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