[PATCH v2] stm32mp: Reserve OPTEE area in EFI memory map

[Patrice Chotard]

Since commit 7b78d6438a2b3 ("efi_loader: Reserve unaccessible memory")
memory region above ram_top is tagged in EFI memory map as
EFI_BOOT_SERVICES_DATA.
In case of STM32MP1/STM32MP13 platforms, above ram_top, there is one
reserved-memory region tagged "no-map" dedicated to OP-TEE :
 _ addr=de000000 size=2000000 for stm32mp157x-dkx and stm32mp135f-dk
 _ addr=fe000000 size=2000000 for stm32mp157c-ev1

Before booting kernel, EFI memory map is first built, the OPTEE region is
tagged as EFI_BOOT_SERVICES_DATA and when reserving LMB, the tag LMB_NONE
is used.

Then after, the LMB are completed by boot_fdt_add_mem_rsv_regions()
which try to add again the same OPTEE region (addr=de000000 size=2000000
in case of stm32mp157x-dkx / stm32mp135f-dk or addr=fe000000 size=2000000
in case for stm2mp157c-ev1)
but now with LMB_NOMAP tag which produces the following error message :

 _ for stm32mp157x-dkx / stm32mp135f-dk :
  "ERROR: reserving fdt memory region failed (addr=de000000 size=2000000 flags=4)"

 _ for stm32mp157c-ev1 :
  "ERROR: reserving fdt memory region failed (addr=fe000000 size=2000000 flags=4)"

To avoid this, OPTEE area shouldn't be used by EFI, so we need to mark
it as reserved.

Signed-off-by: Patrice Chotard <patrice.chotard at foss.st.com>

---

Changes in v2:
 _ update commit message by adding information about memory area
   dedicated for OPTEE for various STM32MP1/STM32MP13 boards.

 arch/arm/mach-stm32mp/dram_init.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/arch/arm/mach-stm32mp/dram_init.c b/arch/arm/mach-stm32mp/dram_init.c
index fb1208fc5d5..f67f54f2ae0 100644
--- a/arch/arm/mach-stm32mp/dram_init.c
+++ b/arch/arm/mach-stm32mp/dram_init.c
@@ -7,6 +7,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <efi_loader.h>
 #include <image.h>
 #include <init.h>
 #include <lmb.h>
@@ -75,3 +76,14 @@ phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
 
 	return reg + size;
 }
+
+void efi_add_known_memory(void)
+{
+	if (IS_ENABLED(CONFIG_EFI_LOADER))
+		/*
+		 * Memory over ram_top is reserved to OPTEE.
+		 * Declare to EFI only memory area below ram_top
+		 */
+		efi_add_memory_map(gd->ram_base, gd->ram_top - gd->ram_base,
+				   EFI_CONVENTIONAL_MEMORY);
+}
-- 
2.25.1