regmap: Add RAM backed register map

Add a register map that is a simple array of memory, for use in
KUnit testing of the framework. This is not exposed in regmap.h
since I can't think of a non-test use case, it is purely for use
internally. To facilitate testing we track if registers have been
read or written to.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230324-regmap-kunit-v2-1-b208801dc2c8@kernel.org

diff --git a/drivers/base/regmap/Kconfig b/drivers/base/regmap/Kconfig
index 9f8dcb3..3d3445b 100644 (file)
--- a/drivers/base/regmap/Kconfig
+++ b/drivers/base/regmap/Kconfig
@@ -41,6 +41,9 @@ config REGMAP_MMIO
 config REGMAP_IRQ
        bool
 
+config REGMAP_RAM
+       tristate
+
 config REGMAP_SOUNDWIRE
        tristate
        depends on SOUNDWIRE

diff --git a/drivers/base/regmap/Makefile b/drivers/base/regmap/Makefile
index 8900c34..b4b0e8f 100644 (file)
--- a/drivers/base/regmap/Makefile
+++ b/drivers/base/regmap/Makefile
@@ -7,6 +7,7 @@ obj-$(CONFIG_REGMAP) += regcache-rbtree.o regcache-flat.o
 obj-$(CONFIG_DEBUG_FS) += regmap-debugfs.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_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 919d790..10aca71 100644 (file)
--- a/drivers/base/regmap/internal.h
+++ b/drivers/base/regmap/internal.h
@@ -306,4 +306,23 @@ static inline unsigned int regcache_get_index_by_order(const struct regmap *map,
        return reg >> map->reg_stride_order;
 }
 
+struct regmap_ram_data {
+       unsigned int *vals;  /* Allocatd by caller */
+       bool *read;
+       bool *written;
+};
+
+/*
+ * Create a test register map with data stored in RAM, not intended
+ * for practical use.
+ */
+struct regmap *__regmap_init_ram(const struct regmap_config *config,
+                                struct regmap_ram_data *data,
+                                struct lock_class_key *lock_key,
+                                const char *lock_name);
+
+#define regmap_init_ram(config, data)                                  \
+       __regmap_lockdep_wrapper(__regmap_init_ram, #config, config, data)
+
+
 #endif

diff --git a/drivers/base/regmap/regmap-ram.c b/drivers/base/regmap/regmap-ram.c
new file mode 100644 (file)
index 0000000..85f34a5
--- /dev/null
+++ b/drivers/base/regmap/regmap-ram.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+// Register map access API - Memory region
+//
+// 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 int regmap_ram_write(void *context, unsigned int reg, unsigned int val)
+{
+       struct regmap_ram_data *data = context;
+
+       data->vals[reg] = val;
+       data->written[reg] = true;
+
+       return 0;
+}
+
+static int regmap_ram_read(void *context, unsigned int reg, unsigned int *val)
+{
+       struct regmap_ram_data *data = context;
+
+       *val = data->vals[reg];
+       data->read[reg] = true;
+
+       return 0;
+}
+
+static void regmap_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_ram = {
+       .fast_io = true,
+       .reg_write = regmap_ram_write,
+       .reg_read = regmap_ram_read,
+       .free_context = regmap_ram_free_context,
+};
+
+struct regmap *__regmap_init_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->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);
+
+       map = __regmap_init(NULL, &regmap_ram, data, config,
+                           lock_key, lock_name);
+
+       return map;
+}
+EXPORT_SYMBOL_GPL(__regmap_init_ram);
+
+MODULE_LICENSE("GPL v2");