From 370422921b2a3f4f7b73ce5b08820c24e82bba19 Mon Sep 17 00:00:00 2001
From: Gowtham Suresh Kumar <gowtham.sureshkumar@arm.com>
Date: Thu, 18 Nov 2021 16:42:59 +0000
Subject: [PATCH 13/24] corstone1000: Make sure shared buffer contents are not
 cached

After updating the shared buffer, it is required to flush the cache
to ensure that the secure world sees expected the shared buffer
contents.

The MM communication shared buffer is configured in device region of optee
which has cache disabled. So we need to invalidate the cache every time we
update the buffer on uboot otherwise the secure world does not see the
accurate values.

Signed-off-by: Gowtham Suresh Kumar <gowtham.sureshkumar@arm.com>
%% original patch: 0027-Make-sure-shared-buffer-contents-are-not-cached.patch

%% original patch: 0027-Make-sure-shared-buffer-contents-are-not-cached.patch

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
---
 lib/efi_loader/efi_variable_tee.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c
index 9cb8cfb9c779..b6be2b54a030 100644
--- a/lib/efi_loader/efi_variable_tee.c
+++ b/lib/efi_loader/efi_variable_tee.c
@@ -22,6 +22,7 @@
 #if (IS_ENABLED(CONFIG_ARM_FFA_TRANSPORT))
 
 #include <arm_ffa_helper.h>
+#include <cpu_func.h>
 #include <mapmem.h>
 
 /* MM return codes */
@@ -335,6 +336,11 @@ static efi_status_t __efi_runtime ffa_mm_communicate(void *comm_buf, ulong comm_
 	virt_shared_buf = (void *)map_sysmem((phys_addr_t)FFA_SHARED_MM_BUFFER_ADDR, 0);
 	efi_memcpy_runtime(virt_shared_buf, comm_buf, tx_data_size);
 
+	/* The secure world has cache disabled for device region which we use for shared buffer
+	So, the secure world reads the data from DDR. Let's flush the cache so the DDR is
+	updated with the latest data */
+	invalidate_dcache_all();
+
 	/* Announce there is data in the shared buffer */
 
 	ffa_ret = ffa_notify_mm_sp();
-- 
2.37.1