/* * AIRcable USB Bluetooth Dongle Driver. * * Copyright (C) 2006 Manuel Francisco Naranjo (naranjo.manuel@gmail.com) * This program is free software; you can redistribute it and/or modify it under * the terms of the GNU General Public License version 2 as published by the * Free Software Foundation. * * The device works as an standard CDC device, it has 2 interfaces, the first * one is for firmware access and the second is the serial one. * The protocol is very simply, there are two posibilities reading or writing. * When writing the first urb must have a Header that starts with 0x20 0x29 the * next two bytes must say how much data will be sended. * When reading the process is almost equal except that the header starts with * 0x00 0x20. * * The device simply need some stuff to understand data comming from the usb * buffer: The First and Second byte is used for a Header, the Third and Fourth * tells the device the amount of information the package holds. * Packages are 60 bytes long Header Stuff. * When writing to the device the first two bytes of the header are 0x20 0x29 * When reading the bytes are 0x00 0x20, or 0x00 0x10, there is an strange * situation, when too much data arrives to the device because it sends the data * but with out the header. I will use a simply hack to override this situation, * if there is data coming that does not contain any header, then that is data * that must go directly to the tty, as there is no documentation about if there * is any other control code, I will simply check for the first * one. * * The driver registers himself with the USB-serial core and the USB Core. I had * to implement a probe function agains USB-serial, because other way, the * driver was attaching himself to both interfaces. I have tryed with different * configurations of usb_serial_driver with out exit, only the probe function * could handle this correctly. * * I have taken some info from a Greg Kroah-Hartman article: * http://www.linuxjournal.com/article/6573 * And from Linux Device Driver Kit CD, which is a great work, the authors taken * the work to recompile lots of information an knowladge in drivers development * and made it all avaible inside a cd. * URL: http://kernel.org/pub/linux/kernel/people/gregkh/ddk/ * */ #include <linux/tty.h> #include <linux/tty_flip.h> #include <linux/circ_buf.h> #include <linux/usb.h> #include <linux/usb/serial.h> static int debug; /* Vendor and Product ID */ #define AIRCABLE_VID 0x16CA #define AIRCABLE_USB_PID 0x1502 /* write buffer size defines */ #define AIRCABLE_BUF_SIZE 2048 /* Protocol Stuff */ #define HCI_HEADER_LENGTH 0x4 #define TX_HEADER_0 0x20 #define TX_HEADER_1 0x29 #define RX_HEADER_0 0x00 #define RX_HEADER_1 0x20 #define MAX_HCI_FRAMESIZE 60 #define HCI_COMPLETE_FRAME 64 /* rx_flags */ #define THROTTLED 0x01 #define ACTUALLY_THROTTLED 0x02 /* * Version Information */ #define DRIVER_VERSION "v1.0b2" #define DRIVER_AUTHOR "Naranjo, Manuel Francisco <naranjo.manuel@gmail.com>" #define DRIVER_DESC "AIRcable USB Driver" /* ID table that will be registered with USB core */ static struct usb_device_id id_table [] = { { USB_DEVICE(AIRCABLE_VID, AIRCABLE_USB_PID) }, { }, }; MODULE_DEVICE_TABLE(usb, id_table); /* Internal Structure */ struct aircable_private { spinlock_t rx_lock; /* spinlock for the receive lines */ struct circ_buf *tx_buf; /* write buffer */ struct circ_buf *rx_buf; /* read buffer */ int rx_flags; /* for throttilng */ struct work_struct rx_work; /* work cue for the receiving line */ struct usb_serial_port *port; /* USB port with which associated */ }; /* Private methods */ /* Circular Buffer Methods, code from ti_usb_3410_5052 used */ /* * serial_buf_clear * * Clear out all data in the circular buffer. */ static void serial_buf_clear(struct circ_buf *cb) { cb->head = cb->tail = 0; } /* * serial_buf_alloc * * Allocate a circular buffer and all associated memory. */ static struct circ_buf *serial_buf_alloc(void) { struct circ_buf *cb; cb = kmalloc(sizeof(struct circ_buf), GFP_KERNEL); if (cb == NULL) return NULL; cb->buf = kmalloc(AIRCABLE_BUF_SIZE, GFP_KERNEL); if (cb->buf == NULL) { kfree(cb); return NULL; } serial_buf_clear(cb); return cb; } /* * serial_buf_free * * Free the buffer and all associated memory. */ static void serial_buf_free(struct circ_buf *cb) { kfree(cb->buf); kfree(cb); } /* * serial_buf_data_avail * * Return the number of bytes of data available in the circular * buffer. */ static int serial_buf_data_avail(struct circ_buf *cb) { return CIRC_CNT(cb->head,cb->tail,AIRCABLE_BUF_SIZE); } /* * serial_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 int serial_buf_put(struct circ_buf *cb, const char *buf, int count) { int c, ret = 0; while (1) { c = CIRC_SPACE_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE); if (count < c) c = count; if (c <= 0) break; memcpy(cb->buf + cb->head, buf, c); cb->head = (cb->head + c) & (AIRCABLE_BUF_SIZE-1); buf += c; count -= c; ret= c; } return ret; } /* * serial_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 int serial_buf_get(struct circ_buf *cb, char *buf, int count) { int c, ret = 0; while (1) { c = CIRC_CNT_TO_END(cb->head, cb->tail, AIRCABLE_BUF_SIZE); if (count < c) c = count; if (c <= 0) break; memcpy(buf, cb->buf + cb->tail, c); cb->tail = (cb->tail + c) & (AIRCABLE_BUF_SIZE-1); buf += c; count -= c; ret= c; } return ret; } /* End of circula buffer methods */ static void aircable_send(struct usb_serial_port *port) { int count, result; struct aircable_private *priv = usb_get_serial_port_data(port); unsigned char* buf; __le16 *dbuf; dbg("%s - port %d", __func__, port->number); if (port->write_urb_busy) return; count = min(serial_buf_data_avail(priv->tx_buf), MAX_HCI_FRAMESIZE); if (count == 0) return; buf = kzalloc(count + HCI_HEADER_LENGTH, GFP_ATOMIC); if (!buf) { err("%s- kzalloc(%d) failed.", __func__, count + HCI_HEADER_LENGTH); return; } buf[0] = TX_HEADER_0; buf[1] = TX_HEADER_1; dbuf = (__le16 *)&buf[2]; *dbuf = cpu_to_le16((u16)count); serial_buf_get(priv->tx_buf,buf + HCI_HEADER_LENGTH, MAX_HCI_FRAMESIZE); memcpy(port->write_urb->transfer_buffer, buf, count + HCI_HEADER_LENGTH); kfree(buf); port->write_urb_busy = 1; usb_serial_debug_data(debug, &port->dev, __func__, count + HCI_HEADER_LENGTH, port->write_urb->transfer_buffer); port->write_urb->transfer_buffer_length = count + HCI_HEADER_LENGTH; port->write_urb->dev = port->serial->dev; result = usb_submit_urb(port->write_urb, GFP_ATOMIC); if (result) { dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __func__, result); port->write_urb_busy = 0; } schedule_work(&port->work); } static void aircable_read(struct work_struct *work) { struct aircable_private *priv = container_of(work, struct aircable_private, rx_work); struct usb_serial_port *port = priv->port; struct tty_struct *tty; unsigned char *data; int count; if (priv->rx_flags & THROTTLED){ if (priv->rx_flags & ACTUALLY_THROTTLED) schedule_work(&priv->rx_work); return; } /* By now I will flush data to the tty in packages of no more than * 64 bytes, to ensure I do not get throttled. * Ask USB mailing list for better aproach. */ tty = port->tty; if (!tty) { schedule_work(&priv->rx_work); err("%s - No tty available", __func__); return ; } count = min(64, serial_buf_data_avail(priv->rx_buf)); if (count <= 0) return; //We have finished sending everything. tty_prepare_flip_string(tty, &data, count); if (!data){ err("%s- kzalloc(%d) failed.", __func__, count); return; } serial_buf_get(priv->rx_buf, data, count); tty_flip_buffer_push(tty); if (serial_buf_data_avail(priv->rx_buf)) schedule_work(&priv->rx_work); return; } /* End of private methods */ static int aircable_probe(struct usb_serial *serial, const struct usb_device_id *id) { struct usb_host_interface *iface_desc = serial->interface->cur_altsetting; struct usb_endpoint_descriptor *endpoint; int num_bulk_out=0; int i; for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) { endpoint = &iface_desc->endpoint[i].desc; if (usb_endpoint_is_bulk_out(endpoint)) { dbg("found bulk out on endpoint %d", i); ++num_bulk_out; } } if (num_bulk_out == 0) { dbg("Invalid interface, discarding"); return -ENODEV; } return 0; } static int aircable_attach (struct usb_serial *serial) { struct usb_serial_port *port = serial->port[0]; struct aircable_private *priv; priv = kzalloc(sizeof(struct aircable_private), GFP_KERNEL); if (!priv){ err("%s- kmalloc(%Zd) failed.", __func__, sizeof(struct aircable_private)); return -ENOMEM; } /* Allocation of Circular Buffers */ priv->tx_buf = serial_buf_alloc(); if (priv->tx_buf == NULL) { kfree(priv); return -ENOMEM; } priv->rx_buf = serial_buf_alloc(); if (priv->rx_buf == NULL) { kfree(priv->tx_buf); kfree(priv); return -ENOMEM; } priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED); priv->port = port; INIT_WORK(&priv->rx_work, aircable_read); usb_set_serial_port_data(serial->port[0], priv); return 0; } static void aircable_shutdown(struct usb_serial *serial) { struct usb_serial_port *port = serial->port[0]; struct aircable_private *priv = usb_get_serial_port_data(port); dbg("%s", __func__); if (priv) { serial_buf_free(priv->tx_buf); serial_buf_free(priv->rx_buf); usb_set_serial_port_data(port, NULL); kfree(priv); } } static int aircable_write_room(struct usb_serial_port *port) { struct aircable_private *priv = usb_get_serial_port_data(port); return serial_buf_data_avail(priv->tx_buf); } static int aircable_write(struct usb_serial_port *port, const unsigned char *source, int count) { struct aircable_private *priv = usb_get_serial_port_data(port); int temp; dbg("%s - port %d, %d bytes", __func__, port->number, count); usb_serial_debug_data(debug, &port->dev, __func__, count, source); if (!count){ dbg("%s - write request of 0 bytes", __func__); return count; } temp = serial_buf_put(priv->tx_buf, source, count); aircable_send(port); if (count > AIRCABLE_BUF_SIZE) count = AIRCABLE_BUF_SIZE; return count; } static void aircable_write_bulk_callback(struct urb *urb) { struct usb_serial_port *port = urb->context; int status = urb->status; int result; dbg("%s - urb status: %d", __func__ , status); /* This has been taken from cypress_m8.c cypress_write_int_callback */ switch (status) { case 0: /* success */ break; case -ECONNRESET: case -ENOENT: case -ESHUTDOWN: /* this urb is terminated, clean up */ dbg("%s - urb shutting down with status: %d", __func__, status); port->write_urb_busy = 0; return; default: /* error in the urb, so we have to resubmit it */ dbg("%s - Overflow in write", __func__); dbg("%s - nonzero write bulk status received: %d", __func__, status); port->write_urb->transfer_buffer_length = 1; port->write_urb->dev = port->serial->dev; result = usb_submit_urb(port->write_urb, GFP_ATOMIC); if (result) dev_err(&urb->dev->dev, "%s - failed resubmitting write urb, error %d\n", __func__, result); else return; } port->write_urb_busy = 0; aircable_send(port); } static void aircable_read_bulk_callback(struct urb *urb) { struct usb_serial_port *port = urb->context; struct aircable_private *priv = usb_get_serial_port_data(port); struct tty_struct *tty; unsigned long no_packages, remaining, package_length, i; int result, shift = 0; unsigned char *temp; int status = urb->status; dbg("%s - port %d", __func__, port->number); if (status) { dbg("%s - urb status = %d", __func__, status); if (!port->open_count) { dbg("%s - port is closed, exiting.", __func__); return; } if (status == -EPROTO) { dbg("%s - caught -EPROTO, resubmitting the urb", __func__); usb_fill_bulk_urb(port->read_urb, port->serial->dev, usb_rcvbulkpipe(port->serial->dev, port->bulk_in_endpointAddress), port->read_urb->transfer_buffer, port->read_urb->transfer_buffer_length, aircable_read_bulk_callback, port); result = usb_submit_urb(urb, GFP_ATOMIC); if (result) dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __func__, result); return; } dbg("%s - unable to handle the error, exiting.", __func__); return; } usb_serial_debug_data(debug, &port->dev, __func__, urb->actual_length,urb->transfer_buffer); tty = port->tty; if (tty && urb->actual_length) { if (urb->actual_length <= 2) { /* This is an incomplete package */ serial_buf_put(priv->rx_buf, urb->transfer_buffer, urb->actual_length); } else { temp = urb->transfer_buffer; if (temp[0] == RX_HEADER_0) shift = HCI_HEADER_LENGTH; remaining = urb->actual_length; no_packages = urb->actual_length / (HCI_COMPLETE_FRAME); if (urb->actual_length % HCI_COMPLETE_FRAME != 0) no_packages+=1; for (i = 0; i < no_packages ;i++) { if (remaining > (HCI_COMPLETE_FRAME)) package_length = HCI_COMPLETE_FRAME; else package_length = remaining; remaining -= package_length; serial_buf_put(priv->rx_buf, urb->transfer_buffer + shift + (HCI_COMPLETE_FRAME) * (i), package_length - shift); } } aircable_read(&priv->rx_work); } /* Schedule the next read _if_ we are still open */ if (port->open_count) { usb_fill_bulk_urb(port->read_urb, port->serial->dev, usb_rcvbulkpipe(port->serial->dev, port->bulk_in_endpointAddress), port->read_urb->transfer_buffer, port->read_urb->transfer_buffer_length, aircable_read_bulk_callback, port); result = usb_submit_urb(urb, GFP_ATOMIC); if (result) dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __func__, result); } return; } /* Based on ftdi_sio.c throttle */ static void aircable_throttle(struct usb_serial_port *port) { struct aircable_private *priv = usb_get_serial_port_data(port); unsigned long flags; dbg("%s - port %d", __func__, port->number); spin_lock_irqsave(&priv->rx_lock, flags); priv->rx_flags |= THROTTLED; spin_unlock_irqrestore(&priv->rx_lock, flags); } /* Based on ftdi_sio.c unthrottle */ static void aircable_unthrottle(struct usb_serial_port *port) { struct aircable_private *priv = usb_get_serial_port_data(port); int actually_throttled; unsigned long flags; dbg("%s - port %d", __func__, port->number); spin_lock_irqsave(&priv->rx_lock, flags); actually_throttled = priv->rx_flags & ACTUALLY_THROTTLED; priv->rx_flags &= ~(THROTTLED | ACTUALLY_THROTTLED); spin_unlock_irqrestore(&priv->rx_lock, flags); if (actually_throttled) schedule_work(&priv->rx_work); } static struct usb_driver aircable_driver = { .name = "aircable", .probe = usb_serial_probe, .disconnect = usb_serial_disconnect, .id_table = id_table, .no_dynamic_id = 1, }; static struct usb_serial_driver aircable_device = { .driver = { .owner = THIS_MODULE, .name = "aircable", }, .usb_driver = &aircable_driver, .id_table = id_table, .num_ports = 1, .attach = aircable_attach, .probe = aircable_probe, .shutdown = aircable_shutdown, .write = aircable_write, .write_room = aircable_write_room, .write_bulk_callback = aircable_write_bulk_callback, .read_bulk_callback = aircable_read_bulk_callback, .throttle = aircable_throttle, .unthrottle = aircable_unthrottle, }; static int __init aircable_init (void) { int retval; retval = usb_serial_register(&aircable_device); if (retval) goto failed_serial_register; retval = usb_register(&aircable_driver); if (retval) goto failed_usb_register; return 0; failed_serial_register: usb_serial_deregister(&aircable_device); failed_usb_register: return retval; } static void __exit aircable_exit (void) { usb_deregister(&aircable_driver); usb_serial_deregister(&aircable_device); } MODULE_AUTHOR(DRIVER_AUTHOR); MODULE_DESCRIPTION(DRIVER_DESC); MODULE_VERSION(DRIVER_VERSION); MODULE_LICENSE("GPL"); module_init(aircable_init); module_exit(aircable_exit); module_param(debug, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(debug, "Debug enabled or not");