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>
"unsigned int" speed cannot be negative, it's thus pointless
to test if it is.
Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.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 removes "volatile" from the MMIO pointer udbg_comport
in udbg_16550.c driver, it's useless and makes checkpatch.pl
complain when adding things to this file.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.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>
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 makes it possible to provide 0 as the clock value for
udbg_16550, making it default to the standard 1.8432Mhz clock
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
arch/powerpc/kernel/udbg_16550.c: In function `udbg_init_maple_realmode':
arch/powerpc/kernel/udbg_16550.c:162: warning: assignment from incompatible pointer type
Signed-off-by: Olaf Hering <olh@suse.de>
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>
The checking of the baudrate in udbg_probe_uart_speed was
too tight and would cause reporting back of the default
baud rate in cases where the computed speed was valid.
Signed-off-by: Kumar Gala <galak@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>
