ARM: stm32mp: add bootm handler for images

STM32 images are preceded by a fixed-size 256 byte header, which is
interpreted by the TF-A first stage bootloader and isn't executable
as ARM code.

To maintain the ability to network boot them, add a bootm handler that
skips the header.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

2 files changed, 51 insertions, 1 deletions

diff --git a/arch/arm/mach-stm32mp/Makefile b/arch/arm/mach-stm32mp/Makefile
index 16a218658a..204cad608f 100644
--- a/arch/arm/mach-stm32mp/Makefile
+++ b/arch/arm/mach-stm32mp/Makefile
@@ -1 +1 @@
-obj- := __dummy__.o
+obj-$(CONFIG_BOOTM) := stm32image.o
diff --git a/arch/arm/mach-stm32mp/stm32image.c b/arch/arm/mach-stm32mp/stm32image.c
new file mode 100644
index 0000000000..84975c5c3b
--- /dev/null
+++ b/arch/arm/mach-stm32mp/stm32image.c
@@ -0,0 +1,50 @@
+#define pr_fmt(fmt) "stm32image: " fmt
+
+#include <bootm.h>
+#include <common.h>
+#include <init.h>
+#include <memory.h>
+#include <linux/sizes.h>
+
+#define BAREBOX_STAGE2_OFFSET	256
+
+static int do_bootm_stm32image(struct image_data *data)
+{
+	void (*barebox)(void);
+	resource_size_t start, end;
+	int ret;
+
+	ret = memory_bank_first_find_space(&start, &end);
+	if (ret)
+		return ret;
+
+	ret = bootm_load_os(data, start);
+	if (ret)
+		return ret;
+
+	barebox = (void*)start + BAREBOX_STAGE2_OFFSET;
+
+	if (data->verbose)
+		printf("Loaded barebox image to 0x%08lx\n",
+		       (unsigned long)barebox);
+
+	shutdown_barebox();
+
+	barebox();
+
+	return -EIO;
+}
+
+static struct image_handler image_handler_stm32_image_v1_handler = {
+	.name = "STM32 image (v1)",
+	.bootm = do_bootm_stm32image,
+	.filetype = filetype_stm32_image_v1,
+};
+
+static int stm32mp_register_stm32image_image_handler(void)
+{
+	register_image_handler(&image_handler_stm32_image_v1_handler);
+
+	return 0;
+}
+late_initcall(stm32mp_register_stm32image_image_handler);