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linux/drivers/usb/serial/ch341.c
Greg Kroah-Hartman 6ca98bc284 USB: serial: Remove redundant license text 
Now that the SPDX tag is in all USB files, that identifies the license
in a specific and legally-defined manner.  So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text.  And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-04 11:55:38 +01:00

645 lines
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// SPDX-License-Identifier: GPL-2.0
/*
* 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.
*/
#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_READ_VERSION 0x5F
#define CH341_REQ_WRITE_REG 0x9A
#define CH341_REQ_READ_REG 0x95
#define CH341_REQ_SERIAL_INIT 0xA1
#define CH341_REQ_MODEM_CTRL 0xA4
#define CH341_REG_BREAK 0x05
#define CH341_REG_LCR 0x18
#define CH341_NBREAK_BITS 0x01
#define CH341_LCR_ENABLE_RX 0x80
#define CH341_LCR_ENABLE_TX 0x40
#define CH341_LCR_MARK_SPACE 0x20
#define CH341_LCR_PAR_EVEN 0x10
#define CH341_LCR_ENABLE_PAR 0x08
#define CH341_LCR_STOP_BITS_2 0x04
#define CH341_LCR_CS8 0x03
#define CH341_LCR_CS7 0x02
#define CH341_LCR_CS6 0x01
#define CH341_LCR_CS5 0x00
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 mcr;
u8 msr;
u8 lcr;
};
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, "%s - (%02x,%04x,%04x)\n", __func__,
request, value, 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);
if (r < 0)
dev_err(&dev->dev, "failed to send control message: %d\n", r);
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, "%s - (%02x,%04x,%04x,%u)\n", __func__,
request, value, index, 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);
if (r < bufsize) {
if (r >= 0) {
dev_err(&dev->dev,
"short control message received (%d < %u)\n",
r, bufsize);
r = -EIO;
}
dev_err(&dev->dev, "failed to receive control message: %d\n",
r);
return r;
}
return 0;
}
static int ch341_set_baudrate_lcr(struct usb_device *dev,
struct ch341_private *priv, u8 lcr)
{
short a;
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;
/*
* CH341A buffers data until a full endpoint-size packet (32 bytes)
* has been received unless bit 7 is set.
*/
a |= BIT(7);
r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x1312, a);
if (r)
return r;
r = ch341_control_out(dev, CH341_REQ_WRITE_REG, 0x2518, lcr);
if (r)
return r;
return r;
}
static int ch341_set_handshake(struct usb_device *dev, u8 control)
{
return ch341_control_out(dev, CH341_REQ_MODEM_CTRL, ~control, 0);
}
static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
{
const unsigned int size = 2;
char *buffer;
int r;
unsigned long flags;
buffer = kmalloc(size, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
if (r < 0)
goto out;
spin_lock_irqsave(&priv->lock, flags);
priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT;
spin_unlock_irqrestore(&priv->lock, flags);
out: kfree(buffer);
return r;
}
/* -------------------------------------------------------------------------- */
static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
{
const unsigned int size = 2;
char *buffer;
int r;
buffer = kmalloc(size, GFP_KERNEL);
if (!buffer)
return -ENOMEM;
/* expect two bytes 0x27 0x00 */
r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
if (r < 0)
goto out;
dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
if (r < 0)
goto out;
r = ch341_set_baudrate_lcr(dev, priv, priv->lcr);
if (r < 0)
goto out;
r = ch341_set_handshake(dev, priv->mcr);
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;
/*
* Some CH340 devices appear unable to change the initial LCR
* settings, so set a sane 8N1 default.
*/
priv->lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX | CH341_LCR_CS8;
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->msr & 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->mcr |= CH341_BIT_RTS | CH341_BIT_DTR;
else
priv->mcr &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
spin_unlock_irqrestore(&priv->lock, flags);
ch341_set_handshake(port->serial->dev, priv->mcr);
}
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 ch341_private *priv = usb_get_serial_port_data(port);
int r;
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);
return r;
}
r = ch341_get_status(port->serial->dev, priv);
if (r < 0) {
dev_err(&port->dev, "failed to read modem status: %d\n", r);
goto err_kill_interrupt_urb;
}
r = usb_serial_generic_open(tty, port);
if (r)
goto err_kill_interrupt_urb;
return 0;
err_kill_interrupt_urb:
usb_kill_urb(port->interrupt_in_urb);
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;
u8 lcr;
int r;
/* redundant changes may cause the chip to lose bytes */
if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios))
return;
baud_rate = tty_get_baud_rate(tty);
lcr = CH341_LCR_ENABLE_RX | CH341_LCR_ENABLE_TX;
switch (C_CSIZE(tty)) {
case CS5:
lcr |= CH341_LCR_CS5;
break;
case CS6:
lcr |= CH341_LCR_CS6;
break;
case CS7:
lcr |= CH341_LCR_CS7;
break;
case CS8:
lcr |= CH341_LCR_CS8;
break;
}
if (C_PARENB(tty)) {
lcr |= CH341_LCR_ENABLE_PAR;
if (C_PARODD(tty) == 0)
lcr |= CH341_LCR_PAR_EVEN;
if (C_CMSPAR(tty))
lcr |= CH341_LCR_MARK_SPACE;
}
if (C_CSTOPB(tty))
lcr |= CH341_LCR_STOP_BITS_2;
if (baud_rate) {
priv->baud_rate = baud_rate;
r = ch341_set_baudrate_lcr(port->serial->dev, priv, lcr);
if (r < 0 && old_termios) {
priv->baud_rate = tty_termios_baud_rate(old_termios);
tty_termios_copy_hw(&tty->termios, old_termios);
} else if (r == 0) {
priv->lcr = lcr;
}
}
spin_lock_irqsave(&priv->lock, flags);
if (C_BAUD(tty) == B0)
priv->mcr &= ~(CH341_BIT_DTR | CH341_BIT_RTS);
else if (old_termios && (old_termios->c_cflag & CBAUD) == B0)
priv->mcr |= (CH341_BIT_DTR | CH341_BIT_RTS);
spin_unlock_irqrestore(&priv->lock, flags);
ch341_set_handshake(port->serial->dev, priv->mcr);
}
static void ch341_break_ctl(struct tty_struct *tty, int break_state)
{
const uint16_t ch341_break_reg =
((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK;
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;
break_reg[1] &= ~CH341_LCR_ENABLE_TX;
} else {
dev_dbg(&port->dev, "%s - Leave break state requested\n", __func__);
break_reg[0] |= CH341_NBREAK_BITS;
break_reg[1] |= CH341_LCR_ENABLE_TX;
}
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->mcr |= CH341_BIT_RTS;
if (set & TIOCM_DTR)
priv->mcr |= CH341_BIT_DTR;
if (clear & TIOCM_RTS)
priv->mcr &= ~CH341_BIT_RTS;
if (clear & TIOCM_DTR)
priv->mcr &= ~CH341_BIT_DTR;
control = priv->mcr;
spin_unlock_irqrestore(&priv->lock, flags);
return ch341_set_handshake(port->serial->dev, control);
}
static void ch341_update_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->msr;
priv->msr = 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_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->mcr;
status = priv->msr;
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 usb_serial_port *port = serial->port[0];
struct ch341_private *priv = usb_get_serial_port_data(port);
int ret;
/* reconfigure ch341 serial port after bus-reset */
ch341_configure(serial->dev, priv);
if (tty_port_initialized(&port->port)) {
ret = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
if (ret) {
dev_err(&port->dev, "failed to submit interrupt urb: %d\n",
ret);
return ret;
}
ret = ch341_get_status(port->serial->dev, priv);
if (ret < 0) {
dev_err(&port->dev, "failed to read modem status: %d\n",
ret);
}
}
return usb_serial_generic_resume(serial);
}
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");
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