[linux-block.git] / drivers / tty / serial / vt8500_serial.c

/*
 * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
 *
 * Based on msm_serial.c, which is:
 * Copyright (C) 2007 Google, Inc.
 * Author: Robert Love <rlove@google.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#if defined(CONFIG_SERIAL_VT8500_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
# define SUPPORT_SYSRQ
#endif

#include <linux/hrtimer.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/slab.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/of.h>

/*
 * UART Register offsets
 */

#define VT8500_URTDR		0x0000	/* Transmit data */
#define VT8500_URRDR		0x0004	/* Receive data */
#define VT8500_URDIV		0x0008	/* Clock/Baud rate divisor */
#define VT8500_URLCR		0x000C	/* Line control */
#define VT8500_URICR		0x0010	/* IrDA control */
#define VT8500_URIER		0x0014	/* Interrupt enable */
#define VT8500_URISR		0x0018	/* Interrupt status */
#define VT8500_URUSR		0x001c	/* UART status */
#define VT8500_URFCR		0x0020	/* FIFO control */
#define VT8500_URFIDX		0x0024	/* FIFO index */
#define VT8500_URBKR		0x0028	/* Break signal count */
#define VT8500_URTOD		0x002c	/* Time out divisor */
#define VT8500_TXFIFO		0x1000	/* Transmit FIFO (16x8) */
#define VT8500_RXFIFO		0x1020	/* Receive FIFO (16x10) */

/*
 * Interrupt enable and status bits
 */

#define TXDE	(1 << 0)	/* Tx Data empty */
#define RXDF	(1 << 1)	/* Rx Data full */
#define TXFAE	(1 << 2)	/* Tx FIFO almost empty */
#define TXFE	(1 << 3)	/* Tx FIFO empty */
#define RXFAF	(1 << 4)	/* Rx FIFO almost full */
#define RXFF	(1 << 5)	/* Rx FIFO full */
#define TXUDR	(1 << 6)	/* Tx underrun */
#define RXOVER	(1 << 7)	/* Rx overrun */
#define PER	(1 << 8)	/* Parity error */
#define FER	(1 << 9)	/* Frame error */
#define TCTS	(1 << 10)	/* Toggle of CTS */
#define RXTOUT	(1 << 11)	/* Rx timeout */
#define BKDONE	(1 << 12)	/* Break signal done */
#define ERR	(1 << 13)	/* AHB error response */

#define RX_FIFO_INTS	(RXFAF | RXFF | RXOVER | PER | FER | RXTOUT)
#define TX_FIFO_INTS	(TXFAE | TXFE | TXUDR)

#define VT8500_MAX_PORTS	6

struct vt8500_port {
	struct uart_port	uart;
	char			name[16];
	struct clk		*clk;
	unsigned int		ier;
};

/*
 * we use this variable to keep track of which ports
 * have been allocated as we can't use pdev->id in
 * devicetree
 */
static unsigned long vt8500_ports_in_use;

static inline void vt8500_write(struct uart_port *port, unsigned int val,
			     unsigned int off)
{
	writel(val, port->membase + off);
}

static inline unsigned int vt8500_read(struct uart_port *port, unsigned int off)
{
	return readl(port->membase + off);
}

static void vt8500_stop_tx(struct uart_port *port)
{
	struct vt8500_port *vt8500_port = container_of(port,
						       struct vt8500_port,
						       uart);

	vt8500_port->ier &= ~TX_FIFO_INTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}

static void vt8500_stop_rx(struct uart_port *port)
{
	struct vt8500_port *vt8500_port = container_of(port,
						       struct vt8500_port,
						       uart);

	vt8500_port->ier &= ~RX_FIFO_INTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}

static void vt8500_enable_ms(struct uart_port *port)
{
	struct vt8500_port *vt8500_port = container_of(port,
						       struct vt8500_port,
						       uart);

	vt8500_port->ier |= TCTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}

static void handle_rx(struct uart_port *port)
{
	struct tty_struct *tty = tty_port_tty_get(&port->state->port);
	if (!tty) {
		/* Discard data: no tty available */
		int count = (vt8500_read(port, VT8500_URFIDX) & 0x1f00) >> 8;
		u16 ch;
		while (count--)
			ch = readw(port->membase + VT8500_RXFIFO);
		return;
	}

	/*
	 * Handle overrun
	 */
	if ((vt8500_read(port, VT8500_URISR) & RXOVER)) {
		port->icount.overrun++;
		tty_insert_flip_char(tty, 0, TTY_OVERRUN);
	}

	/* and now the main RX loop */
	while (vt8500_read(port, VT8500_URFIDX) & 0x1f00) {
		unsigned int c;
		char flag = TTY_NORMAL;

		c = readw(port->membase + VT8500_RXFIFO) & 0x3ff;

		/* Mask conditions we're ignorning. */
		c &= ~port->read_status_mask;

		if (c & FER) {
			port->icount.frame++;
			flag = TTY_FRAME;
		} else if (c & PER) {
			port->icount.parity++;
			flag = TTY_PARITY;
		}
		port->icount.rx++;

		if (!uart_handle_sysrq_char(port, c))
			tty_insert_flip_char(tty, c, flag);
	}

	tty_flip_buffer_push(tty);
	tty_kref_put(tty);
}

static void handle_tx(struct uart_port *port)
{
	struct circ_buf *xmit = &port->state->xmit;

	if (port->x_char) {
		writeb(port->x_char, port->membase + VT8500_TXFIFO);
		port->icount.tx++;
		port->x_char = 0;
	}
	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
		vt8500_stop_tx(port);
		return;
	}

	while ((vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16) {
		if (uart_circ_empty(xmit))
			break;

		writeb(xmit->buf[xmit->tail], port->membase + VT8500_TXFIFO);

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

	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
		uart_write_wakeup(port);

	if (uart_circ_empty(xmit))
		vt8500_stop_tx(port);
}

static void vt8500_start_tx(struct uart_port *port)
{
	struct vt8500_port *vt8500_port = container_of(port,
						       struct vt8500_port,
						       uart);

	vt8500_port->ier &= ~TX_FIFO_INTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
	handle_tx(port);
	vt8500_port->ier |= TX_FIFO_INTS;
	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
}

static void handle_delta_cts(struct uart_port *port)
{
	port->icount.cts++;
	wake_up_interruptible(&port->state->port.delta_msr_wait);
}

static irqreturn_t vt8500_irq(int irq, void *dev_id)
{
	struct uart_port *port = dev_id;
	unsigned long isr;

	spin_lock(&port->lock);
	isr = vt8500_read(port, VT8500_URISR);

	/* Acknowledge active status bits */
	vt8500_write(port, isr, VT8500_URISR);

	if (isr & RX_FIFO_INTS)
		handle_rx(port);
	if (isr & TX_FIFO_INTS)
		handle_tx(port);
	if (isr & TCTS)
		handle_delta_cts(port);

	spin_unlock(&port->lock);

	return IRQ_HANDLED;
}

static unsigned int vt8500_tx_empty(struct uart_port *port)
{
	return (vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16 ?
						TIOCSER_TEMT : 0;
}

static unsigned int vt8500_get_mctrl(struct uart_port *port)
{
	unsigned int usr;

	usr = vt8500_read(port, VT8500_URUSR);
	if (usr & (1 << 4))
		return TIOCM_CTS;
	else
		return 0;
}

static void vt8500_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
}

static void vt8500_break_ctl(struct uart_port *port, int break_ctl)
{
	if (break_ctl)
		vt8500_write(port, vt8500_read(port, VT8500_URLCR) | (1 << 9),
			     VT8500_URLCR);
}

static int vt8500_set_baud_rate(struct uart_port *port, unsigned int baud)
{
	unsigned long div;
	unsigned int loops = 1000;

	div = vt8500_read(port, VT8500_URDIV) & ~(0x3ff);

	if (unlikely((baud < 900) || (baud > 921600)))
		div |= 7;
	else
		div |= (921600 / baud) - 1;

	while ((vt8500_read(port, VT8500_URUSR) & (1 << 5)) && --loops)
		cpu_relax();
	vt8500_write(port, div, VT8500_URDIV);

	return baud;
}

static int vt8500_startup(struct uart_port *port)
{
	struct vt8500_port *vt8500_port =
			container_of(port, struct vt8500_port, uart);
	int ret;

	snprintf(vt8500_port->name, sizeof(vt8500_port->name),
		 "vt8500_serial%d", port->line);

	ret = request_irq(port->irq, vt8500_irq, IRQF_TRIGGER_HIGH,
			  vt8500_port->name, port);
	if (unlikely(ret))
		return ret;

	vt8500_write(port, 0x03, VT8500_URLCR);	/* enable TX & RX */

	return 0;
}

static void vt8500_shutdown(struct uart_port *port)
{
	struct vt8500_port *vt8500_port =
			container_of(port, struct vt8500_port, uart);

	vt8500_port->ier = 0;

	/* disable interrupts and FIFOs */
	vt8500_write(&vt8500_port->uart, 0, VT8500_URIER);
	vt8500_write(&vt8500_port->uart, 0x880, VT8500_URFCR);
	free_irq(port->irq, port);
}

static void vt8500_set_termios(struct uart_port *port,
			       struct ktermios *termios,
			       struct ktermios *old)
{
	struct vt8500_port *vt8500_port =
			container_of(port, struct vt8500_port, uart);
	unsigned long flags;
	unsigned int baud, lcr;
	unsigned int loops = 1000;

	spin_lock_irqsave(&port->lock, flags);

	/* calculate and set baud rate */
	baud = uart_get_baud_rate(port, termios, old, 900, 921600);
	baud = vt8500_set_baud_rate(port, baud);
	if (tty_termios_baud_rate(termios))
		tty_termios_encode_baud_rate(termios, baud, baud);

	/* calculate parity */
	lcr = vt8500_read(&vt8500_port->uart, VT8500_URLCR);
	lcr &= ~((1 << 5) | (1 << 4));
	if (termios->c_cflag & PARENB) {
		lcr |= (1 << 4);
		termios->c_cflag &= ~CMSPAR;
		if (termios->c_cflag & PARODD)
			lcr |= (1 << 5);
	}

	/* calculate bits per char */
	lcr &= ~(1 << 2);
	switch (termios->c_cflag & CSIZE) {
	case CS7:
		break;
	case CS8:
	default:
		lcr |= (1 << 2);
		termios->c_cflag &= ~CSIZE;
		termios->c_cflag |= CS8;
		break;
	}

	/* calculate stop bits */
	lcr &= ~(1 << 3);
	if (termios->c_cflag & CSTOPB)
		lcr |= (1 << 3);

	/* set parity, bits per char, and stop bit */
	vt8500_write(&vt8500_port->uart, lcr, VT8500_URLCR);

	/* Configure status bits to ignore based on termio flags. */
	port->read_status_mask = 0;
	if (termios->c_iflag & IGNPAR)
		port->read_status_mask = FER | PER;

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

	/* Reset FIFOs */
	vt8500_write(&vt8500_port->uart, 0x88c, VT8500_URFCR);
	while ((vt8500_read(&vt8500_port->uart, VT8500_URFCR) & 0xc)
							&& --loops)
		cpu_relax();

	/* Every possible FIFO-related interrupt */
	vt8500_port->ier = RX_FIFO_INTS | TX_FIFO_INTS;

	/*
	 * CTS flow control
	 */
	if (UART_ENABLE_MS(&vt8500_port->uart, termios->c_cflag))
		vt8500_port->ier |= TCTS;

	vt8500_write(&vt8500_port->uart, 0x881, VT8500_URFCR);
	vt8500_write(&vt8500_port->uart, vt8500_port->ier, VT8500_URIER);

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

static const char *vt8500_type(struct uart_port *port)
{
	struct vt8500_port *vt8500_port =
			container_of(port, struct vt8500_port, uart);
	return vt8500_port->name;
}

static void vt8500_release_port(struct uart_port *port)
{
}

static int vt8500_request_port(struct uart_port *port)
{
	return 0;
}

static void vt8500_config_port(struct uart_port *port, int flags)
{
	port->type = PORT_VT8500;
}

static int vt8500_verify_port(struct uart_port *port,
			      struct serial_struct *ser)
{
	if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_VT8500))
		return -EINVAL;
	if (unlikely(port->irq != ser->irq))
		return -EINVAL;
	return 0;
}

static struct vt8500_port *vt8500_uart_ports[VT8500_MAX_PORTS];
static struct uart_driver vt8500_uart_driver;

#ifdef CONFIG_SERIAL_VT8500_CONSOLE

static inline void wait_for_xmitr(struct uart_port *port)
{
	unsigned int status, tmout = 10000;

	/* Wait up to 10ms for the character(s) to be sent. */
	do {
		status = vt8500_read(port, VT8500_URFIDX);

		if (--tmout == 0)
			break;
		udelay(1);
	} while (status & 0x10);
}

static void vt8500_console_putchar(struct uart_port *port, int c)
{
	wait_for_xmitr(port);
	writeb(c, port->membase + VT8500_TXFIFO);
}

static void vt8500_console_write(struct console *co, const char *s,
			      unsigned int count)
{
	struct vt8500_port *vt8500_port = vt8500_uart_ports[co->index];
	unsigned long ier;

	BUG_ON(co->index < 0 || co->index >= vt8500_uart_driver.nr);

	ier = vt8500_read(&vt8500_port->uart, VT8500_URIER);
	vt8500_write(&vt8500_port->uart, VT8500_URIER, 0);

	uart_console_write(&vt8500_port->uart, s, count,
			   vt8500_console_putchar);

	/*
	 *	Finally, wait for transmitter to become empty
	 *	and switch back to FIFO
	 */
	wait_for_xmitr(&vt8500_port->uart);
	vt8500_write(&vt8500_port->uart, VT8500_URIER, ier);
}

static int __init vt8500_console_setup(struct console *co, char *options)
{
	struct vt8500_port *vt8500_port;
	int baud = 9600;
	int bits = 8;
	int parity = 'n';
	int flow = 'n';

	if (unlikely(co->index >= vt8500_uart_driver.nr || co->index < 0))
		return -ENXIO;

	vt8500_port = vt8500_uart_ports[co->index];

	if (!vt8500_port)
		return -ENODEV;

	if (options)
		uart_parse_options(options, &baud, &parity, &bits, &flow);

	return uart_set_options(&vt8500_port->uart,
				 co, baud, parity, bits, flow);
}

static struct console vt8500_console = {
	.name = "ttyWMT",
	.write = vt8500_console_write,
	.device = uart_console_device,
	.setup = vt8500_console_setup,
	.flags = CON_PRINTBUFFER,
	.index = -1,
	.data = &vt8500_uart_driver,
};

#define VT8500_CONSOLE	(&vt8500_console)

#else
#define VT8500_CONSOLE	NULL
#endif

static struct uart_ops vt8500_uart_pops = {
	.tx_empty	= vt8500_tx_empty,
	.set_mctrl	= vt8500_set_mctrl,
	.get_mctrl	= vt8500_get_mctrl,
	.stop_tx	= vt8500_stop_tx,
	.start_tx	= vt8500_start_tx,
	.stop_rx	= vt8500_stop_rx,
	.enable_ms	= vt8500_enable_ms,
	.break_ctl	= vt8500_break_ctl,
	.startup	= vt8500_startup,
	.shutdown	= vt8500_shutdown,
	.set_termios	= vt8500_set_termios,
	.type		= vt8500_type,
	.release_port	= vt8500_release_port,
	.request_port	= vt8500_request_port,
	.config_port	= vt8500_config_port,
	.verify_port	= vt8500_verify_port,
};

static struct uart_driver vt8500_uart_driver = {
	.owner		= THIS_MODULE,
	.driver_name	= "vt8500_serial",
	.dev_name	= "ttyWMT",
	.nr		= 6,
	.cons		= VT8500_CONSOLE,
};

static int vt8500_serial_probe(struct platform_device *pdev)
{
	struct vt8500_port *vt8500_port;
	struct resource *mmres, *irqres;
	struct device_node *np = pdev->dev.of_node;
	int ret;
	int port;

	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!mmres || !irqres)
		return -ENODEV;

	if (np)
		port = of_alias_get_id(np, "serial");
		if (port > VT8500_MAX_PORTS)
			port = -1;
	else
		port = -1;

	if (port < 0) {
		/* calculate the port id */
		port = find_first_zero_bit(&vt8500_ports_in_use,
					sizeof(vt8500_ports_in_use));
	}

	if (port > VT8500_MAX_PORTS)
		return -ENODEV;

	/* reserve the port id */
	if (test_and_set_bit(port, &vt8500_ports_in_use)) {
		/* port already in use - shouldn't really happen */
		return -EBUSY;
	}

	vt8500_port = kzalloc(sizeof(struct vt8500_port), GFP_KERNEL);
	if (!vt8500_port)
		return -ENOMEM;

	vt8500_port->uart.type = PORT_VT8500;
	vt8500_port->uart.iotype = UPIO_MEM;
	vt8500_port->uart.mapbase = mmres->start;
	vt8500_port->uart.irq = irqres->start;
	vt8500_port->uart.fifosize = 16;
	vt8500_port->uart.ops = &vt8500_uart_pops;
	vt8500_port->uart.line = port;
	vt8500_port->uart.dev = &pdev->dev;
	vt8500_port->uart.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF;

	vt8500_port->clk = of_clk_get(pdev->dev.of_node, 0);
	if (vt8500_port->clk) {
		vt8500_port->uart.uartclk = clk_get_rate(vt8500_port->clk);
	} else {
		/* use the default of 24Mhz if not specified and warn */
		pr_warn("%s: serial clock source not specified\n", __func__);
		vt8500_port->uart.uartclk = 24000000;
	}

	snprintf(vt8500_port->name, sizeof(vt8500_port->name),
		 "VT8500 UART%d", pdev->id);

	vt8500_port->uart.membase = ioremap(mmres->start, resource_size(mmres));
	if (!vt8500_port->uart.membase) {
		ret = -ENOMEM;
		goto err;
	}

	vt8500_uart_ports[port] = vt8500_port;

	uart_add_one_port(&vt8500_uart_driver, &vt8500_port->uart);

	platform_set_drvdata(pdev, vt8500_port);

	return 0;

err:
	kfree(vt8500_port);
	return ret;
}

static int vt8500_serial_remove(struct platform_device *pdev)
{
	struct vt8500_port *vt8500_port = platform_get_drvdata(pdev);

	platform_set_drvdata(pdev, NULL);
	uart_remove_one_port(&vt8500_uart_driver, &vt8500_port->uart);
	kfree(vt8500_port);

	return 0;
}

static const struct of_device_id wmt_dt_ids[] = {
	{ .compatible = "via,vt8500-uart", },
	{}
};

static struct platform_driver vt8500_platform_driver = {
	.probe  = vt8500_serial_probe,
	.remove = vt8500_serial_remove,
	.driver = {
		.name = "vt8500_serial",
		.owner = THIS_MODULE,
		.of_match_table = of_match_ptr(wmt_dt_ids),
	},
};

static int __init vt8500_serial_init(void)
{
	int ret;

	ret = uart_register_driver(&vt8500_uart_driver);
	if (unlikely(ret))
		return ret;

	ret = platform_driver_register(&vt8500_platform_driver);

	if (unlikely(ret))
		uart_unregister_driver(&vt8500_uart_driver);

	return ret;
}

static void __exit vt8500_serial_exit(void)
{
#ifdef CONFIG_SERIAL_VT8500_CONSOLE
	unregister_console(&vt8500_console);
#endif
	platform_driver_unregister(&vt8500_platform_driver);
	uart_unregister_driver(&vt8500_uart_driver);
}

module_init(vt8500_serial_init);
module_exit(vt8500_serial_exit);

MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
MODULE_DESCRIPTION("Driver for vt8500 serial device");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
304e1266	1	/*
304e1266 AC	2	* Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
	3	*
	4	* Based on msm_serial.c, which is:
	5	* Copyright (C) 2007 Google, Inc.
	6	* Author: Robert Love <rlove@google.com>
	7	*
	8	* This software is licensed under the terms of the GNU General Public
	9	* License version 2, as published by the Free Software Foundation, and
	10	* may be copied, distributed, and modified under those terms.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*/
	17
	18	#if defined(CONFIG_SERIAL_VT8500_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
	19	# define SUPPORT_SYSRQ
	20	#endif
	21
	22	#include <linux/hrtimer.h>
	23	#include <linux/delay.h>
	24	#include <linux/module.h>
	25	#include <linux/io.h>
	26	#include <linux/ioport.h>
	27	#include <linux/irq.h>
	28	#include <linux/init.h>
	29	#include <linux/console.h>
	30	#include <linux/tty.h>
	31	#include <linux/tty_flip.h>
	32	#include <linux/serial_core.h>
	33	#include <linux/serial.h>
	34	#include <linux/slab.h>
	35	#include <linux/clk.h>
	36	#include <linux/platform_device.h>
4001130d	37	#include <linux/of.h>
304e1266 AC	38
	39	/*
	40	* UART Register offsets
	41	*/
	42
	43	#define VT8500_URTDR 0x0000 /* Transmit data */
	44	#define VT8500_URRDR 0x0004 /* Receive data */
	45	#define VT8500_URDIV 0x0008 /* Clock/Baud rate divisor */
	46	#define VT8500_URLCR 0x000C /* Line control */
	47	#define VT8500_URICR 0x0010 /* IrDA control */
	48	#define VT8500_URIER 0x0014 /* Interrupt enable */
	49	#define VT8500_URISR 0x0018 /* Interrupt status */
	50	#define VT8500_URUSR 0x001c /* UART status */
	51	#define VT8500_URFCR 0x0020 /* FIFO control */
	52	#define VT8500_URFIDX 0x0024 /* FIFO index */
	53	#define VT8500_URBKR 0x0028 /* Break signal count */
	54	#define VT8500_URTOD 0x002c /* Time out divisor */
	55	#define VT8500_TXFIFO 0x1000 /* Transmit FIFO (16x8) */
	56	#define VT8500_RXFIFO 0x1020 /* Receive FIFO (16x10) */
	57
	58	/*
	59	* Interrupt enable and status bits
	60	*/
	61
	62	#define TXDE (1 << 0) /* Tx Data empty */
	63	#define RXDF (1 << 1) /* Rx Data full */
	64	#define TXFAE (1 << 2) /* Tx FIFO almost empty */
	65	#define TXFE (1 << 3) /* Tx FIFO empty */
	66	#define RXFAF (1 << 4) /* Rx FIFO almost full */
	67	#define RXFF (1 << 5) /* Rx FIFO full */
	68	#define TXUDR (1 << 6) /* Tx underrun */
	69	#define RXOVER (1 << 7) /* Rx overrun */
	70	#define PER (1 << 8) /* Parity error */
	71	#define FER (1 << 9) /* Frame error */
	72	#define TCTS (1 << 10) /* Toggle of CTS */
	73	#define RXTOUT (1 << 11) /* Rx timeout */
	74	#define BKDONE (1 << 12) /* Break signal done */
	75	#define ERR (1 << 13) /* AHB error response */
	76
	77	#define RX_FIFO_INTS (RXFAF \| RXFF \| RXOVER \| PER \| FER \| RXTOUT)
	78	#define TX_FIFO_INTS (TXFAE \| TXFE \| TXUDR)
	79
4001130d TP	80	#define VT8500_MAX_PORTS 6
4001130d TP	81
304e1266 AC	82	struct vt8500_port {
	83	struct uart_port uart;
	84	char name[16];
	85	struct clk *clk;
	86	unsigned int ier;
	87	};
	88
4001130d TP	89	/*
	90	* we use this variable to keep track of which ports
	91	* have been allocated as we can't use pdev->id in
	92	* devicetree
	93	*/
	94	static unsigned long vt8500_ports_in_use;
	95
304e1266 AC	96	static inline void vt8500_write(struct uart_port *port, unsigned int val,
	97	unsigned int off)
	98	{
	99	writel(val, port->membase + off);
	100	}
	101
	102	static inline unsigned int vt8500_read(struct uart_port *port, unsigned int off)
	103	{
	104	return readl(port->membase + off);
	105	}
	106
	107	static void vt8500_stop_tx(struct uart_port *port)
	108	{
	109	struct vt8500_port *vt8500_port = container_of(port,
	110	struct vt8500_port,
	111	uart);
	112
	113	vt8500_port->ier &= ~TX_FIFO_INTS;
	114	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
	115	}
	116
	117	static void vt8500_stop_rx(struct uart_port *port)
	118	{
	119	struct vt8500_port *vt8500_port = container_of(port,
	120	struct vt8500_port,
	121	uart);
	122
	123	vt8500_port->ier &= ~RX_FIFO_INTS;
	124	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
	125	}
	126
	127	static void vt8500_enable_ms(struct uart_port *port)
	128	{
	129	struct vt8500_port *vt8500_port = container_of(port,
	130	struct vt8500_port,
	131	uart);
	132
	133	vt8500_port->ier \|= TCTS;
	134	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
	135	}
	136
	137	static void handle_rx(struct uart_port *port)
	138	{
	139	struct tty_struct *tty = tty_port_tty_get(&port->state->port);
	140	if (!tty) {
	141	/* Discard data: no tty available */
	142	int count = (vt8500_read(port, VT8500_URFIDX) & 0x1f00) >> 8;
	143	u16 ch;
	144	while (count--)
	145	ch = readw(port->membase + VT8500_RXFIFO);
	146	return;
	147	}
	148
	149	/*
	150	* Handle overrun
	151	*/
	152	if ((vt8500_read(port, VT8500_URISR) & RXOVER)) {
	153	port->icount.overrun++;
	154	tty_insert_flip_char(tty, 0, TTY_OVERRUN);
	155	}
	156
	157	/* and now the main RX loop */
	158	while (vt8500_read(port, VT8500_URFIDX) & 0x1f00) {
	159	unsigned int c;
160	char flag = TTY_NORMAL;
161
162	c = readw(port->membase + VT8500_RXFIFO) & 0x3ff;
163
164	/* Mask conditions we're ignorning. */
165	c &= ~port->read_status_mask;
166
167	if (c & FER) {
168	port->icount.frame++;
169	flag = TTY_FRAME;
170	} else if (c & PER) {
171	port->icount.parity++;
172	flag = TTY_PARITY;
173	}
174	port->icount.rx++;
175
176	if (!uart_handle_sysrq_char(port, c))
177	tty_insert_flip_char(tty, c, flag);
178	}
179
180	tty_flip_buffer_push(tty);
181	tty_kref_put(tty);
182	}
183
184	static void handle_tx(struct uart_port *port)
185	{
186	struct circ_buf *xmit = &port->state->xmit;
187
188	if (port->x_char) {
189	writeb(port->x_char, port->membase + VT8500_TXFIFO);
190	port->icount.tx++;
191	port->x_char = 0;
192	}
193	if (uart_circ_empty(xmit) \|\| uart_tx_stopped(port)) {
194	vt8500_stop_tx(port);
195	return;
196	}
197
198	while ((vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16) {
199	if (uart_circ_empty(xmit))
200	break;
201
202	writeb(xmit->buf[xmit->tail], port->membase + VT8500_TXFIFO);
203
204	xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
205	port->icount.tx++;
206	}
207
208	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
209	uart_write_wakeup(port);
210
211	if (uart_circ_empty(xmit))
212	vt8500_stop_tx(port);
213	}
214
215	static void vt8500_start_tx(struct uart_port *port)
216	{
217	struct vt8500_port *vt8500_port = container_of(port,
218	struct vt8500_port,
219	uart);
220
221	vt8500_port->ier &= ~TX_FIFO_INTS;
222	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
223	handle_tx(port);
224	vt8500_port->ier \|= TX_FIFO_INTS;
225	vt8500_write(port, vt8500_port->ier, VT8500_URIER);
226	}
227
228	static void handle_delta_cts(struct uart_port *port)
229	{
230	port->icount.cts++;
231	wake_up_interruptible(&port->state->port.delta_msr_wait);
232	}
233
234	static irqreturn_t vt8500_irq(int irq, void *dev_id)
235	{
236	struct uart_port *port = dev_id;
237	unsigned long isr;
238
239	spin_lock(&port->lock);
240	isr = vt8500_read(port, VT8500_URISR);
241
242	/* Acknowledge active status bits */
243	vt8500_write(port, isr, VT8500_URISR);
244
245	if (isr & RX_FIFO_INTS)
246	handle_rx(port);
247	if (isr & TX_FIFO_INTS)
248	handle_tx(port);
249	if (isr & TCTS)
250	handle_delta_cts(port);
251
252	spin_unlock(&port->lock);
253
254	return IRQ_HANDLED;
255	}
256
257	static unsigned int vt8500_tx_empty(struct uart_port *port)
258	{
259	return (vt8500_read(port, VT8500_URFIDX) & 0x1f) < 16 ?
260	TIOCSER_TEMT : 0;
261	}
262
263	static unsigned int vt8500_get_mctrl(struct uart_port *port)
264	{
265	unsigned int usr;
266
267	usr = vt8500_read(port, VT8500_URUSR);
268	if (usr & (1 << 4))
269	return TIOCM_CTS;
270	else
271	return 0;
272	}
273
274	static void vt8500_set_mctrl(struct uart_port *port, unsigned int mctrl)
275	{
276	}
277
278	static void vt8500_break_ctl(struct uart_port *port, int break_ctl)
279	{
280	if (break_ctl)
281	vt8500_write(port, vt8500_read(port, VT8500_URLCR) \| (1 << 9),
282	VT8500_URLCR);
283	}
284
285	static int vt8500_set_baud_rate(struct uart_port *port, unsigned int baud)
286	{
287	unsigned long div;
288	unsigned int loops = 1000;
289
290	div = vt8500_read(port, VT8500_URDIV) & ~(0x3ff);
291
292	if (unlikely((baud < 900) \|\| (baud > 921600)))
293	div \|= 7;
294	else
295	div \|= (921600 / baud) - 1;
296
297	while ((vt8500_read(port, VT8500_URUSR) & (1 << 5)) && --loops)
298	cpu_relax();
299	vt8500_write(port, div, VT8500_URDIV);
300
301	return baud;
302	}
303
304	static int vt8500_startup(struct uart_port *port)
305	{
306	struct vt8500_port *vt8500_port =
307	container_of(port, struct vt8500_port, uart);
308	int ret;
309
310	snprintf(vt8500_port->name, sizeof(vt8500_port->name),
311	"vt8500_serial%d", port->line);
312
313	ret = request_irq(port->irq, vt8500_irq, IRQF_TRIGGER_HIGH,
314	vt8500_port->name, port);
315	if (unlikely(ret))
316	return ret;
317
318	vt8500_write(port, 0x03, VT8500_URLCR); /* enable TX & RX */
319
320	return 0;
321	}
322
323	static void vt8500_shutdown(struct uart_port *port)
324	{
325	struct vt8500_port *vt8500_port =
326	container_of(port, struct vt8500_port, uart);
327
328	vt8500_port->ier = 0;
329
330	/* disable interrupts and FIFOs */
331	vt8500_write(&vt8500_port->uart, 0, VT8500_URIER);
332	vt8500_write(&vt8500_port->uart, 0x880, VT8500_URFCR);
333	free_irq(port->irq, port);
334	}
335
336	static void vt8500_set_termios(struct uart_port *port,
337	struct ktermios *termios,
338	struct ktermios *old)
339	{
340	struct vt8500_port *vt8500_port =
341	container_of(port, struct vt8500_port, uart);
342	unsigned long flags;
343	unsigned int baud, lcr;
344	unsigned int loops = 1000;
345
346	spin_lock_irqsave(&port->lock, flags);
347
348	/* calculate and set baud rate */
349	baud = uart_get_baud_rate(port, termios, old, 900, 921600);
350	baud = vt8500_set_baud_rate(port, baud);
351	if (tty_termios_baud_rate(termios))
352	tty_termios_encode_baud_rate(termios, baud, baud);
353
354	/* calculate parity */
355	lcr = vt8500_read(&vt8500_port->uart, VT8500_URLCR);
356	lcr &= ~((1 << 5) \| (1 << 4));
357	if (termios->c_cflag & PARENB) {
358	lcr \|= (1 << 4);
359	termios->c_cflag &= ~CMSPAR;
360	if (termios->c_cflag & PARODD)
361	lcr \|= (1 << 5);
362	}
363
364	/* calculate bits per char */
365	lcr &= ~(1 << 2);
366	switch (termios->c_cflag & CSIZE) {
367	case CS7:
368	break;
369	case CS8:
370	default:
371	lcr \|= (1 << 2);
372	termios->c_cflag &= ~CSIZE;
373	termios->c_cflag \|= CS8;
374	break;
375	}
376
377	/* calculate stop bits */
378	lcr &= ~(1 << 3);
379	if (termios->c_cflag & CSTOPB)
380	lcr \|= (1 << 3);
381
382	/* set parity, bits per char, and stop bit */
383	vt8500_write(&vt8500_port->uart, lcr, VT8500_URLCR);
384
385	/* Configure status bits to ignore based on termio flags. */
386	port->read_status_mask = 0;
387	if (termios->c_iflag & IGNPAR)
388	port->read_status_mask = FER \| PER;
389
390	uart_update_timeout(port, termios->c_cflag, baud);
391
392	/* Reset FIFOs */
393	vt8500_write(&vt8500_port->uart, 0x88c, VT8500_URFCR);
394	while ((vt8500_read(&vt8500_port->uart, VT8500_URFCR) & 0xc)
395	&& --loops)
396	cpu_relax();
397
398	/* Every possible FIFO-related interrupt */
399	vt8500_port->ier = RX_FIFO_INTS \| TX_FIFO_INTS;
400
401	/*
402	* CTS flow control
403	*/
404	if (UART_ENABLE_MS(&vt8500_port->uart, termios->c_cflag))
405	vt8500_port->ier \|= TCTS;
406
407	vt8500_write(&vt8500_port->uart, 0x881, VT8500_URFCR);
408	vt8500_write(&vt8500_port->uart, vt8500_port->ier, VT8500_URIER);
409
410	spin_unlock_irqrestore(&port->lock, flags);
411	}
412
413	static const char vt8500_type(struct uart_port port)
414	{
415	struct vt8500_port *vt8500_port =
416	container_of(port, struct vt8500_port, uart);
417	return vt8500_port->name;
418	}
419
420	static void vt8500_release_port(struct uart_port *port)
421	{
422	}
423
424	static int vt8500_request_port(struct uart_port *port)
425	{
426	return 0;
427	}
428
429	static void vt8500_config_port(struct uart_port *port, int flags)
430	{
431	port->type = PORT_VT8500;
432	}
433
434	static int vt8500_verify_port(struct uart_port *port,
435	struct serial_struct *ser)
436	{
437	if (unlikely(ser->type != PORT_UNKNOWN && ser->type != PORT_VT8500))
438	return -EINVAL;
439	if (unlikely(port->irq != ser->irq))
440	return -EINVAL;
441	return 0;
442	}
443
4001130d	444	static struct vt8500_port *vt8500_uart_ports[VT8500_MAX_PORTS];
304e1266 AC	445	static struct uart_driver vt8500_uart_driver;
	446
	447	#ifdef CONFIG_SERIAL_VT8500_CONSOLE
	448
	449	static inline void wait_for_xmitr(struct uart_port *port)
	450	{
	451	unsigned int status, tmout = 10000;
	452
	453	/* Wait up to 10ms for the character(s) to be sent. */
	454	do {
	455	status = vt8500_read(port, VT8500_URFIDX);
	456
	457	if (--tmout == 0)
	458	break;
	459	udelay(1);
	460	} while (status & 0x10);
	461	}
	462
	463	static void vt8500_console_putchar(struct uart_port *port, int c)
	464	{
	465	wait_for_xmitr(port);
	466	writeb(c, port->membase + VT8500_TXFIFO);
	467	}
	468
	469	static void vt8500_console_write(struct console co, const char s,
	470	unsigned int count)
	471	{
	472	struct vt8500_port *vt8500_port = vt8500_uart_ports[co->index];
	473	unsigned long ier;
	474
	475	BUG_ON(co->index < 0 \|\| co->index >= vt8500_uart_driver.nr);
	476
	477	ier = vt8500_read(&vt8500_port->uart, VT8500_URIER);
	478	vt8500_write(&vt8500_port->uart, VT8500_URIER, 0);
	479
	480	uart_console_write(&vt8500_port->uart, s, count,
	481	vt8500_console_putchar);
	482
	483	/*
	484	* Finally, wait for transmitter to become empty
	485	* and switch back to FIFO
	486	*/
	487	wait_for_xmitr(&vt8500_port->uart);
	488	vt8500_write(&vt8500_port->uart, VT8500_URIER, ier);
	489	}
	490
	491	static int __init vt8500_console_setup(struct console co, char options)
	492	{
	493	struct vt8500_port *vt8500_port;
	494	int baud = 9600;
	495	int bits = 8;
	496	int parity = 'n';
	497	int flow = 'n';
	498
	499	if (unlikely(co->index >= vt8500_uart_driver.nr \|\| co->index < 0))
	500	return -ENXIO;
	501
	502	vt8500_port = vt8500_uart_ports[co->index];
	503
	504	if (!vt8500_port)
	505	return -ENODEV;
	506
	507	if (options)
	508	uart_parse_options(options, &baud, &parity, &bits, &flow);
509
510	return uart_set_options(&vt8500_port->uart,
511	co, baud, parity, bits, flow);
512	}
513
514	static struct console vt8500_console = {
515	.name = "ttyWMT",
516	.write = vt8500_console_write,
517	.device = uart_console_device,
518	.setup = vt8500_console_setup,
519	.flags = CON_PRINTBUFFER,
520	.index = -1,
521	.data = &vt8500_uart_driver,
522	};
523
524	#define VT8500_CONSOLE (&vt8500_console)
525
526	#else
527	#define VT8500_CONSOLE NULL
528	#endif
529
530	static struct uart_ops vt8500_uart_pops = {
531	.tx_empty = vt8500_tx_empty,
532	.set_mctrl = vt8500_set_mctrl,
533	.get_mctrl = vt8500_get_mctrl,
534	.stop_tx = vt8500_stop_tx,
535	.start_tx = vt8500_start_tx,
536	.stop_rx = vt8500_stop_rx,
537	.enable_ms = vt8500_enable_ms,
538	.break_ctl = vt8500_break_ctl,
539	.startup = vt8500_startup,
540	.shutdown = vt8500_shutdown,
541	.set_termios = vt8500_set_termios,
542	.type = vt8500_type,
543	.release_port = vt8500_release_port,
544	.request_port = vt8500_request_port,
545	.config_port = vt8500_config_port,
546	.verify_port = vt8500_verify_port,
547	};
548
549	static struct uart_driver vt8500_uart_driver = {
550	.owner = THIS_MODULE,
551	.driver_name = "vt8500_serial",
552	.dev_name = "ttyWMT",
553	.nr = 6,
554	.cons = VT8500_CONSOLE,
555	};
556
9671f099	557	static int vt8500_serial_probe(struct platform_device *pdev)
304e1266 AC	558	{
	559	struct vt8500_port *vt8500_port;
	560	struct resource mmres, irqres;
4001130d	561	struct device_node *np = pdev->dev.of_node;
304e1266	562	int ret;
4001130d	563	int port;
304e1266 AC	564
	565	mmres = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	566	irqres = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	567	if (!mmres \|\| !irqres)
	568	return -ENODEV;
	569
4001130d TP	570	if (np)
	571	port = of_alias_get_id(np, "serial");
	572	if (port > VT8500_MAX_PORTS)
	573	port = -1;
	574	else
	575	port = -1;
	576
	577	if (port < 0) {
	578	/* calculate the port id */
	579	port = find_first_zero_bit(&vt8500_ports_in_use,
	580	sizeof(vt8500_ports_in_use));
	581	}
	582
	583	if (port > VT8500_MAX_PORTS)
	584	return -ENODEV;
	585
	586	/* reserve the port id */
	587	if (test_and_set_bit(port, &vt8500_ports_in_use)) {
	588	/* port already in use - shouldn't really happen */
	589	return -EBUSY;
	590	}
	591
59c2e855 WY	592	vt8500_port = kzalloc(sizeof(struct vt8500_port), GFP_KERNEL);
	593	if (!vt8500_port)
	594	return -ENOMEM;
	595
304e1266 AC	596	vt8500_port->uart.type = PORT_VT8500;
	597	vt8500_port->uart.iotype = UPIO_MEM;
	598	vt8500_port->uart.mapbase = mmres->start;
	599	vt8500_port->uart.irq = irqres->start;
	600	vt8500_port->uart.fifosize = 16;
	601	vt8500_port->uart.ops = &vt8500_uart_pops;
4001130d	602	vt8500_port->uart.line = port;
304e1266 AC	603	vt8500_port->uart.dev = &pdev->dev;
304e1266 AC	604	vt8500_port->uart.flags = UPF_IOREMAP \| UPF_BOOT_AUTOCONF;
4001130d TP	605
	606	vt8500_port->clk = of_clk_get(pdev->dev.of_node, 0);
	607	if (vt8500_port->clk) {
	608	vt8500_port->uart.uartclk = clk_get_rate(vt8500_port->clk);
	609	} else {
	610	/* use the default of 24Mhz if not specified and warn */
	611	pr_warn("%s: serial clock source not specified\n", __func__);
	612	vt8500_port->uart.uartclk = 24000000;
	613	}
304e1266 AC	614
	615	snprintf(vt8500_port->name, sizeof(vt8500_port->name),
	616	"VT8500 UART%d", pdev->id);
	617
28f65c11	618	vt8500_port->uart.membase = ioremap(mmres->start, resource_size(mmres));
304e1266 AC	619	if (!vt8500_port->uart.membase) {
	620	ret = -ENOMEM;
	621	goto err;
	622	}
	623
4001130d	624	vt8500_uart_ports[port] = vt8500_port;
304e1266 AC	625
	626	uart_add_one_port(&vt8500_uart_driver, &vt8500_port->uart);
	627
	628	platform_set_drvdata(pdev, vt8500_port);
	629
	630	return 0;
	631
	632	err:
	633	kfree(vt8500_port);
	634	return ret;
	635	}
	636
ae8d8a14	637	static int vt8500_serial_remove(struct platform_device *pdev)
304e1266 AC	638	{
	639	struct vt8500_port *vt8500_port = platform_get_drvdata(pdev);
	640
	641	platform_set_drvdata(pdev, NULL);
	642	uart_remove_one_port(&vt8500_uart_driver, &vt8500_port->uart);
	643	kfree(vt8500_port);
	644
	645	return 0;
	646	}
	647
4001130d TP	648	static const struct of_device_id wmt_dt_ids[] = {
	649	{ .compatible = "via,vt8500-uart", },
	650	{}
	651	};
	652
304e1266 AC	653	static struct platform_driver vt8500_platform_driver = {
304e1266 AC	654	.probe = vt8500_serial_probe,
2d47b716	655	.remove = vt8500_serial_remove,
304e1266 AC	656	.driver = {
	657	.name = "vt8500_serial",
	658	.owner = THIS_MODULE,
4001130d	659	.of_match_table = of_match_ptr(wmt_dt_ids),
304e1266 AC	660	},
	661	};
	662
	663	static int __init vt8500_serial_init(void)
	664	{
	665	int ret;
	666
	667	ret = uart_register_driver(&vt8500_uart_driver);
	668	if (unlikely(ret))
	669	return ret;
	670
	671	ret = platform_driver_register(&vt8500_platform_driver);
	672
	673	if (unlikely(ret))
	674	uart_unregister_driver(&vt8500_uart_driver);
	675
	676	return ret;
	677	}
	678
	679	static void __exit vt8500_serial_exit(void)
	680	{
	681	#ifdef CONFIG_SERIAL_VT8500_CONSOLE
	682	unregister_console(&vt8500_console);
	683	#endif
	684	platform_driver_unregister(&vt8500_platform_driver);
	685	uart_unregister_driver(&vt8500_uart_driver);
	686	}
	687
	688	module_init(vt8500_serial_init);
	689	module_exit(vt8500_serial_exit);
	690
	691	MODULE_AUTHOR("Alexey Charkov <alchark@gmail.com>");
	692	MODULE_DESCRIPTION("Driver for vt8500 serial device");
4001130d	693	MODULE_LICENSE("GPL v2");