linux-stable/arch/powerpc/kernel/udbg.c

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/*
* polling mode stateless debugging stuff, originally for NS16550 Serial Ports
*
* c 2001 PPC 64 Team, IBM Corp
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <stdarg.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/console.h>
#include <linux/init.h>
#include <asm/processor.h>
#include <asm/udbg.h>
void (*udbg_putc)(char c);
void (*udbg_flush)(void);
int (*udbg_getc)(void);
int (*udbg_getc_poll)(void);
/*
* Early debugging facilities. You can enable _one_ of these via .config,
* if you do so your kernel _will not boot_ on anything else. Be careful.
*/
void __init udbg_early_init(void)
{
#if defined(CONFIG_PPC_EARLY_DEBUG_LPAR)
/* For LPAR machines that have an HVC console on vterm 0 */
udbg_init_debug_lpar();
powerpc/pseries: Re-implement HVSI as part of hvc_vio On pseries machines, consoles are provided by the hypervisor using a low level get_chars/put_chars type interface. However, this is really just a transport to the service processor which implements them either as "raw" console (networked consoles, HMC, ...) or as "hvsi" serial ports. The later is a simple packet protocol on top of the raw character interface that is supposed to convey additional "serial port" style semantics. In practice however, all it does is provide a way to read the CD line and set/clear our DTR line, that's it. We currently implement the "raw" protocol as an hvc console backend (/dev/hvcN) and the "hvsi" protocol using a separate tty driver (/dev/hvsi0). However this is quite impractical. The arbitrary difference between the two type of devices has been a major source of user (and distro) confusion. Additionally, there's an additional mini -hvsi implementation in the pseries platform code for our low level debug console and early boot kernel messages, which means code duplication, though that low level variant is impractical as it's incapable of doing the initial protocol negociation to establish the link to the FSP. This essentially replaces the dedicated hvsi driver and the platform udbg code completely by extending the existing hvc_vio backend used in "raw" mode so that: - It now supports HVSI as well - We add support for hvc backend providing tiocm{get,set} - It also provides a udbg interface for early debug and boot console This is overall less code, though this will only be obvious once we remove the old "hvsi" driver, which is still available for now. When the old driver is enabled, the new code still kicks in for the low level udbg console, replacing the old mini implementation in the platform code, it just doesn't provide the higher level "hvc" interface. In addition to producing generally simler code, this has several benefits over our current situation: - The user/distro only has to deal with /dev/hvcN for the hypervisor console, avoiding all sort of confusion that has plagued us in the past - The tty, kernel and low level debug console all use the same code base which supports the full protocol establishment process, thus the console is now available much earlier than it used to be with the old HVSI driver. The kernel console works much earlier and udbg is available much earlier too. Hackers can enable a hard coded very-early debug console as well that works with HVSI (previously that was only supported for the "raw" mode). I've tried to keep the same semantics as hvsi relative to how I react to things like CD changes, with some subtle differences though: - I clear DTR on close if HUPCL is set - Current hvsi triggers a hangup if it detects a up->down transition on CD (you can still open a console with CD down). My new implementation triggers a hangup if the link to the FSP is severed, and severs it upon detecting a up->down transition on CD. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-05-12 03:46:38 +00:00
#elif defined(CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI)
/* For LPAR machines that have an HVSI console on vterm 0 */
udbg_init_debug_lpar_hvsi();
#elif defined(CONFIG_PPC_EARLY_DEBUG_G5)
/* For use on Apple G5 machines */
udbg_init_pmac_realmode();
#elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_PANEL)
/* RTAS panel debug */
udbg_init_rtas_panel();
#elif defined(CONFIG_PPC_EARLY_DEBUG_RTAS_CONSOLE)
/* RTAS console debug */
udbg_init_rtas_console();
#elif defined(CONFIG_PPC_EARLY_DEBUG_MAPLE)
/* Maple real mode debug */
udbg_init_maple_realmode();
#elif defined(CONFIG_PPC_EARLY_DEBUG_PAS_REALMODE)
udbg_init_pas_realmode();
#elif defined(CONFIG_PPC_EARLY_DEBUG_BOOTX)
udbg_init_btext();
#elif defined(CONFIG_PPC_EARLY_DEBUG_44x)
/* PPC44x debug */
udbg_init_44x_as1();
#elif defined(CONFIG_PPC_EARLY_DEBUG_40x)
/* PPC40x debug */
udbg_init_40x_realmode();
#elif defined(CONFIG_PPC_EARLY_DEBUG_CPM)
udbg_init_cpm();
#elif defined(CONFIG_PPC_EARLY_DEBUG_USBGECKO)
udbg_init_usbgecko();
#elif defined(CONFIG_PPC_EARLY_DEBUG_MEMCONS)
/* In memory console */
udbg_init_memcons();
#elif defined(CONFIG_PPC_EARLY_DEBUG_EHV_BC)
udbg_init_ehv_bc();
#elif defined(CONFIG_PPC_EARLY_DEBUG_PS3GELIC)
udbg_init_ps3gelic();
#elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_RAW)
udbg_init_debug_opal_raw();
#elif defined(CONFIG_PPC_EARLY_DEBUG_OPAL_HVSI)
udbg_init_debug_opal_hvsi();
#endif
#ifdef CONFIG_PPC_EARLY_DEBUG
console_loglevel = 10;
register_early_udbg_console();
#endif
}
/* udbg library, used by xmon et al */
void udbg_puts(const char *s)
{
if (udbg_putc) {
char c;
if (s && *s != '\0') {
while ((c = *s++) != '\0')
udbg_putc(c);
}
if (udbg_flush)
udbg_flush();
}
#if 0
else {
printk("%s", s);
}
#endif
}
int udbg_write(const char *s, int n)
{
int remain = n;
char c;
if (!udbg_putc)
return 0;
if (s && *s != '\0') {
while (((c = *s++) != '\0') && (remain-- > 0)) {
udbg_putc(c);
}
}
if (udbg_flush)
udbg_flush();
return n - remain;
}
#define UDBG_BUFSIZE 256
void udbg_printf(const char *fmt, ...)
{
char buf[UDBG_BUFSIZE];
va_list args;
va_start(args, fmt);
vsnprintf(buf, UDBG_BUFSIZE, fmt, args);
udbg_puts(buf);
va_end(args);
}
void __init udbg_progress(char *s, unsigned short hex)
{
udbg_puts(s);
udbg_puts("\n");
}
/*
* Early boot console based on udbg
*/
static void udbg_console_write(struct console *con, const char *s,
unsigned int n)
{
udbg_write(s, n);
}
static struct console udbg_console = {
.name = "udbg",
.write = udbg_console_write,
.flags = CON_PRINTBUFFER | CON_ENABLED | CON_BOOT | CON_ANYTIME,
.index = 0,
};
/*
* Called by setup_system after ppc_md->probe and ppc_md->early_init.
* Call it again after setting udbg_putc in ppc_md->setup_arch.
*/
void __init register_early_udbg_console(void)
{
if (early_console)
return;
Fixes and cleanups for earlyprintk aka boot console The console subsystem already has an idea of a boot console, using the CON_BOOT flag. The implementation has some flaws though. The major problem is that presence of a boot console makes register_console() ignore any other console devices (unless explicitly specified on the kernel command line). This patch fixes the console selection code to *not* consider a boot console a full-featured one, so the first non-boot console registering will become the default console instead. This way the unregister call for the boot console in the register_console() function actually triggers and the handover from the boot console to the real console device works smoothly. Added a printk for the handover, so you know which console device the output goes to when the boot console stops printing messages. The disable_early_printk() call is obsolete with that patch, explicitly disabling the early console isn't needed any more as it works automagically with that patch. I've walked through the tree, dropped all disable_early_printk() instances found below arch/ and tagged the consoles with CON_BOOT if needed. The code is tested on x86, sh (thanks to Paul) and mips (thanks to Ralf). Changes to last version: Rediffed against -rc3, adapted to mips cleanups by Ralf, fixed "udbg-immortal" cmd line arg on powerpc. Signed-off-by: Gerd Hoffmann <kraxel@exsuse.de> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Andi Kleen <ak@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 07:26:49 +00:00
if (!udbg_putc)
return;
Fixes and cleanups for earlyprintk aka boot console The console subsystem already has an idea of a boot console, using the CON_BOOT flag. The implementation has some flaws though. The major problem is that presence of a boot console makes register_console() ignore any other console devices (unless explicitly specified on the kernel command line). This patch fixes the console selection code to *not* consider a boot console a full-featured one, so the first non-boot console registering will become the default console instead. This way the unregister call for the boot console in the register_console() function actually triggers and the handover from the boot console to the real console device works smoothly. Added a printk for the handover, so you know which console device the output goes to when the boot console stops printing messages. The disable_early_printk() call is obsolete with that patch, explicitly disabling the early console isn't needed any more as it works automagically with that patch. I've walked through the tree, dropped all disable_early_printk() instances found below arch/ and tagged the consoles with CON_BOOT if needed. The code is tested on x86, sh (thanks to Paul) and mips (thanks to Ralf). Changes to last version: Rediffed against -rc3, adapted to mips cleanups by Ralf, fixed "udbg-immortal" cmd line arg on powerpc. Signed-off-by: Gerd Hoffmann <kraxel@exsuse.de> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Ralf Baechle <ralf@linux-mips.org> Cc: Andi Kleen <ak@suse.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08 07:26:49 +00:00
if (strstr(boot_command_line, "udbg-immortal")) {
printk(KERN_INFO "early console immortal !\n");
udbg_console.flags &= ~CON_BOOT;
}
early_console = &udbg_console;
register_console(&udbg_console);
}
#if 0 /* if you want to use this as a regular output console */
console_initcall(register_udbg_console);
#endif