--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2023 SberDevices, Inc.
+ *
+ * Author: Alexey Romanov <avromanov@salutedevices.com>
+ */
+
+#include <common.h>
+#include <sm.h>
+#include <sm-uclass.h>
+#include <sandbox-sm.h>
+#include <asm/ptrace.h>
+#include <dm/device.h>
+#include <linux/sizes.h>
+
+static u8 test_buffer[SZ_4K];
+
+static int sandbox_sm_call(struct udevice *dev, u32 cmd_index, s32 *smc_ret,
+ struct pt_regs *args)
+{
+ if (cmd_index >= SANDBOX_SMC_CMD_COUNT)
+ return -EINVAL;
+
+ if (smc_ret)
+ *smc_ret = 0;
+
+ return 0;
+}
+
+static int sandbox_sm_call_read(struct udevice *dev, void *buffer, size_t size,
+ u32 cmd_index, struct pt_regs *args)
+{
+ if (cmd_index >= SANDBOX_SMC_CMD_COUNT || !buffer)
+ return -EINVAL;
+
+ if (size > sizeof(test_buffer))
+ return -EINVAL;
+
+ memcpy(buffer, test_buffer, size);
+
+ return size;
+}
+
+static int sandbox_sm_call_write(struct udevice *dev, void *buffer, size_t size,
+ u32 cmd_index, struct pt_regs *args)
+{
+ if (cmd_index >= SANDBOX_SMC_CMD_COUNT || !buffer)
+ return -EINVAL;
+
+ if (size > sizeof(test_buffer))
+ return -EINVAL;
+
+ memcpy(test_buffer, buffer, size);
+
+ return size;
+}
+
+static const struct udevice_id sandbox_sm_ids[] = {
+ {
+ .compatible = "sandbox,sm",
+ },
+ {},
+};
+
+static const struct sm_ops sandbox_sm_ops = {
+ .sm_call = sandbox_sm_call,
+ .sm_call_read = sandbox_sm_call_read,
+ .sm_call_write = sandbox_sm_call_write,
+};
+
+U_BOOT_DRIVER(sm) = {
+ .name = "sm",
+ .id = UCLASS_SM,
+ .of_match = sandbox_sm_ids,
+ .ops = &sandbox_sm_ops,
+};
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (c) 2023 SberDevices, Inc.
+ *
+ * Author: Alexey Romanov <avromanov@salutedevices.com>
+ */
+
+#ifndef __SANDBOX_SM_H__
+#define __SANDBOX_SM_H__
+
+enum sandbox_smc_cmd {
+ SANDBOX_SMC_CMD_READ_MEM,
+ SANDBOX_SMC_CMD_WRITE_MEM,
+ SANDBOX_SMC_CMD_COMMON,
+ SANDBOX_SMC_CMD_COUNT,
+};
+
+#endif