xref: /openbmc/linux/arch/powerpc/kernel/udbg.c (revision 3a9a231d)
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_LPAR_HVSI)
35 	/* For LPAR machines that have an HVSI console on vterm 0 */
36 	udbg_init_debug_lpar_hvsi();
37 #elif defined(CONFIG_PPC_EARLY_DEBUG_G5)
38 	/* For use on Apple G5 machines */
39 	udbg_init_pmac_realmode();
40 #elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_PANEL)
41 	/* RTAS panel debug */
42 	udbg_init_rtas_panel();
43 #elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_CONSOLE)
44 	/* RTAS console debug */
45 	udbg_init_rtas_console();
46 #elif defined(CONFIG_PPC_EARLY_DEBUG_MAPLE)
47 	/* Maple real mode debug */
48 	udbg_init_maple_realmode();
49 #elif defined(CONFIG_PPC_EARLY_DEBUG_ISERIES)
50 	/* For iSeries - hit Ctrl-x Ctrl-x to see the output */
51 	udbg_init_iseries();
52 #elif defined(CONFIG_PPC_EARLY_DEBUG_BEAT)
53 	udbg_init_debug_beat();
54 #elif defined(CONFIG_PPC_EARLY_DEBUG_PAS_REALMODE)
55 	udbg_init_pas_realmode();
56 #elif defined(CONFIG_BOOTX_TEXT)
57 	udbg_init_btext();
58 #elif defined(CONFIG_PPC_EARLY_DEBUG_44x)
59 	/* PPC44x debug */
60 	udbg_init_44x_as1();
61 #elif defined(CONFIG_PPC_EARLY_DEBUG_40x)
62 	/* PPC40x debug */
63 	udbg_init_40x_realmode();
64 #elif defined(CONFIG_PPC_EARLY_DEBUG_CPM)
65 	udbg_init_cpm();
66 #elif defined(CONFIG_PPC_EARLY_DEBUG_USBGECKO)
67 	udbg_init_usbgecko();
68 #elif defined(CONFIG_PPC_EARLY_DEBUG_WSP)
69 	udbg_init_wsp();
70 #elif defined(CONFIG_PPC_EARLY_DEBUG_EHV_BC)
71 	udbg_init_ehv_bc();
72 #endif
73 
74 #ifdef CONFIG_PPC_EARLY_DEBUG
75 	console_loglevel = 10;
76 
77 	register_early_udbg_console();
78 #endif
79 }
80 
81 /* udbg library, used by xmon et al */
82 void udbg_puts(const char *s)
83 {
84 	if (udbg_putc) {
85 		char c;
86 
87 		if (s && *s != '\0') {
88 			while ((c = *s++) != '\0')
89 				udbg_putc(c);
90 		}
91 
92 		if (udbg_flush)
93 			udbg_flush();
94 	}
95 #if 0
96 	else {
97 		printk("%s", s);
98 	}
99 #endif
100 }
101 
102 int udbg_write(const char *s, int n)
103 {
104 	int remain = n;
105 	char c;
106 
107 	if (!udbg_putc)
108 		return 0;
109 
110 	if (s && *s != '\0') {
111 		while (((c = *s++) != '\0') && (remain-- > 0)) {
112 			udbg_putc(c);
113 		}
114 	}
115 
116 	if (udbg_flush)
117 		udbg_flush();
118 
119 	return n - remain;
120 }
121 
122 int udbg_read(char *buf, int buflen)
123 {
124 	char *p = buf;
125 	int i, c;
126 
127 	if (!udbg_getc)
128 		return 0;
129 
130 	for (i = 0; i < buflen; ++i) {
131 		do {
132 			c = udbg_getc();
133 			if (c == -1 && i == 0)
134 				return -1;
135 
136 		} while (c == 0x11 || c == 0x13);
137 		if (c == 0 || c == -1)
138 			break;
139 		*p++ = c;
140 	}
141 
142 	return i;
143 }
144 
145 #define UDBG_BUFSIZE 256
146 void udbg_printf(const char *fmt, ...)
147 {
148 	char buf[UDBG_BUFSIZE];
149 	va_list args;
150 
151 	va_start(args, fmt);
152 	vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
153 	udbg_puts(buf);
154 	va_end(args);
155 }
156 
157 void __init udbg_progress(char *s, unsigned short hex)
158 {
159 	udbg_puts(s);
160 	udbg_puts("\n");
161 }
162 
163 /*
164  * Early boot console based on udbg
165  */
166 static void udbg_console_write(struct console *con, const char *s,
167 		unsigned int n)
168 {
169 	udbg_write(s, n);
170 }
171 
172 static struct console udbg_console = {
173 	.name	= "udbg",
174 	.write	= udbg_console_write,
175 	.flags	= CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
176 	.index	= 0,
177 };
178 
179 static int early_console_initialized;
180 
181 /*
182  * Called by setup_system after ppc_md->probe and ppc_md->early_init.
183  * Call it again after setting udbg_putc in ppc_md->setup_arch.
184  */
185 void __init register_early_udbg_console(void)
186 {
187 	if (early_console_initialized)
188 		return;
189 
190 	if (!udbg_putc)
191 		return;
192 
193 	if (strstr(boot_command_line, "udbg-immortal")) {
194 		printk(KERN_INFO "early console immortal !\n");
195 		udbg_console.flags &= ~CON_BOOT;
196 	}
197 	early_console_initialized = 1;
198 	register_console(&udbg_console);
199 }
200 
201 #if 0   /* if you want to use this as a regular output console */
202 console_initcall(register_udbg_console);
203 #endif
204