MIPS: Netlogic: Add support for built in DTB

Provide a config option to embed a device tree for XLP evaluation
boards. This DTB will be used if the firmware does not pass in a
device tree pointer.
Signed-off-by: NJayachandran C <jayachandranc@netlogicmicro.com>
Patchwork: http://patchwork.linux-mips.org/patch/4103/Signed-off-by: NJohn Crispin <blogic@openwrt.org>

arch/mips/Kconfig

@@ -830,6 +830,7 @@ config NLM_XLP_BOARD
 	select ZONE_DMA if 64BIT
 	select SYNC_R4K
 	select SYS_HAS_EARLY_PRINTK
+	select USE_OF
 	help
 	  This board is based on Netlogic XLP Processor.
 	  Say Y here if you have a XLP based board.

arch/mips/netlogic/Kconfig

+if NLM_XLP_BOARD || NLM_XLR_BOARD
+
+if NLM_XLP_BOARD
+config DT_XLP_EVP
+	bool "Built-in device tree for XLP EVP/SVP boards"
+	default y
+	help
+	  Add an FDT blob for XLP EVP and SVP boards into the kernel.
+	  This DTB will be used if the firmware does not pass in a DTB
+          pointer to the kernel.  The corresponding DTS file is at
+          arch/mips/netlogic/dts/xlp_evp.dts
+endif
+
 config NLM_COMMON
 	bool
+
+endif

arch/mips/netlogic/Makefile

 obj-$(CONFIG_NLM_COMMON)	+=	common/
 obj-$(CONFIG_CPU_XLR)		+=	xlr/
 obj-$(CONFIG_CPU_XLP)		+=	xlp/
+obj-$(CONFIG_CPU_XLP)		+=	dts/

arch/mips/netlogic/dts/Makefile

+obj-$(CONFIG_DT_XLP_EVP) := xlp_evp.dtb.o
+
+$(obj)/%.dtb: $(obj)/%.dts
+	$(call if_changed,dtc)

arch/mips/netlogic/xlp/setup.c

@@ -57,6 +57,7 @@ unsigned long nlm_common_ebase = 0x0;
 /* default to uniprocessor */
 uint32_t nlm_coremask = 1, nlm_cpumask  = 1;
 int  nlm_threads_per_core = 1;
+extern u32 __dtb_start[];
 
 static void nlm_linux_exit(void)
 {
@@ -97,9 +98,18 @@ void __init prom_init(void)
 {
 	void *fdtp;
 
-	fdtp = (void *)(long)fw_arg0;
 	xlp_mmu_init();
 	nlm_hal_init();
+
+	/*
+	 * If no FDT pointer is passed in, use the built-in FDT.
+	 * device_tree_init() does not handle CKSEG0 pointers in
+	 * 64-bit, so convert pointer.
+	 */
+	fdtp = (void *)(long)fw_arg0;
+	if (!fdtp)
+		fdtp = __dtb_start;
+	fdtp = phys_to_virt(__pa(fdtp));
 	early_init_devtree(fdtp);
 
 	nlm_common_ebase = read_c0_ebase() & (~((1 << 12) - 1));