microblaze: Add support for device tree driven board configuration

This is minimum code required to be able to use device-tree
for u-boot initialization.
Currently only for device driver initialization.

Linker script change ensures DTB to be aligned
for both options CONFIG_OF_EMBED and CONFIG_OF_SEPARATE.

Signed-off-by: Michal Simek <monstr@monstr.eu>
Acked-by: Stephan Linz <linz@li-pro.net>
CC: Simon Glass <sjg@chromium.org>

arch/microblaze/config.mk

@@ -31,3 +31,5 @@ CONFIG_STANDALONE_LOAD_ADDR ?= 0x80F00000
 PLATFORM_CPPFLAGS += -ffixed-r31 -D__microblaze__
 
 LDSCRIPT ?= $(SRCTREE)/$(CPUDIR)/u-boot.lds
+
+CONFIG_ARCH_DEVICE_TREE := microblaze

arch/microblaze/cpu/u-boot.lds

@@ -45,6 +45,7 @@ SECTIONS
 	.data ALIGN(0x4):
 	{
 		__data_start = .;
+		dts/libdts.o (.data)
 		*(.data)
 		__data_end = .;
 	}

arch/microblaze/include/asm/global_data.h

@@ -41,6 +41,7 @@ typedef	struct	global_data {
 	unsigned long	precon_buf_idx;	/* Pre-Console buffer index */
 #endif
 	unsigned long	env_addr;	/* Address  of Environment struct */
+	const void	*fdt_blob;	/* Our device tree, NULL if none */
 	unsigned long	env_valid;	/* Checksum of Environment valid? */
 	unsigned long	fb_base;	/* base address of frame buffer */
 	void		**jt;		/* jump table */

arch/microblaze/lib/board.c

@@ -34,6 +34,7 @@
 #include <net.h>
 #include <asm/processor.h>
 #include <asm/microblaze_intc.h>
+#include <fdtdec.h>
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -63,6 +64,9 @@ typedef int (init_fnc_t) (void);
 
 init_fnc_t *init_sequence[] = {
 	env_init,
+#ifdef CONFIG_OF_CONTROL
+	fdtdec_check_fdt,
+#endif
 	serial_init,
 	console_init_f,
 #ifdef CONFIG_SYS_GPIO_0
@@ -103,6 +107,17 @@ void board_init (void)
 
 	monitor_flash_len = __end - __text_start;
 
+#ifdef CONFIG_OF_EMBED
+	/* Get a pointer to the FDT */
+	gd->fdt_blob = _binary_dt_dtb_start;
+#elif defined CONFIG_OF_SEPARATE
+	/* FDT is at end of image */
+	gd->fdt_blob = (void *)__end;
+#endif
+	/* Allow the early environment to override the fdt address */
+	gd->fdt_blob = (void *)getenv_ulong("fdtcontroladdr", 16,
+						(uintptr_t)gd->fdt_blob);
+
 	/*
 	 * The Malloc area is immediately below the monitor copy in DRAM
 	 * aka CONFIG_SYS_MONITOR_BASE - Note there is no need for reloc_off
@@ -121,6 +136,15 @@ void board_init (void)
 		}
 	}
 
+#ifdef CONFIG_OF_CONTROL
+	/* For now, put this check after the console is ready */
+	if (fdtdec_prepare_fdt()) {
+		panic("** CONFIG_OF_CONTROL defined but no FDT - please see "
+			"doc/README.fdt-control");
+	} else
+		printf("DTB: 0x%x\n", (u32)gd->fdt_blob);
+#endif
+
 	puts ("SDRAM :\n");
 	printf ("\t\tIcache:%s\n", icache_status() ? "ON" : "OFF");
 	printf ("\t\tDcache:%s\n", dcache_status() ? "ON" : "OFF");