xref: /linux/arch/powerpc/kernel/udbg.c (revision 132db93572821ec2fdf81e354cc40f558faf7e4f)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * polling mode stateless debugging stuff, originally for NS16550 Serial Ports
4  *
5  * c 2001 PPC 64 Team, IBM Corp
6  */
7 
8 #include <stdarg.h>
9 #include <linux/types.h>
10 #include <linux/sched.h>
11 #include <linux/console.h>
12 #include <linux/init.h>
13 #include <asm/processor.h>
14 #include <asm/udbg.h>
15 
16 void (*udbg_putc)(char c);
17 void (*udbg_flush)(void);
18 int (*udbg_getc)(void);
19 int (*udbg_getc_poll)(void);
20 
21 /*
22  * Early debugging facilities. You can enable _one_ of these via .config,
23  * if you do so your kernel _will not boot_ on anything else. Be careful.
24  */
25 void __init udbg_early_init(void)
26 {
27 #if defined(CONFIG_PPC_EARLY_DEBUG_LPAR)
28 	/* For LPAR machines that have an HVC console on vterm 0 */
29 	udbg_init_debug_lpar();
30 #elif defined(CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI)
31 	/* For LPAR machines that have an HVSI console on vterm 0 */
32 	udbg_init_debug_lpar_hvsi();
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_PAS_REALMODE)
46 	udbg_init_pas_realmode();
47 #elif defined(CONFIG_PPC_EARLY_DEBUG_BOOTX)
48 	udbg_init_btext();
49 #elif defined(CONFIG_PPC_EARLY_DEBUG_44x)
50 	/* PPC44x debug */
51 	udbg_init_44x_as1();
52 #elif defined(CONFIG_PPC_EARLY_DEBUG_40x)
53 	/* PPC40x debug */
54 	udbg_init_40x_realmode();
55 #elif defined(CONFIG_PPC_EARLY_DEBUG_CPM)
56 	udbg_init_cpm();
57 #elif defined(CONFIG_PPC_EARLY_DEBUG_USBGECKO)
58 	udbg_init_usbgecko();
59 #elif defined(CONFIG_PPC_EARLY_DEBUG_MEMCONS)
60 	/* In memory console */
61 	udbg_init_memcons();
62 #elif defined(CONFIG_PPC_EARLY_DEBUG_EHV_BC)
63 	udbg_init_ehv_bc();
64 #elif defined(CONFIG_PPC_EARLY_DEBUG_PS3GELIC)
65 	udbg_init_ps3gelic();
66 #elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_RAW)
67 	udbg_init_debug_opal_raw();
68 #elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI)
69 	udbg_init_debug_opal_hvsi();
70 #endif
71 
72 #ifdef CONFIG_PPC_EARLY_DEBUG
73 	console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
74 
75 	register_early_udbg_console();
76 #endif
77 }
78 
79 /* udbg library, used by xmon et al */
80 void udbg_puts(const char *s)
81 {
82 	if (udbg_putc) {
83 		char c;
84 
85 		if (s && *s != '\0') {
86 			while ((c = *s++) != '\0')
87 				udbg_putc(c);
88 		}
89 
90 		if (udbg_flush)
91 			udbg_flush();
92 	}
93 #if 0
94 	else {
95 		printk("%s", s);
96 	}
97 #endif
98 }
99 
100 int udbg_write(const char *s, int n)
101 {
102 	int remain = n;
103 	char c;
104 
105 	if (!udbg_putc)
106 		return 0;
107 
108 	if (s && *s != '\0') {
109 		while (((c = *s++) != '\0') && (remain-- > 0)) {
110 			udbg_putc(c);
111 		}
112 	}
113 
114 	if (udbg_flush)
115 		udbg_flush();
116 
117 	return n - remain;
118 }
119 
120 #define UDBG_BUFSIZE 256
121 void udbg_printf(const char *fmt, ...)
122 {
123 	if (udbg_putc) {
124 		char buf[UDBG_BUFSIZE];
125 		va_list args;
126 
127 		va_start(args, fmt);
128 		vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
129 		udbg_puts(buf);
130 		va_end(args);
131 	}
132 }
133 
134 void __init udbg_progress(char *s, unsigned short hex)
135 {
136 	udbg_puts(s);
137 	udbg_puts("\n");
138 }
139 
140 /*
141  * Early boot console based on udbg
142  */
143 static void udbg_console_write(struct console *con, const char *s,
144 		unsigned int n)
145 {
146 	udbg_write(s, n);
147 }
148 
149 static struct console udbg_console = {
150 	.name	= "udbg",
151 	.write	= udbg_console_write,
152 	.flags	= CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
153 	.index	= 0,
154 };
155 
156 /*
157  * Called by setup_system after ppc_md->probe and ppc_md->early_init.
158  * Call it again after setting udbg_putc in ppc_md->setup_arch.
159  */
160 void __init register_early_udbg_console(void)
161 {
162 	if (early_console)
163 		return;
164 
165 	if (!udbg_putc)
166 		return;
167 
168 	if (strstr(boot_command_line, "udbg-immortal")) {
169 		printk(KERN_INFO "early console immortal !\n");
170 		udbg_console.flags &= ~CON_BOOT;
171 	}
172 	early_console = &udbg_console;
173 	register_console(&udbg_console);
174 }
175 
176 #if 0   /* if you want to use this as a regular output console */
177 console_initcall(register_udbg_console);
178 #endif
179