ARM: stm32mp: build extra barebox-stm32mp-generic-bl33.img

barebox-dt-2nd.img expects being loaded at an offset, so the stack can
grow down from entry point. The STM32MP TF-A default is to not have an
offset. Avoid this issue by having a stm32mp specific entry point that
sets up a 64 byte stack after end of barebox. As it's stm32mp-specific
anyway, we can skip the early FDT parsing and ask the SDRAM controller
about RAM size.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20220220124736.3052502-8-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 24 insertions, 0 deletions

diff --git a/arch/arm/mach-stm32mp/bl33-generic.c b/arch/arm/mach-stm32mp/bl33-generic.c
new file mode 100644
index 0000000000..6f779b19cf
--- /dev/null
+++ b/arch/arm/mach-stm32mp/bl33-generic.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <mach/entry.h>
+#include <debug_ll.h>
+
+/*
+ * barebox-dt-2nd.img expects being loaded at an offset, so the
+ * stack can grow down from entry point. The STM32MP TF-A default
+ * is to not have an offset. This stm32mp specific entry points
+ * avoids this issue by setting up a 64 byte stack after end of
+ * barebox and by asking the memory controller about RAM size
+ * instead of parsing it out of the DT.
+ *
+ * When using OP-TEE, ensure CONFIG_OPTEE_SIZE is appopriately set.
+ */
+
+ENTRY_FUNCTION(start_stm32mp_bl33, r0, r1, r2)
+{
+	stm32mp_cpu_lowlevel_init();
+
+	putc_ll('>');
+
+	stm32mp1_barebox_entry((void *)r2);
+}