[PATCH] stm32mp: correctly handle board_get_usable_ram_top(0)

[Patrick Delaunay]

The function board_get_usable_ram_top can to called after relocation
with total_size = 0 to get the uppermost pointer that is valid to access
in U-Boot.

When total_size = 0, the reserved memory should be not take in account
with lmb library and 'gd->ram_base + gd->ram_size' can be used.

It is the case today in lib/efi_loader/efi_memory.c:efi_add_known_memory()
and this patch avoids that the reserved memory for OP-TEE is not part of
the EFI available memory regions.

Signed-off-by: Patrick Delaunay <patrick.delaunay at foss.st.com>
---
Patch to correct the UEFI support for STM32MP platform
after Heinrich's remark on patch [1].

[1] efi_loader: replace board_get_usable_ram_top by gd->ram_top
http://patchwork.ozlabs.org/project/uboot/patch/20210709124630.1.I212e7cd96724368b8272300c59c2a1c1f227ed67@changeid/

 arch/arm/mach-stm32mp/dram_init.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm/mach-stm32mp/dram_init.c b/arch/arm/mach-stm32mp/dram_init.c
index 3c097029bd..94f25f34e0 100644
--- a/arch/arm/mach-stm32mp/dram_init.c
+++ b/arch/arm/mach-stm32mp/dram_init.c
@@ -46,6 +46,9 @@ ulong board_get_usable_ram_top(ulong total_size)
 	phys_addr_t reg;
 	struct lmb lmb;
 
+	if (!total_size)
+		return gd->ram_base + gd->ram_size;
+
 	/* found enough not-reserved memory to relocated U-Boot */
 	lmb_init(&lmb);
 	lmb_add(&lmb, gd->ram_base, gd->ram_size);
-- 
2.25.1