/*
* serialGT.c
*
* BRIEF MODULE DESCRIPTION
* Low Level Serial Port control for use
* with the Galileo EVB64120A MIPS eval board and
* its on board two channel 16552 Uart.
*
* Copyright (C) 2000 RidgeRun, Inc.
* Author: RidgeRun, Inc.
* glonnon@ridgerun.com, skranz@ridgerun.com, stevej@ridgerun.com
*
* 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 SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* 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.
*
*/
// Note:
// Serial CHANNELS - 0 is the bottom connector of evb64120A.
// (The one that maps to the "B" channel of the
// board's uart)
// 1 is the top connector of evb64120A.
// (The one that maps to the "A" channel of the
// board's uart)
int DEBUG_CHANNEL = 0; // See Note Above
int CONSOLE_CHANNEL = 1; // See Note Above
#define DUART 0xBD000000 /* Base address of Uart. */
#define CHANNELOFFSET 0x20 /* DUART+CHANNELOFFSET gets you to the ChanA
register set of the 16552 Uart device.
DUART+0 gets you to the ChanB register set.
*/
#define DUART_DELTA 0x4
#define FIFO_ENABLE 0x07
#define INT_ENABLE 0x04 /* default interrupt mask */
#define RBR 0x00
#define THR 0x00
#define DLL 0x00
#define IER 0x01
#define DLM 0x01
#define IIR 0x02
#define FCR 0x02
#define LCR 0x03
#define MCR 0x04
#define LSR 0x05
#define MSR 0x06
#define SCR 0x07
#define LCR_DLAB 0x80
#define XTAL 1843200
#define LSR_THRE 0x20
#define LSR_BI 0x10
#define LSR_DR 0x01
#define MCR_LOOP 0x10
#define ACCESS_DELAY 0x10000
/******************************
Routine:
Description:
******************************/
int inreg(int channel, int reg)
{
int val;
val =
*((volatile unsigned char *) DUART +
(channel * CHANNELOFFSET) + (reg * DUART_DELTA));
return val;
}
/******************************
Routine:
Description:
******************************/
void outreg(int channel, int reg, unsigned char val)
{
*((volatile unsigned char *) DUART + (channel * CHANNELOFFSET)
+ (reg * DUART_DELTA)) = val;
}
/******************************
Routine:
Description:
Initialize the device driver.
******************************/
void serial_init(int channel)
{
/*
* Configure active port, (CHANNELOFFSET already set.)
*
* Set 8 bits, 1 stop bit, no parity.
*
* LCR<7> 0 divisor latch access bit
* LCR<6> 0 break control (1=send break)
* LCR<5> 0 stick parity (0=space, 1=mark)
* LCR<4> 0 parity even (0=odd, 1=even)
* LCR<3> 0 parity enable (1=enabled)
* LCR<2> 0 # stop bits (0=1, 1=1.5)
* LCR<1:0> 11 bits per character(00=5, 01=6, 10=7, 11=8)
*/
outreg(channel, LCR, 0x3);
outreg(channel, FCR, FIFO_ENABLE); /* Enable the FIFO */
outreg(channel, IER, INT_ENABLE); /* Enable appropriate interrupts */
}
/******************************
Routine:
Description:
Set the baud rate.
******************************/
void serial_set(int channel, unsigned long baud)
{
unsigned char sav_lcr;
/*
* Enable access to the divisor latches by setting DLAB in LCR.
*
*/
sav_lcr = inreg(channel, LCR);
#if 0
/*
* Set baud rate
*/
outreg(channel, LCR, LCR_DLAB | sav_lcr);
// outreg(DLL,(XTAL/(16*2*(baud))-2));
outreg(channel, DLL, XTAL / (16 * baud));
// outreg(DLM,(XTAL/(16*2*(baud))-2)>>8);
outreg(channel, DLM, (XTAL / (16 * baud)) >> 8);
#else
/*
* Note: Set baud rate, hardcoded here for rate of 115200
* since became unsure of above "baud rate" algorithm (??).
*/
outreg(channel, LCR, 0x83);
outreg(channel, DLM, 0x00); // See note above
outreg(channel, DLL, 0x02); // See note above.
outreg(channel, LCR, 0x03);
#endif
/*
* Restore line control register
*/
outreg(channel, LCR, sav_lcr);
}
/******************************
Routine:
Description:
Transmit a character.
******************************/
void serial_putc(int channel, int c)
{
while ((inreg(channel, LSR) & LSR_THRE) == 0);
outreg(channel, THR, c);
}
/******************************
Routine:
Description:
Read a received character if one is
available. Return -1 otherwise.
******************************/
int serial_getc(int channel)
{
if (inreg(channel, LSR) & LSR_DR) {
return inreg(channel, RBR);
}
return -1;
}
/******************************
Routine:
Description:
Used by embedded gdb client. (example; gdb-stub.c)
******************************/
char getDebugChar()
{
int val;
while ((val = serial_getc(DEBUG_CHANNEL)) == -1); // loop until we get a character in.
return (char) val;
}
/******************************
Routine:
Description:
Used by embedded gdb target. (example; gdb-stub.c)
******************************/
void putDebugChar(char c)
{
serial_putc(DEBUG_CHANNEL, (int) c);
}
