xref: /openbmc/linux/arch/powerpc/kernel/udbg.c (revision 22246614)
1 /*
2  * polling mode stateless debugging stuff, originally for NS16550 Serial Ports
3  *
4  * c 2001 PPC 64 Team, IBM Corp
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 <stdarg.h>
13 #include <linux/types.h>
14 #include <linux/sched.h>
15 #include <linux/console.h>
16 #include <linux/init.h>
17 #include <asm/processor.h>
18 #include <asm/udbg.h>
19 
20 void (*udbg_putc)(char c);
21 int (*udbg_getc)(void);
22 int (*udbg_getc_poll)(void);
23 
24 /*
25  * Early debugging facilities. You can enable _one_ of these via .config,
26  * if you do so your kernel _will not boot_ on anything else. Be careful.
27  */
28 void __init udbg_early_init(void)
29 {
30 #if defined(CONFIG_PPC_EARLY_DEBUG_LPAR)
31 	/* For LPAR machines that have an HVC console on vterm 0 */
32 	udbg_init_debug_lpar();
33 #elif defined(CONFIG_PPC_EARLY_DEBUG_G5)
34 	/* For use on Apple G5 machines */
35 	udbg_init_pmac_realmode();
36 #elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_PANEL)
37 	/* RTAS panel debug */
38 	udbg_init_rtas_panel();
39 #elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_CONSOLE)
40 	/* RTAS console debug */
41 	udbg_init_rtas_console();
42 #elif defined(CONFIG_PPC_EARLY_DEBUG_MAPLE)
43 	/* Maple real mode debug */
44 	udbg_init_maple_realmode();
45 #elif defined(CONFIG_PPC_EARLY_DEBUG_ISERIES)
46 	/* For iSeries - hit Ctrl-x Ctrl-x to see the output */
47 	udbg_init_iseries();
48 #elif defined(CONFIG_PPC_EARLY_DEBUG_BEAT)
49 	udbg_init_debug_beat();
50 #elif defined(CONFIG_PPC_EARLY_DEBUG_PAS_REALMODE)
51 	udbg_init_pas_realmode();
52 #elif defined(CONFIG_BOOTX_TEXT)
53 	udbg_init_btext();
54 #elif defined(CONFIG_PPC_EARLY_DEBUG_44x)
55 	/* PPC44x debug */
56 	udbg_init_44x_as1();
57 #elif defined(CONFIG_PPC_EARLY_DEBUG_40x)
58 	/* PPC40x debug */
59 	udbg_init_40x_realmode();
60 #elif defined(CONFIG_PPC_EARLY_DEBUG_CPM)
61 	udbg_init_cpm();
62 #endif
63 
64 #ifdef CONFIG_PPC_EARLY_DEBUG
65 	console_loglevel = 10;
66 #endif
67 }
68 
69 /* udbg library, used by xmon et al */
70 void udbg_puts(const char *s)
71 {
72 	if (udbg_putc) {
73 		char c;
74 
75 		if (s && *s != '\0') {
76 			while ((c = *s++) != '\0')
77 				udbg_putc(c);
78 		}
79 	}
80 #if 0
81 	else {
82 		printk("%s", s);
83 	}
84 #endif
85 }
86 
87 int udbg_write(const char *s, int n)
88 {
89 	int remain = n;
90 	char c;
91 
92 	if (!udbg_putc)
93 		return 0;
94 
95 	if (s && *s != '\0') {
96 		while (((c = *s++) != '\0') && (remain-- > 0)) {
97 			udbg_putc(c);
98 		}
99 	}
100 
101 	return n - remain;
102 }
103 
104 int udbg_read(char *buf, int buflen)
105 {
106 	char *p = buf;
107 	int i, c;
108 
109 	if (!udbg_getc)
110 		return 0;
111 
112 	for (i = 0; i < buflen; ++i) {
113 		do {
114 			c = udbg_getc();
115 			if (c == -1 && i == 0)
116 				return -1;
117 
118 		} while (c == 0x11 || c == 0x13);
119 		if (c == 0 || c == -1)
120 			break;
121 		*p++ = c;
122 	}
123 
124 	return i;
125 }
126 
127 #define UDBG_BUFSIZE 256
128 void udbg_printf(const char *fmt, ...)
129 {
130 	char buf[UDBG_BUFSIZE];
131 	va_list args;
132 
133 	va_start(args, fmt);
134 	vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
135 	udbg_puts(buf);
136 	va_end(args);
137 }
138 
139 void __init udbg_progress(char *s, unsigned short hex)
140 {
141 	udbg_puts(s);
142 	udbg_puts("\n");
143 }
144 
145 /*
146  * Early boot console based on udbg
147  */
148 static void udbg_console_write(struct console *con, const char *s,
149 		unsigned int n)
150 {
151 	udbg_write(s, n);
152 }
153 
154 static struct console udbg_console = {
155 	.name	= "udbg",
156 	.write	= udbg_console_write,
157 	.flags	= CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
158 	.index	= 0,
159 };
160 
161 static int early_console_initialized;
162 
163 /*
164  * Called by setup_system after ppc_md->probe and ppc_md->early_init.
165  * Call it again after setting udbg_putc in ppc_md->setup_arch.
166  */
167 void __init register_early_udbg_console(void)
168 {
169 	if (early_console_initialized)
170 		return;
171 
172 	if (!udbg_putc)
173 		return;
174 
175 	if (strstr(boot_command_line, "udbg-immortal")) {
176 		printk(KERN_INFO "early console immortal !\n");
177 		udbg_console.flags &= ~CON_BOOT;
178 	}
179 	early_console_initialized = 1;
180 	register_console(&udbg_console);
181 }
182 
183 #if 0   /* if you want to use this as a regular output console */
184 console_initcall(register_udbg_console);
185 #endif
186