clocksource/drivers/fttmr010: Pass around less pointers

Just pass bool flags from the different initcalls and use the
flags to set the right pointers. This results in less pointers
passed around in init.

Cc: Cédric Le Goater <clg@kaod.org>
Cc: Joel Stanley <joel@jms.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210724224424.2085404-1-linus.walleij@linaro.org

clocksource/drivers/fttmr010: Set interrupt and shutdown

In preparation for supporting the ast2600, pass the shutdown and
interrupt functions to the common init callback.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20191107094218.13210-3-joel@jms.id.au

clocksource/drivers/fttmr010: Parametrise shutdown

In preparation for supporting the ast2600 which uses a different method
to clear bits in the control register, use a callback for performing the
shutdown sequence.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20191107094218.13210-2-joel@jms.id.au

clocksource/drivers/fttmr010: Fix invalid interrupt register access

TIMER_INTR_MASK register (Base Address of Timer + 0x38) is not designed
for masking interrupts on ast2500 chips, and it's not even listed in
ast2400 datasheet, so it's not safe to access TIMER_INTR_MASK on aspeed
chips.

Similarly, TIMER_INTR_STATE register (Base Address of Timer + 0x34) is
not interrupt status register on ast2400 and ast2500 chips. Although
there is no side effect to reset the register in fttmr010_common_init(),
it's just misleading to do so.

Besides, "count_down" is renamed to "is_aspeed" in "fttmr010" structure,
and more comments are added so the code is more readble.

Signed-off-by: Tao Ren <taoren@fb.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Fix set_next_event handler

Currently, the aspeed MATCH1 register is updated to <current_count -
cycles> in set_next_event handler, with the assumption that COUNT
register value is preserved when the timer is disabled and it continues
decrementing after the timer is enabled. But the assumption is wrong:
RELOAD register is loaded into COUNT register when the aspeed timer is
enabled, which means the next event may be delayed because timer
interrupt won't be generated until <0xFFFFFFFF - current_count +
cycles>.

The problem can be fixed by updating RELOAD register to <cycles>, and
COUNT register will be re-loaded when the timer is enabled and interrupt
is generated when COUNT register overflows.

The test result on Facebook Backpack-CMM BMC hardware (AST2500) shows
the issue is fixed: without the patch, usleep(100) suspends the process
for several milliseconds (and sometimes even over 40 milliseconds);
after applying the fix, usleep(100) takes averagely 240 microseconds to
return under the same workload level.

Signed-off-by: Tao Ren <taoren@fb.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Lei YU <mine260309@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

clocksource/drivers/fttmr010: pr_err() strings should end with newlines

pr_err() messages should end with a new-line to avoid other messages being
concatenated.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Factor out clock read code

The sched_clock() and delay timer callbacks can just call
each other and we can save an #ifdef.

Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Andrew Jeffery <andrew@aj.id.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Implement delay timer

This timer is often used on the ARM architecture, so as with so
many siblings, we can implement delay timers, removing the need
for the system to calibrate jiffys at boot, and potentially
handling CPU frequency scaling on targets.

We cannot just protect the Kconfig with a "depends on ARM" because
it is already known that different architectures are using Faraday
IP blocks, so it is better to make things open-ended and use

Result on boot dmesg:

Switching to timer-based delay loop, resolution 40n
Calibrating delay loop (skipped), value calculated using
timer frequency.. 50.00 BogoMIPS (lpj=250000)

This is accurately the timer frequency, 250MHz on the APB
bus.

Cc: Andrew Jeffery <andrew@aj.id.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Jonas Jensen <jonas.jensen@gmail.com>
Tested-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Optimize sched_clock()

The sched_clock() call should be really fast so we want to
avoid an extra if() clause on the read path if possible.

Implement two sched_clock_read() functions, one if the timer
counts up and one if it counts down. Incidentally this also
mirrors how clocksource_mmio_init() works and make things
simple and easy to understand.

Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Andrew Jeffery <andrew@aj.id.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers: Rename CLOCKSOURCE_OF_DECLARE to TIMER_OF_DECLARE

The CLOCKSOURCE_OF_DECLARE macro is used widely for the timers to declare the
clocksource at early stage. However, this macro is also used to initialize
the clockevent if any, or the clockevent only.

It was originally suggested to declare another macro to initialize a
clockevent, so in order to separate the two entities even they belong to the
same IP. This was not accepted because of the impact on the DT where splitting
a clocksource/clockevent definition does not make sense as it is a Linux
concept not a hardware description.

On the other side, the clocksource has not interrupt declared while the
clockevent has, so it is easy from the driver to know if the description is
for a clockevent or a clocksource, IOW it could be implemented at the driver
level.

So instead of dealing with a named clocksource macro, let's use a more generic
one: TIMER_OF_DECLARE.

The patch has not functional changes.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

clocksource/drivers/fttmr010: Fix aspeed-2500 initialization

The recent changes made the fttmr010 to be more generic and support different
timers with a very few differences like moxart or aspeed.

The aspeed timer uses a countdown and there is a test against the aspeed2400
compatible string to set a flag.

With the previous patch, we added the aspeed2500 compatible string but without
taking care of setting the countdown flag.

Fix this by specifiying a init function and pass the aspeed flag to a common
init function.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Add AST2500 compatible string

Also clean up space-before-tab issues in the documentation.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Acked-by: Joel Stanley <joel@jms.id.au>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Merge Moxa into FTTMR010

This merges the Moxa Art timer driver into the Faraday FTTMR010
driver and replaces all Kconfig symbols to use the Faraday
driver instead. We are now so similar that the drivers can
be merged by just adding a few lines to the Faraday timer.

Differences:

- The Faraday driver explicitly sets the counter to count
upwards for the clocksource, removing the need for the
clocksource core to invert the value.

- The Faraday driver also handles sched_clock()

On the Aspeed, the counter can only count downwards, so support
the timers in downward-counting mode as well, and flag the
Aspeed to use this mode. This mode was tested on the Gemini so
I have high hopes that it'll work fine on the Aspeed as well.

After this we have one driver for all three SoCs and a generic
Faraday FTTMR010 timer driver, which is nice.

Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Switch to use TIMER2 src

This switches the clocksource to TIMER2 like the Moxart driver
does. Mainly to make it more similar to the Moxart/Aspeed driver
but also because it seems more neat to use the timers in order:
use timer 1, then timer 2.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Switch to use bitops

This switches the drivers to use the bitops BIT() macro
to define bits.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Use state container

This converts the Faraday FTTMR010 to use the state container
design pattern. Take some care to handle the state container
and free:ing of resources as has been done in the Moxa driver.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Drop Gemini specifics

The Gemini now has a proper clock driver and a proper PCLK
assigned in its device tree. Drop the Gemini-specific hacks
to look up the system speed and rely on the clock framework
like everyone else.

Cc: Joel Stanley <joel@jms.id.au>
Tested-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Fix the clock handling

We need to also prepare and enable the clock we are using to get
the right reference count and avoid it being shut off.

Tested-by: Jonas Jensen <jonas.jensen@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/fttmr010: Refactor to handle clock

The plain Faraday FTTMR010 timer needs a clock to figure out its
tick rate, and the gemini reads it directly from the system
controller set-up. Split the init function and add two paths for
the two compatible-strings. We only support clocking using PCLK
because of lack of documentation on how EXTCLK works.

The Gemini still works like before, but we can also support a
generic, clock-based version.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

clocksource/drivers/gemini: Rename Gemini timer to Faraday

After some research it turns out that the "Gemini" timer is
actually a generic IP block from Faraday Technology named
FTTMR010, so as to not make things too confusing we need to
rename the driver and its symbols to make sense.

The implementation remains the same in this patch but we fix
the copy-paste error in the timer name "nomadik_mtu" as we're
at it.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>