/*
   * Copyright (c) 2005 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2
   * as published by the Free Software Foundation.
   *
   * 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.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  #if defined(CONFIG_SERIAL_NETX_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  #define SUPPORT_SYSRQ
  #endif
  
  #include <linux/device.h>
  #include <linux/module.h>
  #include <linux/ioport.h>
  #include <linux/init.h>
  #include <linux/console.h>
  #include <linux/sysrq.h>
  #include <linux/platform_device.h>
  #include <linux/tty.h>
  #include <linux/tty_flip.h>
  #include <linux/serial_core.h>
  #include <linux/serial.h>
  
  #include <asm/io.h>
  #include <asm/irq.h>
  #include <mach/hardware.h>
  #include <mach/netx-regs.h>
  
  /* We've been assigned a range on the "Low-density serial ports" major */
  #define SERIAL_NX_MAJOR	204
  #define MINOR_START	170
  
  enum uart_regs {
  	UART_DR              = 0x00,
  	UART_SR              = 0x04,
  	UART_LINE_CR         = 0x08,
  	UART_BAUDDIV_MSB     = 0x0c,
  	UART_BAUDDIV_LSB     = 0x10,
  	UART_CR              = 0x14,
  	UART_FR              = 0x18,
  	UART_IIR             = 0x1c,
  	UART_ILPR            = 0x20,
  	UART_RTS_CR          = 0x24,
  	UART_RTS_LEAD        = 0x28,
  	UART_RTS_TRAIL       = 0x2c,
  	UART_DRV_ENABLE      = 0x30,
  	UART_BRM_CR          = 0x34,
  	UART_RXFIFO_IRQLEVEL = 0x38,
  	UART_TXFIFO_IRQLEVEL = 0x3c,
  };
  
  #define SR_FE (1<<0)
  #define SR_PE (1<<1)
  #define SR_BE (1<<2)
  #define SR_OE (1<<3)
  
  #define LINE_CR_BRK       (1<<0)
  #define LINE_CR_PEN       (1<<1)
  #define LINE_CR_EPS       (1<<2)
  #define LINE_CR_STP2      (1<<3)
  #define LINE_CR_FEN       (1<<4)
  #define LINE_CR_5BIT      (0<<5)
  #define LINE_CR_6BIT      (1<<5)
  #define LINE_CR_7BIT      (2<<5)
  #define LINE_CR_8BIT      (3<<5)
  #define LINE_CR_BITS_MASK (3<<5)
  
  #define CR_UART_EN (1<<0)
  #define CR_SIREN   (1<<1)
  #define CR_SIRLP   (1<<2)
  #define CR_MSIE    (1<<3)
  #define CR_RIE     (1<<4)
  #define CR_TIE     (1<<5)
  #define CR_RTIE    (1<<6)
  #define CR_LBE     (1<<7)
  
  #define FR_CTS  (1<<0)
  #define FR_DSR  (1<<1)
  #define FR_DCD  (1<<2)
  #define FR_BUSY (1<<3)
  #define FR_RXFE (1<<4)
  #define FR_TXFF (1<<5)
  #define FR_RXFF (1<<6)
  #define FR_TXFE (1<<7)
  
  #define IIR_MIS (1<<0)
  #define IIR_RIS (1<<1)
  #define IIR_TIS (1<<2)
  #define IIR_RTIS (1<<3)
  #define IIR_MASK 0xf
  
  #define RTS_CR_AUTO (1<<0)
  #define RTS_CR_RTS  (1<<1)
  #define RTS_CR_COUNT (1<<2)
  #define RTS_CR_MOD2  (1<<3)
  #define RTS_CR_RTS_POL (1<<4)
  #define RTS_CR_CTS_CTR (1<<5)
  #define RTS_CR_CTS_POL (1<<6)
  #define RTS_CR_STICK   (1<<7)
  
  #define UART_PORT_SIZE 0x40
  #define DRIVER_NAME "netx-uart"
  
  struct netx_port {
  	struct uart_port	port;
  };
  
  static void netx_stop_tx(struct uart_port *port)
  {
  	unsigned int val;
  	val = readl(port->membase + UART_CR);
  	writel(val & ~CR_TIE,  port->membase + UART_CR);
  }
  
  static void netx_stop_rx(struct uart_port *port)
  {
  	unsigned int val;
  	val = readl(port->membase + UART_CR);
  	writel(val & ~CR_RIE,  port->membase + UART_CR);
  }
  
  static void netx_enable_ms(struct uart_port *port)
  {
  	unsigned int val;
  	val = readl(port->membase + UART_CR);
  	writel(val | CR_MSIE, port->membase + UART_CR);
  }
  
  static inline void netx_transmit_buffer(struct uart_port *port)
  {
  	struct circ_buf *xmit = &port->state->xmit;
  
  	if (port->x_char) {
  		writel(port->x_char, port->membase + UART_DR);
  		port->icount.tx++;
  		port->x_char = 0;
  		return;
  	}
  
  	if (uart_tx_stopped(port) || uart_circ_empty(xmit)) {
  		netx_stop_tx(port);
  		return;
  	}
  
  	do {
  		/* send xmit->buf[xmit->tail]
  		 * out the port here */
  		writel(xmit->buf[xmit->tail], port->membase + UART_DR);
  		xmit->tail = (xmit->tail + 1) &
  		         (UART_XMIT_SIZE - 1);
  		port->icount.tx++;
  		if (uart_circ_empty(xmit))
  			break;
  	} while (!(readl(port->membase + UART_FR) & FR_TXFF));
  
  	if (uart_circ_empty(xmit))
  		netx_stop_tx(port);
  }
  
  static void netx_start_tx(struct uart_port *port)
  {
  	writel(
  	    readl(port->membase + UART_CR) | CR_TIE, port->membase + UART_CR);
  
  	if (!(readl(port->membase + UART_FR) & FR_TXFF))
  		netx_transmit_buffer(port);
  }
  
  static unsigned int netx_tx_empty(struct uart_port *port)
  {
  	return readl(port->membase + UART_FR) & FR_BUSY ? 0 : TIOCSER_TEMT;
  }
  
  static void netx_txint(struct uart_port *port)
  {
  	struct circ_buf *xmit = &port->state->xmit;
  
  	if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
  		netx_stop_tx(port);
  		return;
  	}
  
  	netx_transmit_buffer(port);
  
  	if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
  		uart_write_wakeup(port);
  }
  
  static void netx_rxint(struct uart_port *port, unsigned long *flags)
  {
  	unsigned char rx, flg, status;
  
  	while (!(readl(port->membase + UART_FR) & FR_RXFE)) {
  		rx = readl(port->membase + UART_DR);
  		flg = TTY_NORMAL;
  		port->icount.rx++;
  		status = readl(port->membase + UART_SR);
  		if (status & SR_BE) {
  			writel(0, port->membase + UART_SR);
  			if (uart_handle_break(port))
  				continue;
  		}
  
  		if (unlikely(status & (SR_FE | SR_PE | SR_OE))) {
  
  			if (status & SR_PE)
  				port->icount.parity++;
  			else if (status & SR_FE)
  				port->icount.frame++;
  			if (status & SR_OE)
  				port->icount.overrun++;
  
  			status &= port->read_status_mask;
  
  			if (status & SR_BE)
  				flg = TTY_BREAK;
  			else if (status & SR_PE)
  				flg = TTY_PARITY;
  			else if (status & SR_FE)
  				flg = TTY_FRAME;
  		}
  
  		if (uart_handle_sysrq_char(port, rx))
  			continue;
  
  		uart_insert_char(port, status, SR_OE, rx, flg);
  	}
  
  	spin_unlock_irqrestore(&port->lock, *flags);
  	tty_flip_buffer_push(&port->state->port);
  	spin_lock_irqsave(&port->lock, *flags);
  }
  
  static irqreturn_t netx_int(int irq, void *dev_id)
  {
  	struct uart_port *port = dev_id;
  	unsigned long flags;
  	unsigned char status;
  
  	spin_lock_irqsave(&port->lock,flags);
  
  	status = readl(port->membase + UART_IIR) & IIR_MASK;
  	while (status) {
  		if (status & IIR_RIS)
  			netx_rxint(port, &flags);
  		if (status & IIR_TIS)
  			netx_txint(port);
  		if (status & IIR_MIS) {
  			if (readl(port->membase + UART_FR) & FR_CTS)
  				uart_handle_cts_change(port, 1);
  			else
  				uart_handle_cts_change(port, 0);
  		}
  		writel(0, port->membase + UART_IIR);
  		status = readl(port->membase + UART_IIR) & IIR_MASK;
  	}
  
  	spin_unlock_irqrestore(&port->lock,flags);
  	return IRQ_HANDLED;
  }
  
  static unsigned int netx_get_mctrl(struct uart_port *port)
  {
  	unsigned int ret = TIOCM_DSR | TIOCM_CAR;
  
  	if (readl(port->membase + UART_FR) & FR_CTS)
  		ret |= TIOCM_CTS;
  
  	return ret;
  }
  
  static void netx_set_mctrl(struct uart_port *port, unsigned int mctrl)
  {
  	unsigned int val;
  
  	/* FIXME: Locking needed ? */
  	if (mctrl & TIOCM_RTS) {
  		val = readl(port->membase + UART_RTS_CR);
  		writel(val | RTS_CR_RTS, port->membase + UART_RTS_CR);
  	}
  }
  
  static void netx_break_ctl(struct uart_port *port, int break_state)
  {
  	unsigned int line_cr;
  	spin_lock_irq(&port->lock);
  
  	line_cr = readl(port->membase + UART_LINE_CR);
  	if (break_state != 0)
  		line_cr |= LINE_CR_BRK;
  	else
  		line_cr &= ~LINE_CR_BRK;
  	writel(line_cr, port->membase + UART_LINE_CR);
  
  	spin_unlock_irq(&port->lock);
  }
  
  static int netx_startup(struct uart_port *port)
  {
  	int ret;
  
  	ret = request_irq(port->irq, netx_int, 0,
  			     DRIVER_NAME, port);
  	if (ret) {
  		dev_err(port->dev, "unable to grab irq%d
  ",port->irq);
  		goto exit;
  	}
  
  	writel(readl(port->membase + UART_LINE_CR) | LINE_CR_FEN,
  		port->membase + UART_LINE_CR);
  
  	writel(CR_MSIE | CR_RIE | CR_TIE | CR_RTIE | CR_UART_EN,
  		port->membase + UART_CR);
  
  exit:
  	return ret;
  }
  
  static void netx_shutdown(struct uart_port *port)
  {
  	writel(0, port->membase + UART_CR) ;
  
  	free_irq(port->irq, port);
  }
  
  static void
  netx_set_termios(struct uart_port *port, struct ktermios *termios,
  		   struct ktermios *old)
  {
  	unsigned int baud, quot;
  	unsigned char old_cr;
  	unsigned char line_cr = LINE_CR_FEN;
  	unsigned char rts_cr = 0;
  
  	switch (termios->c_cflag & CSIZE) {
  	case CS5:
  		line_cr |= LINE_CR_5BIT;
  		break;
  	case CS6:
  		line_cr |= LINE_CR_6BIT;
  		break;
  	case CS7:
  		line_cr |= LINE_CR_7BIT;
  		break;
  	case CS8:
  		line_cr |= LINE_CR_8BIT;
  		break;
  	}
  
  	if (termios->c_cflag & CSTOPB)
  		line_cr |= LINE_CR_STP2;
  
  	if (termios->c_cflag & PARENB) {
  		line_cr |= LINE_CR_PEN;
  		if (!(termios->c_cflag & PARODD))
  			line_cr |= LINE_CR_EPS;
  	}
  
  	if (termios->c_cflag & CRTSCTS)
  		rts_cr = RTS_CR_AUTO | RTS_CR_CTS_CTR | RTS_CR_RTS_POL;
  
  	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
  	quot = baud * 4096;
  	quot /= 1000;
  	quot *= 256;
  	quot /= 100000;
  
  	spin_lock_irq(&port->lock);
  
  	uart_update_timeout(port, termios->c_cflag, baud);
  
  	old_cr = readl(port->membase + UART_CR);
  
  	/* disable interrupts */
  	writel(old_cr & ~(CR_MSIE | CR_RIE | CR_TIE | CR_RTIE),
  		port->membase + UART_CR);
  
  	/* drain transmitter */
  	while (readl(port->membase + UART_FR) & FR_BUSY);
  
  	/* disable UART */
  	writel(old_cr & ~CR_UART_EN, port->membase + UART_CR);
  
  	/* modem status interrupts */
  	old_cr &= ~CR_MSIE;
  	if (UART_ENABLE_MS(port, termios->c_cflag))
  		old_cr |= CR_MSIE;
  
  	writel((quot>>8) & 0xff, port->membase + UART_BAUDDIV_MSB);
  	writel(quot & 0xff, port->membase + UART_BAUDDIV_LSB);
  	writel(line_cr, port->membase + UART_LINE_CR);
  
  	writel(rts_cr, port->membase + UART_RTS_CR);
  
  	/*
  	 * Characters to ignore
  	 */
  	port->ignore_status_mask = 0;
  	if (termios->c_iflag & IGNPAR)
  		port->ignore_status_mask |= SR_PE;
  	if (termios->c_iflag & IGNBRK) {
  		port->ignore_status_mask |= SR_BE;
  		/*
  		 * If we're ignoring parity and break indicators,
  		 * ignore overruns too (for real raw support).
  		 */
  		if (termios->c_iflag & IGNPAR)
  			port->ignore_status_mask |= SR_PE;
  	}
  
  	port->read_status_mask = 0;
  	if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
  		port->read_status_mask |= SR_BE;
  	if (termios->c_iflag & INPCK)
  		port->read_status_mask |= SR_PE | SR_FE;
  
  	writel(old_cr, port->membase + UART_CR);
  
  	spin_unlock_irq(&port->lock);
  }
  
  static const char *netx_type(struct uart_port *port)
  {
  	return port->type == PORT_NETX ? "NETX" : NULL;
  }
  
  static void netx_release_port(struct uart_port *port)
  {
  	release_mem_region(port->mapbase, UART_PORT_SIZE);
  }
  
  static int netx_request_port(struct uart_port *port)
  {
  	return request_mem_region(port->mapbase, UART_PORT_SIZE,
  			DRIVER_NAME) != NULL ? 0 : -EBUSY;
  }
  
  static void netx_config_port(struct uart_port *port, int flags)
  {
  	if (flags & UART_CONFIG_TYPE && netx_request_port(port) == 0)
  		port->type = PORT_NETX;
  }
  
  static int
  netx_verify_port(struct uart_port *port, struct serial_struct *ser)
  {
  	int ret = 0;
  
  	if (ser->type != PORT_UNKNOWN && ser->type != PORT_NETX)
  		ret = -EINVAL;
  
  	return ret;
  }
  
  static struct uart_ops netx_pops = {
  	.tx_empty	= netx_tx_empty,
  	.set_mctrl	= netx_set_mctrl,
  	.get_mctrl	= netx_get_mctrl,
  	.stop_tx	= netx_stop_tx,
  	.start_tx	= netx_start_tx,
  	.stop_rx	= netx_stop_rx,
  	.enable_ms	= netx_enable_ms,
  	.break_ctl	= netx_break_ctl,
  	.startup	= netx_startup,
  	.shutdown	= netx_shutdown,
  	.set_termios	= netx_set_termios,
  	.type		= netx_type,
  	.release_port	= netx_release_port,
  	.request_port	= netx_request_port,
  	.config_port	= netx_config_port,
  	.verify_port	= netx_verify_port,
  };
  
  static struct netx_port netx_ports[] = {
  	{
  	.port = {
  		.type = PORT_NETX,
  		.iotype = UPIO_MEM,
  		.membase = (char __iomem *)io_p2v(NETX_PA_UART0),
  		.mapbase = NETX_PA_UART0,
  		.irq = NETX_IRQ_UART0,
  		.uartclk = 100000000,
  		.fifosize = 16,
  		.flags = UPF_BOOT_AUTOCONF,
  		.ops = &netx_pops,
  		.line = 0,
  	},
  	}, {
  	.port = {
  		.type = PORT_NETX,
  		.iotype = UPIO_MEM,
  		.membase = (char __iomem *)io_p2v(NETX_PA_UART1),
  		.mapbase = NETX_PA_UART1,
  		.irq = NETX_IRQ_UART1,
  		.uartclk = 100000000,
  		.fifosize = 16,
  		.flags = UPF_BOOT_AUTOCONF,
  		.ops = &netx_pops,
  		.line = 1,
  	},
  	}, {
  	.port = {
  		.type = PORT_NETX,
  		.iotype = UPIO_MEM,
  		.membase = (char __iomem *)io_p2v(NETX_PA_UART2),
  		.mapbase = NETX_PA_UART2,
  		.irq = NETX_IRQ_UART2,
  		.uartclk = 100000000,
  		.fifosize = 16,
  		.flags = UPF_BOOT_AUTOCONF,
  		.ops = &netx_pops,
  		.line = 2,
  	},
  	}
  };
  
  #ifdef CONFIG_SERIAL_NETX_CONSOLE
  
  static void netx_console_putchar(struct uart_port *port, int ch)
  {
  	while (readl(port->membase + UART_FR) & FR_BUSY);
  	writel(ch, port->membase + UART_DR);
  }
  
  static void
  netx_console_write(struct console *co, const char *s, unsigned int count)
  {
  	struct uart_port *port = &netx_ports[co->index].port;
  	unsigned char cr_save;
  
  	cr_save = readl(port->membase + UART_CR);
  	writel(cr_save | CR_UART_EN, port->membase + UART_CR);
  
  	uart_console_write(port, s, count, netx_console_putchar);
  
  	while (readl(port->membase + UART_FR) & FR_BUSY);
  	writel(cr_save, port->membase + UART_CR);
  }
  
  static void __init
  netx_console_get_options(struct uart_port *port, int *baud,
  			int *parity, int *bits, int *flow)
  {
  	unsigned char line_cr;
  
  	*baud = (readl(port->membase + UART_BAUDDIV_MSB) << 8) |
  		readl(port->membase + UART_BAUDDIV_LSB);
  	*baud *= 1000;
  	*baud /= 4096;
  	*baud *= 1000;
  	*baud /= 256;
  	*baud *= 100;
  
  	line_cr = readl(port->membase + UART_LINE_CR);
  	*parity = 'n';
  	if (line_cr & LINE_CR_PEN) {
  		if (line_cr & LINE_CR_EPS)
  			*parity = 'e';
  		else
  			*parity = 'o';
  	}
  
  	switch (line_cr & LINE_CR_BITS_MASK) {
  	case LINE_CR_8BIT:
  		*bits = 8;
  		break;
  	case LINE_CR_7BIT:
  		*bits = 7;
  		break;
  	case LINE_CR_6BIT:
  		*bits = 6;
  		break;
  	case LINE_CR_5BIT:
  		*bits = 5;
  		break;
  	}
  
  	if (readl(port->membase + UART_RTS_CR) & RTS_CR_AUTO)
  		*flow = 'r';
  }
  
  static int __init
  netx_console_setup(struct console *co, char *options)
  {
  	struct netx_port *sport;
  	int baud = 9600;
  	int bits = 8;
  	int parity = 'n';
  	int flow = 'n';
  
  	/*
  	 * Check whether an invalid uart number has been specified, and
  	 * if so, search for the first available port that does have
  	 * console support.
  	 */
  	if (co->index == -1 || co->index >= ARRAY_SIZE(netx_ports))
  		co->index = 0;
  	sport = &netx_ports[co->index];
  
  	if (options) {
  		uart_parse_options(options, &baud, &parity, &bits, &flow);
  	} else {
  		/* if the UART is enabled, assume it has been correctly setup
  		 * by the bootloader and get the options
  		 */
  		if (readl(sport->port.membase + UART_CR) & CR_UART_EN) {
  			netx_console_get_options(&sport->port, &baud,
  			&parity, &bits, &flow);
  		}
  
  	}
  
  	return uart_set_options(&sport->port, co, baud, parity, bits, flow);
  }
  
  static struct uart_driver netx_reg;
  static struct console netx_console = {
  	.name		= "ttyNX",
  	.write		= netx_console_write,
  	.device		= uart_console_device,
  	.setup		= netx_console_setup,
  	.flags		= CON_PRINTBUFFER,
  	.index		= -1,
  	.data		= &netx_reg,
  };
  
  static int __init netx_console_init(void)
  {
  	register_console(&netx_console);
  	return 0;
  }
  console_initcall(netx_console_init);
  
  #define NETX_CONSOLE	&netx_console
  #else
  #define NETX_CONSOLE	NULL
  #endif
  
  static struct uart_driver netx_reg = {
  	.owner          = THIS_MODULE,
  	.driver_name    = DRIVER_NAME,
  	.dev_name       = "ttyNX",
  	.major          = SERIAL_NX_MAJOR,
  	.minor          = MINOR_START,
  	.nr             = ARRAY_SIZE(netx_ports),
  	.cons           = NETX_CONSOLE,
  };
  
  static int serial_netx_suspend(struct platform_device *pdev, pm_message_t state)
  {
  	struct netx_port *sport = platform_get_drvdata(pdev);
  
  	if (sport)
  		uart_suspend_port(&netx_reg, &sport->port);
  
  	return 0;
  }
  
  static int serial_netx_resume(struct platform_device *pdev)
  {
  	struct netx_port *sport = platform_get_drvdata(pdev);
  
  	if (sport)
  		uart_resume_port(&netx_reg, &sport->port);
  
  	return 0;
  }
  
  static int serial_netx_probe(struct platform_device *pdev)
  {
  	struct uart_port *port = &netx_ports[pdev->id].port;
  
  	dev_info(&pdev->dev, "initialising
  ");
  
  	port->dev = &pdev->dev;
  
  	writel(1, port->membase + UART_RXFIFO_IRQLEVEL);
  	uart_add_one_port(&netx_reg, &netx_ports[pdev->id].port);
  	platform_set_drvdata(pdev, &netx_ports[pdev->id]);
  
  	return 0;
  }
  
  static int serial_netx_remove(struct platform_device *pdev)
  {
  	struct netx_port *sport = platform_get_drvdata(pdev);
  
  	if (sport)
  		uart_remove_one_port(&netx_reg, &sport->port);
  
  	return 0;
  }
  
  static struct platform_driver serial_netx_driver = {
  	.probe          = serial_netx_probe,
  	.remove         = serial_netx_remove,
  
  	.suspend	= serial_netx_suspend,
  	.resume		= serial_netx_resume,
  
  	.driver		= {
  		.name   = DRIVER_NAME,
  	},
  };
  
  static int __init netx_serial_init(void)
  {
  	int ret;
  
  	printk(KERN_INFO "Serial: NetX driver
  ");
  
  	ret = uart_register_driver(&netx_reg);
  	if (ret)
  		return ret;
  
  	ret = platform_driver_register(&serial_netx_driver);
  	if (ret != 0)
  		uart_unregister_driver(&netx_reg);
  
  	return 0;
  }
  
  static void __exit netx_serial_exit(void)
  {
  	platform_driver_unregister(&serial_netx_driver);
  	uart_unregister_driver(&netx_reg);
  }
  
  module_init(netx_serial_init);
  module_exit(netx_serial_exit);
  
  MODULE_AUTHOR("Sascha Hauer");
  MODULE_DESCRIPTION("NetX serial port driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("platform:" DRIVER_NAME);