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
16void (*udbg_putc)(char c);
17void (*udbg_flush)(void);
18int (*udbg_getc)(void);
19int (*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 */
25void __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 */
82void 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
102int 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
123void 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(s: buf);
132 va_end(args);
133 }
134}
135
136void __init udbg_progress(char *s, unsigned short hex)
137{
138 udbg_puts(s);
139 udbg_puts(s: "\n");
140}
141
142/*
143 * Early boot console based on udbg
144 */
145static void udbg_console_write(struct console *con, const char *s,
146 unsigned int n)
147{
148 udbg_write(s, n);
149}
150
151static 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 */
162void __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 */
179console_initcall(register_udbg_console);
180#endif
181

source code of linux/arch/powerpc/kernel/udbg.c