bbram: npcx: Add emulator

Add an emulator for the NPCX BBRAM which supports reading and writing

Signed-off-by: Yuval Peress <peress@google.com>

drivers/bbram/CMakeLists.txt

@@ -7,6 +7,8 @@ zephyr_library_sources_ifdef(CONFIG_BBRAM_SHELL bbram_shell.c)
 
 zephyr_library_sources_ifdef(CONFIG_USERSPACE bbram_handlers.c)
 zephyr_library_sources_ifdef(CONFIG_BBRAM_NPCX bbram_npcx.c)
+zephyr_library_sources_ifdef(CONFIG_BBRAM_NPCX_EMUL bbram_npcx_emul.c)
+zephyr_library_include_directories_ifdef(CONFIG_BBRAM_NPCX .)
 zephyr_library_sources_ifdef(CONFIG_BBRAM_IT8XXX2 bbram_it8xxx2.c)
 zephyr_library_sources_ifdef(CONFIG_BBRAM_IT8XXX2_EMUL bbram_it8xxx2_emul.c)
 zephyr_library_include_directories_ifdef(CONFIG_BBRAM_IT8XXX2 .)

drivers/bbram/Kconfig.npcx

@@ -7,3 +7,11 @@ config BBRAM_NPCX
 	depends on DT_HAS_NUVOTON_NPCX_BBRAM_ENABLED
 	help
 	  This option enables the BBRAM driver for NPCX family of processors.
+
+config BBRAM_NPCX_EMUL
+	bool "Emulator for the NPCX BBRAM driver"
+	default y
+	depends on BBRAM_NPCX
+	depends on EMUL
+	help
+	  Enable the emulator for the NPCX BBRAM.

drivers/bbram/bbram_npcx.c

@@ -11,17 +11,9 @@
 #include <zephyr/sys/util.h>
 
 #include <zephyr/logging/log.h>
-LOG_MODULE_REGISTER(bbram, CONFIG_BBRAM_LOG_LEVEL);
+LOG_MODULE_REGISTER(npcx_bbram, CONFIG_BBRAM_LOG_LEVEL);
 
-/** Device config */
+#include "npcx.h"
-struct bbram_npcx_config {
-	/** BBRAM base address */
-	uintptr_t base_addr;
-	/** BBRAM size (Unit:bytes) */
-	int size;
-	/** Status register base address */
-	uintptr_t status_reg_addr;
-};
 
 #define NPCX_STATUS_IBBR BIT(7)
 #define NPCX_STATUS_VSBY BIT(1)
@@ -35,7 +27,7 @@ static int get_bit_and_reset(const struct device *dev, int mask)
 	int result = DRV_STATUS(dev) & mask;
 
 	/* Clear the bit(s) */
-	DRV_STATUS(dev) = mask;
+	DRV_STATUS(dev) &= ~mask;
 
 	return result;
 }
@@ -69,7 +61,7 @@ static int bbram_npcx_read(const struct device *dev, size_t offset, size_t size,
 	const struct bbram_npcx_config *config = dev->config;
 
 	if (size < 1 || offset + size > config->size || bbram_npcx_check_invalid(dev)) {
-		return -EFAULT;
+		return -EINVAL;
 	}
 
 
@@ -83,7 +75,7 @@ static int bbram_npcx_write(const struct device *dev, size_t offset, size_t size
 	const struct bbram_npcx_config *config = dev->config;
 
 	if (size < 1 || offset + size > config->size || bbram_npcx_check_invalid(dev)) {
-		return -EFAULT;
+		return -EINVAL;
 	}
 
 	bytecpy(((uint8_t *)config->base_addr + offset), data, size);
@@ -100,14 +92,8 @@ static const struct bbram_driver_api bbram_npcx_driver_api = {
 };
 
 #define BBRAM_INIT(inst)                                                                           \
-	static struct {                                                                            \
+	BBRAM_NPCX_DECL_CONFIG(inst);                                                              \
-	} bbram_data_##inst;                                                                       \
+	DEVICE_DT_INST_DEFINE(inst, NULL, NULL, NULL, &bbram_cfg_##inst, PRE_KERNEL_1,             \
-	static const struct bbram_npcx_config bbram_cfg_##inst = {                                 \
+			      CONFIG_BBRAM_INIT_PRIORITY, &bbram_npcx_driver_api);
-		.base_addr = DT_INST_REG_ADDR_BY_NAME(inst, memory),                               \
-		.size = DT_INST_REG_SIZE_BY_NAME(inst, memory),                                    \
-		.status_reg_addr = DT_INST_REG_ADDR_BY_NAME(inst, status),                         \
-	};                                                                                         \
-	DEVICE_DT_INST_DEFINE(inst, NULL, NULL, &bbram_data_##inst, &bbram_cfg_##inst,             \
-			      PRE_KERNEL_1, CONFIG_BBRAM_INIT_PRIORITY, &bbram_npcx_driver_api);
 
 DT_INST_FOREACH_STATUS_OKAY(BBRAM_INIT);

drivers/bbram/bbram_npcx_emul.c

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2024 Google Inc
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/emul.h>
+#include <zephyr/drivers/emul_bbram.h>
+
+#include "npcx.h"
+
+#define DT_DRV_COMPAT nuvoton_npcx_bbram
+
+struct bbram_npcx_emul_config {
+	const struct device *dev;
+};
+
+#define GET_CONFIG(target)                                                                         \
+	((const struct bbram_npcx_config                                                           \
+		  *)(((const struct bbram_npcx_emul_config *)((target)->cfg))->dev->config))
+
+static int npcx_emul_backend_set_data(const struct emul *target, size_t offset, size_t count,
+			       const uint8_t *buffer)
+{
+	const struct bbram_npcx_config *config = GET_CONFIG(target);
+
+	if (offset + count > config->size) {
+		return -ERANGE;
+	}
+
+	bytecpy(((uint8_t *)config->base_addr + offset), buffer, count);
+	return 0;
+}
+
+static int npcx_emul_backend_get_data(const struct emul *target, size_t offset, size_t count,
+			       uint8_t *buffer)
+{
+	const struct bbram_npcx_config *config = GET_CONFIG(target);
+
+	if (offset + count > config->size) {
+		return -ERANGE;
+	}
+
+	bytecpy(buffer, ((uint8_t *)config->base_addr + offset), count);
+	return 0;
+}
+
+static const struct emul_bbram_backend_api npcx_emul_backend_api = {
+	.set_data = npcx_emul_backend_set_data,
+	.get_data = npcx_emul_backend_get_data,
+};
+
+#define BBRAM_EMUL_INIT(inst)                                                                      \
+	static struct bbram_npcx_emul_config bbram_npcx_emul_config_##inst = {                     \
+		.dev = DEVICE_DT_INST_GET(inst),                                                   \
+	};                                                                                         \
+	EMUL_DT_INST_DEFINE(inst, NULL, NULL, &bbram_npcx_emul_config_##inst, NULL,                \
+			    &npcx_emul_backend_api)
+
+DT_INST_FOREACH_STATUS_OKAY(BBRAM_EMUL_INIT);

drivers/bbram/npcx.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright (c) 2024 Google Inc
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef INCLUDE_ZEPHYR_DRIVERS_BBRAM_NPCX_H_
+#define INCLUDE_ZEPHYR_DRIVERS_BBRAM_NPCX_H_
+
+#include <stdint.h>
+
+#include <zephyr/devicetree.h>
+
+/** Device config */
+struct bbram_npcx_config {
+	/** BBRAM base address */
+	uintptr_t base_addr;
+	/** BBRAM size (Unit:bytes) */
+	int size;
+	/** Status register base address */
+	uintptr_t status_reg_addr;
+};
+
+#ifdef CONFIG_BBRAM_NPCX_EMUL
+#define BBRAM_NPCX_DECL_CONFIG(inst)                                                               \
+	static uint8_t bbram_npcx_emul_buffer_##inst[DT_INST_REG_SIZE_BY_NAME(inst, memory)];      \
+	static uint8_t bbram_npcx_emul_status_##inst;                                              \
+	static const struct bbram_npcx_config bbram_cfg_##inst = {                                 \
+		.base_addr = (uintptr_t)bbram_npcx_emul_buffer_##inst,                             \
+		.size = DT_INST_REG_SIZE_BY_NAME(inst, memory),                                    \
+		.status_reg_addr = (uintptr_t)&bbram_npcx_emul_status_##inst,                      \
+	}
+#else
+#define BBRAM_NPCX_DECL_CONFIG(inst)                                                               \
+	static const struct bbram_npcx_config bbram_cfg_##inst = {                                 \
+		.base_addr = DT_INST_REG_ADDR_BY_NAME(inst, memory),                               \
+		.size = DT_INST_REG_SIZE_BY_NAME(inst, memory),                                    \
+		.status_reg_addr = DT_INST_REG_ADDR_BY_NAME(inst, status),                         \
+	}
+#endif
+
+#endif /* INCLUDE_ZEPHYR_DRIVERS_BBRAM_NPCX_H_ */