MIPS: Octeon: Initialize and fixup device tree.

If a compiled in device tree template is used, trim out unwanted parts
based on legacy platform probing.
Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: linux-kernel@vger.kernel.org
Cc: David Daney <david.daney@cavium.com>
Patchwork: https://patchwork.linux-mips.org/patch/3935/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -1432,6 +1432,8 @@ config CPU_CAVIUM_OCTEON
 	select WEAK_ORDERING
 	select CPU_SUPPORTS_HIGHMEM
 	select CPU_SUPPORTS_HUGEPAGES
+	select LIBFDT
+	select USE_OF
 	help
 	  The Cavium Octeon processor is a highly integrated chip containing
 	  many ethernet hardware widgets for networking tasks. The processor

arch/mips/cavium-octeon/Makefile

@@ -9,6 +9,9 @@
 # Copyright (C) 2005-2009 Cavium Networks
 #
 
+CFLAGS_octeon-platform.o = -I$(src)/../../../scripts/dtc/libfdt
+CFLAGS_setup.o = -I$(src)/../../../scripts/dtc/libfdt
+
 obj-y := cpu.o setup.o serial.o octeon-platform.o octeon-irq.o csrc-octeon.o
 obj-y += dma-octeon.o flash_setup.o
 obj-y += octeon-memcpy.o

arch/mips/cavium-octeon/setup.c

@@ -21,6 +21,8 @@
 #include <linux/platform_device.h>
 #include <linux/serial_core.h>
 #include <linux/serial_8250.h>
+#include <linux/of_fdt.h>
+#include <linux/libfdt.h>
 
 #include <asm/processor.h>
 #include <asm/reboot.h>
@@ -775,3 +777,46 @@ void prom_free_prom_memory(void)
 	}
 #endif
 }
+
+int octeon_prune_device_tree(void);
+
+extern const char __dtb_octeon_3xxx_begin;
+extern const char __dtb_octeon_3xxx_end;
+extern const char __dtb_octeon_68xx_begin;
+extern const char __dtb_octeon_68xx_end;
+void __init device_tree_init(void)
+{
+	int dt_size;
+	struct boot_param_header *fdt;
+	bool do_prune;
+
+	if (octeon_bootinfo->minor_version >= 3 && octeon_bootinfo->fdt_addr) {
+		fdt = phys_to_virt(octeon_bootinfo->fdt_addr);
+		if (fdt_check_header(fdt))
+			panic("Corrupt Device Tree passed to kernel.");
+		dt_size = be32_to_cpu(fdt->totalsize);
+		do_prune = false;
+	} else if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
+		fdt = (struct boot_param_header *)&__dtb_octeon_68xx_begin;
+		dt_size = &__dtb_octeon_68xx_end - &__dtb_octeon_68xx_begin;
+		do_prune = true;
+	} else {
+		fdt = (struct boot_param_header *)&__dtb_octeon_3xxx_begin;
+		dt_size = &__dtb_octeon_3xxx_end - &__dtb_octeon_3xxx_begin;
+		do_prune = true;
+	}
+
+	/* Copy the default tree from init memory. */
+	initial_boot_params = early_init_dt_alloc_memory_arch(dt_size, 8);
+	if (initial_boot_params == NULL)
+		panic("Could not allocate initial_boot_params\n");
+	memcpy(initial_boot_params, fdt, dt_size);
+
+	if (do_prune) {
+		octeon_prune_device_tree();
+		pr_info("Using internal Device Tree.\n");
+	} else {
+		pr_info("Using passed Device Tree.\n");
+	}
+	unflatten_device_tree();
+}