summaryrefslogtreecommitdiffstats
path: root/arch/frv/kernel/debug-stub.c
blob: 4761cc4b4a90567059e8a69913415e92eb3ccbd0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
/* debug-stub.c: debug-mode stub
 *
 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/serial_reg.h>

#include <asm/system.h>
#include <asm/serial-regs.h>
#include <asm/timer-regs.h>
#include <asm/irc-regs.h>
#include <asm/gdb-stub.h>
#include "gdb-io.h"

/* CPU board CON5 */
#define __UART0(X) (*(volatile uint8_t *)(UART0_BASE + (UART_##X)))

#define LSR_WAIT_FOR0(STATE)			\
do {						\
} while (!(__UART0(LSR) & UART_LSR_##STATE))

#define FLOWCTL_QUERY0(LINE)	({ __UART0(MSR) & UART_MSR_##LINE; })
#define FLOWCTL_CLEAR0(LINE)	do { __UART0(MCR) &= ~UART_MCR_##LINE; } while (0)
#define FLOWCTL_SET0(LINE)	do { __UART0(MCR) |= UART_MCR_##LINE; } while (0)

#define FLOWCTL_WAIT_FOR0(LINE)			\
do {						\
	gdbstub_do_rx();			\
} while(!FLOWCTL_QUERY(LINE))

static void __init debug_stub_init(void);

extern asmlinkage void __break_hijack_kernel_event(void);
extern asmlinkage void __break_hijack_kernel_event_breaks_here(void);

/*****************************************************************************/
/*
 * debug mode handler stub
 * - we come here with the CPU in debug mode and with exceptions disabled
 * - handle debugging services for userspace
 */
asmlinkage void debug_stub(void)
{
	unsigned long hsr0;
	int type = 0;

	static u8 inited = 0;
	if (!inited) {
		debug_stub_init();
		type = -1;
		inited = 1;
	}

	hsr0 = __get_HSR(0);
	if (hsr0 & HSR0_ETMD)
		__set_HSR(0, hsr0 & ~HSR0_ETMD);

	/* disable single stepping */
	__debug_regs->dcr &= ~DCR_SE;

	/* kernel mode can propose an exception be handled in debug mode by jumping to a special
	 * location */
	if (__debug_frame->pc == (unsigned long) __break_hijack_kernel_event_breaks_here) {
		/* replace the debug frame with the kernel frame and discard
		 * the top kernel context */
		*__debug_frame = *__frame;
		__frame = __debug_frame->next_frame;
		__debug_regs->brr = (__debug_frame->tbr & TBR_TT) << 12;
		__debug_regs->brr |= BRR_EB;
	}

	if (__debug_frame->pc == (unsigned long) __debug_bug_trap + 4) {
		__debug_frame->pc = __debug_frame->lr;
		type = __debug_frame->gr8;
	}

#ifdef CONFIG_GDBSTUB
	gdbstub(type);
#endif

	if (hsr0 & HSR0_ETMD)
		__set_HSR(0, __get_HSR(0) | HSR0_ETMD);

} /* end debug_stub() */

/*****************************************************************************/
/*
 * debug stub initialisation
 */
static void __init debug_stub_init(void)
{
	__set_IRR(6, 0xff000000);	/* map ERRs to NMI */
	__set_IITMR(1, 0x20000000);	/* ERR0/1, UART0/1 IRQ detect levels */

	asm volatile("	movgs	gr0,ibar0	\n"
		     "	movgs	gr0,ibar1	\n"
		     "	movgs	gr0,ibar2	\n"
		     "	movgs	gr0,ibar3	\n"
		     "	movgs	gr0,dbar0	\n"
		     "	movgs	gr0,dbmr00	\n"
		     "	movgs	gr0,dbmr01	\n"
		     "	movgs	gr0,dbdr00	\n"
		     "	movgs	gr0,dbdr01	\n"
		     "	movgs	gr0,dbar1	\n"
		     "	movgs	gr0,dbmr10	\n"
		     "	movgs	gr0,dbmr11	\n"
		     "	movgs	gr0,dbdr10	\n"
		     "	movgs	gr0,dbdr11	\n"
		     );

	/* deal with debugging stub initialisation and initial pause */
	if (__debug_frame->pc == (unsigned long) __debug_stub_init_break)
		__debug_frame->pc = (unsigned long) start_kernel;

	/* enable the debug events we want to trap */
	__debug_regs->dcr = DCR_EBE;

#ifdef CONFIG_GDBSTUB
	gdbstub_init();
#endif

	__clr_MASK_all();
	__clr_MASK(15);
	__clr_RC(15);

} /* end debug_stub_init() */

/*****************************************************************************/
/*
 * kernel "exit" trap for gdb stub
 */
void debug_stub_exit(int status)
{

#ifdef CONFIG_GDBSTUB
	gdbstub_exit(status);
#endif

} /* end debug_stub_exit() */

/*****************************************************************************/
/*
 * send string to serial port
 */
void debug_to_serial(const char *p, int n)
{
	char ch;

	for (; n > 0; n--) {
		ch = *p++;
		FLOWCTL_SET0(DTR);
		LSR_WAIT_FOR0(THRE);
		// FLOWCTL_WAIT_FOR(CTS);

		if (ch == 0x0a) {
			__UART0(TX) = 0x0d;
			mb();
			LSR_WAIT_FOR0(THRE);
			// FLOWCTL_WAIT_FOR(CTS);
		}
		__UART0(TX) = ch;
		mb();

		FLOWCTL_CLEAR0(DTR);
	}

} /* end debug_to_serial() */

/*****************************************************************************/
/*
 * send string to serial port
 */
void debug_to_serial2(const char *fmt, ...)
{
	va_list va;
	char buf[64];
	int n;

	va_start(va, fmt);
	n = vsprintf(buf, fmt, va);
	va_end(va);

	debug_to_serial(buf, n);

} /* end debug_to_serial2() */

/*****************************************************************************/
/*
 * set up the ttyS0 serial port baud rate timers
 */
void __init console_set_baud(unsigned baud)
{
	unsigned value, high, low;
	u8 lcr;

	/* work out the divisor to give us the nearest higher baud rate */
	value = __serial_clock_speed_HZ / 16 / baud;

	/* determine the baud rate range */
	high = __serial_clock_speed_HZ / 16 / value;
	low = __serial_clock_speed_HZ / 16 / (value + 1);

	/* pick the nearest bound */
	if (low + (high - low) / 2 > baud)
		value++;

	lcr = __UART0(LCR);
	__UART0(LCR) |= UART_LCR_DLAB;
	mb();
	__UART0(DLL) = value & 0xff;
	__UART0(DLM) = (value >> 8) & 0xff;
	mb();
	__UART0(LCR) = lcr;
	mb();

} /* end console_set_baud() */

/*****************************************************************************/
/*
 *
 */
int __init console_get_baud(void)
{
	unsigned value;
	u8 lcr;

	lcr = __UART0(LCR);
	__UART0(LCR) |= UART_LCR_DLAB;
	mb();
	value =  __UART0(DLM) << 8;
	value |= __UART0(DLL);
	__UART0(LCR) = lcr;
	mb();

	return value;
} /* end console_get_baud() */

/*****************************************************************************/
/*
 * display BUG() info
 */
#ifndef CONFIG_NO_KERNEL_MSG
void __debug_bug_printk(const char *file, unsigned line)
{
	printk("kernel BUG at %s:%d!\n", file, line);

} /* end __debug_bug_printk() */
#endif