[mirror_ubuntu-artful-kernel.git] / drivers / tty / serial / nwpserial.c

/*
 *  Serial Port driver for a NWP uart device
 *
 *    Copyright (C) 2008 IBM Corp., Benjamin Krill <ben@codiert.org>
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */
#include <linux/init.h>
#include <linux/export.h>
#include <linux/console.h>
#include <linux/serial.h>
#include <linux/serial_reg.h>
#include <linux/serial_core.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/irqreturn.h>
#include <linux/mutex.h>
#include <linux/of_platform.h>
#include <linux/of_device.h>
#include <linux/nwpserial.h>
#include <asm/prom.h>
#include <asm/dcr.h>

#define NWPSERIAL_NR               2

#define NWPSERIAL_STATUS_RXVALID 0x1
#define NWPSERIAL_STATUS_TXFULL  0x2

struct nwpserial_port {
	struct uart_port port;
	dcr_host_t dcr_host;
	unsigned int ier;
	unsigned int mcr;
};

static DEFINE_MUTEX(nwpserial_mutex);
static struct nwpserial_port nwpserial_ports[NWPSERIAL_NR];

static void wait_for_bits(struct nwpserial_port *up, int bits)
{
	unsigned int status, tmout = 10000;

	/* Wait up to 10ms for the character(s) to be sent. */
	do {
		status = dcr_read(up->dcr_host, UART_LSR);

		if (--tmout == 0)
			break;
		udelay(1);
	} while ((status & bits) != bits);
}

#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
static void nwpserial_console_putchar(struct uart_port *port, int c)
{
	struct nwpserial_port *up;
	up = container_of(port, struct nwpserial_port, port);
	/* check if tx buffer is full */
	wait_for_bits(up, UART_LSR_THRE);
	dcr_write(up->dcr_host, UART_TX, c);
	up->port.icount.tx++;
}

static void
nwpserial_console_write(struct console *co, const char *s, unsigned int count)
{
	struct nwpserial_port *up = &nwpserial_ports[co->index];
	unsigned long flags;
	int locked = 1;

	if (oops_in_progress)
		locked = spin_trylock_irqsave(&up->port.lock, flags);
	else
		spin_lock_irqsave(&up->port.lock, flags);

	/* save and disable interrupt */
	up->ier = dcr_read(up->dcr_host, UART_IER);
	dcr_write(up->dcr_host, UART_IER, up->ier & ~UART_IER_RDI);

	uart_console_write(&up->port, s, count, nwpserial_console_putchar);

	/* wait for transmitter to become empty */
	while ((dcr_read(up->dcr_host, UART_LSR) & UART_LSR_THRE) == 0)
		cpu_relax();

	/* restore interrupt state */
	dcr_write(up->dcr_host, UART_IER, up->ier);

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

static struct uart_driver nwpserial_reg;
static struct console nwpserial_console = {
	.name		= "ttySQ",
	.write		= nwpserial_console_write,
	.device		= uart_console_device,
	.flags		= CON_PRINTBUFFER,
	.index		= -1,
	.data		= &nwpserial_reg,
};
#define NWPSERIAL_CONSOLE	(&nwpserial_console)
#else
#define NWPSERIAL_CONSOLE	NULL
#endif /* CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE */

/**************************************************************************/

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

static void nwpserial_release_port(struct uart_port *port)
{
	/* N/A */
}

static void nwpserial_config_port(struct uart_port *port, int flags)
{
	port->type = PORT_NWPSERIAL;
}

static irqreturn_t nwpserial_interrupt(int irq, void *dev_id)
{
	struct nwpserial_port *up = dev_id;
	struct tty_port *port = &up->port.state->port;
	irqreturn_t ret;
	unsigned int iir;
	unsigned char ch;

	spin_lock(&up->port.lock);

	/* check if the uart was the interrupt source. */
	iir = dcr_read(up->dcr_host, UART_IIR);
	if (!iir) {
		ret = IRQ_NONE;
		goto out;
	}

	do {
		up->port.icount.rx++;
		ch = dcr_read(up->dcr_host, UART_RX);
		if (up->port.ignore_status_mask != NWPSERIAL_STATUS_RXVALID)
			tty_insert_flip_char(port, ch, TTY_NORMAL);
	} while (dcr_read(up->dcr_host, UART_LSR) & UART_LSR_DR);

	tty_flip_buffer_push(port);
	ret = IRQ_HANDLED;

	/* clear interrupt */
	dcr_write(up->dcr_host, UART_IIR, 1);
out:
	spin_unlock(&up->port.lock);
	return ret;
}

static int nwpserial_startup(struct uart_port *port)
{
	struct nwpserial_port *up;
	int err;

	up = container_of(port, struct nwpserial_port, port);

	/* disable flow control by default */
	up->mcr = dcr_read(up->dcr_host, UART_MCR) & ~UART_MCR_AFE;
	dcr_write(up->dcr_host, UART_MCR, up->mcr);

	/* register interrupt handler */
	err = request_irq(up->port.irq, nwpserial_interrupt,
			IRQF_SHARED, "nwpserial", up);
	if (err)
		return err;

	/* enable interrupts */
	up->ier = UART_IER_RDI;
	dcr_write(up->dcr_host, UART_IER, up->ier);

	/* enable receiving */
	up->port.ignore_status_mask &= ~NWPSERIAL_STATUS_RXVALID;

	return 0;
}

static void nwpserial_shutdown(struct uart_port *port)
{
	struct nwpserial_port *up;
	up = container_of(port, struct nwpserial_port, port);

	/* disable receiving */
	up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;

	/* disable interrupts from this port */
	up->ier = 0;
	dcr_write(up->dcr_host, UART_IER, up->ier);

	/* free irq */
	free_irq(up->port.irq, up);
}

static int nwpserial_verify_port(struct uart_port *port,
			struct serial_struct *ser)
{
	return -EINVAL;
}

static const char *nwpserial_type(struct uart_port *port)
{
	return port->type == PORT_NWPSERIAL ? "nwpserial" : NULL;
}

static void nwpserial_set_termios(struct uart_port *port,
			struct ktermios *termios, struct ktermios *old)
{
	struct nwpserial_port *up;
	up = container_of(port, struct nwpserial_port, port);

	up->port.read_status_mask = NWPSERIAL_STATUS_RXVALID
				| NWPSERIAL_STATUS_TXFULL;

	up->port.ignore_status_mask = 0;
	/* ignore all characters if CREAD is not set */
	if ((termios->c_cflag & CREAD) == 0)
		up->port.ignore_status_mask |= NWPSERIAL_STATUS_RXVALID;

	/* Copy back the old hardware settings */
	if (old)
		tty_termios_copy_hw(termios, old);
}

static void nwpserial_break_ctl(struct uart_port *port, int ctl)
{
	/* N/A */
}

static void nwpserial_enable_ms(struct uart_port *port)
{
	/* N/A */
}

static void nwpserial_stop_rx(struct uart_port *port)
{
	struct nwpserial_port *up;
	up = container_of(port, struct nwpserial_port, port);
	/* don't forward any more data (like !CREAD) */
	up->port.ignore_status_mask = NWPSERIAL_STATUS_RXVALID;
}

static void nwpserial_putchar(struct nwpserial_port *up, unsigned char c)
{
	/* check if tx buffer is full */
	wait_for_bits(up, UART_LSR_THRE);
	dcr_write(up->dcr_host, UART_TX, c);
	up->port.icount.tx++;
}

static void nwpserial_start_tx(struct uart_port *port)
{
	struct nwpserial_port *up;
	struct circ_buf *xmit;
	up = container_of(port, struct nwpserial_port, port);
	xmit  = &up->port.state->xmit;

	if (port->x_char) {
		nwpserial_putchar(up, up->port.x_char);
		port->x_char = 0;
	}

	while (!(uart_circ_empty(xmit) || uart_tx_stopped(&up->port))) {
		nwpserial_putchar(up, xmit->buf[xmit->tail]);
		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
	}
}

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

static void nwpserial_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
	/* N/A */
}

static void nwpserial_stop_tx(struct uart_port *port)
{
	/* N/A */
}

static unsigned int nwpserial_tx_empty(struct uart_port *port)
{
	struct nwpserial_port *up;
	unsigned long flags;
	int ret;
	up = container_of(port, struct nwpserial_port, port);

	spin_lock_irqsave(&up->port.lock, flags);
	ret = dcr_read(up->dcr_host, UART_LSR);
	spin_unlock_irqrestore(&up->port.lock, flags);

	return ret & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
}

static struct uart_ops nwpserial_pops = {
	.tx_empty     = nwpserial_tx_empty,
	.set_mctrl    = nwpserial_set_mctrl,
	.get_mctrl    = nwpserial_get_mctrl,
	.stop_tx      = nwpserial_stop_tx,
	.start_tx     = nwpserial_start_tx,
	.stop_rx      = nwpserial_stop_rx,
	.enable_ms    = nwpserial_enable_ms,
	.break_ctl    = nwpserial_break_ctl,
	.startup      = nwpserial_startup,
	.shutdown     = nwpserial_shutdown,
	.set_termios  = nwpserial_set_termios,
	.type         = nwpserial_type,
	.release_port = nwpserial_release_port,
	.request_port = nwpserial_request_port,
	.config_port  = nwpserial_config_port,
	.verify_port  = nwpserial_verify_port,
};

static struct uart_driver nwpserial_reg = {
	.owner       = THIS_MODULE,
	.driver_name = "nwpserial",
	.dev_name    = "ttySQ",
	.major       = TTY_MAJOR,
	.minor       = 68,
	.nr          = NWPSERIAL_NR,
	.cons        = NWPSERIAL_CONSOLE,
};

int nwpserial_register_port(struct uart_port *port)
{
	struct nwpserial_port *up = NULL;
	int ret = -1;
	int i;
	static int first = 1;
	int dcr_len;
	int dcr_base;
	struct device_node *dn;

	mutex_lock(&nwpserial_mutex);

	dn = port->dev->of_node;
	if (dn == NULL)
		goto out;

	/* get dcr base. */
	dcr_base = dcr_resource_start(dn, 0);

	/* find matching entry */
	for (i = 0; i < NWPSERIAL_NR; i++)
		if (nwpserial_ports[i].port.iobase == dcr_base) {
			up = &nwpserial_ports[i];
			break;
		}

	/* we didn't find a mtching entry, search for a free port */
	if (up == NULL)
		for (i = 0; i < NWPSERIAL_NR; i++)
			if (nwpserial_ports[i].port.type == PORT_UNKNOWN &&
				nwpserial_ports[i].port.iobase == 0) {
				up = &nwpserial_ports[i];
				break;
			}

	if (up == NULL) {
		ret = -EBUSY;
		goto out;
	}

	if (first)
		uart_register_driver(&nwpserial_reg);
	first = 0;

	up->port.membase      = port->membase;
	up->port.irq          = port->irq;
	up->port.uartclk      = port->uartclk;
	up->port.fifosize     = port->fifosize;
	up->port.regshift     = port->regshift;
	up->port.iotype       = port->iotype;
	up->port.flags        = port->flags;
	up->port.mapbase      = port->mapbase;
	up->port.private_data = port->private_data;

	if (port->dev)
		up->port.dev = port->dev;

	if (up->port.iobase != dcr_base) {
		up->port.ops          = &nwpserial_pops;
		up->port.fifosize     = 16;

		spin_lock_init(&up->port.lock);

		up->port.iobase = dcr_base;
		dcr_len = dcr_resource_len(dn, 0);

		up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
		if (!DCR_MAP_OK(up->dcr_host)) {
			printk(KERN_ERR "Cannot map DCR resources for NWPSERIAL");
			goto out;
		}
	}

	ret = uart_add_one_port(&nwpserial_reg, &up->port);
	if (ret == 0)
		ret = up->port.line;

out:
	mutex_unlock(&nwpserial_mutex);

	return ret;
}
EXPORT_SYMBOL(nwpserial_register_port);

void nwpserial_unregister_port(int line)
{
	struct nwpserial_port *up = &nwpserial_ports[line];
	mutex_lock(&nwpserial_mutex);
	uart_remove_one_port(&nwpserial_reg, &up->port);

	up->port.type = PORT_UNKNOWN;

	mutex_unlock(&nwpserial_mutex);
}
EXPORT_SYMBOL(nwpserial_unregister_port);

#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
static int __init nwpserial_console_init(void)
{
	struct nwpserial_port *up = NULL;
	struct device_node *dn;
	const char *name;
	int dcr_base;
	int dcr_len;
	int i;

	/* search for a free port */
	for (i = 0; i < NWPSERIAL_NR; i++)
		if (nwpserial_ports[i].port.type == PORT_UNKNOWN) {
			up = &nwpserial_ports[i];
			break;
		}

	if (up == NULL)
		return -1;

	name = of_get_property(of_chosen, "linux,stdout-path", NULL);
	if (name == NULL)
		return -1;

	dn = of_find_node_by_path(name);
	if (!dn)
		return -1;

	spin_lock_init(&up->port.lock);
	up->port.ops = &nwpserial_pops;
	up->port.type = PORT_NWPSERIAL;
	up->port.fifosize = 16;

	dcr_base = dcr_resource_start(dn, 0);
	dcr_len = dcr_resource_len(dn, 0);
	up->port.iobase = dcr_base;

	up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
	if (!DCR_MAP_OK(up->dcr_host)) {
		printk("Cannot map DCR resources for SERIAL");
		return -1;
	}
	register_console(&nwpserial_console);
	return 0;
}
console_initcall(nwpserial_console_init);
#endif /* CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE */
Commit	Line	Data
5886188d BK	1	/*
	2	* Serial Port driver for a NWP uart device
	3	*
	4	* Copyright (C) 2008 IBM Corp., Benjamin Krill <ben@codiert.org>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*
	11	*/
	12	#include <linux/init.h>
0e648f42	13	#include <linux/export.h>
5886188d BK	14	#include <linux/console.h>
	15	#include <linux/serial.h>
	16	#include <linux/serial_reg.h>
	17	#include <linux/serial_core.h>
	18	#include <linux/tty.h>
ee160a38	19	#include <linux/tty_flip.h>
5886188d BK	20	#include <linux/irqreturn.h>
	21	#include <linux/mutex.h>
	22	#include <linux/of_platform.h>
	23	#include <linux/of_device.h>
	24	#include <linux/nwpserial.h>
	25	#include <asm/prom.h>
	26	#include <asm/dcr.h>
	27
	28	#define NWPSERIAL_NR 2
	29
	30	#define NWPSERIAL_STATUS_RXVALID 0x1
	31	#define NWPSERIAL_STATUS_TXFULL 0x2
	32
	33	struct nwpserial_port {
	34	struct uart_port port;
	35	dcr_host_t dcr_host;
	36	unsigned int ier;
	37	unsigned int mcr;
	38	};
	39
	40	static DEFINE_MUTEX(nwpserial_mutex);
	41	static struct nwpserial_port nwpserial_ports[NWPSERIAL_NR];
	42
	43	static void wait_for_bits(struct nwpserial_port *up, int bits)
	44	{
	45	unsigned int status, tmout = 10000;
	46
	47	/* Wait up to 10ms for the character(s) to be sent. */
	48	do {
	49	status = dcr_read(up->dcr_host, UART_LSR);
	50
	51	if (--tmout == 0)
	52	break;
	53	udelay(1);
	54	} while ((status & bits) != bits);
	55	}
	56
	57	#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
	58	static void nwpserial_console_putchar(struct uart_port *port, int c)
	59	{
	60	struct nwpserial_port *up;
	61	up = container_of(port, struct nwpserial_port, port);
	62	/* check if tx buffer is full */
	63	wait_for_bits(up, UART_LSR_THRE);
	64	dcr_write(up->dcr_host, UART_TX, c);
	65	up->port.icount.tx++;
	66	}
	67
	68	static void
	69	nwpserial_console_write(struct console co, const char s, unsigned int count)
	70	{
	71	struct nwpserial_port *up = &nwpserial_ports[co->index];
	72	unsigned long flags;
	73	int locked = 1;
	74
	75	if (oops_in_progress)
	76	locked = spin_trylock_irqsave(&up->port.lock, flags);
	77	else
	78	spin_lock_irqsave(&up->port.lock, flags);
	79
	80	/* save and disable interrupt */
	81	up->ier = dcr_read(up->dcr_host, UART_IER);
	82	dcr_write(up->dcr_host, UART_IER, up->ier & ~UART_IER_RDI);
	83
84	uart_console_write(&up->port, s, count, nwpserial_console_putchar);
85
a7ce2e0d	86	/* wait for transmitter to become empty */
5886188d BK	87	while ((dcr_read(up->dcr_host, UART_LSR) & UART_LSR_THRE) == 0)
	88	cpu_relax();
	89
	90	/* restore interrupt state */
	91	dcr_write(up->dcr_host, UART_IER, up->ier);
	92
	93	if (locked)
	94	spin_unlock_irqrestore(&up->port.lock, flags);
	95	}
	96
	97	static struct uart_driver nwpserial_reg;
	98	static struct console nwpserial_console = {
	99	.name = "ttySQ",
	100	.write = nwpserial_console_write,
	101	.device = uart_console_device,
	102	.flags = CON_PRINTBUFFER,
	103	.index = -1,
	104	.data = &nwpserial_reg,
	105	};
	106	#define NWPSERIAL_CONSOLE (&nwpserial_console)
	107	#else
	108	#define NWPSERIAL_CONSOLE NULL
	109	#endif /* CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE */
	110
	111	/**************************************************************************/
	112
	113	static int nwpserial_request_port(struct uart_port *port)
	114	{
	115	return 0;
	116	}
	117
	118	static void nwpserial_release_port(struct uart_port *port)
	119	{
	120	/* N/A */
	121	}
	122
	123	static void nwpserial_config_port(struct uart_port *port, int flags)
	124	{
	125	port->type = PORT_NWPSERIAL;
	126	}
	127
	128	static irqreturn_t nwpserial_interrupt(int irq, void *dev_id)
	129	{
	130	struct nwpserial_port *up = dev_id;
92a19f9c	131	struct tty_port *port = &up->port.state->port;
5886188d BK	132	irqreturn_t ret;
	133	unsigned int iir;
	134	unsigned char ch;
	135
	136	spin_lock(&up->port.lock);
	137
	138	/* check if the uart was the interrupt source. */
	139	iir = dcr_read(up->dcr_host, UART_IIR);
	140	if (!iir) {
	141	ret = IRQ_NONE;
	142	goto out;
	143	}
	144
	145	do {
	146	up->port.icount.rx++;
	147	ch = dcr_read(up->dcr_host, UART_RX);
	148	if (up->port.ignore_status_mask != NWPSERIAL_STATUS_RXVALID)
92a19f9c	149	tty_insert_flip_char(port, ch, TTY_NORMAL);
951c4df5	150	} while (dcr_read(up->dcr_host, UART_LSR) & UART_LSR_DR);
5886188d	151
2e124b4a	152	tty_flip_buffer_push(port);
5886188d BK	153	ret = IRQ_HANDLED;
5886188d BK	154
951c4df5 BK	155	/* clear interrupt */
951c4df5 BK	156	dcr_write(up->dcr_host, UART_IIR, 1);
5886188d BK	157	out:
	158	spin_unlock(&up->port.lock);
	159	return ret;
	160	}
	161
	162	static int nwpserial_startup(struct uart_port *port)
	163	{
	164	struct nwpserial_port *up;
	165	int err;
	166
	167	up = container_of(port, struct nwpserial_port, port);
	168
	169	/* disable flow control by default */
	170	up->mcr = dcr_read(up->dcr_host, UART_MCR) & ~UART_MCR_AFE;
	171	dcr_write(up->dcr_host, UART_MCR, up->mcr);
	172
	173	/* register interrupt handler */
	174	err = request_irq(up->port.irq, nwpserial_interrupt,
	175	IRQF_SHARED, "nwpserial", up);
	176	if (err)
	177	return err;
	178
	179	/* enable interrupts */
	180	up->ier = UART_IER_RDI;
	181	dcr_write(up->dcr_host, UART_IER, up->ier);
	182
	183	/* enable receiving */
	184	up->port.ignore_status_mask &= ~NWPSERIAL_STATUS_RXVALID;
	185
	186	return 0;
	187	}
	188
	189	static void nwpserial_shutdown(struct uart_port *port)
	190	{
	191	struct nwpserial_port *up;
	192	up = container_of(port, struct nwpserial_port, port);
	193
	194	/* disable receiving */
	195	up->port.ignore_status_mask \|= NWPSERIAL_STATUS_RXVALID;
	196
	197	/* disable interrupts from this port */
	198	up->ier = 0;
	199	dcr_write(up->dcr_host, UART_IER, up->ier);
	200
	201	/* free irq */
383d2fc9	202	free_irq(up->port.irq, up);
5886188d BK	203	}
	204
	205	static int nwpserial_verify_port(struct uart_port *port,
	206	struct serial_struct *ser)
	207	{
	208	return -EINVAL;
	209	}
	210
	211	static const char nwpserial_type(struct uart_port port)
	212	{
	213	return port->type == PORT_NWPSERIAL ? "nwpserial" : NULL;
	214	}
	215
	216	static void nwpserial_set_termios(struct uart_port *port,
	217	struct ktermios termios, struct ktermios old)
	218	{
	219	struct nwpserial_port *up;
	220	up = container_of(port, struct nwpserial_port, port);
	221
	222	up->port.read_status_mask = NWPSERIAL_STATUS_RXVALID
	223	\| NWPSERIAL_STATUS_TXFULL;
	224
	225	up->port.ignore_status_mask = 0;
	226	/* ignore all characters if CREAD is not set */
	227	if ((termios->c_cflag & CREAD) == 0)
	228	up->port.ignore_status_mask \|= NWPSERIAL_STATUS_RXVALID;
	229
	230	/* Copy back the old hardware settings */
	231	if (old)
	232	tty_termios_copy_hw(termios, old);
	233	}
	234
	235	static void nwpserial_break_ctl(struct uart_port *port, int ctl)
	236	{
	237	/* N/A */
	238	}
	239
	240	static void nwpserial_enable_ms(struct uart_port *port)
	241	{
	242	/* N/A */
	243	}
	244
	245	static void nwpserial_stop_rx(struct uart_port *port)
	246	{
	247	struct nwpserial_port *up;
	248	up = container_of(port, struct nwpserial_port, port);
	249	/* don't forward any more data (like !CREAD) */
	250	up->port.ignore_status_mask = NWPSERIAL_STATUS_RXVALID;
	251	}
	252
	253	static void nwpserial_putchar(struct nwpserial_port *up, unsigned char c)
	254	{
	255	/* check if tx buffer is full */
	256	wait_for_bits(up, UART_LSR_THRE);
	257	dcr_write(up->dcr_host, UART_TX, c);
	258	up->port.icount.tx++;
	259	}
	260
	261	static void nwpserial_start_tx(struct uart_port *port)
	262	{
	263	struct nwpserial_port *up;
	264	struct circ_buf *xmit;
	265	up = container_of(port, struct nwpserial_port, port);
ebd2c8f6	266	xmit = &up->port.state->xmit;
5886188d BK	267
	268	if (port->x_char) {
	269	nwpserial_putchar(up, up->port.x_char);
	270	port->x_char = 0;
	271	}
	272
	273	while (!(uart_circ_empty(xmit) \|\| uart_tx_stopped(&up->port))) {
	274	nwpserial_putchar(up, xmit->buf[xmit->tail]);
	275	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
	276	}
	277	}
	278
	279	static unsigned int nwpserial_get_mctrl(struct uart_port *port)
	280	{
	281	return 0;
	282	}
	283
	284	static void nwpserial_set_mctrl(struct uart_port *port, unsigned int mctrl)
	285	{
	286	/* N/A */
	287	}
	288
	289	static void nwpserial_stop_tx(struct uart_port *port)
	290	{
	291	/* N/A */
	292	}
	293
	294	static unsigned int nwpserial_tx_empty(struct uart_port *port)
	295	{
	296	struct nwpserial_port *up;
	297	unsigned long flags;
	298	int ret;
	299	up = container_of(port, struct nwpserial_port, port);
	300
	301	spin_lock_irqsave(&up->port.lock, flags);
	302	ret = dcr_read(up->dcr_host, UART_LSR);
	303	spin_unlock_irqrestore(&up->port.lock, flags);
	304
	305	return ret & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
	306	}
	307
	308	static struct uart_ops nwpserial_pops = {
	309	.tx_empty = nwpserial_tx_empty,
	310	.set_mctrl = nwpserial_set_mctrl,
	311	.get_mctrl = nwpserial_get_mctrl,
	312	.stop_tx = nwpserial_stop_tx,
	313	.start_tx = nwpserial_start_tx,
	314	.stop_rx = nwpserial_stop_rx,
	315	.enable_ms = nwpserial_enable_ms,
	316	.break_ctl = nwpserial_break_ctl,
	317	.startup = nwpserial_startup,
	318	.shutdown = nwpserial_shutdown,
	319	.set_termios = nwpserial_set_termios,
	320	.type = nwpserial_type,
	321	.release_port = nwpserial_release_port,
	322	.request_port = nwpserial_request_port,
	323	.config_port = nwpserial_config_port,
	324	.verify_port = nwpserial_verify_port,
	325	};
	326
	327	static struct uart_driver nwpserial_reg = {
	328	.owner = THIS_MODULE,
	329	.driver_name = "nwpserial",
	330	.dev_name = "ttySQ",
331	.major = TTY_MAJOR,
332	.minor = 68,
333	.nr = NWPSERIAL_NR,
334	.cons = NWPSERIAL_CONSOLE,
335	};
336
337	int nwpserial_register_port(struct uart_port *port)
338	{
339	struct nwpserial_port *up = NULL;
340	int ret = -1;
341	int i;
342	static int first = 1;
343	int dcr_len;
344	int dcr_base;
345	struct device_node *dn;
346
347	mutex_lock(&nwpserial_mutex);
348
2dc11581	349	dn = port->dev->of_node;
5886188d BK	350	if (dn == NULL)
	351	goto out;
	352
	353	/* get dcr base. */
	354	dcr_base = dcr_resource_start(dn, 0);
	355
	356	/* find matching entry */
	357	for (i = 0; i < NWPSERIAL_NR; i++)
	358	if (nwpserial_ports[i].port.iobase == dcr_base) {
	359	up = &nwpserial_ports[i];
	360	break;
	361	}
	362
	363	/* we didn't find a mtching entry, search for a free port */
	364	if (up == NULL)
	365	for (i = 0; i < NWPSERIAL_NR; i++)
	366	if (nwpserial_ports[i].port.type == PORT_UNKNOWN &&
	367	nwpserial_ports[i].port.iobase == 0) {
	368	up = &nwpserial_ports[i];
	369	break;
	370	}
	371
	372	if (up == NULL) {
	373	ret = -EBUSY;
	374	goto out;
	375	}
	376
	377	if (first)
	378	uart_register_driver(&nwpserial_reg);
	379	first = 0;
	380
	381	up->port.membase = port->membase;
	382	up->port.irq = port->irq;
	383	up->port.uartclk = port->uartclk;
	384	up->port.fifosize = port->fifosize;
	385	up->port.regshift = port->regshift;
	386	up->port.iotype = port->iotype;
	387	up->port.flags = port->flags;
	388	up->port.mapbase = port->mapbase;
	389	up->port.private_data = port->private_data;
	390
	391	if (port->dev)
	392	up->port.dev = port->dev;
	393
	394	if (up->port.iobase != dcr_base) {
	395	up->port.ops = &nwpserial_pops;
	396	up->port.fifosize = 16;
	397
	398	spin_lock_init(&up->port.lock);
	399
	400	up->port.iobase = dcr_base;
	401	dcr_len = dcr_resource_len(dn, 0);
	402
	403	up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
	404	if (!DCR_MAP_OK(up->dcr_host)) {
	405	printk(KERN_ERR "Cannot map DCR resources for NWPSERIAL");
	406	goto out;
	407	}
	408	}
	409
	410	ret = uart_add_one_port(&nwpserial_reg, &up->port);
	411	if (ret == 0)
	412	ret = up->port.line;
	413
414	out:
415	mutex_unlock(&nwpserial_mutex);
416
417	return ret;
418	}
419	EXPORT_SYMBOL(nwpserial_register_port);
420
421	void nwpserial_unregister_port(int line)
422	{
423	struct nwpserial_port *up = &nwpserial_ports[line];
424	mutex_lock(&nwpserial_mutex);
425	uart_remove_one_port(&nwpserial_reg, &up->port);
426
427	up->port.type = PORT_UNKNOWN;
428
429	mutex_unlock(&nwpserial_mutex);
430	}
431	EXPORT_SYMBOL(nwpserial_unregister_port);
432
433	#ifdef CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE
434	static int __init nwpserial_console_init(void)
435	{
436	struct nwpserial_port *up = NULL;
437	struct device_node *dn;
438	const char *name;
439	int dcr_base;
440	int dcr_len;
441	int i;
442
443	/* search for a free port */
444	for (i = 0; i < NWPSERIAL_NR; i++)
445	if (nwpserial_ports[i].port.type == PORT_UNKNOWN) {
446	up = &nwpserial_ports[i];
447	break;
448	}
449
450	if (up == NULL)
451	return -1;
452
453	name = of_get_property(of_chosen, "linux,stdout-path", NULL);
454	if (name == NULL)
455	return -1;
456
457	dn = of_find_node_by_path(name);
458	if (!dn)
459	return -1;
460
461	spin_lock_init(&up->port.lock);
462	up->port.ops = &nwpserial_pops;
463	up->port.type = PORT_NWPSERIAL;
464	up->port.fifosize = 16;
465
466	dcr_base = dcr_resource_start(dn, 0);
467	dcr_len = dcr_resource_len(dn, 0);
468	up->port.iobase = dcr_base;
469
470	up->dcr_host = dcr_map(dn, dcr_base, dcr_len);
471	if (!DCR_MAP_OK(up->dcr_host)) {
472	printk("Cannot map DCR resources for SERIAL");
473	return -1;
474	}
475	register_console(&nwpserial_console);
476	return 0;
477	}
478	console_initcall(nwpserial_console_init);
479	#endif /* CONFIG_SERIAL_OF_PLATFORM_NWPSERIAL_CONSOLE */