/* * Copyright 2007, Frank A Kingswood * * ch341.c implements a serial port driver for the Winchiphead CH341. * * The CH341 device can be used to implement an RS232 asynchronous * serial port, an IEEE-1284 parallel printer port or a memory-like * interface. In all cases the CH341 supports an I2C interface as well. * This driver only supports the asynchronous serial interface. * * 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. */ #include #include #include #include #include #include #include #define DEFAULT_BAUD_RATE 2400 #define DEFAULT_TIMEOUT 1000 #define CH341_BIT_RTS (1 << 6) #define CH341_BIT_DTR (1 << 5) #define CH341_MULT_STAT 0x04 /* multiple status since last interrupt event */ /* status returned in third interrupt answer byte, inverted in data from irq */ #define CH341_BIT_CTS 0x01 #define CH341_BIT_DSR 0x02 #define CH341_BIT_RI 0x04 #define CH341_BIT_DCD 0x08 #define CH341_BITS_MODEM_STAT 0x0f /* all bits */ /*******************************/ /* baudrate calculation factor */ /*******************************/ #define CH341_BAUDBASE_FACTOR 1532620800 #define CH341_BAUDBASE_DIVMAX 3 static int debug; static struct usb_device_id id_table [] = { { USB_DEVICE(0x4348, 0x5523) }, { USB_DEVICE(0x1a86, 0x7523) }, { }, }; MODULE_DEVICE_TABLE(usb, id_table); struct ch341_private { spinlock_t lock; /* access lock */ wait_queue_head_t delta_msr_wait; /* wait queue for modem status */ unsigned baud_rate; /* set baud rate */ u8 line_control; /* set line control value RTS/DTR */ u8 line_status; /* active status of modem control inputs */ u8 multi_status_change; /* status changed multiple since last call */ }; static int ch341_control_out(struct usb_device *dev, u8 request, u16 value, u16 index) { int r; dbg("ch341_control_out(%02x,%02x,%04x,%04x)", USB_DIR_OUT|0x40, (int)request, (int)value, (int)index); r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, value, index, NULL, 0, DEFAULT_TIMEOUT); return r; } static int ch341_control_in(struct usb_device *dev, u8 request, u16 value, u16 index, char *buf, unsigned bufsize) { int r; dbg("ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)", USB_DIR_IN|0x40, (int)request, (int)value, (int)index, buf, (int)bufsize); r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN, value, index, buf, bufsize, DEFAULT_TIMEOUT); return r; } static int ch341_set_baudrate(struct usb_device *dev, struct ch341_private *priv) { short a, b; int r; unsigned long factor; short divisor; if (!priv->baud_rate) return -EINVAL; factor = (CH341_BAUDBASE_FACTOR / priv->baud_rate); divisor = CH341_BAUDBASE_DIVMAX; while ((factor > 0xfff0) && divisor) { factor >>= 3; divisor--; } if (factor > 0xfff0) return -EINVAL; factor = 0x10000 - factor; a = (factor & 0xff00) | divisor; b = factor & 0xff; r = ch341_control_out(dev, 0x9a, 0x1312, a); if (!r) r = ch341_control_out(dev, 0x9a, 0x0f2c, b); return r; } static int ch341_set_handshake(struct usb_device *dev, u8 control) { dbg("ch341_set_handshake(0x%02x)", control); return ch341_control_out(dev, 0xa4, ~control, 0); } static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv) { char *buffer; int r; const unsigned size = 8; unsigned long flags; dbg("ch341_get_status()"); buffer = kmalloc(size, GFP_KERNEL); if (!buffer) return -ENOMEM; r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size); if (r < 0) goto out; /* Not having the datasheet for the CH341, we ignore the bytes returned * from the device. Return error if the device did not respond in time. */ if (r == 2) { r = 0; spin_lock_irqsave(&priv->lock, flags); priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT; priv->multi_status_change = 0; spin_unlock_irqrestore(&priv->lock, flags); } else r = -EPROTO; out: kfree(buffer); return r; } /* -------------------------------------------------------------------------- */ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) { char *buffer; int r; const unsigned size = 8; dbg("ch341_configure()"); buffer = kmalloc(size, GFP_KERNEL); if (!buffer) return -ENOMEM; /* expect two bytes 0x27 0x00 */ r = ch341_control_in(dev, 0x5f, 0, 0, buffer, size); if (r < 0) goto out; r = ch341_control_out(dev, 0xa1, 0, 0); if (r < 0) goto out; r = ch341_set_baudrate(dev, priv); if (r < 0) goto out; /* expect two bytes 0x56 0x00 */ r = ch341_control_in(dev, 0x95, 0x2518, 0, buffer, size); if (r < 0) goto out; r = ch341_control_out(dev, 0x9a, 0x2518, 0x0050); if (r < 0) goto out; /* expect 0xff 0xee */ r = ch341_get_status(dev, priv); if (r < 0) goto out; r = ch341_control_out(dev, 0xa1, 0x501f, 0xd90a); if (r < 0) goto out; r = ch341_set_baudrate(dev, priv); if (r < 0) goto out; r = ch341_set_handshake(dev, priv->line_control); if (r < 0) goto out; /* expect 0x9f 0xee */ r = ch341_get_status(dev, priv); out: kfree(buffer); return r; } /* allocate private data */ static int ch341_attach(struct usb_serial *serial) { struct ch341_private *priv; int r; dbg("ch341_attach()"); /* private data */ priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL); if (!priv) return -ENOMEM; spin_lock_init(&priv->lock); init_waitqueue_head(&priv->delta_msr_wait); priv->baud_rate = DEFAULT_BAUD_RATE; priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; r = ch341_configure(serial->dev, priv); if (r < 0) goto error; usb_set_serial_port_data(serial->port[0], priv); return 0; error: kfree(priv); return r; } static void ch341_close(struct tty_struct *tty, struct usb_serial_port *port, struct file *filp) { struct ch341_private *priv = usb_get_serial_port_data(port); #if 0 unsigned long flags; unsigned int c_cflag; #endif dbg("%s - port %d", __func__, port->number); /* shutdown our urbs */ dbg("%s - shutting down urbs", __func__); usb_kill_urb(port->write_urb); usb_kill_urb(port->read_urb); usb_kill_urb(port->interrupt_in_urb); #if 0 if (port->tty) { c_cflag = port->tty->termios->c_cflag; if (c_cflag & HUPCL) { /* drop DTR and RTS */ spin_lock_irqsave(&priv->lock, flags); priv->line_control = 0; spin_unlock_irqrestore(&priv->lock, flags); ch341_set_handshake(port->serial->dev, 0); } } #endif wake_up_interruptible(&priv->delta_msr_wait); } /* open this device, set default parameters */ static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port, struct file *filp) { struct usb_serial *serial = port->serial; struct ch341_private *priv = usb_get_serial_port_data(serial->port[0]); int r; dbg("ch341_open()"); priv->baud_rate = DEFAULT_BAUD_RATE; priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR; r = ch341_configure(serial->dev, priv); if (r) goto out; r = ch341_set_handshake(serial->dev, priv->line_control); if (r) goto out; r = ch341_set_baudrate(serial->dev, priv); if (r) goto out; dbg("%s - submitting interrupt urb", __func__); port->interrupt_in_urb->dev = serial->dev; r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL); if (r) { dev_err(&port->dev, "%s - failed submitting interrupt urb," " error %d\n", __func__, r); ch341_close(tty, port, NULL); return -EPROTO; } r = usb_serial_generic_open(tty, port, filp); out: return r; } /* Old_termios contains the original termios settings and * tty->termios contains the new setting to be used. */ static void ch341_set_termios(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios) { struct ch341_private *priv = usb_get_serial_port_data(port); unsigned baud_rate; unsigned long flags; dbg("ch341_set_termios()"); if (!tty || !tty->termios) return; baud_rate = tty_get_baud_rate(tty); priv->baud_rate = baud_rate; if (baud_rate) { spin_lock_irqsave(&priv->lock, flags); priv->line_control |= (CH341_BIT_DTR | CH341_BIT_RTS); spin_unlock_irqrestore(&priv->lock, flags); ch341_set_baudrate(port->serial->dev, priv); } else { spin_lock_irqsave(&priv->lock, flags); priv->line_control &= ~(CH341_BIT_DTR | CH341_BIT_RTS); spin_unlock_irqrestore(&priv->lock, flags); } ch341_set_handshake(port->serial->dev, priv->line_control); /* Unimplemented: * (cflag & CSIZE) : data bits [5, 8] * (cflag & PARENB) : parity {NONE, EVEN, ODD} * (cflag & CSTOPB) : stop bits [1, 2] */ /* Copy back the old hardware settings */ tty_termios_copy_hw(tty->termios, old_termios); /* And re-encode with the new baud */ tty_encode_baud_rate(tty, baud_rate, baud_rate); } static int ch341_tiocmset(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear) { struct usb_serial_port *port = tty->driver_data; struct ch341_private *priv = usb_get_serial_port_data(port); unsigned long flags; u8 control; spin_lock_irqsave(&priv->lock, flags); if (set & TIOCM_RTS) priv->line_control |= CH341_BIT_RTS; if (set & TIOCM_DTR) priv->line_control |= CH341_BIT_DTR; if (clear & TIOCM_RTS) priv->line_control &= ~CH341_BIT_RTS; if (clear & TIOCM_DTR) priv->line_control &= ~CH341_BIT_DTR; control = priv->line_control; spin_unlock_irqrestore(&priv->lock, flags); return ch341_set_handshake(port->serial->dev, control); } static void ch341_read_int_callback(struct urb *urb) { struct usb_serial_port *port = (struct usb_serial_port *) urb->context; unsigned char *data = urb->transfer_buffer; unsigned int actual_length = urb->actual_length; int status; dbg("%s (%d)", __func__, port->number); switch (urb->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__, urb->status); return; default: dbg("%s - nonzero urb status received: %d", __func__, urb->status); goto exit; } usb_serial_debug_data(debug, &port->dev, __func__, urb->actual_length, urb->transfer_buffer); if (actual_length >= 4) { struct ch341_private *priv = usb_get_serial_port_data(port); unsigned long flags; spin_lock_irqsave(&priv->lock, flags); priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT; if ((data[1] & CH341_MULT_STAT)) priv->multi_status_change = 1; spin_unlock_irqrestore(&priv->lock, flags); wake_up_interruptible(&priv->delta_msr_wait); } exit: status = usb_submit_urb(urb, GFP_ATOMIC); if (status) dev_err(&urb->dev->dev, "%s - usb_submit_urb failed with result %d\n", __func__, status); } static int wait_modem_info(struct tty_struct *tty, unsigned int arg) { struct usb_serial_port *port = tty->driver_data; struct ch341_private *priv = usb_get_serial_port_data(port); unsigned long flags; u8 prevstatus; u8 status; u8 changed; u8 multi_change = 0; spin_lock_irqsave(&priv->lock, flags); prevstatus = priv->line_status; priv->multi_status_change = 0; spin_unlock_irqrestore(&priv->lock, flags); while (!multi_change) { interruptible_sleep_on(&priv->delta_msr_wait); /* see if a signal did it */ if (signal_pending(current)) return -ERESTARTSYS; spin_lock_irqsave(&priv->lock, flags); status = priv->line_status; multi_change = priv->multi_status_change; spin_unlock_irqrestore(&priv->lock, flags); changed = prevstatus ^ status; if (((arg & TIOCM_RNG) && (changed & CH341_BIT_RI)) || ((arg & TIOCM_DSR) && (changed & CH341_BIT_DSR)) || ((arg & TIOCM_CD) && (changed & CH341_BIT_DCD)) || ((arg & TIOCM_CTS) && (changed & CH341_BIT_CTS))) { return 0; } prevstatus = status; } return 0; } static int ch341_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg) { struct usb_serial_port *port = tty->driver_data; dbg("%s (%d) cmd = 0x%04x", __func__, port->number, cmd); switch (cmd) { case TIOCMIWAIT: dbg("%s (%d) TIOCMIWAIT", __func__, port->number); return wait_modem_info(tty, arg); default: dbg("%s not supported = 0x%04x", __func__, cmd); break; } return -ENOIOCTLCMD; } static int ch341_tiocmget(struct tty_struct *tty, struct file *file) { struct usb_serial_port *port = tty->driver_data; struct ch341_private *priv = usb_get_serial_port_data(port); unsigned long flags; u8 mcr; u8 status; unsigned int result; dbg("%s (%d)", __func__, port->number); spin_lock_irqsave(&priv->lock, flags); mcr = priv->line_control; status = priv->line_status; spin_unlock_irqrestore(&priv->lock, flags); result = ((mcr & CH341_BIT_DTR) ? TIOCM_DTR : 0) | ((mcr & CH341_BIT_RTS) ? TIOCM_RTS : 0) | ((status & CH341_BIT_CTS) ? TIOCM_CTS : 0) | ((status & CH341_BIT_DSR) ? TIOCM_DSR : 0) | ((status & CH341_BIT_RI) ? TIOCM_RI : 0) | ((status & CH341_BIT_DCD) ? TIOCM_CD : 0); return result; } static struct usb_driver ch341_driver = { .name = "ch341", .probe = usb_serial_probe, .disconnect = usb_serial_disconnect, .id_table = id_table, .no_dynamic_id = 1, }; static struct usb_serial_driver ch341_device = { .driver = { .owner = THIS_MODULE, .name = "ch341-uart", }, .id_table = id_table, .usb_driver = &ch341_driver, .num_ports = 1, .open = ch341_open, .set_termios = ch341_set_termios, .attach = ch341_attach, .tiocmget = ch341_tiocmget, .tiocmset = ch341_tiocmset, .read_int_callback = ch341_read_int_callback, .close = ch341_close, .ioctl = ch341_ioctl, }; static int __init ch341_init(void) { int retval; retval = usb_serial_register(&ch341_device); if (retval) return retval; retval = usb_register(&ch341_driver); if (retval) usb_serial_deregister(&ch341_device); return retval; } static void __exit ch341_exit(void) { usb_deregister(&ch341_driver); usb_serial_deregister(&ch341_device); } module_init(ch341_init); module_exit(ch341_exit); MODULE_LICENSE("GPL"); module_param(debug, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(debug, "Debug enabled or not"); /* EOF ch341.c */