powerpc: Remove orphaned reg_a2.h

Commit fb5a515704d7 ("powerpc: Remove platforms/wsp and associated
pieces") removed the A2 CPU support, but missed removal of reg_a2.h.

None of the defines contained in it are used, with the exception of the
SPRN_TEN* values, but they are also defined in reg_booke.h.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231113043947.1931831-1-mpe@ellerman.id.au

powerpc: Add support for early debugging via Serial 16550 console

Currently powerpc early debugging contains lot of platform specific
options, but does not support standard UART / serial 16550 console.

Later legacy_serial.c code supports registering UART as early debug console
from device tree but it is not early during booting, but rather later after
machine description code finishes.

So for real early debugging via UART is current code unsuitable.

Add support for new early debugging option CONFIG_PPC_EARLY_DEBUG_16550
which enable Serial 16550 console on address defined by new option
CONFIG_PPC_EARLY_DEBUG_16550_PHYSADDR and by stride by option
CONFIG_PPC_EARLY_DEBUG_16550_STRIDE.

With this change it is possible to debug powerpc machine descriptor code.
For example this early debugging code can print on serial console also
"No suitable machine description found" error which is done before
legacy_serial.c code.

Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220822231501.16827-1-pali@kernel.org

powerpc/microwatt: Remove unused early debug code

The original microwatt submission[1] included some early debug code for
using the Microwatt "potato" UART.

The series that was eventually merged switched to using a standard UART,
and so doesn't need any special early debug handling. But some of the
original code was merged accidentally under the non-existent
CONFIG_PPC_EARLY_DEBUG_MICROWATT.

Drop the unused code.

1: https://lore.kernel.org/linuxppc-dev/20200509050340.GD1464954@thinks.paulus.ozlabs.org/

Fixes: 48b545b8018d ("powerpc/microwatt: Use standard 16550 UART for console")
Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220919052755.800907-1-mpe@ellerman.id.au

powerpc/kernel: Add __init attribute to eligible functions

Some functions defined in `arch/powerpc/kernel` (and one in `arch/powerpc/
kexec`) are deserving of an `__init` macro attribute. These functions are
only called by other initialization functions and therefore should inherit
the attribute.
Also, change function declarations in header files to include `__init`.

Signed-off-by: Nick Child <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-2-nick.child@ibm.com

powerpc/microwatt: Use standard 16550 UART for console

This adds support to the Microwatt platform to use the standard
16550-style UART which available in the standalone Microwatt FPGA.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/YMwXGCTzedpQje7r@thinks.paulus.ozlabs.org

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

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

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

powerpc: Fix bad NULL pointer check in udbg_uart_getc_poll()

We have some code in udbg_uart_getc_poll() that tries to protect
against a NULL udbg_uart_in, but gets it all wrong.

Found with the LLVM static analyzer (scan-build).

Fixes: 309257484cc1 ("powerpc: Cleanup udbg_16550 and add support for LPC PIO-only UARTs")
Signed-off-by: Anton Blanchard <anton@samba.org>
[mpe: Add some newlines for readability while we're here]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

powerpc: Remove platforms/wsp and associated pieces

__attribute__ ((unused))

WSP is the last user of CONFIG_PPC_A2, so we remove that as well.

Although CONFIG_PPC_ICSWX still exists, it's no longer selectable for
any Book3E platform, so we can remove the code in mmu-book3e.h that
depended on it.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/wsp: Fix early debug build

When reworking udbg_16550.c I forgot to remove the old and now useless
code for the CONFIG_PPC_EARLY_DEBUG_WSP case, which doesn't build as
a result. I also missed a cast.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc: Cleanup udbg_16550 and add support for LPC PIO-only UARTs

The udbg_16550 code, which we use for our early consoles and debug
backends was fairly messy. Especially for the debug consoles, it
would re-implement the "high level" getc/putc/poll functions for
each access method. It also had code to configure the UART but only
for the straight MMIO method.

This changes it to instead abstract at the register accessor level,
and have the various functions and configuration routines use these.

The result is simpler and slightly smaller code, and free support
for non-MMIO mapped PIO UARTs, which such as the ones that can be
present on a POWER 8 LPC bus.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc: Add early debug for WSP platforms

Signed-off-by: Jack Miller <jack@codezen.org>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

trivial: fix typo "for for" in multiple files

trivial: fix typo "for for" in multiple files

Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

powerpc/440: Fix warning early debug code

The function udbg_44x_as1_flush() has the wrong prototype causing
a warning when enabling 440 early debug.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

powerpc/udbg: Fix lost byte during console handover; change LFCR to CRLF

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>

powerpc: Unsigned speed cannot be negative in udbg_16559.c

"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>

[POWERPC] 4xx: Add early udbg support for 40x processors

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>

[POWERPC] Remove useless volatiles in udbg_16550.c

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>

[POWERPC] 4xx: Implement udbg_getc() for 440

Implement udbg_getc() for 440, which fixes xmon input.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

[POWERPC] Early serial debug support for PPC44x

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>

[PATCH] constant should be long

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[POWERPC] pasemi: UART udbg support

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>

[POWERPC] Fix default clock for udbg_16550

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>

[POWERPC] Fix default clock for udbg_16550

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>

Remove obsolete #include <linux/config.h>

Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

[PATCH] powerpc: fix compile warning in udbg_init_maple_realmode

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>

[PATCH] powerpc: Make early debugging configurable via Kconfig

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>

[PATCH] powerpc: Loosen udbg_probe_uart_speed sanity checking

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>

[PATCH] powerpc: udbg updates

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>

[PATCH] powerpc: Unify udbg (#2)

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>

[PATCH] powerpc: serial port discovery (#2)

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>

[PATCH] powerpc: Move udbg code to arch/powerpc

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>