text: /*
   * (C) Copyright 2003
   *
   * Pantelis Antoniou <panto@intracom.gr>
   * Intracom S.A.
   *
   * See file CREDITS for list of people who contributed to this
   * project.
   *
   * 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.
   *
   * 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
   */
  
  #include <common.h>
  #include <watchdog.h>
  #include <serial.h>
  #include <linux/compiler.h>
  
  DECLARE_GLOBAL_DATA_PTR;
  
  /**************************************************************/
  
  /* convienient macros */
  #define MAX3100_SPI_RXD() (MAX3100_SPI_RXD_PORT & MAX3100_SPI_RXD_BIT)
  
  #define MAX3100_SPI_TXD(x) \
  	do { \
  		if (x) \
  			MAX3100_SPI_TXD_PORT |=  MAX3100_SPI_TXD_BIT; \
  		else \
  			MAX3100_SPI_TXD_PORT &= ~MAX3100_SPI_TXD_BIT; \
  	} while(0)
  
  #define MAX3100_SPI_CLK(x) \
  	do { \
  		if (x) \
  			MAX3100_SPI_CLK_PORT |=  MAX3100_SPI_CLK_BIT; \
  		else \
  			MAX3100_SPI_CLK_PORT &= ~MAX3100_SPI_CLK_BIT; \
  	} while(0)
  
  #define MAX3100_SPI_CLK_TOGGLE() (MAX3100_SPI_CLK_PORT ^= MAX3100_SPI_CLK_BIT)
  
  #define MAX3100_CS(x) \
  	do { \
  		if (x) \
  			MAX3100_CS_PORT |=  MAX3100_CS_BIT; \
  		else \
  			MAX3100_CS_PORT &= ~MAX3100_CS_BIT; \
  	} while(0)
  
  /**************************************************************/
  
  /* MAX3100 definitions */
  
  #define MAX3100_WC	(3 << 14)		/* write configuration */
  #define MAX3100_RC	(1 << 14)		/* read  configuration */
  #define MAX3100_WD	(2 << 14)		/* write data          */
  #define MAX3100_RD	(0 << 14)		/* read  data          */
  
  /* configuration register bits */
  #define MAX3100_FEN	(1 << 13)		/* FIFO enable           */
  #define MAX3100_SHDN    (1 << 12)		/* shutdown bit          */
  #define MAX3100_TM	(1 << 11)		/* T bit irq mask        */
  #define MAX3100_RM	(1 << 10)		/* R bit irq mask        */
  #define MAX3100_PM	(1 <<  9)		/* P bit irq mask        */
  #define MAX3100_RAM	(1 <<  8)		/* mask for RA/FE bit    */
  #define MAX3100_IR	(1 <<  7)		/* IRDA timing mode      */
  #define MAX3100_ST	(1 <<  6)		/* transmit stop bit     */
  #define MAX3100_PE	(1 <<  5)		/* parity enable bit     */
  #define MAX3100_L	(1 <<  4)		/* Length bit            */
  #define MAX3100_B_MASK	(0x000F)		/* baud rate bits mask   */
  #define MAX3100_B(x)	((x) & 0x000F)	/* baud rate select bits */
  
  /* data register bits (write) */
  #define MAX3100_TE	(1 << 10)		/* transmit enable bit (active low)        */
  #define MAX3100_RTS	(1 <<  9)		/* request-to-send bit (inverted ~RTS pin) */
  
  /* data register bits (read) */
  #define MAX3100_RA	(1 << 10)		/* receiver activity when in shutdown mode */
  #define MAX3100_FE	(1 << 10)		/* framing error when in normal mode       */
  #define MAX3100_CTS	(1 <<  9)		/* clear-to-send bit (inverted ~CTS pin)   */
  
  /* data register bits (both directions) */
  #define MAX3100_R	(1 << 15)		/* receive bit    */
  #define MAX3100_T	(1 << 14)		/* transmit bit   */
  #define MAX3100_P	(1 <<  8)		/* parity bit     */
  #define MAX3100_D_MASK	0x00FF                  /* data bits mask */
  #define MAX3100_D(x)	((x) & 0x00FF)		/* data bits      */
  
  /* these definitions are valid only for fOSC = 3.6864MHz */
  #define MAX3100_B_230400        MAX3100_B(0)
  #define MAX3100_B_115200        MAX3100_B(1)
  #define MAX3100_B_57600         MAX3100_B(2)
  #define MAX3100_B_38400         MAX3100_B(9)
  #define MAX3100_B_19200         MAX3100_B(10)
  #define MAX3100_B_9600          MAX3100_B(11)
  #define MAX3100_B_4800          MAX3100_B(12)
  #define MAX3100_B_2400          MAX3100_B(13)
  #define MAX3100_B_1200          MAX3100_B(14)
  #define MAX3100_B_600           MAX3100_B(15)
  
  /**************************************************************/
  
  static inline unsigned int max3100_transfer(unsigned int val)
  {
  	unsigned int rx;
  	int b;
  
  	MAX3100_SPI_CLK(0);
  	MAX3100_CS(0);
  
  	rx = 0; b = 16;
  	while (--b >= 0) {
  		MAX3100_SPI_TXD(val & 0x8000);
  		val <<= 1;
  		MAX3100_SPI_CLK_TOGGLE();
  		udelay(1);
  		rx <<= 1;
  		if (MAX3100_SPI_RXD())
  			rx |= 1;
  		MAX3100_SPI_CLK_TOGGLE();
  		udelay(1);
  	}
  
  	MAX3100_SPI_CLK(1);
  	MAX3100_CS(1);
  
  	return rx;
  }
  
  /**************************************************************/
  
  /* must be power of 2 */
  #define RXFIFO_SZ	16
  
  static int rxfifo_cnt;
  static int rxfifo_in;
  static int rxfifo_out;
  static unsigned char rxfifo_buf[16];
  
  static void max3100_serial_putc_raw(int c)
  {
  	unsigned int rx;
  
  	while (((rx = max3100_transfer(MAX3100_RC)) & MAX3100_T) == 0)
  		WATCHDOG_RESET();
  
  	rx = max3100_transfer(MAX3100_WD | (c & 0xff));
  	if ((rx & MAX3100_RD) != 0 && rxfifo_cnt < RXFIFO_SZ) {
  		rxfifo_cnt++;
  		rxfifo_buf[rxfifo_in++] = rx & 0xff;
  		rxfifo_in &= RXFIFO_SZ - 1;
  	}
  }
  
  static int max3100_serial_getc(void)
  {
  	int c;
  	unsigned int rx;
  
  	while (rxfifo_cnt == 0) {
  		rx = max3100_transfer(MAX3100_RD);
  		if ((rx & MAX3100_R) != 0) {
  			do {
  				rxfifo_cnt++;
  				rxfifo_buf[rxfifo_in++] = rx & 0xff;
  				rxfifo_in &= RXFIFO_SZ - 1;
  
  				if (rxfifo_cnt >= RXFIFO_SZ)
  					break;
  			} while (((rx = max3100_transfer(MAX3100_RD)) & MAX3100_R) != 0);
  		}
  		WATCHDOG_RESET();
  	}
  
  	rxfifo_cnt--;
  	c = rxfifo_buf[rxfifo_out++];
  	rxfifo_out &= RXFIFO_SZ - 1;
  	return c;
  }
  
  static int max3100_serial_tstc(void)
  {
  	unsigned int rx;
  
  	if (rxfifo_cnt > 0)
  		return 1;
  
  	rx = max3100_transfer(MAX3100_RD);
  	if ((rx & MAX3100_R) == 0)
  		return 0;
  
  	do {
  		rxfifo_cnt++;
  		rxfifo_buf[rxfifo_in++] = rx & 0xff;
  		rxfifo_in &= RXFIFO_SZ - 1;
  
  		if (rxfifo_cnt >= RXFIFO_SZ)
  			break;
  	} while (((rx = max3100_transfer(MAX3100_RD)) & MAX3100_R) != 0);
  
  	return 1;
  }
  
  static int max3100_serial_init(void)
  {
  	unsigned int wconf, rconf;
  	int i;
  
  	wconf = 0;
  
  	/* Set baud rate */
  	switch (gd->baudrate) {
  		case 1200:
  			wconf = MAX3100_B_1200;
  			break;
  		case 2400:
  			wconf = MAX3100_B_2400;
  			break;
  		case 4800:
  			wconf = MAX3100_B_4800;
  			break;
  		case 9600:
  			wconf = MAX3100_B_9600;
  			break;
  		case 19200:
  			wconf = MAX3100_B_19200;
  			break;
  		case 38400:
  			wconf = MAX3100_B_38400;
  			break;
  		case 57600:
  			wconf = MAX3100_B_57600;
  			break;
  		default:
  		case 115200:
  			wconf = MAX3100_B_115200;
  			break;
  		case 230400:
  			wconf = MAX3100_B_230400;
  			break;
  	}
  
  	/* try for 10ms, with a 100us gap */
  	for (i = 0; i < 10000; i += 100) {
  
  		max3100_transfer(MAX3100_WC | wconf);
  		rconf = max3100_transfer(MAX3100_RC) & 0x3fff;
  
  		if (rconf == wconf)
  			break;
  		udelay(100);
  	}
  
  	rxfifo_in = rxfifo_out = rxfifo_cnt = 0;
  
  	return (0);
  }
  
  static void max3100_serial_putc(const char c)
  {
  	if (c == '\n')
  		max3100_serial_putc_raw('\r');
  
  	max3100_serial_putc_raw(c);
  }
  
  static void max3100_serial_puts(const char *s)
  {
  	while (*s)
  		max3100_serial_putc_raw(*s++);
  }
  
  static void max3100_serial_setbrg(void)
  {
  }
  
  static struct serial_device max3100_serial_drv = {
  	.name	= "max3100_serial",
  	.start	= max3100_serial_init,
  	.stop	= NULL,
  	.setbrg	= max3100_serial_setbrg,
  	.putc	= max3100_serial_putc,
  	.puts	= max3100_serial_puts,
  	.getc	= max3100_serial_getc,
  	.tstc	= max3100_serial_tstc,
  };
  
  void max3100_serial_initialize(void)
  {
  	serial_register(&max3100_serial_drv);
  }
  
  __weak struct serial_device *default_serial_console(void)
  {
  	return &max3100_serial_drv;
  }
  