1 /* debug-stub.c: debug-mode stub
2 *
3 * Copyright (C) 2004 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/init.h>
17 #include <linux/serial_reg.h>
18 #include <linux/start_kernel.h>
19
20 #include <asm/system.h>
21 #include <asm/serial-regs.h>
22 #include <asm/timer-regs.h>
23 #include <asm/irc-regs.h>
24 #include <asm/gdb-stub.h>
25 #include "gdb-io.h"
26
27 /* CPU board CON5 */
28 #define __UART0(X) (*(volatile uint8_t *)(UART0_BASE + (UART_##X)))
29
30 #define LSR_WAIT_FOR0(STATE) \
31 do { \
32 } while (!(__UART0(LSR) & UART_LSR_##STATE))
33
34 #define FLOWCTL_QUERY0(LINE) ({ __UART0(MSR) & UART_MSR_##LINE; })
35 #define FLOWCTL_CLEAR0(LINE) do { __UART0(MCR) &= ~UART_MCR_##LINE; } while (0)
36 #define FLOWCTL_SET0(LINE) do { __UART0(MCR) |= UART_MCR_##LINE; } while (0)
37
38 #define FLOWCTL_WAIT_FOR0(LINE) \
39 do { \
40 gdbstub_do_rx(); \
41 } while(!FLOWCTL_QUERY(LINE))
42
43 struct frv_debug_status __debug_status;
44
45 static void __init debug_stub_init(void);
46
47 /*****************************************************************************/
48 /*
49 * debug mode handler stub
50 * - we come here with the CPU in debug mode and with exceptions disabled
51 * - handle debugging services for userspace
52 */
debug_stub(void)53 asmlinkage void debug_stub(void)
54 {
55 unsigned long hsr0;
56 int type = 0;
57
58 static u8 inited = 0;
59 if (!inited) {
60 debug_stub_init();
61 type = -1;
62 inited = 1;
63 }
64
65 hsr0 = __get_HSR(0);
66 if (hsr0 & HSR0_ETMD)
67 __set_HSR(0, hsr0 & ~HSR0_ETMD);
68
69 /* disable single stepping */
70 __debug_status.dcr &= ~DCR_SE;
71
72 /* kernel mode can propose an exception be handled in debug mode by jumping to a special
73 * location */
74 if (__debug_frame->pc == (unsigned long) __break_hijack_kernel_event_breaks_here) {
75 /* replace the debug frame with the kernel frame and discard
76 * the top kernel context */
77 *__debug_frame = *__frame;
78 __frame = __debug_frame->next_frame;
79 __debug_status.brr = (__debug_frame->tbr & TBR_TT) << 12;
80 __debug_status.brr |= BRR_EB;
81 }
82
83 if (__debug_frame->pc == (unsigned long) __debug_bug_trap + 4) {
84 __debug_frame->pc = __debug_frame->lr;
85 type = __debug_frame->gr8;
86 }
87
88 #ifdef CONFIG_GDBSTUB
89 gdbstub(type);
90 #endif
91
92 if (hsr0 & HSR0_ETMD)
93 __set_HSR(0, __get_HSR(0) | HSR0_ETMD);
94
95 } /* end debug_stub() */
96
97 /*****************************************************************************/
98 /*
99 * debug stub initialisation
100 */
debug_stub_init(void)101 static void __init debug_stub_init(void)
102 {
103 __set_IRR(6, 0xff000000); /* map ERRs to NMI */
104 __set_IITMR(1, 0x20000000); /* ERR0/1, UART0/1 IRQ detect levels */
105
106 asm volatile(" movgs gr0,ibar0 \n"
107 " movgs gr0,ibar1 \n"
108 " movgs gr0,ibar2 \n"
109 " movgs gr0,ibar3 \n"
110 " movgs gr0,dbar0 \n"
111 " movgs gr0,dbmr00 \n"
112 " movgs gr0,dbmr01 \n"
113 " movgs gr0,dbdr00 \n"
114 " movgs gr0,dbdr01 \n"
115 " movgs gr0,dbar1 \n"
116 " movgs gr0,dbmr10 \n"
117 " movgs gr0,dbmr11 \n"
118 " movgs gr0,dbdr10 \n"
119 " movgs gr0,dbdr11 \n"
120 );
121
122 /* deal with debugging stub initialisation and initial pause */
123 if (__debug_frame->pc == (unsigned long) __debug_stub_init_break)
124 __debug_frame->pc = (unsigned long) start_kernel;
125
126 /* enable the debug events we want to trap */
127 __debug_status.dcr = DCR_EBE;
128
129 #ifdef CONFIG_GDBSTUB
130 gdbstub_init();
131 #endif
132
133 __clr_MASK_all();
134 __clr_MASK(15);
135 __clr_RC(15);
136
137 } /* end debug_stub_init() */
138
139 /*****************************************************************************/
140 /*
141 * kernel "exit" trap for gdb stub
142 */
debug_stub_exit(int status)143 void debug_stub_exit(int status)
144 {
145
146 #ifdef CONFIG_GDBSTUB
147 gdbstub_exit(status);
148 #endif
149
150 } /* end debug_stub_exit() */
151
152 /*****************************************************************************/
153 /*
154 * send string to serial port
155 */
debug_to_serial(const char * p,int n)156 void debug_to_serial(const char *p, int n)
157 {
158 char ch;
159
160 for (; n > 0; n--) {
161 ch = *p++;
162 FLOWCTL_SET0(DTR);
163 LSR_WAIT_FOR0(THRE);
164 // FLOWCTL_WAIT_FOR(CTS);
165
166 if (ch == 0x0a) {
167 __UART0(TX) = 0x0d;
168 mb();
169 LSR_WAIT_FOR0(THRE);
170 // FLOWCTL_WAIT_FOR(CTS);
171 }
172 __UART0(TX) = ch;
173 mb();
174
175 FLOWCTL_CLEAR0(DTR);
176 }
177
178 } /* end debug_to_serial() */
179
180 /*****************************************************************************/
181 /*
182 * send string to serial port
183 */
debug_to_serial2(const char * fmt,...)184 void debug_to_serial2(const char *fmt, ...)
185 {
186 va_list va;
187 char buf[64];
188 int n;
189
190 va_start(va, fmt);
191 n = vsprintf(buf, fmt, va);
192 va_end(va);
193
194 debug_to_serial(buf, n);
195
196 } /* end debug_to_serial2() */
197
198 /*****************************************************************************/
199 /*
200 * set up the ttyS0 serial port baud rate timers
201 */
console_set_baud(unsigned baud)202 void __init console_set_baud(unsigned baud)
203 {
204 unsigned value, high, low;
205 u8 lcr;
206
207 /* work out the divisor to give us the nearest higher baud rate */
208 value = __serial_clock_speed_HZ / 16 / baud;
209
210 /* determine the baud rate range */
211 high = __serial_clock_speed_HZ / 16 / value;
212 low = __serial_clock_speed_HZ / 16 / (value + 1);
213
214 /* pick the nearest bound */
215 if (low + (high - low) / 2 > baud)
216 value++;
217
218 lcr = __UART0(LCR);
219 __UART0(LCR) |= UART_LCR_DLAB;
220 mb();
221 __UART0(DLL) = value & 0xff;
222 __UART0(DLM) = (value >> 8) & 0xff;
223 mb();
224 __UART0(LCR) = lcr;
225 mb();
226
227 } /* end console_set_baud() */
228
229 /*****************************************************************************/
230 /*
231 *
232 */
console_get_baud(void)233 int __init console_get_baud(void)
234 {
235 unsigned value;
236 u8 lcr;
237
238 lcr = __UART0(LCR);
239 __UART0(LCR) |= UART_LCR_DLAB;
240 mb();
241 value = __UART0(DLM) << 8;
242 value |= __UART0(DLL);
243 __UART0(LCR) = lcr;
244 mb();
245
246 return value;
247 } /* end console_get_baud() */
248
249 /*****************************************************************************/
250 /*
251 * display BUG() info
252 */
253 #ifndef CONFIG_NO_KERNEL_MSG
__debug_bug_printk(const char * file,unsigned line)254 void __debug_bug_printk(const char *file, unsigned line)
255 {
256 printk("kernel BUG at %s:%d!\n", file, line);
257
258 } /* end __debug_bug_printk() */
259 #endif
260