drivers: introduce Secure Monitor uclass

At the moment, we don't have a common API for working with
SM, only the smc_call() function. This approach is not generic
and difficult to configure and maintain.

This patch adds UCLASS_SM with the generic API:

- sm_call()
- sm_call_write()
- sm_call_read()

These functions operate with struct pt_regs, which describes
Secure Monitor arguments.

Signed-off-by: Alexey Romanov <[email protected]>
Reviewed-by: Simon Glass <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Neil Armstrong <[email protected]>

5 files changed, 63 insertions, 0 deletions

diff --git a/drivers/Kconfig b/drivers/Kconfig
index a25f6ae02fd..a073230c26d 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -118,6 +118,8 @@ source "drivers/scsi/Kconfig"
 
 source "drivers/serial/Kconfig"
 
+source "drivers/sm/Kconfig"
+
 source "drivers/smem/Kconfig"
 
 source "drivers/sound/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index efc2a4afb24..74f940a57d3 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_$(SPL_TPL_)VIRTIO) += virtio/
 obj-$(CONFIG_$(SPL_)DM_MAILBOX) += mailbox/
 obj-$(CONFIG_$(SPL_)REMOTEPROC) += remoteproc/
 obj-$(CONFIG_$(SPL_)SYSINFO) += sysinfo/
+obj-$(CONFIG_$(SPL_TPL_)SM) += sm/
 obj-$(CONFIG_$(SPL_TPL_)TPM) += tpm/
 obj-$(CONFIG_$(SPL_)NVME) += nvme/
 obj-$(CONFIG_XEN) += xen/
diff --git a/drivers/sm/Kconfig b/drivers/sm/Kconfig
new file mode 100644
index 00000000000..6cc6d55578e
--- /dev/null
+++ b/drivers/sm/Kconfig
@@ -0,0 +1,2 @@
+config SM
+	bool "Enable Secure Monitor driver support"
diff --git a/drivers/sm/Makefile b/drivers/sm/Makefile
new file mode 100644
index 00000000000..9f4683ba064
--- /dev/null
+++ b/drivers/sm/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-y += sm-uclass.o
diff --git a/drivers/sm/sm-uclass.c b/drivers/sm/sm-uclass.c
new file mode 100644
index 00000000000..6a8b7026293
--- /dev/null
+++ b/drivers/sm/sm-uclass.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2023 SberDevices, Inc.
+ *
+ * Author: Alexey Romanov <[email protected]>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <sm-uclass.h>
+
+static const struct sm_ops *get_sm_ops(struct udevice *dev)
+{
+	return (const struct sm_ops *)dev->driver->ops;
+}
+
+int sm_call(struct udevice *dev, u32 cmd, s32 *ret, struct pt_regs *args)
+{
+	const struct sm_ops *ops = get_sm_ops(dev);
+
+	if (ops->sm_call)
+		return ops->sm_call(dev, cmd, ret, args);
+
+	return -ENOSYS;
+}
+
+int sm_call_read(struct udevice *dev, void *buffer, size_t size,
+		 u32 cmd, struct pt_regs *args)
+{
+	const struct sm_ops *ops = get_sm_ops(dev);
+
+	if (ops->sm_call_read)
+		return ops->sm_call_read(dev, buffer, size, cmd,
+					 args);
+
+	return -ENOSYS;
+}
+
+int sm_call_write(struct udevice *dev, void *buffer, size_t size,
+		   u32 cmd, struct pt_regs *args)
+{
+	const struct sm_ops *ops = get_sm_ops(dev);
+
+	if (ops->sm_call_write)
+		return ops->sm_call_write(dev, buffer, size, cmd,
+					  args);
+
+	return -ENOSYS;
+}
+
+UCLASS_DRIVER(sm) = {
+	.name           = "sm",
+	.id             = UCLASS_SM,
+};