udbg.c

  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_PAS_REALMODE)
 40	udbg_init_pas_realmode();
 41#elif defined(CONFIG_PPC_EARLY_DEBUG_BOOTX)
 42	udbg_init_btext();
 43#elif defined(CONFIG_PPC_EARLY_DEBUG_44x)
 44	/* PPC44x debug */
 45	udbg_init_44x_as1();
 46#elif defined(CONFIG_PPC_EARLY_DEBUG_CPM)
 47	udbg_init_cpm();
 48#elif defined(CONFIG_PPC_EARLY_DEBUG_USBGECKO)
 49	udbg_init_usbgecko();
 50#elif defined(CONFIG_PPC_EARLY_DEBUG_MEMCONS)
 51	/* In memory console */
 52	udbg_init_memcons();
 53#elif defined(CONFIG_PPC_EARLY_DEBUG_EHV_BC)
 54	udbg_init_ehv_bc();
 55#elif defined(CONFIG_PPC_EARLY_DEBUG_PS3GELIC)
 56	udbg_init_ps3gelic();
 57#elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_RAW)
 58	udbg_init_debug_opal_raw();
 59#elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI)
 60	udbg_init_debug_opal_hvsi();
 61#elif defined(CONFIG_PPC_EARLY_DEBUG_16550)
 62	udbg_init_debug_16550();
 63#endif
 64
 65#ifdef CONFIG_PPC_EARLY_DEBUG
 66	console_loglevel = CONSOLE_LOGLEVEL_DEBUG;
 67
 68	register_early_udbg_console();
 69#endif
 70}
 71
 72/* udbg library, used by xmon et al */
 73void udbg_puts(const char *s)
 74{
 75	if (udbg_putc) {
 76		char c;
 77
 78		if (s && *s != '\0') {
 79			while ((c = *s++) != '\0')
 80				udbg_putc(c);
 81		}
 82
 83		if (udbg_flush)
 84			udbg_flush();
 85	}
 86#if 0
 87	else {
 88		printk("%s", s);
 89	}
 90#endif
 91}
 92
 93int udbg_write(const char *s, int n)
 94{
 95	int remain = n;
 96	char c;
 97
 98	if (!udbg_putc)
 99		return 0;
100
101	if (s && *s != '\0') {
102		while (((c = *s++) != '\0') && (remain-- > 0)) {
103			udbg_putc(c);
104		}
105	}
106
107	if (udbg_flush)
108		udbg_flush();
109
110	return n - remain;
111}
112
113#define UDBG_BUFSIZE 256
114void udbg_printf(const char *fmt, ...)
115{
116	if (udbg_putc) {
117		char buf[UDBG_BUFSIZE];
118		va_list args;
119
120		va_start(args, fmt);
121		vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
122		udbg_puts(buf);
123		va_end(args);
124	}
125}
126
127void __init udbg_progress(char *s, unsigned short hex)
128{
129	udbg_puts(s);
130	udbg_puts("\n");
131}
132
133/*
134 * Early boot console based on udbg
135 */
136static void udbg_console_write(struct console *con, const char *s,
137		unsigned int n)
138{
139	udbg_write(s, n);
140}
141
142static struct console udbg_console = {
143	.name	= "udbg",
144	.write	= udbg_console_write,
145	.flags	= CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
146	.index	= 0,
147};
148
149/*
150 * Called by setup_system after ppc_md->probe and ppc_md->early_init.
151 * Call it again after setting udbg_putc in ppc_md->setup_arch.
152 */
153void __init register_early_udbg_console(void)
154{
155	if (early_console)
156		return;
157
158	if (!udbg_putc)
159		return;
160
161	if (strstr(boot_command_line, "udbg-immortal")) {
162		printk(KERN_INFO "early console immortal !\n");
163		udbg_console.flags &= ~CON_BOOT;
164	}
165	early_console = &udbg_console;
166	register_console(&udbg_console);
167}
168
169#if 0   /* if you want to use this as a regular output console */
170console_initcall(register_udbg_console);
171#endif