xref: /openbmc/linux/arch/powerpc/kernel/udbg.c (revision 81d67439)
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 #elif defined(CONFIG_PPC_EARLY_DEBUG_WSP)
66 	udbg_init_wsp();
67 #endif
68 
69 #ifdef CONFIG_PPC_EARLY_DEBUG
70 	console_loglevel = 10;
71 #endif
72 }
73 
74 /* udbg library, used by xmon et al */
75 void udbg_puts(const char *s)
76 {
77 	if (udbg_putc) {
78 		char c;
79 
80 		if (s && *s != '\0') {
81 			while ((c = *s++) != '\0')
82 				udbg_putc(c);
83 		}
84 
85 		if (udbg_flush)
86 			udbg_flush();
87 	}
88 #if 0
89 	else {
90 		printk("%s", s);
91 	}
92 #endif
93 }
94 
95 int udbg_write(const char *s, int n)
96 {
97 	int remain = n;
98 	char c;
99 
100 	if (!udbg_putc)
101 		return 0;
102 
103 	if (s && *s != '\0') {
104 		while (((c = *s++) != '\0') && (remain-- > 0)) {
105 			udbg_putc(c);
106 		}
107 	}
108 
109 	if (udbg_flush)
110 		udbg_flush();
111 
112 	return n - remain;
113 }
114 
115 int udbg_read(char *buf, int buflen)
116 {
117 	char *p = buf;
118 	int i, c;
119 
120 	if (!udbg_getc)
121 		return 0;
122 
123 	for (i = 0; i < buflen; ++i) {
124 		do {
125 			c = udbg_getc();
126 			if (c == -1 && i == 0)
127 				return -1;
128 
129 		} while (c == 0x11 || c == 0x13);
130 		if (c == 0 || c == -1)
131 			break;
132 		*p++ = c;
133 	}
134 
135 	return i;
136 }
137 
138 #define UDBG_BUFSIZE 256
139 void udbg_printf(const char *fmt, ...)
140 {
141 	char buf[UDBG_BUFSIZE];
142 	va_list args;
143 
144 	va_start(args, fmt);
145 	vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
146 	udbg_puts(buf);
147 	va_end(args);
148 }
149 
150 void __init udbg_progress(char *s, unsigned short hex)
151 {
152 	udbg_puts(s);
153 	udbg_puts("\n");
154 }
155 
156 /*
157  * Early boot console based on udbg
158  */
159 static void udbg_console_write(struct console *con, const char *s,
160 		unsigned int n)
161 {
162 	udbg_write(s, n);
163 }
164 
165 static struct console udbg_console = {
166 	.name	= "udbg",
167 	.write	= udbg_console_write,
168 	.flags	= CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
169 	.index	= 0,
170 };
171 
172 static int early_console_initialized;
173 
174 /*
175  * Called by setup_system after ppc_md->probe and ppc_md->early_init.
176  * Call it again after setting udbg_putc in ppc_md->setup_arch.
177  */
178 void __init register_early_udbg_console(void)
179 {
180 	if (early_console_initialized)
181 		return;
182 
183 	if (!udbg_putc)
184 		return;
185 
186 	if (strstr(boot_command_line, "udbg-immortal")) {
187 		printk(KERN_INFO "early console immortal !\n");
188 		udbg_console.flags &= ~CON_BOOT;
189 	}
190 	early_console_initialized = 1;
191 	register_console(&udbg_console);
192 }
193 
194 #if 0   /* if you want to use this as a regular output console */
195 console_initcall(register_udbg_console);
196 #endif
197