unmap RX/TX buffers at ExitBootServices()

Unmapping the RX/TX buffers created by u-boot is needed before EFI
runtime.

At EFI runtime the linux kernel takes care of allocating its own RX/TX
buffers and registering them with the secure world.

Secure world should be using the RX/TX buffers created by the kernel.
So, RX/TX buffers created by u-boot must be unmapped.

Signed-off-by: Abdellatif El Khlifi <abdellatif.elkhl...@arm.com>
Cc: Tom Rini <tr...@konsulko.com>
Cc: Simon Glass <s...@chromium.org>
Cc: Ilias Apalodimas <ilias.apalodi...@linaro.org>
Cc: Jens Wiklander <jens.wiklan...@linaro.org>

---

Changelog:
===============

v7: replace debug() by log_err()

lib/efi_loader/efi_boottime.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index a56021559b..b0b61bc812 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -3,6 +3,9 @@
  * EFI application boot time services
  *
  * Copyright (c) 2016 Alexander Graf
+ *
+ * (C) Copyright 2022 ARM Limited
+ * Abdellatif El Khlifi <abdellatif.elkhl...@arm.com>
  */
 
 #include <common.h>
@@ -23,6 +26,10 @@
 #include <asm/setjmp.h>
 #include <linux/libfdt_env.h>
 
+#if CONFIG_IS_ENABLED(ARM_FFA_TRANSPORT)
+#include <arm_ffa.h>
+#endif
+
 DECLARE_GLOBAL_DATA_PTR;
 
 /* Task priority level */
@@ -2178,6 +2185,12 @@ static efi_status_t EFIAPI 
efi_exit_boot_services(efi_handle_t image_handle,
                dm_remove_devices_flags(DM_REMOVE_ACTIVE_ALL);
        }
 
+#if CONFIG_IS_ENABLED(ARM_FFA_TRANSPORT)
+               /* unmap FF-A RX/TX buffers */
+               if (ffa_bus_ops_get()->rxtx_unmap())
+                       log_err("Can't unmap FF-A RX/TX buffers\n");
+#endif
+
        /* Patch out unsupported runtime function */
        efi_runtime_detach();
 
-- 
2.17.1

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