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gdb-io.c
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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 ([email protected])
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) =
63 
66 
67 // gdbstub_set_baud(115200);
68 
69  /* we want to get serial receive interrupts */
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);
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);
192 // FLOWCTL_WAIT_FOR(CTS);
193 
194  if (ch == 0x0a) {
195  __UART(TX) = 0x0d;
196  mb();
198 // FLOWCTL_WAIT_FOR(CTS);
199  }
200  __UART(TX) = ch;
201  mb();
202 
204 } /* end gdbstub_tx_char() */
205 
206 /*****************************************************************************/
207 /*
208  * send a character to the debugger
209  */
211 {
215 } /* end gdbstub_tx_flush() */