8 *)req->buf+2));
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/* Drop lock while we call out of driver; completions
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* could be issued while we do so. Disconnection may
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* happen too; maybe immediately before we queue this!
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*
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* NOTE that we may keep sending data for a while after
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* the TTY closed (dev->ioport->port_tty is NULL).
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*/
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port->write_busy = true;
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spin_unlock(&port->port_lock);
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status = usb_ep_queue(in, req, GFP_ATOMIC);
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spin_lock(&port->port_lock);
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port->write_busy = false;
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if (status) {
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pr_debug("%s: %s %s err %d\n",
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__func__, "queue", in->name, status);
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list_add(&req->list, pool);
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break;
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}
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port->write_started++;
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/* abort immediately after disconnect */
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if (!port->port_usb)
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break;
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}
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if (do_tty_wake && port->port.tty)
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tty_wakeup(port->port.tty);
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return status;
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}
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/*
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* Context: caller owns port_lock, and port_usb is set
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*/
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static unsigned gs_start_rx(struct gs_port *port)
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/*
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__releases(&port->port_lock)
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__acquires(&port->port_lock)
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*/
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{
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struct list_head *pool = &port->read_pool;
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struct usb_ep *out = port->port_usb->out;
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while (!list_empty(pool)) {
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struct usb_request *req;
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int status;
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struct tty_struct *tty;
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/* no more rx if closed */
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tty = port->port.tty;
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if (!tty)
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break;
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if (port->read_started >= QUEUE_SIZE)
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break;
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req = list_entry(pool->next, struct usb_request, list);
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list_del(&req->list);
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req->length = out->maxpacket;
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/* drop lock while we call out; the controller driver
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* may need to call us back (e.g. for disconnect)
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*/
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spin_unlock(&port->port_lock);
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status = usb_ep_queue(out, req, GFP_ATOMIC);
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spin_lock(&port->port_lock);
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if (status) {
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pr_debug("%s: %s %s err %d\n",
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__func__, "queue", out->name, status);
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list_add(&req->list, pool);
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break;
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}
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port->read_started++;
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/* abort immediately after disconnect */
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if (!port->port_usb)
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break;
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}
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return port->read_started;
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}
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/*
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* RX tasklet takes data out of the RX queue and hands it up to the TTY
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* layer until it refuses to take any more data (or is throttled back).
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* Then it issues reads for any further data.
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*
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* If the RX queue becomes full enough that no usb_request is queued,
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* the OUT endpoint may begin NAKing as soon as its FIFO fills up.
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* So QUEUE_SIZE packets plus however many the FIFO holds (usually two)
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* can be buffered before the TTY layer's buffers (currently 64 KB).
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*/
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static void gs_rx_push(struct work_struct *work)
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{
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struct delayed_work *w = to_delayed_work(work);
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struct gs_port *port = container_of(w, struct gs_port, push);
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struct tty_struct *tty;
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struct list_head *queue = &port->read_queue;
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bool disconnect = false;
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bool do_push = false;
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/* hand any queued data to the tty */
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spin_lock_irq(&port->port_lock);
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tty = port->port.tty;
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while (!list_empty(queue)) {
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struct usb_request *req;
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req = list_first_entry(queue, struct usb_request, list);
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/* leave data queued if tty was rx throttled */
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if (tty && tty_throttled(tty))
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break;
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switch (req->status) {
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case -ESHUTDOWN:
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disconnect = true;
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pr_vdebug("ttyGS%d: shutdown\n", port->port_num);
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break;
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default:
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/* presumably a transient fault */
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pr_warn("ttyGS%d: unexpected RX status %d\n",
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port->port_num, req->status);
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/* FALLTHROUGH */
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case 0:
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/* normal completion */
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break;
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}
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/* push data to (open) tty */
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if (req->actual && tty) {
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char *packet = req->buf;
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unsigned size = req->actual;
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unsigned n;
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int count;
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/* we may have pushed part of this packet already... */
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n = port->n_read;
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if (n) {
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packet += n;
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size -= n;
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}
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count = tty_insert_flip_string(&port->port, packet,
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size);
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if (count)
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do_push = true;
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if (count != size) {
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/* stop pushing; TTY layer can't handle more */
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port->n_read += count;
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pr_vdebug("ttyGS%d: rx block %d/%d\n",
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port->port_num, count, req->actual);
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break;
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}
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port->n_read = 0;
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}
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list_move(&req->list, &port->read_pool);
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port->read_started--;
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}
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/* Push from tty to ldisc; this is handled by a workqueue,
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* so we won't get callbacks and can hold port_lock
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*/
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if (do_push)
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tty_flip_buffer_push(&port->port);
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/* We want our data queue to become empty ASAP, keeping data
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* in the tty and ldisc (not here). If we couldn't push any
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* this time around, RX may be starved, so wait until next jiffy.
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*
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* We may leave non-empty queue only when there is a tty, and
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* either it is throttled or there is no more room in flip buffer.
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*/
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if (!list_empty(queue) && !tty_throttled(tty))
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schedule_delayed_work(&port->push, 1);
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/* If we're still connected, refill the USB RX queue. */
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if (!disconnect && port->port_usb)
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gs_start_rx(port);
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spin_unlock_irq(&port->port_lock);
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}
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static void gs_read_complete(struct usb_ep *ep, struct usb_request *req)
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{
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struct gs_port *port = ep->driver_data;
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/* Queue all received data until the tty layer is ready for it. */
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spin_lock(&port->port_lock);
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list_add_tail(&req->list, &port->read_queue);
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schedule_delayed_work(&port->push, 0);
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spin_unlock(&port->port_lock);
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}
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static void gs_write_complete(struct usb_ep *ep, struct usb_request *req)
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{
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struct gs_port *port = ep->driver_data;
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spin_lock(&port->port_lock);
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list_add(&req->list, &port->write_pool);
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port->write_started--;
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switch (req->status) {
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default:
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/* presumably a transient fault */
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pr_warn("%s: unexpected %s status %d\n",
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__func__, ep->name, req->status);
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/* FALL THROUGH */
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case 0:
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/* normal completion */
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gs_start_tx(port);
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break;
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case -ESHUTDOWN:
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/* disconnect */
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pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
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break;
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}
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spin_unlock(&port->port_lock);
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}
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static void gs_free_requests(struct usb_ep *ep, struct list_head *head,
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int *allocated)
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{
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struct usb_request *req;
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while (!list_empty(head)) {
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req = list_entry(head->next, struct usb_request, list);
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list_del(&req->list);
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gs_free_req(ep, req);
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if (allocated)
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(*allocated)--;
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}
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}
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static int gs_alloc_requests(struct usb_ep *ep, struct list_head *head,
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void (*fn)(struct usb_ep *, struct usb_request *),
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int *allocated)
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{
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int i;
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struct usb_request *req;
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int n = allocated ? QUEUE_SIZE - *allocated : QUEUE_SIZE;
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/* Pre-allocate up to QUEUE_SIZE transfers, but if we can't
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* do quite that many this time, don't fail ... we just won't
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* be as speedy as we might otherwise be.
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*/
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for (i = 0; i < n; i++) {
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req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC);
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if (!req)
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return list_empty(head) ? -ENOMEM : 0;
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req->complete = fn;
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list_add_tail(&req->list, head);
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if (allocated)
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(*allocated)++;
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}
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return 0;
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}
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/**
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* gs_start_io - start USB I/O streams
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* @dev: encapsulates endpoints to use
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* Context: holding port_lock; port_tty and port_usb are non-null
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*
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|
* 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);
|
|
|
|
if (started) {
|
|
gs_start_tx(port);
|
|
/* Unblock any pending writes into our circular buffer, in case
|
|
* we didn't in gs_start_tx() */
|
|
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 = 0;
|
|
|
|
mutex_lock(&ports[port_num].lock);
|
|
port = ports[port_num].port;
|
|
if (!port) {
|
|
status = -ENODEV;
|
|
goto out;
|
|
}
|
|
|
|
spin_lock_irq(&port->port_lock);
|
|
|
|
/* allocate circular buffer on first open */
|
|
if (!kfifo_initialized(&port->port_write_buf)) {
|
|
|
|
spin_unlock_irq(&port->port_lock);
|
|
|
|
/*
|
|
* portmaster's mutex still protects from simultaneous open(),
|
|
* and close() can't happen, yet.
|
|
*/
|
|
|
|
status = kfifo_alloc(&port->port_write_buf,
|
|
WRITE_BUF_SIZE, GFP_KERNEL);
|
|
if (status) {
|
|
pr_debug("gs_open: ttyGS%d (%p,%p) no buffer\n",
|
|
port_num, tty, file);
|
|
goto out;
|
|
}
|
|
|
|
spin_lock_irq(&port->port_lock);
|
|
}
|
|
|
|
/* already open? Great. */
|
|
if (port->port.count++)
|
|
goto exit_unlock_port;
|
|
|
|
tty->driver_data = port;
|
|
port->port.tty = tty;
|
|
|
|
/* 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);
|
|
|
|
exit_unlock_port:
|
|
spin_unlock_irq(&port->port_lock);
|
|
out:
|
|
mutex_unlock(&ports[port_num].lock);
|
|
return status;
|
|
}
|
|
|
|
static int gs_close_flush_done(struct gs_port *p)
|
|
{
|
|
int cond;
|
|
|
|
/* return true on disconnect or empty buffer or if raced with open() */
|
|
spin_lock_irq(&p->port_lock);
|
|
cond = p->port_usb == NULL || !kfifo_len(&p->port_write_buf) ||
|
|
p->port.count > 1;
|
|
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) {
|
|
raced_with_open:
|
|
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);
|
|
|
|
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 (kfifo_len(&port->port_write_buf) > 0 && gser) {
|
|
spin_unlock_irq(&port->port_lock);
|
|
wait_event_interruptible_timeout(port->drain_wait,
|
|
gs_close_flush_done(port),
|
|
GS_CLOSE_TIMEOUT * HZ);
|
|
spin_lock_irq(&port->port_lock);
|
|
|
|
if (port->port.count != 1)
|
|
goto raced_with_open;
|
|
|
|
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)
|
|
kfifo_free(&port->port_write_buf);
|
|
else
|
|
kfifo_reset(&port->port_write_buf);
|
|
|
|
port->port.count = 0;
|
|
port->port.tty = NULL;
|
|
|
|
pr_debug("gs_close: ttyGS%d (%p,%p) done!\n",
|
|
port->port_num, tty, file);
|
|
|
|
wake_up(&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;
|
|
|
|
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 = kfifo_in(&port->port_write_buf, buf, count);
|
|
/* treat count == 0 as flush_chars() */
|
|
if (port->port_usb)
|
|
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 %ps\n",
|
|
port->port_num, tty, ch, __builtin_return_address(0));
|
|
|
|
spin_lock_irqsave(&port->port_lock, flags);
|
|
status = kfifo_put(&port->port_write_buf, ch);
|
|
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 = kfifo_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 = kfifo_len(&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.
|
|
*/
|
|
pr_vdebug("ttyGS%d: unthrottle\n", port->port_num);
|
|
schedule_delayed_work(&port->push, 0);
|
|
}
|
|
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;
|
|
|
|
#ifdef CONFIG_U_SERIAL_CONSOLE
|
|
|
|
static void gs_console_complete_out(struct usb_ep *ep, struct usb_request *req)
|
|
{
|
|
struct gs_console *cons = req->context;
|
|
|
|
switch (req->status) {
|
|
default:
|
|
pr_warn("%s: unexpected %s status %d\n",
|
|
__func__, ep->name, req->status);
|
|
/* fall through */
|
|
case 0:
|
|
/* normal completion */
|
|
spin_lock(&cons->lock);
|
|
req->length = 0;
|
|
schedule_work(&cons->work);
|
|
spin_unlock(&cons->lock);
|
|
break;
|
|
case -ECONNRESET:
|
|
case -ESHUTDOWN:
|
|
/* disconnect */
|
|
pr_vdebug("%s: %s shutdown\n", __func__, ep->name);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void __gs_console_push(struct gs_console *cons)
|
|
{
|
|
struct usb_request *req = cons->req;
|
|
struct usb_ep *ep;
|
|
size_t size;
|
|
|
|
if (!req)
|
|
return; /* disconnected */
|
|
|
|
if (req->length)
|
|
return; /* busy */
|
|
|
|
ep = cons->console.data;
|
|
size = kfifo_out(&cons->buf, req->buf, ep->maxpacket);
|
|
if (!size)
|
|
return;
|
|
|
|
if (cons->missed && ep->maxpacket >= 64) {
|
|
char buf[64];
|
|
size_t len;
|
|
|
|
len = sprintf(buf, "\n[missed %zu bytes]\n", cons->missed);
|
|
kfifo_in(&cons->buf, buf, len);
|
|
cons->missed = 0;
|
|
}
|
|
|
|
req->length = size;
|
|
if (usb_ep_queue(ep, req, GFP_ATOMIC))
|
|
req->length = 0;
|
|
}
|
|
|
|
static void gs_console_work(struct work_struct *work)
|
|
{
|
|
struct gs_console *cons = container_of(work, struct gs_console, work);
|
|
|
|
spin_lock_irq(&cons->lock);
|
|
|
|
__gs_console_push(cons);
|
|
|
|
spin_unlock_irq(&cons->lock);
|
|
}
|
|
|
|
static void gs_console_write(struct console *co,
|
|
const char *buf, unsigned count)
|
|
{
|
|
struct gs_console *cons = container_of(co, struct gs_console, console);
|
|
unsigned long flags;
|
|
size_t n;
|
|
|
|
spin_lock_irqsave(&cons->lock, flags);
|
|
|
|
n = kfifo_in(&cons->buf, buf, count);
|
|
if (n < count)
|
|
cons->missed += count - n;
|
|
|
|
if (cons->req && !cons->req->length)
|
|
schedule_work(&cons->work);
|
|
|
|
spin_unlock_irqrestore(&cons->lock, flags);
|
|
}
|
|
|
|
static struct tty_driver *gs_console_device(struct console *co, int *index)
|
|
{
|
|
*index = co->index;
|
|
return gs_tty_driver;
|
|
}
|
|
|
|
static int gs_console_connect(struct gs_port *port)
|
|
{
|
|
struct gs_console *cons = port->console;
|
|
struct usb_request *req;
|
|
struct usb_ep *ep;
|
|
|
|
if (!cons)
|
|
return 0;
|
|
|
|
ep = port->port_usb->in;
|
|
req = gs_alloc_req(ep, ep->maxpacket, GFP_ATOMIC);
|
|
if (!req)
|
|
return -ENOMEM;
|
|
req->complete = gs_console_complete_out;
|
|
req->context = cons;
|
|
req->length = 0;
|
|
|
|
spin_lock(&cons->lock);
|
|
cons->req = req;
|
|
cons->console.data = ep;
|
|
spin_unlock(&cons->lock);
|
|
|
|
pr_debug("ttyGS%d: console connected!\n", port->port_num);
|
|
|
|
schedule_work(&cons->work);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void gs_console_disconnect(struct gs_port *port)
|
|
{
|
|
struct gs_console *cons = port->console;
|
|
struct usb_request *req;
|
|
struct usb_ep *ep;
|
|
|
|
if (!cons)
|
|
return;
|
|
|
|
spin_lock(&cons->lock);
|
|
|
|
req = cons->req;
|
|
ep = cons->console.data;
|
|
cons->req = NULL;
|
|
|
|
spin_unlock(&cons->lock);
|
|
|
|
if (!req)
|
|
return;
|
|
|
|
usb_ep_dequeue(ep, req);
|
|
gs_free_req(ep, req);
|
|
}
|
|
|
|
static int gs_console_init(struct gs_port *port)
|
|
{
|
|
struct gs_console *cons;
|
|
int err;
|
|
|
|
if (port->console)
|
|
return 0;
|
|
|
|
cons = kzalloc(sizeof(*port->console), GFP_KERNEL);
|
|
if (!cons)
|
|
return -ENOMEM;
|
|
|
|
strcpy(cons->console.name, "ttyGS");
|
|
cons->console.write = gs_console_write;
|
|
cons->console.device = gs_console_device;
|
|
cons->console.flags = CON_PRINTBUFFER;
|
|
cons->console.index = port->port_num;
|
|
|
|
INIT_WORK(&cons->work, gs_console_work);
|
|
spin_lock_init(&cons->lock);
|
|
|
|
err = kfifo_alloc(&cons->buf, GS_CONSOLE_BUF_SIZE, GFP_KERNEL);
|
|
if (err) {
|
|
pr_err("ttyGS%d: allocate console buffer failed\n", port->port_num);
|
|
kfree(cons);
|
|
return err;
|
|
}
|
|
|
|
port->console = cons;
|
|
register_console(&cons->console);
|
|
|
|
spin_lock_irq(&port->port_lock);
|
|
if (port->port_usb)
|
|
gs_console_connect(port);
|
|
spin_unlock_irq(&port->port_lock);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void gs_console_exit(struct gs_port *port)
|
|
{
|
|
struct gs_console *cons = port->console;
|
|
|
|
if (!cons)
|
|
return;
|
|
|
|
unregister_console(&cons->console);
|
|
|
|
spin_lock_irq(&port->port_lock);
|
|
if (cons->req)
|
|
gs_console_disconnect(port);
|
|
spin_unlock_irq(&port->port_lock);
|
|
|
|
cancel_work_sync(&cons->work);
|
|
kfifo_free(&cons->buf);
|
|
kfree(cons);
|
|
port->console = NULL;
|
|
}
|
|
|
|
ssize_t gserial_set_console(unsigned char port_num, const char *page, size_t count)
|
|
{
|
|
struct gs_port *port;
|
|
bool enable;
|
|
int ret;
|
|
|
|
ret = strtobool(page, &enable);
|
|
if (ret)
|
|
return ret;
|
|
|
|
mutex_lock(&ports[port_num].lock);
|
|
port = ports[port_num].port;
|
|
|
|
if (WARN_ON(port == NULL)) {
|
|
ret = -ENXIO;
|
|
goto out;
|
|
}
|
|
|
|
if (enable)
|
|
ret = gs_console_init(port);
|
|
else
|
|
gs_console_exit(port);
|
|
out:
|
|
mutex_unlock(&ports[port_num].lock);
|
|
|
|
return ret < 0 ? ret : count;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gserial_set_console);
|
|
|
|
ssize_t gserial_get_console(unsigned char port_num, char *page)
|
|
{
|
|
struct gs_port *port;
|
|
ssize_t ret;
|
|
|
|
mutex_lock(&ports[port_num].lock);
|
|
port = ports[port_num].port;
|
|
|
|
if (WARN_ON(port == NULL))
|
|
ret = -ENXIO;
|
|
else
|
|
ret = sprintf(page, "%u\n", !!port->console);
|
|
|
|
mutex_unlock(&ports[port_num].lock);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gserial_get_console);
|
|
|
|
#else
|
|
|
|
static int gs_console_connect(struct gs_port *port)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static void gs_console_disconnect(struct gs_port *port)
|
|
{
|
|
}
|
|
|
|
static int gs_console_init(struct gs_port *port)
|
|
{
|
|
return -ENOSYS;
|
|
}
|
|
|
|
static void gs_console_exit(struct gs_port *port)
|
|
{
|
|
}
|
|
|
|
#endif
|
|
|
|
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) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
tty_port_init(&port->port);
|
|
spin_lock_init(&port->port_lock);
|
|
init_waitqueue_head(&port->drain_wait);
|
|
init_waitqueue_head(&port->close_wait);
|
|
|
|
INIT_DELAYED_WORK(&port->push, gs_rx_push);
|
|
|
|
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;
|
|
out:
|
|
mutex_unlock(&ports[port_num].lock);
|
|
return ret;
|
|
}
|
|
|
|
static int gs_closed(struct gs_port *port)
|
|
{
|
|
int cond;
|
|
|
|
spin_lock_irq(&port->port_lock);
|
|
cond = port->port.count == 0;
|
|
spin_unlock_irq(&port->port_lock);
|
|
|
|
return cond;
|
|
}
|
|
|
|
static void gserial_free_port(struct gs_port *port)
|
|
{
|
|
cancel_delayed_work_sync(&port->push);
|
|
/* wait for old opens to finish */
|
|
wait_event(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)
|
|
{
|
|
struct gs_port *port;
|
|
|
|
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;
|
|
gs_console_exit(port);
|
|
ports[port_num].port = NULL;
|
|
mutex_unlock(&ports[port_num].lock);
|
|
|
|
gserial_free_port(port);
|
|
tty_unregister_device(gs_tty_driver, port_num);
|
|
}
|
|
EXPORT_SYMBOL_GPL(gserial_free_line);
|
|
|
|
int gserial_alloc_line_no_console(unsigned char *line_num)
|
|
{
|
|
struct usb_cdc_line_coding coding;
|
|
struct gs_port *port;
|
|
struct device *tty_dev;
|
|
int ret;
|
|
int port_num;
|
|
|
|
coding.dwDTERate = cpu_to_le32(9600);
|
|
coding.bCharFormat = 8;
|
|
coding.bParityType = USB_CDC_NO_PARITY;
|
|
coding.bDataBits = USB_CDC_1_STOP_BITS;
|
|
|
|
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;
|
|
}
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* ... and sysfs class devices, so mdev/udev make /dev/ttyGS* */
|
|
|
|
port = ports[port_num].port;
|
|
tty_dev = tty_port_register_device(&port->port,
|
|
gs_tty_driver, port_num, NULL);
|
|
if (IS_ERR(tty_dev)) {
|
|
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);
|
|
mutex_lock(&ports[port_num].lock);
|
|
ports[port_num].port = NULL;
|
|
mutex_unlock(&ports[port_num].lock);
|
|
gserial_free_port(port);
|
|
goto err;
|
|
}
|
|
*line_num = port_num;
|
|
err:
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gserial_alloc_line_no_console);
|
|
|
|
int gserial_alloc_line(unsigned char *line_num)
|
|
{
|
|
int ret = gserial_alloc_line_no_console(line_num);
|
|
|
|
if (!ret && !*line_num)
|
|
gs_console_init(ports[*line_num].port);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(gserial_alloc_line);
|
|
|
|
/**
|
|
* 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 allocate @port_num by calling
|
|
* @gserial_alloc_line().
|
|
*
|
|
* 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 (port_num >= MAX_U_SERIAL_PORTS)
|
|
return -ENXIO;
|
|
|
|
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);
|
|
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);
|
|
}
|
|
|
|
status = gs_console_connect(port);
|
|
spin_unlock_irqrestore(&port->port_lock, flags);
|
|
|
|
return status;
|
|
|
|
fail_out:
|
|
usb_ep_disable(gser->in);
|
|
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
|
|
* 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);
|
|
|
|
gs_console_disconnect(port);
|
|
|
|
/* 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) {
|
|
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);
|
|
usb_ep_disable(gser->in);
|
|
|
|
/* finally, free any unused/unusable I/O buffers */
|
|
spin_lock_irqsave(&port->port_lock, flags);
|
|
if (port->port.count == 0)
|
|
kfifo_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);
|
|
}
|
|
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 = "ttyGS";
|
|
/* 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");
|