When the console is on a serial port to be driven by serial8250, a
character can be lost from the end of the first line in the two-line
sequence
serial8250.0: ttyS0 at MMIO 0xe0004500 (irq = 42) is a 16550A
console handover: boot [udbg0] -> real [ttyS0]
This happens because udbg_puts or udbg_write stuff the last byte of
the line into the Tx FIFO and return, whereupon the serial8250
initialization code immediately empties that FIFO. The fix: udbg_puts
and udbg_write now wait for the Tx FIFO to clear before returning.
This delays the system by one additional serial frame time for each
line written by udbg, but the effect is not noticeable, a cumulative
17 milliseconds for 200 lines of early printk output at 115200 baud.
Also, the routines in udbg_16550.c now emit CRLF instead of LFCR.
Linux makes a point of emitting CRLF because, when serial output is
captured to a file, LFCR sequences can confuse text editors. See
http://lkml.org/lkml/2006/2/4/50 for some history.
Signed-off-by: Andrew Klossner <andrew@cesa.opbu.xerox.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The udbg console should be safe to call basically at any time after boot.
It does not need any per-cpu resources or for the cpu to be online, as
long as there is a udbg_putc routine hooked up it should work. So mark it
as CON_ANYTIME.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Because the udbg_console has CON_ENABLED set, it's possible that when we
register it with the console code the index won't be set. This leads to
slightly confusing boot messages like:
[ 0.000000] console [udbg-1] enabled
We could remove CON_ENABLED, but we don't want to do that, we always
want the udbg console to be activated, even if the user specified some
other console on the command line.
The simplest fix seems to be just to set the index to 0 by hand. There
is no issue with duplicate udbg consoles, as we guard against registering
multiple times in register_early_udbg_console().
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This adds some basic real mode based early udbg support for 40x
in order to debug things more easily
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
This makes the early debug option force the console loglevel
to the max. The early debug option is meant to catch messages very
early in the kernel boot process, in many cases, before the kernel
has a chance to parse the "debug" command line argument. Thus it
makes sense when CONFIG_PPC_EARLY_DEBUG is set, to force the console
log level to the max at boot time.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This code assumes that the ports have been previously set up, with
buffers in DPRAM.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Fixed the following warnings:
WARNING: vmlinux.o(.text+0x2934): Section mismatch: reference to .init.text:__alloc_bootmem (between 'irq_alloc_host' and 'irq_set_default_host')
WARNING: vmlinux.o(.text+0xb2aa): Section mismatch: reference to .init.data:boot_command_line (between 'register_early_udbg_console' and 'udbg_printf')
WARNING: vmlinux.o(.text+0xb2b2): Section mismatch: reference to .init.data:boot_command_line (between 'register_early_udbg_console' and 'udbg_printf')
WARNING: vmlinux.o(.text+0xe354): Section mismatch: reference to .init.text:__alloc_bootmem (between 'pcibios_alloc_controller' and 'pci_domain_nr')
WARNING: vmlinux.o(.text+0x12768): Section mismatch: reference to .init.text:update_bridge_resource (between 'quirk_fsl_pcie_transparent' and 'indirect_read_config')
WARNING: vmlinux.o(.text+0x127a8): Section mismatch: reference to .init.text:update_bridge_resource (between 'quirk_fsl_pcie_transparent' and 'indirect_read_config')
WARNING: vmlinux.o(.text+0x17566c): Section mismatch: reference to .init.text:pcibios_fixup_bus (between 'pci_scan_child_bus' and 'pci_scan_bus_parented')
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Previously, registering this early console would just result
in dropping early buffered printk output until a udbg_putc
was registered.
However, commit 69331af79c
clears the CON_PRINTBUFFER flag on the main console when a
CON_BOOT (early) console has been registered, resulting in
the buffered messages never being displayed to the user.
This fixes the problem by making sure we don't register udbg_console
on platforms that don't implement udbg_putc.
Signed-off-by: Milton Miller <miltonm@bga.com>
Acked-by: Mark A. Greer <mgreer@mvista.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
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>
This adds support for early serial debugging via the built in
port on IBM/AMCC PowerPC 44x CPUs. It uses a bolted TLB entry in
address space 1 for the UART's mapping, allowing robust debugging both
before and after the initialization of the MMU.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
udbg_early_init() is a function used on 64 bit systems, which
initializes whichever early udbg backend is configured. This function
is not called on 32-bit, however if btext early debug is enabled it
does have an explicit, inline, #ifdef-ed assignment performing
analagous initialization.
This patch makes things more uniform by folding the btext
initialization as an option into udbg_early_init() and calling that
from the 32-bit setup path.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Early debug output for PA Semi UART. Uses the 2.05 CI real mode ops.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch adds udbg support for Celleb platform.
Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Add udbg hooks for the RTAS console, based on the RTAS put-term-char
and get-term-char calls. Along with my previous patches, this should
enable debugging as soon as early_init_dt_scan_rtas() is called.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
When debugging early kernel crashes that happen after console_init() and
before a proper console driver takes over, we often have to go hack into
udbg.c to prevent it from unregistering so we can "see" what is
happening. This patch adds a kernel command line option "udbg-immortal"
instead to avoid having to modify the kernel.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch adds Kconfig entries to control the early debugging options,
currently in setup_64.c.
Doing this via Kconfig rather than #defines means you can have one source tree,
which is buildable for multiple platforms - and you can enable the correct
early debug option for each platform via .config.
I made udbg_early_init() a static inline because otherwise GCC is to daft to
optimise it away when debugging is off.
Now that we have udbg_init_rtas() we can make call_rtas_display_status* static.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Added a common udbg_progress for use by ppc_md.progress()
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This adds some very basic support for the new machines, including the
Quad G5 (tested), and other new dual core based machines and iMac G5
iSight (untested). This is still experimental ! There is no thermal
control yet, there is no proper handing of MSIs, etc.. but it
boots, I have all 4 cores up on my machine. Compared to the previous
version of this patch, this one adds DART IOMMU support for the U4
chipset and thus should work fine on setups with more than 2Gb of RAM.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The udbg low level io layer has an issue with udbg_getc() returning a
char (unsigned on ppc) instead of an int, thus the -1 if you had no
available input device could end up turned into 0xff, filling your
display with bogus characters. This fixes it, along with adding a little
blob to xmon to do a delay before exiting when getting an EOF and fixing
the detection of ADB keyboards in udbg_adb.c
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch unifies udbg for both ppc32 and ppc64 when building the
merged achitecture. xmon now has a single "back end". The powermac udbg
stuff gets enriched with some ADB capabilities and btext output. In
addition, the early_init callback is now called on ppc32 as well,
approx. in the same order as ppc64 regarding device-tree manipulations.
The init sequences of ppc32 and ppc64 are getting closer, I'll unify
them in a later patch.
For now, you can force udbg to the scc using "sccdbg" or to btext using
"btextdbg" on powermacs. I'll implement a cleaner way of forcing udbg
output to something else than the autodetected OF output device in a
later patch.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This moves the discovery of legacy serial ports to a separate file,
makes it common to ppc32 and ppc64, and reworks it to use the new OF
address translators to get to the ports early. This new version can also
detect some PCI serial cards using legacy chips and will probably match
those discovered port with the default console choice.
Only ppc64 gets udbg still yet, unifying udbg isn't finished yet.
It also adds some speed-probing code to udbg so that the default console
can come up at the same speed it was set to by the firmware.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Since the udbg code in ppc64 has no ppc32 equivalent, move it straight
over into arch/powerpc (and include/asm-powerpc for udbg.h). In time,
we probably want to meld the various bits and pieces of 32-bit early
debugging code into udbg, but for now only include it on
CONFIG_PPC64=y builds. The only change during the move is to
standardise the protecting #ifdef/#define in udbg.h, and move its
banner comment above the initial #ifdef (which seems to be normal
practice).
Built and booted on POWER5 LPAR (ARCH=powerpc and ARCH=ppc64). Built
for 32bit multiplatform (ARCH=powerpc).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
