feat(stm32mp1): add the decryption support

Add the decryption support for STM32MP1 binaries.
Decryption is limited to the BL32 loaded images.

Limitation: STM32MP15 doesn't support the feature.

Change-Id: I96800bac7b22109f8471eb2953fc0dc269fc4fd1
Signed-off-by: Lionel Debieve <lionel.debieve@foss.st.com>
diff --git a/plat/st/common/bl2_io_storage.c b/plat/st/common/bl2_io_storage.c
index 7222584..b271ed6 100644
--- a/plat/st/common/bl2_io_storage.c
+++ b/plat/st/common/bl2_io_storage.c
@@ -14,6 +14,7 @@
 #include <drivers/fwu/fwu_metadata.h>
 #include <drivers/io/io_block.h>
 #include <drivers/io/io_driver.h>
+#include <drivers/io/io_encrypted.h>
 #include <drivers/io/io_fip.h>
 #include <drivers/io/io_memmap.h>
 #include <drivers/io/io_mtd.h>
@@ -48,6 +49,11 @@
 
 static const io_dev_connector_t *fip_dev_con;
 
+#ifndef DECRYPTION_SUPPORT_none
+static const io_dev_connector_t *enc_dev_con;
+uintptr_t enc_dev_handle;
+#endif
+
 #if STM32MP_SDMMC || STM32MP_EMMC
 static struct mmc_device_info mmc_info;
 
@@ -118,6 +124,29 @@
 	return io_dev_init(fip_dev_handle, (uintptr_t)FIP_IMAGE_ID);
 }
 
+#ifndef DECRYPTION_SUPPORT_none
+int open_enc_fip(const uintptr_t spec)
+{
+	int result;
+	uintptr_t local_image_handle;
+
+	result = io_dev_init(enc_dev_handle, (uintptr_t)ENC_IMAGE_ID);
+	if (result != 0) {
+		return result;
+	}
+
+	result = io_open(enc_dev_handle, spec, &local_image_handle);
+	if (result != 0) {
+		return result;
+	}
+
+	VERBOSE("Using encrypted FIP\n");
+	io_close(local_image_handle);
+
+	return 0;
+}
+#endif
+
 int open_storage(const uintptr_t spec)
 {
 	return io_dev_init(storage_dev_handle, 0);
@@ -383,6 +412,15 @@
 	io_result = io_dev_open(fip_dev_con, (uintptr_t)NULL,
 				&fip_dev_handle);
 
+#ifndef DECRYPTION_SUPPORT_none
+	io_result = register_io_dev_enc(&enc_dev_con);
+	assert(io_result == 0);
+
+	io_result = io_dev_open(enc_dev_con, (uintptr_t)NULL,
+				&enc_dev_handle);
+	assert(io_result == 0);
+#endif
+
 	switch (boot_context->boot_interface_selected) {
 #if STM32MP_SDMMC
 	case BOOT_API_CTX_BOOT_INTERFACE_SEL_FLASH_SD: