[PATCH 2/2] regmap: Test rbtree and maple caches for very high register numbers

We've had bugs in the cache code with handling of register numbers with the
top bit set before, add some test cases for this. It's not really worth
fixing up all the individual tests to support a base address, instead
write a specific test that reproduces a bunch of the coverge. Run this on
the rbtree and maple caches which are the only ones that can reasonably
support this case.

Signed-off-by: Mark Brown <[email protected]>
---
 drivers/base/regmap/regmap-kunit.c | 94 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 93 insertions(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regmap-kunit.c b/drivers/base/regmap/regmap-kunit.c
index 2999d9c185d5..98093451a7b4 100644
--- a/drivers/base/regmap/regmap-kunit.c
+++ b/drivers/base/regmap/regmap-kunit.c
@@ -11,6 +11,8 @@
 
 #define BLOCK_TEST_SIZE 12
 
+#define HIGH_BIT_REG (UINT_MAX - 0x5000)
+
 KUNIT_DEFINE_ACTION_WRAPPER(regmap_exit_action, regmap_exit, struct regmap *);
 
 struct regmap_test_priv {
@@ -23,6 +25,7 @@ struct regmap_test_param {
 	enum regcache_type cache;
 	enum regmap_endian val_endian;
 
+	unsigned int base_reg;
 	unsigned int from_reg;
 	bool fast_io;
 };
@@ -204,7 +207,8 @@ static struct regmap *gen_regmap(struct kunit *test,
 			config->max_register += (BLOCK_TEST_SIZE * config->reg_stride);
 	}
 
-	size = array_size(config->max_register + 1, sizeof(*buf));
+	size = array_size(config->max_register - param->base_reg + 1,
+			  sizeof(*buf));
 	buf = kmalloc(size, GFP_KERNEL);
 	if (!buf)
 		return ERR_PTR(-ENOMEM);
@@ -215,6 +219,7 @@ static struct regmap *gen_regmap(struct kunit *test,
 	if (!(*data))
 		goto out_free;
 	(*data)->vals = buf;
+	(*data)->base_reg = param->base_reg;
 
 	if (config->num_reg_defaults) {
 		defaults = kunit_kcalloc(test,
@@ -1648,6 +1653,92 @@ static void cache_write_zero(struct kunit *test)
 	KUNIT_ASSERT_FALSE(test, regcache_reg_cached(map, 1));
 }
 
+static const struct regmap_test_param high_bit_cache_types_list[] = {
+	{ .cache = REGCACHE_RBTREE, .from_reg = HIGH_BIT_REG,
+				    .base_reg = HIGH_BIT_REG },
+	{ .cache = REGCACHE_MAPLE,  .from_reg = HIGH_BIT_REG,
+				    .base_reg = HIGH_BIT_REG },
+};
+
+KUNIT_ARRAY_PARAM(high_bit_cache_types, high_bit_cache_types_list, param_to_desc);
+
+/*
+ * Dynamically allocated cache types should support registers with the
+ * high bit set, the backend will return an error for any operation on
+ * a register below the expected window.
+ */
+static void cache_high_bit_reg(struct kunit *test)
+{
+	const struct regmap_test_param *param = test->param_value;
+	struct regmap_ram_data *data;
+	struct regmap_config config;
+	struct regmap *map;
+	unsigned int val[BLOCK_TEST_SIZE], rval;
+	int i;
+
+	config = test_regmap_config;
+
+	map = gen_regmap(test, &config, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	get_random_bytes(&val, sizeof(val));
+
+	/* No defaults so no registers cached */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_FALSE(test, regcache_reg_cached(map, param->from_reg + i));
+
+	/* Writes should reach the device */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, param->from_reg + i,
+						      val[i]));
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		KUNIT_EXPECT_TRUE(test, data->written[i]);
+		KUNIT_EXPECT_EQ(test, val[i], data->vals[i]);
+	}
+
+	/* Reads should be satisfied from the cache */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		KUNIT_EXPECT_TRUE(test, regcache_reg_cached(map, param->from_reg + i));
+		KUNIT_EXPECT_EQ(test, 0, regmap_read(map, param->from_reg + i,
+						     &rval));
+		KUNIT_EXPECT_EQ(test, val[i], rval);
+		KUNIT_EXPECT_FALSE(test, data->read[i]);
+	}
+
+	/* Trash the data on the device then resync */
+	regcache_mark_dirty(map);
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		data->vals[i] = 0;
+		data->written[i] = false;
+	}
+	KUNIT_EXPECT_EQ(test, 0, regcache_sync(map));
+
+	/* Did we just write the correct data out? */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		KUNIT_EXPECT_TRUE(test, data->written[i]);
+		KUNIT_EXPECT_EQ(test, val[i], data->vals[i]);
+	}
+
+	/* Drop some registers */
+	KUNIT_EXPECT_EQ(test, 0, regcache_drop_region(map, param->from_reg + 3,
+						      param->from_reg + 5));
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		KUNIT_EXPECT_EQ(test, i < 3 || i > 5,
+				regcache_reg_cached(map, param->from_reg + i));
+
+	/* Reread and check only the dropped registers hit the device */
+	for (i = 0; i < BLOCK_TEST_SIZE; i++)
+		data->read[i] = false;
+	for (i = 0; i < BLOCK_TEST_SIZE; i++) {
+		KUNIT_EXPECT_EQ(test, 0, regmap_read(map, param->from_reg + i,
+						     &rval));
+		KUNIT_EXPECT_EQ(test, val[i], rval);
+		KUNIT_EXPECT_EQ(test, i >= 3 && i <= 5, data->read[i]);
+	}
+}
+
 /* Check that caching the window register works with sync */
 static void cache_range_window_reg(struct kunit *test)
 {
@@ -2168,6 +2259,7 @@ static struct kunit_case regmap_test_cases[] = {
 	KUNIT_CASE_PARAM(cache_drop_all_and_sync_has_defaults, sparse_cache_types_gen_params),
 	KUNIT_CASE_PARAM(cache_present, sparse_cache_types_gen_params),
 	KUNIT_CASE_PARAM(cache_write_zero, sparse_cache_types_gen_params),
+	KUNIT_CASE_PARAM(cache_high_bit_reg, high_bit_cache_types_gen_params),
 	KUNIT_CASE_PARAM(cache_range_window_reg, real_cache_types_only_gen_params),
 
 	KUNIT_CASE_PARAM(raw_read_defaults_single, raw_test_types_gen_params),

-- 
2.47.3