regmap: Provide basic test coverage for raw I/O

Merge series from Mark Brown <broonie@kernel.org>:

Our existing coverage only deals with buses that provide single register
read and write operations, extend it to cover raw buses using a similar
approach with a RAM backed register map that the tests can inspect to
check operations.  This coverage could be more complete but provides a
good start.

4 files changed, 469 insertions, 1 deletions

diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index f6c6cb017200..5fdd0845b45e 100644
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -8,7 +8,7 @@ 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-$(CONFIG_REGMAP_RAM) += regmap-ram.o
+obj-$(CONFIG_REGMAP_RAM) += regmap-ram.o regmap-raw-ram.o
 obj-$(CONFIG_REGMAP_SLIMBUS) += regmap-slimbus.o
 obj-$(CONFIG_REGMAP_SPI) += regmap-spi.o
 obj-$(CONFIG_REGMAP_SPMI) += regmap-spmi.o
diff --git a/drivers/base/regmap/internal.h b/drivers/base/regmap/internal.h
index 00848303b193..7211babbe4ee 100644
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -314,6 +314,7 @@ struct regmap_ram_data {
 	unsigned int *vals;  /* Allocatd by caller */
 	bool *read;
 	bool *written;
+	enum regmap_endian reg_endian;
 };
 
 /*
@@ -328,5 +329,12 @@ struct regmap *__regmap_init_ram(const struct regmap_config *config,
 #define regmap_init_ram(config, data)					\
 	__regmap_lockdep_wrapper(__regmap_init_ram, #config, config, data)
 
+struct regmap *__regmap_init_raw_ram(const struct regmap_config *config,
+				     struct regmap_ram_data *data,
+				     struct lock_class_key *lock_key,
+				     const char *lock_name);
+
+#define regmap_init_raw_ram(config, data)				\
+	__regmap_lockdep_wrapper(__regmap_init_raw_ram, #config, config, data)
 
 #endif
diff --git a/drivers/base/regmap/regmap-kunit.c b/drivers/base/regmap/regmap-kunit.c
index f76d41688134..4ec5cbfc0ca0 100644
--- a/drivers/base/regmap/regmap-kunit.c
+++ b/drivers/base/regmap/regmap-kunit.c
@@ -712,6 +712,327 @@ static void cache_drop(struct kunit *test)
 	regmap_exit(map);
 }
 
+struct raw_test_types {
+	const char *name;
+
+	enum regcache_type cache_type;
+	enum regmap_endian val_endian;
+};
+
+static void raw_to_desc(const struct raw_test_types *t, char *desc)
+{
+	strcpy(desc, t->name);
+}
+
+static const struct raw_test_types raw_types_list[] = {
+	{ "none-little",   REGCACHE_NONE,   REGMAP_ENDIAN_LITTLE },
+	{ "none-big",      REGCACHE_NONE,   REGMAP_ENDIAN_BIG },
+	{ "flat-little",   REGCACHE_FLAT,   REGMAP_ENDIAN_LITTLE },
+	{ "flat-big",      REGCACHE_FLAT,   REGMAP_ENDIAN_BIG },
+	{ "rbtree-little", REGCACHE_RBTREE, REGMAP_ENDIAN_LITTLE },
+	{ "rbtree-big",    REGCACHE_RBTREE, REGMAP_ENDIAN_BIG },
+	{ "maple-little",  REGCACHE_MAPLE,  REGMAP_ENDIAN_LITTLE },
+	{ "maple-big",     REGCACHE_MAPLE,  REGMAP_ENDIAN_BIG },
+};
+
+KUNIT_ARRAY_PARAM(raw_test_types, raw_types_list, raw_to_desc);
+
+static const struct raw_test_types raw_cache_types_list[] = {
+	{ "flat-little",   REGCACHE_FLAT,   REGMAP_ENDIAN_LITTLE },
+	{ "flat-big",      REGCACHE_FLAT,   REGMAP_ENDIAN_BIG },
+	{ "rbtree-little", REGCACHE_RBTREE, REGMAP_ENDIAN_LITTLE },
+	{ "rbtree-big",    REGCACHE_RBTREE, REGMAP_ENDIAN_BIG },
+	{ "maple-little",  REGCACHE_MAPLE,  REGMAP_ENDIAN_LITTLE },
+	{ "maple-big",     REGCACHE_MAPLE,  REGMAP_ENDIAN_BIG },
+};
+
+KUNIT_ARRAY_PARAM(raw_test_cache_types, raw_cache_types_list, raw_to_desc);
+
+static const struct regmap_config raw_regmap_config = {
+	.max_register = BLOCK_TEST_SIZE,
+
+	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
+	.reg_bits = 16,
+	.val_bits = 16,
+};
+
+static struct regmap *gen_raw_regmap(struct regmap_config *config,
+				     struct raw_test_types *test_type,
+				     struct regmap_ram_data **data)
+{
+	u16 *buf;
+	struct regmap *ret;
+	size_t size = (config->max_register + 1) * config->reg_bits / 8;
+	int i;
+	struct reg_default *defaults;
+
+	config->cache_type = test_type->cache_type;
+	config->val_format_endian = test_type->val_endian;
+
+	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 = (void *)buf;
+
+	config->num_reg_defaults = config->max_register + 1;
+	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;
+		switch (test_type->val_endian) {
+		case REGMAP_ENDIAN_LITTLE:
+			defaults[i].def = le16_to_cpu(buf[i]);
+			break;
+		case REGMAP_ENDIAN_BIG:
+			defaults[i].def = be16_to_cpu(buf[i]);
+			break;
+		default:
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/*
+	 * We use the defaults in the tests but they don't make sense
+	 * to the core if there's no cache.
+	 */
+	if (config->cache_type == REGCACHE_NONE)
+		config->num_reg_defaults = 0;
+
+	ret = regmap_init_raw_ram(config, *data);
+	if (IS_ERR(ret)) {
+		kfree(buf);
+		kfree(*data);
+	}
+
+	return ret;
+}
+
+static void raw_read_defaults_single(struct kunit *test)
+{
+	struct raw_test_types *t = (struct raw_test_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	unsigned int rval;
+	int i;
+
+	config = raw_regmap_config;
+
+	map = gen_raw_regmap(&config, t, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	/* Check that we can read the defaults via the API */
+	for (i = 0; i < config.max_register + 1; i++) {
+		KUNIT_EXPECT_EQ(test, 0, regmap_read(map, i, &rval));
+		KUNIT_EXPECT_EQ(test, config.reg_defaults[i].def, rval);
+	}
+
+	regmap_exit(map);
+}
+
+static void raw_read_defaults(struct kunit *test)
+{
+	struct raw_test_types *t = (struct raw_test_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	u16 *rval;
+	u16 def;
+	size_t val_len;
+	int i;
+
+	config = raw_regmap_config;
+
+	map = gen_raw_regmap(&config, t, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	val_len = sizeof(*rval) * (config.max_register + 1);
+	rval = kmalloc(val_len, GFP_KERNEL);
+	KUNIT_ASSERT_TRUE(test, rval != NULL);
+	if (!rval)
+		return;
+	
+	/* Check that we can read the defaults via the API */
+	KUNIT_EXPECT_EQ(test, 0, regmap_raw_read(map, 0, rval, val_len));
+	for (i = 0; i < config.max_register + 1; i++) {
+		def = config.reg_defaults[i].def;
+		if (config.val_format_endian == REGMAP_ENDIAN_BIG) {
+			KUNIT_EXPECT_EQ(test, def, be16_to_cpu(rval[i]));
+		} else {
+			KUNIT_EXPECT_EQ(test, def, le16_to_cpu(rval[i]));
+		}
+	}
+	
+	kfree(rval);
+	regmap_exit(map);
+}
+
+static void raw_write_read_single(struct kunit *test)
+{
+	struct raw_test_types *t = (struct raw_test_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	u16 val;
+	unsigned int rval;
+
+	config = raw_regmap_config;
+
+	map = gen_raw_regmap(&config, t, &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);
+
+	regmap_exit(map);
+}
+
+static void raw_write(struct kunit *test)
+{
+	struct raw_test_types *t = (struct raw_test_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	u16 *hw_buf;
+	u16 val[2];
+	unsigned int rval;
+	int i;
+
+	config = raw_regmap_config;
+
+	map = gen_raw_regmap(&config, t, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	hw_buf = (u16 *)data->vals;
+
+	get_random_bytes(&val, sizeof(val));
+
+	/* Do a raw write */
+	KUNIT_EXPECT_EQ(test, 0, regmap_raw_write(map, 2, val, sizeof(val)));
+
+	/* We should read back the new values, and defaults for the rest */
+	for (i = 0; i < config.max_register + 1; i++) {
+		KUNIT_EXPECT_EQ(test, 0, regmap_read(map, i, &rval));
+
+		switch (i) {
+		case 2:
+		case 3:
+			if (config.val_format_endian == REGMAP_ENDIAN_BIG) {
+				KUNIT_EXPECT_EQ(test, rval,
+						be16_to_cpu(val[i % 2]));
+			} else {
+				KUNIT_EXPECT_EQ(test, rval,
+						le16_to_cpu(val[i % 2]));
+			}
+			break;
+		default:
+			KUNIT_EXPECT_EQ(test, config.reg_defaults[i].def, rval);
+			break;
+		}
+	}
+
+	/* The values should appear in the "hardware" */
+	KUNIT_EXPECT_MEMEQ(test, &hw_buf[2], val, sizeof(val));
+
+	regmap_exit(map);
+}
+
+static void raw_sync(struct kunit *test)
+{
+	struct raw_test_types *t = (struct raw_test_types *)test->param_value;
+	struct regmap *map;
+	struct regmap_config config;
+	struct regmap_ram_data *data;
+	u16 val[2];
+	u16 *hw_buf;
+	unsigned int rval;
+	int i;
+
+	config = raw_regmap_config;
+
+	map = gen_raw_regmap(&config, t, &data);
+	KUNIT_ASSERT_FALSE(test, IS_ERR(map));
+	if (IS_ERR(map))
+		return;
+
+	hw_buf = (u16 *)data->vals;
+
+	get_random_bytes(&val, sizeof(val));
+
+	/* Do a regular write and a raw write in cache only mode */
+	regcache_cache_only(map, true);
+	KUNIT_EXPECT_EQ(test, 0, regmap_raw_write(map, 2, val, sizeof(val)));
+	if (config.val_format_endian == REGMAP_ENDIAN_BIG)
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, 6,
+						      be16_to_cpu(val[0])));
+	else
+		KUNIT_EXPECT_EQ(test, 0, regmap_write(map, 6,
+						      le16_to_cpu(val[0])));
+
+	/* We should read back the new values, and defaults for the rest */
+	for (i = 0; i < config.max_register + 1; i++) {
+		KUNIT_EXPECT_EQ(test, 0, regmap_read(map, i, &rval));
+
+		switch (i) {
+		case 2:
+		case 3:
+		case 6:
+			if (config.val_format_endian == REGMAP_ENDIAN_BIG) {
+				KUNIT_EXPECT_EQ(test, rval,
+						be16_to_cpu(val[i % 2]));
+			} else {
+				KUNIT_EXPECT_EQ(test, rval,
+						le16_to_cpu(val[i % 2]));
+			}
+			break;
+		default:
+			KUNIT_EXPECT_EQ(test, config.reg_defaults[i].def, rval);
+			break;
+		}
+	}
+	
+	/* The values should not appear in the "hardware" */
+	KUNIT_EXPECT_MEMNEQ(test, &hw_buf[2], val, sizeof(val));
+	KUNIT_EXPECT_MEMNEQ(test, &hw_buf[6], val, sizeof(u16));
+
+	for (i = 0; i < config.max_register + 1; i++)
+		data->written[i] = false;
+
+	/* Do the sync */
+	regcache_cache_only(map, false);
+	regcache_mark_dirty(map);
+	KUNIT_EXPECT_EQ(test, 0, regcache_sync(map));
+
+	/* The values should now appear in the "hardware" */
+	KUNIT_EXPECT_MEMEQ(test, &hw_buf[2], val, sizeof(val));
+	KUNIT_EXPECT_MEMEQ(test, &hw_buf[6], val, sizeof(u16));
+
+	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),
@@ -727,6 +1048,12 @@ static struct kunit_case regmap_test_cases[] = {
 	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),
+
+	KUNIT_CASE_PARAM(raw_read_defaults_single, raw_test_types_gen_params),
+	KUNIT_CASE_PARAM(raw_read_defaults, raw_test_types_gen_params),
+	KUNIT_CASE_PARAM(raw_write_read_single, raw_test_types_gen_params),
+	KUNIT_CASE_PARAM(raw_write, raw_test_types_gen_params),
+	KUNIT_CASE_PARAM(raw_sync, raw_test_cache_types_gen_params),
 	{}
 };
 
diff --git a/drivers/base/regmap/regmap-raw-ram.c b/drivers/base/regmap/regmap-raw-ram.c
new file mode 100644
index 000000000000..c9b800885f3b
--- /dev/null
+++ b/drivers/base/regmap/regmap-raw-ram.c
@@ -0,0 +1,133 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Register map access API - Memory region with raw access
+//
+// This is intended for testing only
+//
+// Copyright (c) 2023, Arm Ltd
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+#include <linux/swab.h>
+
+#include "internal.h"
+
+static unsigned int decode_reg(enum regmap_endian endian, const void *reg)
+{
+	const u16 *r = reg;
+
+	if (endian == REGMAP_ENDIAN_BIG)
+		return be16_to_cpu(*r);
+	else
+		return le16_to_cpu(*r);
+}
+
+static int regmap_raw_ram_gather_write(void *context,
+				       const void *reg, size_t reg_len,
+				       const void *val, size_t val_len)
+{
+	struct regmap_ram_data *data = context;
+	unsigned int r;
+	u16 *our_buf = (u16 *)data->vals;
+	int i;
+
+	if (reg_len != 2)
+		return -EINVAL;
+	if (val_len % 2)
+		return -EINVAL;
+
+	r = decode_reg(data->reg_endian, reg);
+	memcpy(&our_buf[r], val, val_len);
+
+	for (i = 0; i < val_len / 2; i++)
+		data->written[r + i] = true;
+	
+	return 0;
+}
+
+static int regmap_raw_ram_write(void *context, const void *data, size_t count)
+{
+	return regmap_raw_ram_gather_write(context, data, 2,
+					   data + 2, count - 2);
+}
+
+static int regmap_raw_ram_read(void *context,
+			       const void *reg, size_t reg_len,
+			       void *val, size_t val_len)
+{
+	struct regmap_ram_data *data = context;
+	unsigned int r;
+	u16 *our_buf = (u16 *)data->vals;
+	int i;
+
+	if (reg_len != 2)
+		return -EINVAL;
+	if (val_len % 2)
+		return -EINVAL;
+
+	r = decode_reg(data->reg_endian, reg);
+	memcpy(val, &our_buf[r], val_len);
+
+	for (i = 0; i < val_len / 2; i++)
+		data->read[r + i] = true;
+
+	return 0;
+}
+
+static void regmap_raw_ram_free_context(void *context)
+{
+	struct regmap_ram_data *data = context;
+
+	kfree(data->vals);
+	kfree(data->read);
+	kfree(data->written);
+	kfree(data);
+}
+
+static const struct regmap_bus regmap_raw_ram = {
+	.fast_io = true,
+	.write = regmap_raw_ram_write,
+	.gather_write = regmap_raw_ram_gather_write,
+	.read = regmap_raw_ram_read,
+	.free_context = regmap_raw_ram_free_context,
+};
+
+struct regmap *__regmap_init_raw_ram(const struct regmap_config *config,
+				     struct regmap_ram_data *data,
+				     struct lock_class_key *lock_key,
+				     const char *lock_name)
+{
+	struct regmap *map;
+
+	if (config->reg_bits != 16)
+		return ERR_PTR(-EINVAL);
+
+	if (!config->max_register) {
+		pr_crit("No max_register specified for RAM regmap\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	data->read = kcalloc(sizeof(bool), config->max_register + 1,
+			     GFP_KERNEL);
+	if (!data->read)
+		return ERR_PTR(-ENOMEM);
+
+	data->written = kcalloc(sizeof(bool), config->max_register + 1,
+				GFP_KERNEL);
+	if (!data->written)
+		return ERR_PTR(-ENOMEM);
+
+	data->reg_endian = config->reg_format_endian;
+
+	map = __regmap_init(NULL, &regmap_raw_ram, data, config,
+			    lock_key, lock_name);
+
+	return map;
+}
+EXPORT_SYMBOL_GPL(__regmap_init_raw_ram);
+
+MODULE_LICENSE("GPL v2");