| // 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 < (int)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 v2"); |