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

3 files changed, 744 insertions, 0 deletions

diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
index 3d3445bff511..33a8366e22a5 100644
--- a/drivers/base/regmap/Kconfig
+++ b/drivers/base/regmap/Kconfig
@@ -9,6 +9,13 @@ config REGMAP
 	select MDIO_BUS if REGMAP_MDIO
 	bool
 
+config REGMAP_KUNIT
+	tristate "KUnit tests for regmap"
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	select REGMAP
+	select REGMAP_RAM
+
 config REGMAP_AC97
 	tristate
 
diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index b4b0e8fe6c1f..4cb73468a197 100644
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -5,6 +5,7 @@ CFLAGS_regmap.o := -I$(src)
 obj-$(CONFIG_REGMAP) += regmap.o regcache.o
 obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-flat.o
 obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.o
+obj-$(CONFIG_REGMAP_KUNIT) += regmap-kunit.o
 obj-$(CONFIG_REGMAP_AC97) += regmap-ac97.o
 obj-$(CONFIG_REGMAP_I2C) += regmap-i2c.o
 obj-$(CONFIG_REGMAP_RAM) += regmap-ram.o
diff --git a/drivers/base/regmap/regmap-kunit.c b/drivers/base/regmap/regmap-kunit.c
new file mode 100644
index 000000000000..c78f45cf9a8d
--- /dev/null
+++ b/drivers/base/regmap/regmap-kunit.c
@@ -0,0 +1,736 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// regmap KUnit tests
+//
+// Copyright 2023 Arm Ltd
+
+#include <kunit/test.h>
+#include "internal.h"
+
+#define BLOCK_TEST_SIZE 12
+
+static const struct regmap_config test_regmap_config = {
+	.max_register = BLOCK_TEST_SIZE,
+	.reg_stride = 1,
+	.val_bits = sizeof(unsigned int) * 8,
+};
+
+struct regcache_types {
+	enum regcache_type type;
+	const char *name;
+};
+
+static void case_to_desc(const struct regcache_types *t, char *desc)
+{
+	strcpy(desc, t->name);
+}
+
+static const struct regcache_types regcache_types_list[] = {
+	{ REGCACHE_NONE, "none" },
+	{ REGCACHE_FLAT, "flat" },
+	{ REGCACHE_RBTREE, "rbtree" },
+};
+
+KUNIT_ARRAY_PARAM(regcache_types, regcache_types_list, case_to_desc);
+
+static const struct regcache_types real_cache_types_list[] = {
+	{ REGCACHE_FLAT, "flat" },
+	{ REGCACHE_RBTREE, "rbtree" },
+};
+
+KUNIT_ARRAY_PARAM(real_cache_types, real_cache_types_list, case_to_desc);
+
+static const struct regcache_types sparse_cache_types_list[] = {
+	{ REGCACHE_RBTREE, "rbtree" },
+};
+
+KUNIT_ARRAY_PARAM(sparse_cache_types, sparse_cache_types_list, case_to_desc);
+
+static struct regmap *gen_regmap(struct regmap_config *config,
+				 struct regmap_ram_data **data)
+{
+	unsigned int *buf;
+	struct regmap *ret;
+	size_t size = (config->max_register + 1) * sizeof(unsigned int);
+	int i;
+	struct reg_default *defaults;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return ERR_PTR(-ENOMEM);
+
+	get_random_bytes(buf, size);
+
+	*data = kzalloc(sizeof(**data), GFP_KERNEL);
+	if (!(*data))
+		return ERR_PTR(-ENOMEM);
+	(*data)->vals = buf;
+
+	if (config->num_reg_defaults) {
+		defaults = kcalloc(config->num_reg_defaults,
+				   sizeof(struct reg_default),
+				   GFP_KERNEL);
+		if (!defaults)
+			return ERR_PTR(-ENOMEM);
+		config->reg_defaults = defaults;
+
+		for (i = 0; i < config->num_reg_defaults; i++) {
+			defaults[i].reg = i * config->reg_stride;
+			defaults[i].def = buf[i * config->reg_stride];
+		}
+	}
+
+	ret = regmap_init_ram(config, *data);
+	if (IS_ERR(ret)) {
+		kfree(buf);
+		kfree(*data);
+	}
+
+	return ret;
+}
+
+static void basic_read_write(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int val, rval;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	get_random_bytes(&val, sizeof(val));
+
+	/* If we write a value to a register we can read it back */
+	KUNIT_EXPECT_EQ(test, 0, regmap_write(map, 0, val));
+	KUNIT_EXPECT_EQ(test, 0, regmap_read(map, 0, &rval));
+	KUNIT_EXPECT_EQ(test, val, rval);
+
+	/* If using a cache the cache satisfied the read */
+	KUNIT_EXPECT_EQ(test, t->type == REGCACHE_NONE, data->read[0]);
+
+	regmap_exit(map);
+}
+
+static void bulk_write(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int val[BLOCK_TEST_SIZE], rval[BLOCK_TEST_SIZE];
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	get_random_bytes(&val, sizeof(val));
+
+	/*
+	 * Data written via the bulk API can be read back with single
+	 * reads.
+	 */
+	KUNIT_EXPECT_EQ(test, 0, regmap_bulk_write(map, 0, val,
+						   BLOCK_TEST_SIZE));
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, 0, regmap_read(map, i, &rval[i]));
+
+	KUNIT_EXPECT_MEMEQ(test, val, rval, sizeof(val));
+
+	/* If using a cache the cache satisfied the read */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, t->type == REGCACHE_NONE, data->read[i]);
+
+	regmap_exit(map);
+}
+
+static void bulk_read(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int val[BLOCK_TEST_SIZE], rval[BLOCK_TEST_SIZE];
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	get_random_bytes(&val, sizeof(val));
+
+	/* Data written as single writes can be read via the bulk API */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, val[i]));
+	KUNIT_EXPECT_EQ(test, 0, regmap_bulk_read(map, 0, rval,
+						  BLOCK_TEST_SIZE));
+	KUNIT_EXPECT_MEMEQ(test, val, rval, sizeof(val));
+
+	/* If using a cache the cache satisfied the read */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, t->type == REGCACHE_NONE, data->read[i]);
+
+	regmap_exit(map);
+}
+
+static void reg_defaults(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int rval[BLOCK_TEST_SIZE];
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+	config.num_reg_defaults = BLOCK_TEST_SIZE;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	/* Read back the expected default data */
+	KUNIT_EXPECT_EQ(test, 0, regmap_bulk_read(map, 0, rval,
+						  BLOCK_TEST_SIZE));
+	KUNIT_EXPECT_MEMEQ(test, data->vals, rval, sizeof(rval));
+
+	/* The data should have been read from cache if there was one */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, t->type == REGCACHE_NONE, data->read[i]);
+}
+
+static void reg_defaults_read_dev(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int rval[BLOCK_TEST_SIZE];
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+	config.num_reg_defaults_raw = BLOCK_TEST_SIZE;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	/* We should have read the cache defaults back from the map */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		KUNIT_EXPECT_EQ(test, t->type != REGCACHE_NONE, data->read[i]);
+		data->read[i] = false;
+	}
+
+	/* Read back the expected default data */
+	KUNIT_EXPECT_EQ(test, 0, regmap_bulk_read(map, 0, rval,
+						  BLOCK_TEST_SIZE));
+	KUNIT_EXPECT_MEMEQ(test, data->vals, rval, sizeof(rval));
+
+	/* The data should have been read from cache if there was one */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, t->type == REGCACHE_NONE, data->read[i]);
+}
+
+static void register_patch(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	struct reg_sequence patch[2];
+	unsigned int rval[BLOCK_TEST_SIZE];
+	int i;
+
+	/* We need defaults so readback works */
+	config = test_regmap_config;
+	config.cache_type = t->type;
+	config.num_reg_defaults = BLOCK_TEST_SIZE;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	/* Stash the original values */
+	KUNIT_EXPECT_EQ(test, 0, regmap_bulk_read(map, 0, rval,
+						  BLOCK_TEST_SIZE));
+
+	/* Patch a couple of values */
+	patch[0].reg = 2;
+	patch[0].def = rval[2] + 1;
+	patch[0].delay_us = 0;
+	patch[1].reg = 5;
+	patch[1].def = rval[5] + 1;
+	patch[1].delay_us = 0;
+	KUNIT_EXPECT_EQ(test, 0, regmap_register_patch(map, patch,
+						       ARRAY_SIZE(patch)));
+
+	/* Only the patched registers are written */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		switch (i) {
+		case 2:
+		case 5:
+			KUNIT_EXPECT_TRUE(test, data->written[i]);
+			KUNIT_EXPECT_EQ(test, data->vals[i], rval[i] + 1);
+			break;
+		default:
+			KUNIT_EXPECT_FALSE(test, data->written[i]);
+			KUNIT_EXPECT_EQ(test, data->vals[i], rval[i]);
+			break;
+		}
+	}
+
+	regmap_exit(map);
+}
+
+static void stride(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int rval;
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+	config.reg_stride = 2;
+	config.num_reg_defaults = BLOCK_TEST_SIZE / 2;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	/* Only even registers can be accessed, try both read and write */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		data->read[i] = false;
+		data->written[i] = false;
+
+		if (i % 2) {
+			KUNIT_EXPECT_NE(test, 0, regmap_read(map, i, &rval));
+			KUNIT_EXPECT_NE(test, 0, regmap_write(map, i, rval));
+			KUNIT_EXPECT_FALSE(test, data->read[i]);
+			KUNIT_EXPECT_FALSE(test, data->written[i]);
+		} else {
+			KUNIT_EXPECT_EQ(test, 0, regmap_read(map, i, &rval));
+			KUNIT_EXPECT_EQ(test, data->vals[i], rval);
+			KUNIT_EXPECT_EQ(test, t->type == REGCACHE_NONE,
+					data->read[i]);
+
+			KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, rval));
+			KUNIT_EXPECT_TRUE(test, data->written[i]);
+		}
+	}
+
+	regmap_exit(map);
+}
+
+static struct regmap_range_cfg test_range = {
+	.selector_reg = 1,
+	.selector_mask = 0xff,
+
+	.window_start = 4,
+	.window_len = 10,
+
+	.range_min = 20,
+	.range_max = 40,
+};
+
+static bool test_range_volatile(struct device *dev, unsigned int reg)
+{
+	if (reg >= test_range.window_start &&
+	    reg <= test_range.selector_reg + test_range.window_len)
+		return true;
+
+	if (reg >= test_range.range_min && reg <= test_range.range_max)
+		return true;
+
+	return false;
+}
+
+static void basic_ranges(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int val;
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+	config.volatile_reg = test_range_volatile;
+	config.ranges = &test_range;
+	config.num_ranges = 1;
+	config.max_register = test_range.range_max;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	for (i = test_range.range_min; i < test_range.range_max; i++) {
+		data->read[i] = false;
+		data->written[i] = false;
+	}
+
+	/* Reset the page to a non-zero value to trigger a change */
+	KUNIT_EXPECT_EQ(test, 0, regmap_write(map, test_range.selector_reg,
+					      test_range.range_max));
+
+	/* Check we set the page and use the window for writes */
+	data->written[test_range.selector_reg] = false;
+	data->written[test_range.window_start] = false;
+	KUNIT_EXPECT_EQ(test, 0, regmap_write(map, test_range.range_min, 0));
+	KUNIT_EXPECT_TRUE(test, data->written[test_range.selector_reg]);
+	KUNIT_EXPECT_TRUE(test, data->written[test_range.window_start]);
+
+	data->written[test_range.selector_reg] = false;
+	data->written[test_range.window_start] = false;
+	KUNIT_EXPECT_EQ(test, 0, regmap_write(map,
+					      test_range.range_min +
+					      test_range.window_len,
+					      0));
+	KUNIT_EXPECT_TRUE(test, data->written[test_range.selector_reg]);
+	KUNIT_EXPECT_TRUE(test, data->written[test_range.window_start]);
+
+	/* Same for reads */
+	data->written[test_range.selector_reg] = false;
+	data->read[test_range.window_start] = false;
+	KUNIT_EXPECT_EQ(test, 0, regmap_read(map, test_range.range_min, &val));
+	KUNIT_EXPECT_TRUE(test, data->written[test_range.selector_reg]);
+	KUNIT_EXPECT_TRUE(test, data->read[test_range.window_start]);
+
+	data->written[test_range.selector_reg] = false;
+	data->read[test_range.window_start] = false;
+	KUNIT_EXPECT_EQ(test, 0, regmap_read(map,
+					     test_range.range_min +
+					     test_range.window_len,
+					     &val));
+	KUNIT_EXPECT_TRUE(test, data->written[test_range.selector_reg]);
+	KUNIT_EXPECT_TRUE(test, data->read[test_range.window_start]);
+
+	/* No physical access triggered in the virtual range */
+	for (i = test_range.range_min; i < test_range.range_max; i++) {
+		KUNIT_EXPECT_FALSE(test, data->read[i]);
+		KUNIT_EXPECT_FALSE(test, data->written[i]);
+	}
+
+	regmap_exit(map);
+}
+
+/* Try to stress dynamic creation of cache data structures */
+static void stress_insert(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int rval, *vals;
+	size_t buf_sz;
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+	config.max_register = 300;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	vals = kunit_kcalloc(test, sizeof(unsigned long), config.max_register,
+			     GFP_KERNEL);
+	KUNIT_ASSERT_FALSE(test, vals == NULL);
+	buf_sz = sizeof(unsigned long) * config.max_register;
+
+	get_random_bytes(vals, buf_sz);
+
+	/* Write data into the map/cache in ever decreasing strides */
+	for (i = 0; i < config.max_register; i += 100)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, vals[i]));
+	for (i = 0; i < config.max_register; i += 50)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, vals[i]));
+	for (i = 0; i < config.max_register; i += 25)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, vals[i]));
+	for (i = 0; i < config.max_register; i += 10)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, vals[i]));
+	for (i = 0; i < config.max_register; i += 5)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, vals[i]));
+	for (i = 0; i < config.max_register; i += 3)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, vals[i]));
+	for (i = 0; i < config.max_register; i += 2)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, vals[i]));
+	for (i = 0; i < config.max_register; i++)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, i, vals[i]));
+
+	/* Do reads from the cache (if there is one) match? */
+	for (i = 0; i < config.max_register; i ++) {
+		KUNIT_EXPECT_EQ(test, 0, regmap_read(map, i, &rval));
+		KUNIT_EXPECT_EQ(test, rval, vals[i]);
+		KUNIT_EXPECT_EQ(test, t->type == REGCACHE_NONE, data->read[i]);
+	}
+
+	regmap_exit(map);
+}
+
+static void cache_bypass(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int val, rval;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	get_random_bytes(&val, sizeof(val));
+
+	/* Ensure the cache has a value in it */
+	KUNIT_EXPECT_EQ(test, 0, regmap_write(map, 0, val));
+
+	/* Bypass then write a different value */
+	regcache_cache_bypass(map, true);
+	KUNIT_EXPECT_EQ(test, 0, regmap_write(map, 0, val + 1));
+
+	/* Read the bypassed value */
+	KUNIT_EXPECT_EQ(test, 0, regmap_read(map, 0, &rval));
+	KUNIT_EXPECT_EQ(test, val + 1, rval);
+	KUNIT_EXPECT_EQ(test, data->vals[0], rval);
+
+	/* Disable bypass, the cache should still return the original value */
+	regcache_cache_bypass(map, false);
+	KUNIT_EXPECT_EQ(test, 0, regmap_read(map, 0, &rval));
+	KUNIT_EXPECT_EQ(test, val, rval);
+
+	regmap_exit(map);
+}
+
+static void cache_sync(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int val[BLOCK_TEST_SIZE];
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	get_random_bytes(&val, sizeof(val));
+
+	/* Put some data into the cache */
+	KUNIT_EXPECT_EQ(test, 0, regmap_bulk_write(map, 0, val,
+						   BLOCK_TEST_SIZE));
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		data->written[i] = false;
+
+	/* Trash the data on the device itself then resync */
+	regcache_mark_dirty(map);
+	memset(data->vals, 0, sizeof(val));
+	KUNIT_EXPECT_EQ(test, 0, regcache_sync(map));
+
+	/* Did we just write the correct data out? */
+	KUNIT_EXPECT_MEMEQ(test, data->vals, val, sizeof(val));
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, true, data->written[i]);
+
+	regmap_exit(map);
+}
+
+static void cache_sync_defaults(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int val;
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+	config.num_reg_defaults = BLOCK_TEST_SIZE;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	get_random_bytes(&val, sizeof(val));
+
+	/* Change the value of one register */
+	KUNIT_EXPECT_EQ(test, 0, regmap_write(map, 2, val));
+
+	/* Resync */
+	regcache_mark_dirty(map);
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		data->written[i] = false;
+	KUNIT_EXPECT_EQ(test, 0, regcache_sync(map));
+
+	/* Did we just sync the one register we touched? */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, i == 2, data->written[i]);
+
+	regmap_exit(map);
+}
+
+static void cache_sync_patch(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	struct reg_sequence patch[2];
+	unsigned int rval[BLOCK_TEST_SIZE], val;
+	int i;
+
+	/* We need defaults so readback works */
+	config = test_regmap_config;
+	config.cache_type = t->type;
+	config.num_reg_defaults = BLOCK_TEST_SIZE;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	/* Stash the original values */
+	KUNIT_EXPECT_EQ(test, 0, regmap_bulk_read(map, 0, rval,
+						  BLOCK_TEST_SIZE));
+
+	/* Patch a couple of values */
+	patch[0].reg = 2;
+	patch[0].def = rval[2] + 1;
+	patch[0].delay_us = 0;
+	patch[1].reg = 5;
+	patch[1].def = rval[5] + 1;
+	patch[1].delay_us = 0;
+	KUNIT_EXPECT_EQ(test, 0, regmap_register_patch(map, patch,
+						       ARRAY_SIZE(patch)));
+
+	/* Sync the cache */
+	regcache_mark_dirty(map);
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		data->written[i] = false;
+	KUNIT_EXPECT_EQ(test, 0, regcache_sync(map));
+
+	/* The patch should be on the device but not in the cache */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		KUNIT_EXPECT_EQ(test, 0, regmap_read(map, i, &val));
+		KUNIT_EXPECT_EQ(test, val, rval[i]);
+
+		switch (i) {
+		case 2:
+		case 5:
+			KUNIT_EXPECT_EQ(test, true, data->written[i]);
+			KUNIT_EXPECT_EQ(test, data->vals[i], rval[i] + 1);
+			break;
+		default:
+			KUNIT_EXPECT_EQ(test, false, data->written[i]);
+			KUNIT_EXPECT_EQ(test, data->vals[i], rval[i]);
+			break;
+		}
+	}
+
+	regmap_exit(map);
+}
+
+static void cache_drop(struct kunit *test)
+{
+	struct regcache_types *t = (struct regcache_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int rval[BLOCK_TEST_SIZE];
+	int i;
+
+	config = test_regmap_config;
+	config.cache_type = t->type;
+	config.num_reg_defaults = BLOCK_TEST_SIZE;
+
+	map = gen_regmap(&config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	/* Ensure the data is read from the cache */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		data->read[i] = false;
+	KUNIT_EXPECT_EQ(test, 0, regmap_bulk_read(map, 0, rval,
+						  BLOCK_TEST_SIZE));
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		KUNIT_EXPECT_FALSE(test, data->read[i]);
+		data->read[i] = false;
+	}
+	KUNIT_EXPECT_MEMEQ(test, data->vals, rval, sizeof(rval));
+
+	/* Drop some registers */
+	KUNIT_EXPECT_EQ(test, 0, regcache_drop_region(map, 3, 5));
+
+	/* Reread and check only the dropped registers hit the device. */
+	KUNIT_EXPECT_EQ(test, 0, regmap_bulk_read(map, 0, rval,
+						  BLOCK_TEST_SIZE));
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, data->read[i], i >= 3 && i <= 5);
+	KUNIT_EXPECT_MEMEQ(test, data->vals, rval, sizeof(rval));
+
+	regmap_exit(map);
+}
+
+static struct kunit_case regmap_test_cases[] = {
+	KUNIT_CASE_PARAM(basic_read_write, regcache_types_gen_params),
+	KUNIT_CASE_PARAM(bulk_write, regcache_types_gen_params),
+	KUNIT_CASE_PARAM(bulk_read, regcache_types_gen_params),
+	KUNIT_CASE_PARAM(reg_defaults, regcache_types_gen_params),
+	KUNIT_CASE_PARAM(reg_defaults_read_dev, regcache_types_gen_params),
+	KUNIT_CASE_PARAM(register_patch, regcache_types_gen_params),
+	KUNIT_CASE_PARAM(stride, regcache_types_gen_params),
+	KUNIT_CASE_PARAM(basic_ranges, regcache_types_gen_params),
+	KUNIT_CASE_PARAM(stress_insert, regcache_types_gen_params),
+	KUNIT_CASE_PARAM(cache_bypass, real_cache_types_gen_params),
+	KUNIT_CASE_PARAM(cache_sync, real_cache_types_gen_params),
+	KUNIT_CASE_PARAM(cache_sync_defaults, real_cache_types_gen_params),
+	KUNIT_CASE_PARAM(cache_sync_patch, real_cache_types_gen_params),
+	KUNIT_CASE_PARAM(cache_drop, sparse_cache_types_gen_params),
+	{}
+};
+
+static struct kunit_suite regmap_test_suite = {
+	.name = "regmap",
+	.test_cases = regmap_test_cases,
+};
+kunit_test_suite(regmap_test_suite);
+
+MODULE_LICENSE("GPL v2");