rpi4: enable dram bank initialization

When booting through the efi stub, the memory map get's created by
reading the dram bank information. Depending on the version of the RPi4
this information changes. Read the device tree to initialize the dram
bank data structure. This way the kernel is able to access the whole
range of available memory.

Signed-off-by: Matthias Brugger <mbrugger@suse.com>

board/raspberrypi/rpi/rpi.c

@@ -312,6 +312,16 @@ int dram_init(void)
 	return 0;
 }
 
+#ifdef CONFIG_OF_BOARD
+#ifdef CONFIG_BCM2711
+int dram_init_banksize(void)
+{
+	return fdtdec_decode_ram_size(gd->fdt_blob, NULL, 0, NULL,
+				     (phys_size_t *)&gd->ram_size, gd->bd);
+}
+#endif
+#endif
+
 static void set_fdtfile(void)
 {
 	const char *fdtfile;

configs/rpi_4_defconfig

@@ -3,7 +3,7 @@ CONFIG_ARCH_BCM283X=y
 CONFIG_SYS_TEXT_BASE=0x00080000
 CONFIG_TARGET_RPI_4=y
 CONFIG_SYS_MALLOC_F_LEN=0x2000
-CONFIG_NR_DRAM_BANKS=1
+CONFIG_NR_DRAM_BANKS=2
 CONFIG_DISTRO_DEFAULTS=y
 CONFIG_OF_BOARD_SETUP=y
 # CONFIG_ARCH_FIXUP_FDT_MEMORY is not set