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/* 16450.h -- Definition of types and structures for 8250/16450 serial UART
   Copyright (C) 2000 Damjan Lampret, lampret@opencores.org
 
This file is part of OpenRISC 1000 Architectural Simulator.
 
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., 675 Mass Ave, Cambridge, MA 02139, USA. */
 
/* Prototypes */
void uart_reset();
void uart_clock();
 
/* Definitions */
#define UART_ADDR_SPACE   (8)         /* UART memory address space size in bytes */
#define UART_RX_BUF       (8192)      /* VAPI should not send more that this amout of char before requesting something back */
#define UART_MAX_FIFO_LEN (16)        /* rx FIFO for uart 16550 */
#define MAX_SKEW          (1)         /* max. clock skew in subclocks */
 
/* Registers */
 
struct dev_16450 {
  struct {
    unsigned char txbuf[UART_MAX_FIFO_LEN];
    unsigned char rxbuf[UART_MAX_FIFO_LEN];
    unsigned char dll;
    unsigned char dlh;
    unsigned char ier;
    unsigned char iir;
    unsigned char lcr;
    unsigned char mcr;
    unsigned char lsr;
    unsigned char msr;
    unsigned char scr;
  } regs;   /* Visible registers */
  struct {
    unsigned long txser;    /* Character just sending */
    unsigned long rxser;    /* Character just receiving */
    unsigned char loopback;
  } iregs;  /* Internal registers */
  struct {
    int txbuf_head;   
    int txbuf_tail;
    int rxbuf_head;
    int rxbuf_tail;
    unsigned int txser_full;
    unsigned int rxser_full;
    unsigned int txbuf_full;
    unsigned int rxbuf_full;
    unsigned char thre_int;
    unsigned long txser_clks;
    unsigned long rxser_clks;
  } istat;  /* Internal status */
 
  /* Clocks per char */
  unsigned long char_clks;  
 
  /* VAPI internal registers */
  struct {
    unsigned long char_clks;
    int dll, dlh;
    int lcr;
    int skew;
    int next_break;
    int next_break_cnt;
    int cur_break;
    int cur_break_cnt;
  } vapi;
 
  /* Required by VAPI - circular buffer */
 unsigned long vapi_buf[UART_RX_BUF];  /* Buffer to store incoming characters to,
                                          since we cannot handle them so fast - we
                                          are serial */
  int vapi_buf_head_ptr;               /* Where we write to */
  int vapi_buf_tail_ptr;               /* Where we read from */
 
  /* Length of FIFO, 16 for 16550, 1 for 16450 */
  int fifo_len;
 
  /* Required by standard file streams */
  FILE * rxfs;
  FILE * txfs;
};
 
/*
 * Addresses of visible registers
 *
 */
#define UART_RXBUF  0 /* R: Rx buffer, DLAB=0 */
#define UART_TXBUF  0 /* W: Tx buffer, DLAB=0 */
#define UART_DLL  0 /* R/W: Divisor Latch Low, DLAB=1 */
#define UART_DLH  1 /* R/W: Divisor Latch High, DLAB=1 */
#define UART_IER  1 /* R/W: Interrupt Enable Register */
#define UART_IIR  2 /* R: Interrupt ID Register */
#define UART_LCR  3 /* R/W: Line Control Register */
#define UART_MCR  4 /* W: Modem Control Register */
#define UART_LSR  5 /* R: Line Status Register */
#define UART_MSR  6 /* R: Modem Status Register */
#define UART_SCR  7 /* R/W: Scratch Register */
 
/*
 * R/W masks for valid bits in 8250/16450 (mask out 16550 and later bits)
 *
 */
#define UART_VALID_LCR  0xff
#define UART_VALID_LSR  0x7f
#define UART_VALID_IIR  0x07
#define UART_VALID_IER  0x0f
#define UART_VALID_MCR  0x1f
#define UART_VALID_MSR  0xff
 
/*
 * Bit definitions for the Line Control Register
 * 
 */
#define UART_LCR_DLAB 0x80  /* Divisor latch access bit */
#define UART_LCR_SBC  0x40  /* Set break control */
#define UART_LCR_SPAR 0x20  /* Stick parity (?) */
#define UART_LCR_EPAR 0x10  /* Even parity select */
#define UART_LCR_PARITY 0x08  /* Parity Enable */
#define UART_LCR_STOP 0x04  /* Stop bits: 0=1 stop bit, 1= 2 stop bits */
#define UART_LCR_WLEN5  0x00  /* Wordlength: 5 bits */
#define UART_LCR_WLEN6  0x01  /* Wordlength: 6 bits */
#define UART_LCR_WLEN7  0x02  /* Wordlength: 7 bits */
#define UART_LCR_WLEN8  0x03  /* Wordlength: 8 bits */
#define UART_LCR_RESET  0x03
/*
 * Bit definitions for the Line Status Register
 */
#define UART_LSR_TXSERE 0x40  /* Transmitter serial register empty */
#define UART_LSR_TXBUFE 0x20  /* Transmitter buffer register empty */
#define UART_LSR_BREAK  0x10  /* Break interrupt indicator */
#define UART_LSR_FRAME  0x08  /* Frame error indicator */
#define UART_LSR_PARITY 0x04  /* Parity error indicator */
#define UART_LSR_OVRRUN 0x02  /* Overrun error indicator */
#define UART_LSR_RDRDY  0x01  /* Receiver data ready */
 
/*
 * Bit definitions for the Interrupt Identification Register
 */
#define UART_IIR_NO_INT 0x01  /* No interrupts pending */
#define UART_IIR_ID 0x06  /* Mask for the interrupt ID */
 
#define UART_IIR_MSI  0x00  /* Modem status interrupt (Low priority) */
#define UART_IIR_THRI 0x02  /* Transmitter holding register empty */
#define UART_IIR_RDI  0x04  /* Receiver data interrupt */
#define UART_IIR_RLSI 0x06  /* Receiver line status interrupt (High p.) */
 
/*
 * Bit definitions for the Interrupt Enable Register
 */
#define UART_IER_MSI  0x08  /* Enable Modem status interrupt */
#define UART_IER_RLSI 0x04  /* Enable receiver line status interrupt */
#define UART_IER_THRI 0x02  /* Enable Transmitter holding register int. */
#define UART_IER_RDI  0x01  /* Enable receiver data interrupt */
 
/*
 * Bit definitions for the Modem Control Register
 */
#define UART_MCR_LOOP 0x10  /* Enable loopback mode */
#define UART_MCR_AUX2 0x08  /* Auxilary 2  */
#define UART_MCR_AUX1 0x04  /* Auxilary 1 */
#define UART_MCR_RTS  0x02  /* Force RTS */
#define UART_MCR_DTR  0x01  /* Force DTR */
 
/*
 * Bit definitions for the Modem Status Register
 */
#define UART_MSR_DCD  0x80  /* Data Carrier Detect */
#define UART_MSR_RI   0x40  /* Ring Indicator */
#define UART_MSR_DSR  0x20  /* Data Set Ready */
#define UART_MSR_CTS  0x10  /* Clear to Send */
#define UART_MSR_DDCD 0x08  /* Delta DCD */
#define UART_MSR_TERI 0x04  /* Trailing edge ring indicator */
#define UART_MSR_DDSR 0x02  /* Delta DSR */
#define UART_MSR_DCTS 0x01  /* Delta CTS */
 
/*
 * Various definitions
 */
#define MAX_BREAK_COUNT 12