[PATCH v3 12/14] security: optee: add helpers to register OF overlays

[Marco Felsch <m.felsch@pengutronix.de>]

Add two helpers to make the OP-TEE overlay handling more convenient.

The first helper registers an optional OF overlay provided by
barebox-pbl.
The second helper can be used to query the status of the OF overlay, e.g
registered or not-registered.

Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 drivers/tee/optee/of_fixup.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/tee/optee.h          | 11 +++++++++++
 2 files changed, 53 insertions(+)

diff --git a/drivers/tee/optee/of_fixup.c b/drivers/tee/optee/of_fixup.c
index 152322901a7e6af9c83da4c6a2d43f6e2c9af329..35403c93dc54b5a5afab5f569e2921248cd68f53 100644
--- a/drivers/tee/optee/of_fixup.c
+++ b/drivers/tee/optee/of_fixup.c
@@ -1,7 +1,10 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#define pr_fmt(fmt) "OP-TEE OF: " fmt
+
 #include <of.h>
 #include <linux/ioport.h>
+#include <linux/printk.h>
 #include <asm/barebox-arm.h>
 #include <tee/optee.h>
 
@@ -64,3 +67,42 @@ int of_optee_fixup(struct device_node *root, void *_data)
 
 	return of_fixup_reserved_memory(root, &res_shm);
 }
+
+static bool optee_ovl_registered;
+
+void optee_register_overlay(void)
+{
+	struct device_node *overlay;
+	size_t size = 0;
+	void *fdto;
+	int err;
+
+	if (optee_ovl_registered) {
+		pr_warn("overlay already registered, skip\n");
+		return;
+	}
+
+	fdto = handoff_data_get_entry(HANDOFF_DATA_TEE_DT_OVL, &size);
+	if (!fdto || size == 0)
+		return;
+
+	overlay = of_unflatten_dtb(fdto, size);
+	if (IS_ERR(overlay)) {
+		pr_warn("failed to unflatten overlay: %pe\n", overlay);
+		return;
+	}
+
+	err = of_register_overlay(overlay);
+	if (err) {
+		pr_warn("failed to register overlay: %pe\n", ERR_PTR(err));
+		of_delete_node(overlay);
+		return;
+	}
+
+	optee_ovl_registered = true;
+}
+
+bool optee_overlay_registered(void)
+{
+	return optee_ovl_registered;
+}
diff --git a/include/tee/optee.h b/include/tee/optee.h
index ba3de3e410c84619cd2baea27fc89e2901df6ecf..45e042cbcc0eef4e6ab30381a7b9139e0ca03f4e 100644
--- a/include/tee/optee.h
+++ b/include/tee/optee.h
@@ -38,6 +38,8 @@ int optee_verify_header (const struct optee_header *hdr);
 void optee_set_membase(const struct optee_header *hdr);
 int optee_get_membase(u64 *membase);
 void optee_handoff_overlay(void *ovl, unsigned int ovl_sz);
+void optee_register_overlay(void);
+bool optee_overlay_registered(void);
 
 #else
 
@@ -54,6 +56,15 @@ static inline void optee_handoff_overlay(void *ovl, unsigned int ovl_sz)
 {
 }
 
+static inline void optee_register_overlay(void)
+{
+}
+
+static inline bool optee_overlay_registered(void)
+{
+	return false;
+}
+
 #endif /* CONFIG_HAVE_OPTEE */
 
 #ifdef __PBL__

-- 
2.47.3