--- /dev/null
+/*
+ * Copyright 2007, Frank A Kingswood <frank@kingswood-consulting.co.uk>
+ * Copyright 2007, Werner Cornelius <werner@cornelius-consult.de>
+ * Copyright 2009, Boris Hajduk <boris@hajduk.org>
+ *
+ * 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 <linux/kernel.h>
+#include <linux/tty.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/usb/serial.h>
+#include <linux/serial.h>
+#include <asm/unaligned.h>
+
+#define DEFAULT_BAUD_RATE 9600
+#define DEFAULT_TIMEOUT 1000
+
+/* flags for IO-Bits */
+#define CH341_BIT_RTS (1 << 6)
+#define CH341_BIT_DTR (1 << 5)
+
+/******************************/
+/* interrupt pipe definitions */
+/******************************/
+/* always 4 interrupt bytes */
+/* first irq byte normally 0x08 */
+/* second irq byte base 0x7d + below */
+/* third irq byte base 0x94 + below */
+/* fourth irq byte normally 0xee */
+
+/* second interrupt byte */
+#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
+
+/* Break support - the information used to implement this was gleaned from
+ * the Net/FreeBSD uchcom.c driver by Takanori Watanabe. Domo arigato.
+ */
+
+#define CH341_REQ_WRITE_REG 0x9A
+#define CH341_REQ_READ_REG 0x95
+#define CH341_REG_BREAK1 0x05
+#define CH341_REG_BREAK2 0x18
+#define CH341_NBREAK_BITS_REG1 0x01
+#define CH341_NBREAK_BITS_REG2 0x40
+
+
+static const struct usb_device_id id_table[] = {
+ { USB_DEVICE(0x4348, 0x5523) },
+ { USB_DEVICE(0x1a86, 0x7523) },
+ { USB_DEVICE(0x1a86, 0x5523) },
+ { },
+};
+MODULE_DEVICE_TABLE(usb, id_table);
+
+struct ch341_private {
+ spinlock_t lock; /* access lock */
+ unsigned baud_rate; /* set baud rate */
+ u8 line_control; /* set line control value RTS/DTR */
+ u8 line_status; /* active status of modem control inputs */
+};
+
+static void ch341_set_termios(struct tty_struct *tty,
+ struct usb_serial_port *port,
+ struct ktermios *old_termios);
+
+static int ch341_control_out(struct usb_device *dev, u8 request,
+ u16 value, u16 index)
+{
+ int r;
+
+ dev_dbg(&dev->dev, "ch341_control_out(%02x,%02x,%04x,%04x)\n",
+ 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;
+
+ dev_dbg(&dev->dev, "ch341_control_in(%02x,%02x,%04x,%04x,%p,%u)\n",
+ 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)
+{
+ 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;
+
+ buffer = kmalloc(size, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+
+ r = ch341_control_in(dev, 0x95, 0x0706, 0, buffer, size);
+ if (r < 0)
+ goto out;
+
+ /* setup the private status if available */
+ if (r == 2) {
+ r = 0;
+ spin_lock_irqsave(&priv->lock, flags);
+ priv->line_status = (~(*buffer)) & CH341_BITS_MODEM_STAT;
+ 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;
+
+ 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;
+}
+
+static int ch341_port_probe(struct usb_serial_port *port)
+{
+ struct ch341_private *priv;
+ int r;
+
+ priv = kzalloc(sizeof(struct ch341_private), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ spin_lock_init(&priv->lock);
+ priv->baud_rate = DEFAULT_BAUD_RATE;
+ priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
+
+ r = ch341_configure(port->serial->dev, priv);
+ if (r < 0)
+ goto error;
+
+ usb_set_serial_port_data(port, priv);
+ return 0;
+
+error: kfree(priv);
+ return r;
+}
+
+static int ch341_port_remove(struct usb_serial_port *port)
+{
+ struct ch341_private *priv;
+
+ priv = usb_get_serial_port_data(port);
+ kfree(priv);
+
+ return 0;
+}
+
+static int ch341_carrier_raised(struct usb_serial_port *port)
+{
+ struct ch341_private *priv = usb_get_serial_port_data(port);
+ if (priv->line_status & CH341_BIT_DCD)
+ return 1;
+ return 0;
+}
+
+static void ch341_dtr_rts(struct usb_serial_port *port, int on)
+{
+ struct ch341_private *priv = usb_get_serial_port_data(port);
+ unsigned long flags;
+
+ /* drop DTR and RTS */
+ spin_lock_irqsave(&priv->lock, flags);
+ if (on)
+ priv->line_control |= CH341_BIT_RTS | CH341_BIT_DTR;
+ else
+ priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
+ spin_unlock_irqrestore(&priv->lock, flags);
+ ch341_set_handshake(port->serial->dev, priv->line_control);
+}
+
+static void ch341_close(struct usb_serial_port *port)
+{
+ usb_serial_generic_close(port);
+ usb_kill_urb(port->interrupt_in_urb);
+}
+
+
+/* open this device, set default parameters */
+static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port)
+{
+ struct usb_serial *serial = port->serial;
+ struct ch341_private *priv = usb_get_serial_port_data(port);
+ int r;
+
+ r = ch341_configure(serial->dev, priv);
+ if (r)
+ goto out;
+
+ if (tty)
+ ch341_set_termios(tty, port, NULL);
+
+ dev_dbg(&port->dev, "%s - submitting interrupt urb\n", __func__);
+ r = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
+ if (r) {
+ dev_err(&port->dev, "%s - failed to submit interrupt urb: %d\n",
+ __func__, r);
+ goto out;
+ }
+
+ r = usb_serial_generic_open(tty, port);
+
+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;
+
+ 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]
+ */
+}
+
+static void ch341_break_ctl(struct tty_struct *tty, int break_state)
+{
+ const uint16_t ch341_break_reg =
+ CH341_REG_BREAK1 | ((uint16_t) CH341_REG_BREAK2 << 8);
+ struct usb_serial_port *port = tty->driver_data;
+ int r;
+ uint16_t reg_contents;
+ uint8_t *break_reg;
+
+ break_reg = kmalloc(2, GFP_KERNEL);
+ if (!break_reg)
+ return;
+
+ r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
+ ch341_break_reg, 0, break_reg, 2);
+ if (r < 0) {
+ dev_err(&port->dev, "%s - USB control read error (%d)\n",
+ __func__, r);
+ goto out;
+ }
+ dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
+ __func__, break_reg[0], break_reg[1]);
+ if (break_state != 0) {
+ dev_dbg(&port->dev, "%s - Enter break state requested\n", __func__);
+ break_reg[0] &= ~CH341_NBREAK_BITS_REG1;
+ break_reg[1] &= ~CH341_NBREAK_BITS_REG2;
+ } else {
+ dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
+ break_reg[0] |= CH341_NBREAK_BITS_REG1;
+ break_reg[1] |= CH341_NBREAK_BITS_REG2;
+ }
+ dev_dbg(&port->dev, "%s - New ch341 break register contents - reg1: %x, reg2: %x\n",
+ __func__, break_reg[0], break_reg[1]);
+ reg_contents = get_unaligned_le16(break_reg);
+ r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
+ ch341_break_reg, reg_contents);
+ if (r < 0)
+ dev_err(&port->dev, "%s - USB control write error (%d)\n",
+ __func__, r);
+out:
+ kfree(break_reg);
+}
+
+static int ch341_tiocmset(struct tty_struct *tty,
+ 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_update_line_status(struct usb_serial_port *port,
+ unsigned char *data, size_t len)
+{
+ struct ch341_private *priv = usb_get_serial_port_data(port);
+ struct tty_struct *tty;
+ unsigned long flags;
+ u8 status;
+ u8 delta;
+
+ if (len < 4)
+ return;
+
+ status = ~data[2] & CH341_BITS_MODEM_STAT;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ delta = status ^ priv->line_status;
+ priv->line_status = status;
+ spin_unlock_irqrestore(&priv->lock, flags);
+
+ if (data[1] & CH341_MULT_STAT)
+ dev_dbg(&port->dev, "%s - multiple status change\n", __func__);
+
+ if (!delta)
+ return;
+
+ if (delta & CH341_BIT_CTS)
+ port->icount.cts++;
+ if (delta & CH341_BIT_DSR)
+ port->icount.dsr++;
+ if (delta & CH341_BIT_RI)
+ port->icount.rng++;
+ if (delta & CH341_BIT_DCD) {
+ port->icount.dcd++;
+ tty = tty_port_tty_get(&port->port);
+ if (tty) {
+ usb_serial_handle_dcd_change(port, tty,
+ status & CH341_BIT_DCD);
+ tty_kref_put(tty);
+ }
+ }
+
+ wake_up_interruptible(&port->port.delta_msr_wait);
+}
+
+static void ch341_read_int_callback(struct urb *urb)
+{
+ struct usb_serial_port *port = urb->context;
+ unsigned char *data = urb->transfer_buffer;
+ unsigned int len = urb->actual_length;
+ int status;
+
+ switch (urb->status) {
+ case 0:
+ /* success */
+ break;
+ case -ECONNRESET:
+ case -ENOENT:
+ case -ESHUTDOWN:
+ /* this urb is terminated, clean up */
+ dev_dbg(&urb->dev->dev, "%s - urb shutting down: %d\n",
+ __func__, urb->status);
+ return;
+ default:
+ dev_dbg(&urb->dev->dev, "%s - nonzero urb status: %d\n",
+ __func__, urb->status);
+ goto exit;
+ }
+
+ usb_serial_debug_data(&port->dev, __func__, len, data);
+ ch341_update_line_status(port, data, len);
+exit:
+ status = usb_submit_urb(urb, GFP_ATOMIC);
+ if (status) {
+ dev_err(&urb->dev->dev, "%s - usb_submit_urb failed: %d\n",
+ __func__, status);
+ }
+}
+
+static int ch341_tiocmget(struct tty_struct *tty)
+{
+ 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;
+
+ 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);
+
+ dev_dbg(&port->dev, "%s - result = %x\n", __func__, result);
+
+ return result;
+}
+
+static int ch341_reset_resume(struct usb_serial *serial)
+{
+ struct ch341_private *priv;
+
+ priv = usb_get_serial_port_data(serial->port[0]);
+
+ /* reconfigure ch341 serial port after bus-reset */
+ ch341_configure(serial->dev, priv);
+
+ return 0;
+}
+
+static struct usb_serial_driver ch341_device = {
+ .driver = {
+ .owner = THIS_MODULE,
+ .name = "ch341-uart",
+ },
+ .id_table = id_table,
+ .num_ports = 1,
+ .open = ch341_open,
+ .dtr_rts = ch341_dtr_rts,
+ .carrier_raised = ch341_carrier_raised,
+ .close = ch341_close,
+ .set_termios = ch341_set_termios,
+ .break_ctl = ch341_break_ctl,
+ .tiocmget = ch341_tiocmget,
+ .tiocmset = ch341_tiocmset,
+ .tiocmiwait = usb_serial_generic_tiocmiwait,
+ .read_int_callback = ch341_read_int_callback,
+ .port_probe = ch341_port_probe,
+ .port_remove = ch341_port_remove,
+ .reset_resume = ch341_reset_resume,
+};
+
+static struct usb_serial_driver * const serial_drivers[] = {
+ &ch341_device, NULL
+};
+
+module_usb_serial_driver(serial_drivers, id_table);
+
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff