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/* 16550 serial driver for gdbstub I/O
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/console.h>
#include <linux/init.h>
#include <linux/nmi.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/gdb-stub.h>
#include <asm/exceptions.h>
#include <asm/serial-regs.h>
#include <unit/serial.h>
/*
* initialise the GDB stub
*/
void gdbstub_io_init(void)
{
u16 tmp;
/* set up the serial port */
GDBPORT_SERIAL_LCR = UART_LCR_WLEN8; /* 1N8 */
GDBPORT_SERIAL_FCR = (UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR |
UART_FCR_CLEAR_XMIT);
FLOWCTL_CLEAR(DTR);
FLOWCTL_SET(RTS);
gdbstub_io_set_baud(115200);
/* we want to get serial receive interrupts */
XIRQxICR(GDBPORT_SERIAL_IRQ) = 0;
tmp = XIRQxICR(GDBPORT_SERIAL_IRQ);
IVAR0 = EXCEP_IRQ_LEVEL0;
set_intr_stub(EXCEP_IRQ_LEVEL0, gdbstub_io_rx_handler);
XIRQxICR(GDBPORT_SERIAL_IRQ) &= ~GxICR_REQUEST;
XIRQxICR(GDBPORT_SERIAL_IRQ) = GxICR_ENABLE | GxICR_LEVEL_0;
tmp = XIRQxICR(GDBPORT_SERIAL_IRQ);
GDBPORT_SERIAL_IER = UART_IER_RDI | UART_IER_RLSI;
/* permit level 0 IRQs to take place */
asm volatile(
" and %0,epsw \n"
" or %1,epsw \n"
:
: "i"(~EPSW_IM), "i"(EPSW_IE | EPSW_IM_1)
);
}
/*
* set up the GDB stub serial port baud rate timers
*/
void gdbstub_io_set_baud(unsigned baud)
{
unsigned value;
u8 lcr;
value = 18432000 / 16 / baud;
lcr = GDBPORT_SERIAL_LCR;
GDBPORT_SERIAL_LCR |= UART_LCR_DLAB;
GDBPORT_SERIAL_DLL = value & 0xff;
GDBPORT_SERIAL_DLM = (value >> 8) & 0xff;
GDBPORT_SERIAL_LCR = lcr;
}
/*
* wait for a character to come from the debugger
*/
int gdbstub_io_rx_char(unsigned char *_ch, int nonblock)
{
unsigned ix;
u8 ch, st;
*_ch = 0xff;
if (gdbstub_rx_unget) {
*_ch = gdbstub_rx_unget;
gdbstub_rx_unget = 0;
return 0;
}
try_again:
/* pull chars out of the buffer */
ix = gdbstub_rx_outp;
barrier();
if (ix == gdbstub_rx_inp) {
if (nonblock)
return -EAGAIN;
#ifdef CONFIG_MN10300_WD_TIMER
watchdog_alert_counter = 0;
#endif /* CONFIG_MN10300_WD_TIMER */
goto try_again;
}
ch = gdbstub_rx_buffer[ix++];
st = gdbstub_rx_buffer[ix++];
barrier();
gdbstub_rx_outp = ix & 0x00000fff;
if (st & UART_LSR_BI) {
gdbstub_proto("### GDB Rx Break Detected ###\n");
return -EINTR;
} else if (st & (UART_LSR_FE | UART_LSR_OE | UART_LSR_PE)) {
gdbstub_proto("### GDB Rx Error (st=%02x) ###\n", st);
return -EIO;
} else {
gdbstub_proto("### GDB Rx %02x (st=%02x) ###\n", ch, st);
*_ch = ch & 0x7f;
return 0;
}
}
/*
* send a character to the debugger
*/
void gdbstub_io_tx_char(unsigned char ch)
{
FLOWCTL_SET(DTR);
LSR_WAIT_FOR(THRE);
/* FLOWCTL_WAIT_FOR(CTS); */
if (ch == 0x0a) {
GDBPORT_SERIAL_TX = 0x0d;
LSR_WAIT_FOR(THRE);
/* FLOWCTL_WAIT_FOR(CTS); */
}
GDBPORT_SERIAL_TX = ch;
FLOWCTL_CLEAR(DTR);
}
/*
* send a character to the debugger
*/
void gdbstub_io_tx_flush(void)
{
LSR_WAIT_FOR(TEMT);
LSR_WAIT_FOR(THRE);
FLOWCTL_CLEAR(DTR);
}
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