sunzilog.c

来自「linux 内核源代码」· C语言 代码 · 共 1,597 行 · 第 1/3 页

	struct uart_sunzilog_port *up = dev_id;

	while (up) {
		struct zilog_channel __iomem *channel
			= ZILOG_CHANNEL_FROM_PORT(&up->port);
		struct tty_struct *tty;
		unsigned char r3;

		spin_lock(&up->port.lock);
		r3 = read_zsreg(channel, R3);

		/* Channel A */
		tty = NULL;
		if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
			writeb(RES_H_IUS, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);

			if (r3 & CHARxIP)
				tty = sunzilog_receive_chars(up, channel);
			if (r3 & CHAEXT)
				sunzilog_status_handle(up, channel);
			if (r3 & CHATxIP)
				sunzilog_transmit_chars(up, channel);
		}
		spin_unlock(&up->port.lock);

		if (tty)
			tty_flip_buffer_push(tty);

		/* Channel B */
		up = up->next;
		channel = ZILOG_CHANNEL_FROM_PORT(&up->port);

		spin_lock(&up->port.lock);
		tty = NULL;
		if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
			writeb(RES_H_IUS, &channel->control);
			ZSDELAY();
			ZS_WSYNC(channel);

			if (r3 & CHBRxIP)
				tty = sunzilog_receive_chars(up, channel);
			if (r3 & CHBEXT)
				sunzilog_status_handle(up, channel);
			if (r3 & CHBTxIP)
				sunzilog_transmit_chars(up, channel);
		}
		spin_unlock(&up->port.lock);

		if (tty)
			tty_flip_buffer_push(tty);

		up = up->next;
	}

	return IRQ_HANDLED;
}

/* A convenient way to quickly get R0 status.  The caller must _not_ hold the
 * port lock, it is acquired here.
 */
static __inline__ unsigned char sunzilog_read_channel_status(struct uart_port *port)
{
	struct zilog_channel __iomem *channel;
	unsigned char status;

	channel = ZILOG_CHANNEL_FROM_PORT(port);
	status = readb(&channel->control);
	ZSDELAY();

	return status;
}

/* The port lock is not held.  */
static unsigned int sunzilog_tx_empty(struct uart_port *port)
{
	unsigned long flags;
	unsigned char status;
	unsigned int ret;

	spin_lock_irqsave(&port->lock, flags);

	status = sunzilog_read_channel_status(port);

	spin_unlock_irqrestore(&port->lock, flags);

	if (status & Tx_BUF_EMP)
		ret = TIOCSER_TEMT;
	else
		ret = 0;

	return ret;
}

/* The port lock is held and interrupts are disabled.  */
static unsigned int sunzilog_get_mctrl(struct uart_port *port)
{
	unsigned char status;
	unsigned int ret;

	status = sunzilog_read_channel_status(port);

	ret = 0;
	if (status & DCD)
		ret |= TIOCM_CAR;
	if (status & SYNC)
		ret |= TIOCM_DSR;
	if (status & CTS)
		ret |= TIOCM_CTS;

	return ret;
}

/* The port lock is held and interrupts are disabled.  */
static void sunzilog_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	struct uart_sunzilog_port *up = (struct uart_sunzilog_port *) port;
	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
	unsigned char set_bits, clear_bits;

	set_bits = clear_bits = 0;

	if (mctrl & TIOCM_RTS)
		set_bits |= RTS;
	else
		clear_bits |= RTS;
	if (mctrl & TIOCM_DTR)
		set_bits |= DTR;
	else
		clear_bits |= DTR;

	/* NOTE: Not subject to 'transmitter active' rule.  */ 
	up->curregs[R5] |= set_bits;
	up->curregs[R5] &= ~clear_bits;
	write_zsreg(channel, R5, up->curregs[R5]);
}

/* The port lock is held and interrupts are disabled.  */
static void sunzilog_stop_tx(struct uart_port *port)
{
	struct uart_sunzilog_port *up = (struct uart_sunzilog_port *) port;

	up->flags |= SUNZILOG_FLAG_TX_STOPPED;
}

/* The port lock is held and interrupts are disabled.  */
static void sunzilog_start_tx(struct uart_port *port)
{
	struct uart_sunzilog_port *up = (struct uart_sunzilog_port *) port;
	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
	unsigned char status;

	up->flags |= SUNZILOG_FLAG_TX_ACTIVE;
	up->flags &= ~SUNZILOG_FLAG_TX_STOPPED;

	status = readb(&channel->control);
	ZSDELAY();

	/* TX busy?  Just wait for the TX done interrupt.  */
	if (!(status & Tx_BUF_EMP))
		return;

	/* Send the first character to jump-start the TX done
	 * IRQ sending engine.
	 */
	if (port->x_char) {
		writeb(port->x_char, &channel->data);
		ZSDELAY();
		ZS_WSYNC(channel);

		port->icount.tx++;
		port->x_char = 0;
	} else {
		struct circ_buf *xmit = &port->info->xmit;

		writeb(xmit->buf[xmit->tail], &channel->data);
		ZSDELAY();
		ZS_WSYNC(channel);

		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
		port->icount.tx++;

		if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
			uart_write_wakeup(&up->port);
	}
}

/* The port lock is held.  */
static void sunzilog_stop_rx(struct uart_port *port)
{
	struct uart_sunzilog_port *up = UART_ZILOG(port);
	struct zilog_channel __iomem *channel;

	if (ZS_IS_CONS(up))
		return;

	channel = ZILOG_CHANNEL_FROM_PORT(port);

	/* Disable all RX interrupts.  */
	up->curregs[R1] &= ~RxINT_MASK;
	sunzilog_maybe_update_regs(up, channel);
}

/* The port lock is held.  */
static void sunzilog_enable_ms(struct uart_port *port)
{
	struct uart_sunzilog_port *up = (struct uart_sunzilog_port *) port;
	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
	unsigned char new_reg;

	new_reg = up->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
	if (new_reg != up->curregs[R15]) {
		up->curregs[R15] = new_reg;

		/* NOTE: Not subject to 'transmitter active' rule.  */ 
		write_zsreg(channel, R15, up->curregs[R15] & ~WR7pEN);
	}
}

/* The port lock is not held.  */
static void sunzilog_break_ctl(struct uart_port *port, int break_state)
{
	struct uart_sunzilog_port *up = (struct uart_sunzilog_port *) port;
	struct zilog_channel __iomem *channel = ZILOG_CHANNEL_FROM_PORT(port);
	unsigned char set_bits, clear_bits, new_reg;
	unsigned long flags;

	set_bits = clear_bits = 0;

	if (break_state)
		set_bits |= SND_BRK;
	else
		clear_bits |= SND_BRK;

	spin_lock_irqsave(&port->lock, flags);

	new_reg = (up->curregs[R5] | set_bits) & ~clear_bits;
	if (new_reg != up->curregs[R5]) {
		up->curregs[R5] = new_reg;

		/* NOTE: Not subject to 'transmitter active' rule.  */ 
		write_zsreg(channel, R5, up->curregs[R5]);
	}

	spin_unlock_irqrestore(&port->lock, flags);
}

static void __sunzilog_startup(struct uart_sunzilog_port *up)
{
	struct zilog_channel __iomem *channel;

	channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
	up->prev_status = readb(&channel->control);

	/* Enable receiver and transmitter.  */
	up->curregs[R3] |= RxENAB;
	up->curregs[R5] |= TxENAB;

	up->curregs[R1] |= EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
	sunzilog_maybe_update_regs(up, channel);
}

static int sunzilog_startup(struct uart_port *port)
{
	struct uart_sunzilog_port *up = UART_ZILOG(port);
	unsigned long flags;

	if (ZS_IS_CONS(up))
		return 0;

	spin_lock_irqsave(&port->lock, flags);
	__sunzilog_startup(up);
	spin_unlock_irqrestore(&port->lock, flags);
	return 0;
}

/*
 * The test for ZS_IS_CONS is explained by the following e-mail:
 *****
 * From: Russell King <[e-mail]>
 * Date: Sun, 8 Dec 2002 10:18:38 +0000
 *
 * On Sun, Dec 08, 2002 at 02:43:36AM -0500, Pete Zaitcev wrote:
 * > I boot my 2.5 boxes using "console=ttyS0,9600" argument,
 * > and I noticed that something is not right with reference
 * > counting in this case. It seems that when the console
 * > is open by kernel initially, this is not accounted
 * > as an open, and uart_startup is not called.
 *
 * That is correct.  We are unable to call uart_startup when the serial
 * console is initialised because it may need to allocate memory (as
 * request_irq does) and the memory allocators may not have been
 * initialised.
 *
 * 1. initialise the port into a state where it can send characters in the
 *    console write method.
 *
 * 2. don't do the actual hardware shutdown in your shutdown() method (but
 *    do the normal software shutdown - ie, free irqs etc)
 *****
 */
static void sunzilog_shutdown(struct uart_port *port)
{
	struct uart_sunzilog_port *up = UART_ZILOG(port);
	struct zilog_channel __iomem *channel;
	unsigned long flags;

	if (ZS_IS_CONS(up))
		return;

	spin_lock_irqsave(&port->lock, flags);

	channel = ZILOG_CHANNEL_FROM_PORT(port);

	/* Disable receiver and transmitter.  */
	up->curregs[R3] &= ~RxENAB;
	up->curregs[R5] &= ~TxENAB;

	/* Disable all interrupts and BRK assertion.  */
	up->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
	up->curregs[R5] &= ~SND_BRK;
	sunzilog_maybe_update_regs(up, channel);

	spin_unlock_irqrestore(&port->lock, flags);
}

/* Shared by TTY driver and serial console setup.  The port lock is held
 * and local interrupts are disabled.
 */
static void
sunzilog_convert_to_zs(struct uart_sunzilog_port *up, unsigned int cflag,
		       unsigned int iflag, int brg)
{

	up->curregs[R10] = NRZ;
	up->curregs[R11] = TCBR | RCBR;

	/* Program BAUD and clock source. */
	up->curregs[R4] &= ~XCLK_MASK;
	up->curregs[R4] |= X16CLK;
	up->curregs[R12] = brg & 0xff;
	up->curregs[R13] = (brg >> 8) & 0xff;
	up->curregs[R14] = BRSRC | BRENAB;

	/* Character size, stop bits, and parity. */
	up->curregs[R3] &= ~RxN_MASK;
	up->curregs[R5] &= ~TxN_MASK;
	switch (cflag & CSIZE) {
	case CS5:
		up->curregs[R3] |= Rx5;
		up->curregs[R5] |= Tx5;
		up->parity_mask = 0x1f;
		break;
	case CS6:
		up->curregs[R3] |= Rx6;
		up->curregs[R5] |= Tx6;
		up->parity_mask = 0x3f;
		break;
	case CS7:
		up->curregs[R3] |= Rx7;
		up->curregs[R5] |= Tx7;
		up->parity_mask = 0x7f;
		break;
	case CS8:
	default:
		up->curregs[R3] |= Rx8;
		up->curregs[R5] |= Tx8;
		up->parity_mask = 0xff;
		break;
	};
	up->curregs[R4] &= ~0x0c;
	if (cflag & CSTOPB)
		up->curregs[R4] |= SB2;
	else
		up->curregs[R4] |= SB1;
	if (cflag & PARENB)
		up->curregs[R4] |= PAR_ENAB;
	else
		up->curregs[R4] &= ~PAR_ENAB;
	if (!(cflag & PARODD))
		up->curregs[R4] |= PAR_EVEN;
	else
		up->curregs[R4] &= ~PAR_EVEN;

	up->port.read_status_mask = Rx_OVR;
	if (iflag & INPCK)
		up->port.read_status_mask |= CRC_ERR | PAR_ERR;
	if (iflag & (BRKINT | PARMRK))
		up->port.read_status_mask |= BRK_ABRT;

	up->port.ignore_status_mask = 0;
	if (iflag & IGNPAR)
		up->port.ignore_status_mask |= CRC_ERR | PAR_ERR;
	if (iflag & IGNBRK) {
		up->port.ignore_status_mask |= BRK_ABRT;
		if (iflag & IGNPAR)
			up->port.ignore_status_mask |= Rx_OVR;
	}

	if ((cflag & CREAD) == 0)
		up->port.ignore_status_mask = 0xff;
}

/* The port lock is not held.  */
static void
sunzilog_set_termios(struct uart_port *port, struct ktermios *termios,
		     struct ktermios *old)
{
	struct uart_sunzilog_port *up = (struct uart_sunzilog_port *) port;
	unsigned long flags;
	int baud, brg;

	baud = uart_get_baud_rate(port, termios, old, 1200, 76800);

	spin_lock_irqsave(&up->port.lock, flags);

	brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);

	sunzilog_convert_to_zs(up, termios->c_cflag, termios->c_iflag, brg);

	if (UART_ENABLE_MS(&up->port, termios->c_cflag))
		up->flags |= SUNZILOG_FLAG_MODEM_STATUS;
	else
		up->flags &= ~SUNZILOG_FLAG_MODEM_STATUS;

	up->cflag = termios->c_cflag;

	sunzilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port));

	uart_update_timeout(port, termios->c_cflag, baud);

	spin_unlock_irqrestore(&up->port.lock, flags);
}

static const char *sunzilog_type(struct uart_port *port)
{
	struct uart_sunzilog_port *up = UART_ZILOG(port);

	return (up->flags & SUNZILOG_FLAG_ESCC) ? "zs (ESCC)" : "zs";
}

/* We do not request/release mappings of the registers here, this
 * happens at early serial probe time.
 */
static void sunzilog_release_port(struct uart_port *port)
{
}

static int sunzilog_request_port(struct uart_port *port)
{
	return 0;
}

/* These do not need to do anything interesting either.  */
static void sunzilog_config_port(struct uart_port *port, int flags)
{
}

/* We do not support letting the user mess with the divisor, IRQ, etc. */
static int sunzilog_verify_port(struct uart_port *port, struct serial_struct *ser)
{
	return -EINVAL;
}

static struct uart_ops sunzilog_pops = {
	.tx_empty	=	sunzilog_tx_empty,
	.set_mctrl	=	sunzilog_set_mctrl,
	.get_mctrl	=	sunzilog_get_mctrl,
	.stop_tx	=	sunzilog_stop_tx,
	.start_tx	=	sunzilog_start_tx,
	.stop_rx	=	sunzilog_stop_rx,
	.enable_ms	=	sunzilog_enable_ms,
	.break_ctl	=	sunzilog_break_ctl,
	.startup	=	sunzilog_startup,
	.shutdown	=	sunzilog_shutdown,
	.set_termios	=	sunzilog_set_termios,
	.type		=	sunzilog_type,
	.release_port	=	sunzilog_release_port,
	.request_port	=	sunzilog_request_port,
	.config_port	=	sunzilog_config_port,
	.verify_port	=	sunzilog_verify_port,
};

static struct uart_sunzilog_port *sunzilog_port_table;
static struct zilog_layout __iomem **sunzilog_chip_regs;

static struct uart_sunzilog_port *sunzilog_irq_chain;

static struct uart_driver sunzilog_reg = {
	.owner		=	THIS_MODULE,
	.driver_name	=	"ttyS",
	.dev_name	=	"ttyS",
	.major		=	TTY_MAJOR,
};

static int __init sunzilog_alloc_tables(int num_sunzilog)
{
	struct uart_sunzilog_port *up;
	unsigned long size;
	int num_channels = num_sunzilog * 2;
	int i;

	size = num_channels * sizeof(struct uart_sunzilog_port);
	sunzilog_port_table = kzalloc(size, GFP_KERNEL);
	if (!sunzilog_port_table)
		return -ENOMEM;

	for (i = 0; i < num_channels; i++) {
		up = &sunzilog_port_table[i];

		spin_lock_init(&up->port.lock);

		if (i == 0)
			sunzilog_irq_chain = up;

		if (i < num_channels - 1)
			up->next = up + 1;
		else
			up->next = NULL;
	}

	size = num_sunzilog * sizeof(struct zilog_layout __iomem *);
	sunzilog_chip_regs = kzalloc(size, GFP_KERNEL);
	if (!sunzilog_chip_regs) {
		kfree(sunzilog_port_table);
		sunzilog_irq_chain = NULL;
		return -ENOMEM;
	}

	return 0;
}