arch/frv/kernel/gdb-io.c

   1 /* gdb-io.c: FR403 GDB stub I/O
   2  *
   3  * Copyright (C) 2003 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 License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/string.h>
  13 #include <linux/kernel.h>
  14 #include <linux/signal.h>
  15 #include <linux/sched.h>
  16 #include <linux/mm.h>
  17 #include <linux/console.h>
  18 #include <linux/init.h>
  19 #include <linux/serial_reg.h>
  20
  21 #include <asm/pgtable.h>
  22 #include <asm/system.h>
  23 #include <asm/irc-regs.h>
  24 #include <asm/timer-regs.h>
  25 #include <asm/gdb-stub.h>
  26 #include "gdb-io.h"
  27
  28 #ifdef CONFIG_GDBSTUB_UART0
  29 #define __UART(X) (*(volatile uint8_t *)(UART0_BASE + (UART_##X)))
  30 #define __UART_IRR_NMI 0xff0f0000
  31 #else /* CONFIG_GDBSTUB_UART1 */
  32 #define __UART(X) (*(volatile uint8_t *)(UART1_BASE + (UART_##X)))
  33 #define __UART_IRR_NMI 0xfff00000
  34 #endif
  35
  36 #define LSR_WAIT_FOR(STATE)                     \
  37 do {                                            \
  38         gdbstub_do_rx();                        \
  39 } while (!(__UART(LSR) & UART_LSR_##STATE))
  40
  41 #define FLOWCTL_QUERY(LINE)     ({ __UART(MSR) & UART_MSR_##LINE; })
  42 #define FLOWCTL_CLEAR(LINE)     do { __UART(MCR) &= ~UART_MCR_##LINE; mb(); } while (0)
  43 #define FLOWCTL_SET(LINE)       do { __UART(MCR) |= UART_MCR_##LINE;  mb(); } while (0)
  44
  45 #define FLOWCTL_WAIT_FOR(LINE)                  \
  46 do {                                            \
  47         gdbstub_do_rx();                        \
  48 } while(!FLOWCTL_QUERY(LINE))
  49
  50 /*****************************************************************************/
  51 /*
  52  * initialise the GDB stub
  53  * - called with PSR.ET==0, so can't incur external interrupts
  54  */
  55 void gdbstub_io_init(void)
  56 {
  57         /* set up the serial port */
  58         __UART(LCR) = UART_LCR_WLEN8; /* 1N8 */
  59         __UART(FCR) =
  60                 UART_FCR_ENABLE_FIFO |
  61                 UART_FCR_CLEAR_RCVR |
  62                 UART_FCR_CLEAR_XMIT |
  63                 UART_FCR_TRIGGER_1;
  64
  65         FLOWCTL_CLEAR(DTR);
  66         FLOWCTL_SET(RTS);
  67
  68 //      gdbstub_set_baud(115200);
  69
  70         /* we want to get serial receive interrupts */
  71         __UART(IER) = UART_IER_RDI | UART_IER_RLSI;
  72         mb();
  73
  74         __set_IRR(6, __UART_IRR_NMI);   /* map ERRs and UARTx to NMI */
  75
  76 } /* end gdbstub_io_init() */
  77
  78 /*****************************************************************************/
  79 /*
  80  * set up the GDB stub serial port baud rate timers
  81  */
  82 void gdbstub_set_baud(unsigned baud)
  83 {
  84         unsigned value, high, low;
  85         u8 lcr;
  86
  87         /* work out the divisor to give us the nearest higher baud rate */
  88         value = __serial_clock_speed_HZ / 16 / baud;
  89
  90         /* determine the baud rate range */
  91         high = __serial_clock_speed_HZ / 16 / value;
  92         low = __serial_clock_speed_HZ / 16 / (value + 1);
  93
  94         /* pick the nearest bound */
  95         if (low + (high - low) / 2 > baud)
  96                 value++;
  97
  98         lcr = __UART(LCR);
  99         __UART(LCR) |= UART_LCR_DLAB;
 100         mb();
 101         __UART(DLL) = value & 0xff;
 102         __UART(DLM) = (value >> 8) & 0xff;
 103         mb();
 104         __UART(LCR) = lcr;
 105         mb();
 106
 107 } /* end gdbstub_set_baud() */
 108
 109 /*****************************************************************************/
 110 /*
 111  * receive characters into the receive FIFO
 112  */
 113 void gdbstub_do_rx(void)
 114 {
 115         unsigned ix, nix;
 116
 117         ix = gdbstub_rx_inp;
 118
 119         while (__UART(LSR) & UART_LSR_DR) {
 120                 nix = (ix + 2) & 0xfff;
 121                 if (nix == gdbstub_rx_outp)
 122                         break;
 123
 124                 gdbstub_rx_buffer[ix++] = __UART(LSR);
 125                 gdbstub_rx_buffer[ix++] = __UART(RX);
 126                 ix = nix;
 127         }
 128
 129         gdbstub_rx_inp = ix;
 130
 131         __clr_RC(15);
 132         __clr_IRL();
 133
 134 } /* end gdbstub_do_rx() */
 135
 136 /*****************************************************************************/
 137 /*
 138  * wait for a character to come from the debugger
 139  */
 140 int gdbstub_rx_char(unsigned char *_ch, int nonblock)
 141 {
 142         unsigned ix;
 143         u8 ch, st;
 144
 145         *_ch = 0xff;
 146
 147         if (gdbstub_rx_unget) {
 148                 *_ch = gdbstub_rx_unget;
 149                 gdbstub_rx_unget = 0;
 150                 return 0;
 151         }
 152
 153  try_again:
 154         gdbstub_do_rx();
 155
 156         /* pull chars out of the buffer */
 157         ix = gdbstub_rx_outp;
 158         if (ix == gdbstub_rx_inp) {
 159                 if (nonblock)
 160                         return -EAGAIN;
 161                 //watchdog_alert_counter = 0;
 162                 goto try_again;
 163         }
 164
 165         st = gdbstub_rx_buffer[ix++];
 166         ch = gdbstub_rx_buffer[ix++];
 167         gdbstub_rx_outp = ix & 0x00000fff;
 168
 169         if (st & UART_LSR_BI) {
 170                 gdbstub_proto("### GDB Rx Break Detected ###\n");
 171                 return -EINTR;
 172         }
 173         else if (st & (UART_LSR_FE|UART_LSR_OE|UART_LSR_PE)) {
 174                 gdbstub_proto("### GDB Rx Error (st=%02x) ###\n",st);
 175                 return -EIO;
 176         }
 177         else {
 178                 gdbstub_proto("### GDB Rx %02x (st=%02x) ###\n",ch,st);
 179                 *_ch = ch & 0x7f;
 180                 return 0;
 181         }
 182
 183 } /* end gdbstub_rx_char() */
 184
 185 /*****************************************************************************/
 186 /*
 187  * send a character to the debugger
 188  */
 189 void gdbstub_tx_char(unsigned char ch)
 190 {
 191         FLOWCTL_SET(DTR);
 192         LSR_WAIT_FOR(THRE);
 193 //      FLOWCTL_WAIT_FOR(CTS);
 194
 195         if (ch == 0x0a) {
 196                 __UART(TX) = 0x0d;
 197                 mb();
 198                 LSR_WAIT_FOR(THRE);
 199 //              FLOWCTL_WAIT_FOR(CTS);
 200         }
 201         __UART(TX) = ch;
 202         mb();
 203
 204         FLOWCTL_CLEAR(DTR);
 205 } /* end gdbstub_tx_char() */
 206
 207 /*****************************************************************************/
 208 /*
 209  * send a character to the debugger
 210  */
 211 void gdbstub_tx_flush(void)
 212 {
 213         LSR_WAIT_FOR(TEMT);
 214         LSR_WAIT_FOR(THRE);
 215         FLOWCTL_CLEAR(DTR);
 216 } /* end gdbstub_tx_flush() */