LXR linux/arch/mn10300/kernel/gdb-io-serial.c

   1/* 16550 serial driver for gdbstub I/O
   2 *
   3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public Licence
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the Licence, or (at your option) any later version.
  10 */
  11#include <linux/string.h>
  12#include <linux/kernel.h>
  13#include <linux/signal.h>
  14#include <linux/sched.h>
  15#include <linux/mm.h>
  16#include <linux/console.h>
  17#include <linux/init.h>
  18#include <linux/nmi.h>
  19
  20#include <asm/pgtable.h>
  21#include <asm/system.h>
  22#include <asm/gdb-stub.h>
  23#include <asm/exceptions.h>
  24#include <asm/serial-regs.h>
  25#include <unit/serial.h>
  26#include <asm/smp.h>
  27
  28/*
  29 * initialise the GDB stub
  30 */
  31void gdbstub_io_init(void)
  32{
  33        u16 tmp;
  34
  35        /* set up the serial port */
  36        GDBPORT_SERIAL_LCR = UART_LCR_WLEN8; /* 1N8 */
  37        GDBPORT_SERIAL_FCR = (UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR |
  38                              UART_FCR_CLEAR_XMIT);
  39
  40        FLOWCTL_CLEAR(DTR);
  41        FLOWCTL_SET(RTS);
  42
  43        gdbstub_io_set_baud(115200);
  44
  45        /* we want to get serial receive interrupts */
  46        XIRQxICR(GDBPORT_SERIAL_IRQ) = 0;
  47        tmp = XIRQxICR(GDBPORT_SERIAL_IRQ);
  48
  49#if   CONFIG_GDBSTUB_IRQ_LEVEL == 0
  50        IVAR0 = EXCEP_IRQ_LEVEL0;
  51#elif CONFIG_GDBSTUB_IRQ_LEVEL == 1
  52        IVAR1 = EXCEP_IRQ_LEVEL1;
  53#elif CONFIG_GDBSTUB_IRQ_LEVEL == 2
  54        IVAR2 = EXCEP_IRQ_LEVEL2;
  55#elif CONFIG_GDBSTUB_IRQ_LEVEL == 3
  56        IVAR3 = EXCEP_IRQ_LEVEL3;
  57#elif CONFIG_GDBSTUB_IRQ_LEVEL == 4
  58        IVAR4 = EXCEP_IRQ_LEVEL4;
  59#elif CONFIG_GDBSTUB_IRQ_LEVEL == 5
  60        IVAR5 = EXCEP_IRQ_LEVEL5;
  61#else
  62#error "Unknown irq level for gdbstub."
  63#endif
  64
  65        set_intr_stub(NUM2EXCEP_IRQ_LEVEL(CONFIG_GDBSTUB_IRQ_LEVEL),
  66                gdbstub_io_rx_handler);
  67
  68        XIRQxICR(GDBPORT_SERIAL_IRQ) &= ~GxICR_REQUEST;
  69        XIRQxICR(GDBPORT_SERIAL_IRQ) =
  70                GxICR_ENABLE | NUM2GxICR_LEVEL(CONFIG_GDBSTUB_IRQ_LEVEL);
  71        tmp = XIRQxICR(GDBPORT_SERIAL_IRQ);
  72
  73        GDBPORT_SERIAL_IER = UART_IER_RDI | UART_IER_RLSI;
  74
  75        /* permit level 0 IRQs to take place */
  76        arch_local_change_intr_mask_level(
  77                NUM2EPSW_IM(CONFIG_GDBSTUB_IRQ_LEVEL + 1));
  78}
  79
  80/*
  81 * set up the GDB stub serial port baud rate timers
  82 */
  83void gdbstub_io_set_baud(unsigned baud)
  84{
  85        unsigned value;
  86        u8 lcr;
  87
  88        value = 18432000 / 16 / baud;
  89
  90        lcr = GDBPORT_SERIAL_LCR;
  91        GDBPORT_SERIAL_LCR |= UART_LCR_DLAB;
  92        GDBPORT_SERIAL_DLL = value & 0xff;
  93        GDBPORT_SERIAL_DLM = (value >> 8) & 0xff;
  94        GDBPORT_SERIAL_LCR = lcr;
  95}
  96
  97/*
  98 * wait for a character to come from the debugger
  99 */
 100int gdbstub_io_rx_char(unsigned char *_ch, int nonblock)
 101{
 102        unsigned ix;
 103        u8 ch, st;
 104#if defined(CONFIG_MN10300_WD_TIMER)
 105        int cpu;
 106#endif
 107
 108        *_ch = 0xff;
 109
 110        if (gdbstub_rx_unget) {
 111                *_ch = gdbstub_rx_unget;
 112                gdbstub_rx_unget = 0;
 113                return 0;
 114        }
 115
 116 try_again:
 117        /* pull chars out of the buffer */
 118        ix = gdbstub_rx_outp;
 119        barrier();
 120        if (ix == gdbstub_rx_inp) {
 121                if (nonblock)
 122                        return -EAGAIN;
 123#ifdef CONFIG_MN10300_WD_TIMER
 124        for (cpu = 0; cpu < NR_CPUS; cpu++)
 125                watchdog_alert_counter[cpu] = 0;
 126#endif
 127                goto try_again;
 128        }
 129
 130        ch = gdbstub_rx_buffer[ix++];
 131        st = gdbstub_rx_buffer[ix++];
 132        barrier();
 133        gdbstub_rx_outp = ix & 0x00000fff;
 134
 135        if (st & UART_LSR_BI) {
 136                gdbstub_proto("### GDB Rx Break Detected ###\n");
 137                return -EINTR;
 138        } else if (st & (UART_LSR_FE | UART_LSR_OE | UART_LSR_PE)) {
 139                gdbstub_proto("### GDB Rx Error (st=%02x) ###\n", st);
 140                return -EIO;
 141        } else {
 142                gdbstub_proto("### GDB Rx %02x (st=%02x) ###\n", ch, st);
 143                *_ch = ch & 0x7f;
 144                return 0;
 145        }
 146}
 147
 148/*
 149 * send a character to the debugger
 150 */
 151void gdbstub_io_tx_char(unsigned char ch)
 152{
 153        FLOWCTL_SET(DTR);
 154        LSR_WAIT_FOR(THRE);
 155        /* FLOWCTL_WAIT_FOR(CTS); */
 156
 157        if (ch == 0x0a) {
 158                GDBPORT_SERIAL_TX = 0x0d;
 159                LSR_WAIT_FOR(THRE);
 160                /* FLOWCTL_WAIT_FOR(CTS); */
 161        }
 162        GDBPORT_SERIAL_TX = ch;
 163
 164        FLOWCTL_CLEAR(DTR);
 165}
 166
 167/*
 168 * send a character to the debugger
 169 */
 170void gdbstub_io_tx_flush(void)
 171{
 172        LSR_WAIT_FOR(TEMT);
 173        LSR_WAIT_FOR(THRE);
 174        FLOWCTL_CLEAR(DTR);
 175}
 176