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

   * (C) Copyright 2004-2009

   * DENX Software Engineering
   * Wolfgang Denk, wd@denx.de

   *
   * Simple 16550A serial driver
   *
   * Originally from linux source (drivers/char/ps2ser.c)
   *
   * Used by the PS/2 multiplexer driver (ps2mult.c)
   *
   ***********************************************************************/
  
  #include <common.h>

  #include <asm/io.h>
  #include <asm/atomic.h>
  #include <ps2mult.h>

  /* This is needed for ns16550.h */
  #ifndef CONFIG_SYS_NS16550_REG_SIZE
  #define CONFIG_SYS_NS16550_REG_SIZE 1

  #endif

  #include <ns16550.h>

  DECLARE_GLOBAL_DATA_PTR;

  /* #define	DEBUG */
  
  #define PS2SER_BAUD	57600

  #if CONFIG_PS2SERIAL == 1

  #define COM_BASE (CONFIG_SYS_CCSRBAR+0x4500)

  #elif CONFIG_PS2SERIAL == 2

  #define COM_BASE (CONFIG_SYS_CCSRBAR+0x4600)

  #else
  #error CONFIG_PS2SERIAL must be in 1 ... 2
  #endif

  static int	ps2ser_getc_hw(void);
  static void	ps2ser_interrupt(void *dev_id);
  
  extern struct	serial_state rs_table[]; /* in serial.c */

  
  static u_char	ps2buf[PS2BUF_SIZE];
  static atomic_t	ps2buf_cnt;
  static int	ps2buf_in_idx;
  static int	ps2buf_out_idx;

  int ps2ser_init(void)
  {
  	NS16550_t com_port = (NS16550_t)COM_BASE;
  
  	com_port->ier = 0x00;

  	com_port->lcr = UART_LCR_BKSE | UART_LCR_8N1;

  	com_port->dll = (CONFIG_SYS_NS16550_CLK / 16 / PS2SER_BAUD) & 0xff;
  	com_port->dlm = ((CONFIG_SYS_NS16550_CLK / 16 / PS2SER_BAUD) >> 8) & 0xff;

  	com_port->lcr = UART_LCR_8N1;
  	com_port->mcr = (UART_MCR_DTR | UART_MCR_RTS);
  	com_port->fcr = (UART_FCR_FIFO_EN | UART_FCR_RXSR | UART_FCR_TXSR);

  
  	return (0);
  }

  void ps2ser_putc(int chr)
  {

  	NS16550_t com_port = (NS16550_t)COM_BASE;

  	debug(">>>> 0x%02x
  ", chr);

  	while ((com_port->lsr & UART_LSR_THRE) == 0);

  	com_port->thr = chr;

  }
  
  static int ps2ser_getc_hw(void)
  {

  	NS16550_t com_port = (NS16550_t)COM_BASE;

  	int res = -1;

  	if (com_port->lsr & UART_LSR_DR) {

  		res = com_port->rbr;
  	}

  
  	return res;
  }
  
  int ps2ser_getc(void)
  {
  	volatile int chr;
  	int flags;

  	debug("<< ");

  
  	flags = disable_interrupts();
  
  	do {
  		if (atomic_read(&ps2buf_cnt) != 0) {
  			chr = ps2buf[ps2buf_out_idx++];
  			ps2buf_out_idx &= (PS2BUF_SIZE - 1);
  			atomic_dec(&ps2buf_cnt);
  		} else {
  			chr = ps2ser_getc_hw();
  		}
  	}
  	while (chr < 0);

  	if (flags)
  		enable_interrupts();

  	debug("0x%02x
  ", chr);

  
  	return chr;
  }
  
  int ps2ser_check(void)
  {
  	int flags;
  
  	flags = disable_interrupts();
  	ps2ser_interrupt(NULL);
  	if (flags) enable_interrupts();
  
  	return atomic_read(&ps2buf_cnt);
  }
  
  static void ps2ser_interrupt(void *dev_id)
  {

  	NS16550_t com_port = (NS16550_t)COM_BASE;

  	int chr;

  	int status;

  
  	do {
  		chr = ps2ser_getc_hw();

  		status = com_port->lsr;

  		if (chr < 0) continue;
  
  		if (atomic_read(&ps2buf_cnt) < PS2BUF_SIZE) {
  			ps2buf[ps2buf_in_idx++] = chr;
  			ps2buf_in_idx &= (PS2BUF_SIZE - 1);
  			atomic_inc(&ps2buf_cnt);
  		} else {
  			printf ("ps2ser.c: buffer overflow
  ");
  		}

  	} while (status & UART_LSR_DR);

  	if (atomic_read(&ps2buf_cnt)) {
  		ps2mult_callback(atomic_read(&ps2buf_cnt));
  	}
  }