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