From 4d19b97f110efff6c0331cc820609d83f941f38d Mon Sep 17 00:00:00 2001
From: Robert Watson <rwatson@FreeBSD.org>
Date: Sat, 12 Jan 2013 13:20:21 +0000
Subject: [PATCH] Merge Perforce change @219948 to head:

  Add code so that the BERI boot process can ask the kernel linker for
  DTB blobs that may have been left for it by the boot loader, as done
  on PowerPC and ARM.  This will require both a more mature boot
  loader, and more mature boot loader argument passing mechanism,
  than currently supported on BERI.

Sponsored by:	DARPA, AFRL
---
 sys/mips/beri/beri_machdep.c | 26 ++++++++++++++++++++++++--
 sys/mips/include/metadata.h  |  1 +
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/sys/mips/beri/beri_machdep.c b/sys/mips/beri/beri_machdep.c
index f3b52c1a116..98fcb85aa3a 100644
--- a/sys/mips/beri/beri_machdep.c
+++ b/sys/mips/beri/beri_machdep.c
@@ -45,6 +45,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/cpu.h>
 #include <sys/cons.h>
 #include <sys/exec.h>
+#include <sys/linker.h>
 #include <sys/ucontext.h>
 #include <sys/proc.h>
 #include <sys/kdb.h>
@@ -70,6 +71,7 @@ __FBSDID("$FreeBSD$");
 #include <machine/cpuregs.h>
 #include <machine/hwfunc.h>
 #include <machine/md_var.h>
+#include <machine/metadata.h>
 #include <machine/pmap.h>
 #include <machine/trap.h>
 
@@ -135,6 +137,10 @@ platform_start(__register_t a0, __register_t a1,  __register_t a2,
 	char **argv = (char **)a1;
 	char **envp = (char **)a2;
 	unsigned int memsize = a3;
+#ifdef FDT
+	vm_offset_t dtbp;
+	void *kmdp;
+#endif
 	int i;
 
 	/* clear the BSS and SBSS segments */
@@ -146,8 +152,24 @@ platform_start(__register_t a0, __register_t a1,  __register_t a2,
 	mips_pcpu0_init();
 
 #ifdef FDT
-#ifndef FDT_DTB_STATIC
-#error	"mips_init with FDT requires FDT_DTB_STATIC"
+	/*
+	 * Find the dtb passed in by the boot loader (currently fictional).
+	 */
+	kmdp = preload_search_by_type("elf kernel");
+	if (kmdp != NULL)
+		dtbp = MD_FETCH(kmdp, MODINFOMD_DTBP, vm_offset_t);
+	else
+		dtbp = (vm_offset_t)NULL;
+
+#if defined(FDT_DTB_STATIC)
+	/*
+	 * In case the device tree blob was not retrieved (from metadata) try
+	 * to use the statically embedded one.
+	 */
+	if (dtbp == (vm_offset_t)NULL)
+		dtbp = (vm_offset_t)&fdt_static_dtb;
+#else
+#error	"Non-static FDT not yet supported on BERI"
 #endif
 
 	if (OF_install(OFW_FDT, 0) == FALSE)
diff --git a/sys/mips/include/metadata.h b/sys/mips/include/metadata.h
index 84e6f873997..779c2f6a474 100644
--- a/sys/mips/include/metadata.h
+++ b/sys/mips/include/metadata.h
@@ -30,5 +30,6 @@
 #define	_MACHINE_METADATA_H_
 
 #define	MODINFOMD_SMAP		0x1001
+#define	MODINFOMD_DTBP	0x1002
 
 #endif /* !_MACHINE_METADATA_H_ */