regmap: kunit: Add a test for ranges in combination with windows

In preparation for taking advantage of the SPI support for pre-coooked
messages add a test case covering the use of windows on a raw regmap,
unfortunately the parameterisation prevents direct reuse and we will
want to add some raw specific coverage anyway.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://msgid.link/r/20240225-regmap-test-format-v1-1-41e4fdfb1c1f@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: kunit: Ensure that changed bytes are actually different

During the cache sync test we verify that values we expect to have been
written only to the cache do not appear in the hardware. This works most
of the time but since we randomly generate both the original and new values
there is a low probability that these values may actually be the same.
Wrap get_random_bytes() to ensure that the values are different, there
are other tests which should have similar verification that we actually
changed something.

While we're at it refactor the test to use three changed values rather
than attempting to use one of them twice, that just complicates checking
that our new values are actually new.

We use random generation to try to avoid data dependencies in the tests.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://msgid.link/r/20240211-regmap-kunit-random-change-v3-1-e387a9ea4468@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: kunit: fix raw noinc write test wrapping

The raw noinc write test places a known value in the register following
the noinc register to verify that it is not disturbed by the noinc
write. This test ensures this value is distinct by adding 100 to the
second element of the noinc write data.

The regmap registers are 16-bit, while the test value is stored in an
unsigned int. Therefore, adding 100 may cause the register to wrap while
the test value does not, causing the test to fail. This patch fixes this
by changing val_test and val_last from unsigned int to u16.

Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/linux-kernel/745d3a11-15bc-48b6-84c8-c8761c943bed@roeck-us.net/T/
Tested-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240206151004.1636761-2-ben.wolsieffer@hefring.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: kunit: add noinc write test

Add a test for writing to a noinc register, which verifies that the
write does not touch adjacent registers. This test succeeds with [1]
applied and fails without it.

[1] 984a4afdc87a ("regmap: prevent noinc writes from clobbering cache")

Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Link: https://lore.kernel.org/r/20231102203039.3069305-2-ben.wolsieffer@hefring.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: kunit: Add test for cache sync interaction with ranges

Hector Martin reports that since when doing a cache sync we enable cache
bypass if the selector register for a range is cached then we might leave
the physical selector register pointing to a different value to that which
we have in the cache. If we then try to write to the page that our cache
tells us is selected we will not update the selector register and write to
the wrong page. Add a test case covering this.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20231023-regmap-test-window-cache-v1-2-d8a71f441968@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: kunit: Fix marking of the range window as volatile

For some reason the regmap used for testing ranges was not including the
end of the range of paged registers as volatile since it found the end by
counting from the selector register rather than the base of the window.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20231023-regmap-test-window-cache-v1-1-d8a71f441968@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Provide test for regcache_reg_present()

Provide a KUnit test for the newly added API.

Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230717-regmap-cache-check-v1-2-73ef688afae3@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Disable locking for RBTREE and MAPLE unit tests

REGCACHE_RBTREE and REGCACHE_MAPLE dynamically allocate memory
for regmap operations. This is incompatible with spinlock based locking
which is used for fast_io operations. Disable locking for the associated
unit tests to avoid lockdep splashes.

Fixes: f033c26de5a5 ("regmap: Add maple tree based register cache")
Fixes: 2238959b6ad2 ("regmap: Add some basic kunit tests")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230720032848.1306349-1-linux@roeck-us.net
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Allow reads from write only registers with the flat cache

The flat cache is intended for devices that need the lowest overhead so
doesn't track any sparseness.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230617-regmap-kunit-read-writeonly-flat-v1-1-efd3ed66dec6@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Add test to make sure we don't sync to read only registers

Ensure that a read only value in the register cache does not result in a
write during regcache_sync().

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230613-regmap-kunit-read-write-v1-3-2db337c52827@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Add a test case for write only registers

Validate that attempts to read from write only registers fail and don't
somehow trigger spurious hardware accesses.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230613-regmap-kunit-read-write-v1-2-2db337c52827@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Add test that writes to write only registers are prevented

We should have error checking that verifies that writes to write only
registers are suppressed, verify that this happens as it should.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230613-regmap-kunit-read-write-v1-1-2db337c52827@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Provide basic KUnit coverage for the raw register I/O

Simple tests that cover basic raw I/O, plus basic coverage of cache sync
since the caches generate bulk I/O with raw register maps. This could be
more comprehensive but it is good for testing generic code.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230610-regcache-raw-kunit-v1-2-583112cd28ac@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Add maple tree based register cache

The current state of the art for sparse register maps is the
rbtree cache. This works well for most applications but isn't
always ideal for sparser register maps since the rbtree can get
deep, requiring a lot of walking. Fortunately the kernel has a
data structure intended to address this very problem, the maple
tree. Provide an initial implementation of a register cache
based on the maple tree to start taking advantage of it.

The entries stored in the maple tree are arrays of register
values, with the maple tree keys holding the register addresses.
We store data in host native format rather than device native
format as we do for rbtree, this will be a benefit for devices
where we don't marshal data within regmap and simplifies the code
but will result in additional CPU overhead when syncing the cache
on devices where we do marshal data in regmap.

This should work well for a lot of devices, though there's some
additional areas that could be looked at such as caching the
last accessed entry like we do for rbtree and trying to minimise
the maple tree level locking. We should also use bulk writes
rather than single register writes when resyncing the cache where
possible, even if we don't store in device native format.

Very small register maps may continue to to better with rbtree
longer term.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230325-regcache-maple-v3-2-23e271f93dc7@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Add some basic kunit tests

On the theory that it's better to make a start let's add some KUnit tests
for regmap. Currently this is a bit of a mess but it passes and hopefully
will at some point help catch problems. We provide very basic cover for
most of the core functionality that operates at the register level,
repeating each test for each cache type in order to exercise the caches.
There is no coverage of anything to do with the bulk operations at the bus
level or formatting for byte stream buses yet.

Each test creates it's own regmap since the cache structures are built
incrementally, meaning we gain coverage from the different access
patterns, and some of the tests cover different init scenarios.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230324-regmap-kunit-v2-2-b208801dc2c8@kernel.org