xref: /openbmc/linux/arch/powerpc/kernel/udbg.c (revision 25985edc)
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 void (*udbg_flush)(void);
22 int (*udbg_getc)(void);
23 int (*udbg_getc_poll)(void);
24 
25 /*
26  * Early debugging facilities. You can enable _one_ of these via .config,
27  * if you do so your kernel _will not boot_ on anything else. Be careful.
28  */
29 void __init udbg_early_init(void)
30 {
31 #if defined(CONFIG_PPC_EARLY_DEBUG_LPAR)
32 	/* For LPAR machines that have an HVC console on vterm 0 */
33 	udbg_init_debug_lpar();
34 #elif defined(CONFIG_PPC_EARLY_DEBUG_G5)
35 	/* For use on Apple G5 machines */
36 	udbg_init_pmac_realmode();
37 #elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_PANEL)
38 	/* RTAS panel debug */
39 	udbg_init_rtas_panel();
40 #elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_CONSOLE)
41 	/* RTAS console debug */
42 	udbg_init_rtas_console();
43 #elif defined(CONFIG_PPC_EARLY_DEBUG_MAPLE)
44 	/* Maple real mode debug */
45 	udbg_init_maple_realmode();
46 #elif defined(CONFIG_PPC_EARLY_DEBUG_ISERIES)
47 	/* For iSeries - hit Ctrl-x Ctrl-x to see the output */
48 	udbg_init_iseries();
49 #elif defined(CONFIG_PPC_EARLY_DEBUG_BEAT)
50 	udbg_init_debug_beat();
51 #elif defined(CONFIG_PPC_EARLY_DEBUG_PAS_REALMODE)
52 	udbg_init_pas_realmode();
53 #elif defined(CONFIG_BOOTX_TEXT)
54 	udbg_init_btext();
55 #elif defined(CONFIG_PPC_EARLY_DEBUG_44x)
56 	/* PPC44x debug */
57 	udbg_init_44x_as1();
58 #elif defined(CONFIG_PPC_EARLY_DEBUG_40x)
59 	/* PPC40x debug */
60 	udbg_init_40x_realmode();
61 #elif defined(CONFIG_PPC_EARLY_DEBUG_CPM)
62 	udbg_init_cpm();
63 #elif defined(CONFIG_PPC_EARLY_DEBUG_USBGECKO)
64 	udbg_init_usbgecko();
65 #endif
66 
67 #ifdef CONFIG_PPC_EARLY_DEBUG
68 	console_loglevel = 10;
69 #endif
70 }
71 
72 /* udbg library, used by xmon et al */
73 void udbg_puts(const char *s)
74 {
75 	if (udbg_putc) {
76 		char c;
77 
78 		if (s && *s != '\0') {
79 			while ((c = *s++) != '\0')
80 				udbg_putc(c);
81 		}
82 
83 		if (udbg_flush)
84 			udbg_flush();
85 	}
86 #if 0
87 	else {
88 		printk("%s", s);
89 	}
90 #endif
91 }
92 
93 int udbg_write(const char *s, int n)
94 {
95 	int remain = n;
96 	char c;
97 
98 	if (!udbg_putc)
99 		return 0;
100 
101 	if (s && *s != '\0') {
102 		while (((c = *s++) != '\0') && (remain-- > 0)) {
103 			udbg_putc(c);
104 		}
105 	}
106 
107 	if (udbg_flush)
108 		udbg_flush();
109 
110 	return n - remain;
111 }
112 
113 int udbg_read(char *buf, int buflen)
114 {
115 	char *p = buf;
116 	int i, c;
117 
118 	if (!udbg_getc)
119 		return 0;
120 
121 	for (i = 0; i < buflen; ++i) {
122 		do {
123 			c = udbg_getc();
124 			if (c == -1 && i == 0)
125 				return -1;
126 
127 		} while (c == 0x11 || c == 0x13);
128 		if (c == 0 || c == -1)
129 			break;
130 		*p++ = c;
131 	}
132 
133 	return i;
134 }
135 
136 #define UDBG_BUFSIZE 256
137 void udbg_printf(const char *fmt, ...)
138 {
139 	char buf[UDBG_BUFSIZE];
140 	va_list args;
141 
142 	va_start(args, fmt);
143 	vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
144 	udbg_puts(buf);
145 	va_end(args);
146 }
147 
148 void __init udbg_progress(char *s, unsigned short hex)
149 {
150 	udbg_puts(s);
151 	udbg_puts("\n");
152 }
153 
154 /*
155  * Early boot console based on udbg
156  */
157 static void udbg_console_write(struct console *con, const char *s,
158 		unsigned int n)
159 {
160 	udbg_write(s, n);
161 }
162 
163 static struct console udbg_console = {
164 	.name	= "udbg",
165 	.write	= udbg_console_write,
166 	.flags	= CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
167 	.index	= 0,
168 };
169 
170 static int early_console_initialized;
171 
172 /*
173  * Called by setup_system after ppc_md->probe and ppc_md->early_init.
174  * Call it again after setting udbg_putc in ppc_md->setup_arch.
175  */
176 void __init register_early_udbg_console(void)
177 {
178 	if (early_console_initialized)
179 		return;
180 
181 	if (!udbg_putc)
182 		return;
183 
184 	if (strstr(boot_command_line, "udbg-immortal")) {
185 		printk(KERN_INFO "early console immortal !\n");
186 		udbg_console.flags &= ~CON_BOOT;
187 	}
188 	early_console_initialized = 1;
189 	register_console(&udbg_console);
190 }
191 
192 #if 0   /* if you want to use this as a regular output console */
193 console_initcall(register_udbg_console);
194 #endif
195