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 <linux/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  */
udbg_early_init(void)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 #elif defined(CONFIG_PPC_EARLY_DEBUG_16550)
71 	udbg_init_debug_16550();
72 #endif
73 
74 #ifdef CONFIG_PPC_EARLY_DEBUG
75 	console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
76 
77 	register_early_udbg_console();
78 #endif
79 }
80 
81 /* udbg library, used by xmon et al */
udbg_puts(const char * s)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 
udbg_write(const char * s,int n)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 #define UDBG_BUFSIZE 256
udbg_printf(const char * fmt,...)123 void udbg_printf(const char *fmt, ...)
124 {
125 	if (udbg_putc) {
126 		char buf[UDBG_BUFSIZE];
127 		va_list args;
128 
129 		va_start(args, fmt);
130 		vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
131 		udbg_puts(buf);
132 		va_end(args);
133 	}
134 }
135 
udbg_progress(char * s,unsigned short hex)136 void __init udbg_progress(char *s, unsigned short hex)
137 {
138 	udbg_puts(s);
139 	udbg_puts("\n");
140 }
141 
142 /*
143  * Early boot console based on udbg
144  */
udbg_console_write(struct console * con,const char * s,unsigned int n)145 static void udbg_console_write(struct console *con, const char *s,
146 		unsigned int n)
147 {
148 	udbg_write(s, n);
149 }
150 
151 static struct console udbg_console = {
152 	.name	= "udbg",
153 	.write	= udbg_console_write,
154 	.flags	= CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
155 	.index	= 0,
156 };
157 
158 /*
159  * Called by setup_system after ppc_md->probe and ppc_md->early_init.
160  * Call it again after setting udbg_putc in ppc_md->setup_arch.
161  */
register_early_udbg_console(void)162 void __init register_early_udbg_console(void)
163 {
164 	if (early_console)
165 		return;
166 
167 	if (!udbg_putc)
168 		return;
169 
170 	if (strstr(boot_command_line, "udbg-immortal")) {
171 		printk(KERN_INFO "early console immortal !\n");
172 		udbg_console.flags &= ~CON_BOOT;
173 	}
174 	early_console = &udbg_console;
175 	register_console(&udbg_console);
176 }
177 
178 #if 0   /* if you want to use this as a regular output console */
179 console_initcall(register_udbg_console);
180 #endif
181