[U-Boot] [PATCH v4 4/6] fdt: ARM: Implement and verify embedded and separate device tree

[Simon Glass]

This locates the device tree either embedded within U-Boot or attached to the
end as a separate binary.

When CONFIG_OF_CONTROL is defined, U-Boot requires a valid fdt. A check is
provided for this early in initialisation.

Signed-off-by: Simon Glass <sjg at chromium.org>
---
 arch/arm/lib/board.c |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/arch/arm/lib/board.c b/arch/arm/lib/board.c
index 1fe3751..b0f3162 100644
--- a/arch/arm/lib/board.c
+++ b/arch/arm/lib/board.c
@@ -48,6 +48,7 @@
 #include <nand.h>
 #include <onenand_uboot.h>
 #include <mmc.h>
+#include <libfdt.h>
 #include <post.h>
 #include <logbuff.h>
 
@@ -197,6 +198,17 @@ static int arm_pci_init(void)
 }
 #endif /* CONFIG_CMD_PCI || CONFIG_PCI */
 
+#ifdef CONFIG_OF_CONTROL
+static int check_fdt(void)
+{
+	/* We must have an fdt */
+	if (fdt_check_header(gd->fdt_blob))
+		panic("No valid fdt found - please append one to U-Boot\n"
+			"binary or define CONFIG_OF_EMBED\n");
+	return 0;
+}
+#endif
+
 /*
  * Breathe some life into the board...
  *
@@ -239,6 +251,9 @@ init_fnc_t *init_sequence[] = {
 #if defined(CONFIG_BOARD_EARLY_INIT_F)
 	board_early_init_f,
 #endif
+#ifdef CONFIG_OF_CONTROL
+	check_fdt,
+#endif
 	timer_init,		/* initialize timer */
 #ifdef CONFIG_FSL_ESDHC
 	get_clocks,
@@ -276,6 +291,13 @@ void board_init_f(ulong bootflag)
 	memset((void *)gd, 0, sizeof(gd_t));
 
 	gd->mon_len = _bss_end_ofs;
+#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_ofs + _TEXT_BASE);
+#endif
 
 	for (init_fnc_ptr = init_sequence; *init_fnc_ptr; ++init_fnc_ptr) {
 		if ((*init_fnc_ptr)() != 0) {
-- 
1.7.3.1