hello

asm/Start.S

@@ -5,6 +5,7 @@
 
     adr	x0, dtb
     adr	x1, kernel
+    adrp x2, end
     b main
 
 .global load_kernel

asm/linker.lds.S

@@ -25,4 +25,7 @@ SECTIONS
 		kernel = .;
 		KERNEL_PATH
 	}
+	end = .;
+
+	kernel_size = SIZEOF(.kernel);
 }

board/generic/board-generic.c

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Markuss Broks <[email protected]>
+ */
+
+/* This is a generic board file. This should work on every device
+ * as long as it's loaded in physical memory with enough space to
+ * put the kernel image ahead of it on closest 2MiB-aligned address.
+ */
+
+void board_init(void) {
+
+}

board/samsung/board-starlte.c

@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Markuss Broks <[email protected]>
+ */
+
+#include <board/board-starlte.h>
+
+void board_init(void) {
+
+}

include/board/board-dreamlte.h

@@ -7,6 +7,5 @@
 #define BOARD_DREAMLTE_H_
 
 #define PAYLOAD_ENTRY		0x90000000
-#define PAYLOAD_SIZE		0x2000000
 
 #endif // BOARD_DREAMLTE_H_

include/board/board-generic.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Markuss Broks <[email protected]>
+ */
+
+#ifndef BOARD_GENERIC_H	/* Include guard */
+#define BOARD_GENERIC_H
+
+/* Nothing really is here :) */
+
+#endif // BOARD_GENERIC_H

include/board/board-n61ap.h

@@ -8,6 +8,5 @@
 
 /* TODO: Adjust PAYLOAD_ENTRY */
 #define PAYLOAD_ENTRY		0x830000000
-#define PAYLOAD_SIZE		0x2000000
 
 #endif // BOARD_N61AP_H_

include/board/board-starlte.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Markuss Broks <[email protected]>
+ */
+
+#ifndef BOARD_STARLTE_H   /* Include guard */
+#define BOARD_STARLTE_H
+
+#define PAYLOAD_ENTRY		0x90000000
+
+#endif // BOARD_STARLTE_H

include/main.h

@@ -6,6 +6,8 @@
 #ifndef MAIN_H_   /* Include guard */
 #define MAIN_H_
 
+#define SZ_2M				0x00200000
+
 extern void load_kernel(void* dtb, void* x1, void* x2, void* x3, void* kernel);
 extern void soc_init(void);
 extern void board_init(void);

include/soc/exynos9810.h

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Markuss Broks <[email protected]>
+ */
+
+#ifndef EXYNOS9810_H_	/* Include guard */
+#define EXYNOS9810_H_
+
+#define DECON_F_BASE		0x16030000
+#define HW_SW_TRIG_CONTROL	0x70
+
+#endif // EXYNOS9810_H_

main.c

@@ -7,12 +7,22 @@
 /* Device specific board config, copied in runtime */
 #include <board-config.h>
 
-void main(void* dt, void* kernel) {
+extern unsigned long kernel_size;
+
+void main(void* dt, void* kernel, void* end) {
+	void* kernel_load;
 	/* Initialize SoC and Board specific peripherals/quirks */
 	soc_init();
 	board_init();
 
+#ifndef PAYLOAD_ENTRY
+	/* Find closest 2MB-aligned address to our load location */
+	kernel_load = (void *) ((((unsigned long long)end - 1) | (SZ_2M - 1)) + 1);
+#else
+	kernel_load = (void *) PAYLOAD_ENTRY;
+#endif
+
 	/* Copy kernel to memory and boot  */
-	memcpy((void*)PAYLOAD_ENTRY, kernel, PAYLOAD_SIZE);
-	load_kernel(dt, 0, 0, 0, (void*)PAYLOAD_ENTRY);	
+	memcpy((void*)kernel_load, kernel, (unsigned long) &kernel_size);
+	load_kernel(dt, 0, 0, 0, (void*)kernel_load);
 }

soc/Makefile

@@ -30,13 +30,20 @@ board_codename := $(word 2,$(split_board))
 # Exynos
 ifeq ($(SOC),exynos8895)
 brand_name=exynos
+else ifeq ($(SOC),exynos9810)
+brand_name=exynos
 endif
 
 # Apple
 ifeq ($(SOC),t7000)
 brand_name=apple
 endif
 
+# Generic
+ifeq ($(SOC),generic)
+brand_name=generic
+endif
+
 all: $(brand_name)/$(SOC).o copy-soc
 
 copy-soc:

soc/exynos/exynos9810.c

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Markuss Broks <[email protected]>
+ */
+
+#include <soc/exynos9810.h>
+
+void soc_init(void) {
+	/* Allow framebuffer to be written to */
+	*(int*) (DECON_F_BASE + HW_SW_TRIG_CONTROL) = 0x1281;
+}

soc/generic/generic.c

@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2022, Markuss Broks <[email protected]>
+ */
+
+void soc_init(void) {
+        /* We don't know anything about the SoC so we can't do anything... */
+}