Commit 662c0002 authored by Chris Packham's avatar Chris Packham Committed by Thomas Bogendoerfer
Browse files

mips: generic: add fdt fixup for Realtek reference board 



The bootloader used on the Realtek RTL9302C boards is an ancient vendor
fork of U-Boot that doesn't understand device trees. So to run a modern
kernel it is necessary use one of the APPENDED_DTB options.

When appending the DTB the inintrd information, if present, needs to be
inserted into the /chosen device tree node. The bootloader provides the
initrd start/size via the firmware environment. Add a fdt fixup that
will update the device tree with the initrd information.

Signed-off-by: default avatarChris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: default avatarThomas Bogendoerfer <tsbogend@alpha.franken.de>
parent 62b8db3a

arch/mips/generic/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -13,3 +13,4 @@ obj-$(CONFIG_LEGACY_BOARD_SEAD3) += board-sead3.o 
obj-$(CONFIG_LEGACY_BOARD_OCELOT)	+= board-ocelot.o

obj-$(CONFIG_MACH_INGENIC)			+= board-ingenic.o

obj-$(CONFIG_VIRT_BOARD_RANCHU)		+= board-ranchu.o

obj-$(CONFIG_MACH_REALTEK_RTL)		+= board-realtek.o

arch/mips/generic/board-realtek.c

0 → 100644
+79 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (C) 2024 Allied Telesis

 */



#include <linux/errno.h>

#include <linux/libfdt.h>

#include <linux/printk.h>

#include <linux/types.h>



#include <asm/fw/fw.h>

#include <asm/machine.h>



static __init int realtek_add_initrd(void *fdt)

{

	int node, err;

	u32 start, size;



	node = fdt_path_offset(fdt, "/chosen");

	if (node < 0) {

		pr_err("/chosen node not found\n");

		return -ENOENT;

	}



	start = fw_getenvl("initrd_start");

	size = fw_getenvl("initrd_size");



	if (start == 0 && size == 0)

		return 0;



	pr_info("Adding initrd info from environment\n");



	err = fdt_setprop_u32(fdt, node, "linux,initrd-start", start);

	if (err) {

		pr_err("unable to set initrd-start: %d\n", err);

		return err;

	}



	err = fdt_setprop_u32(fdt, node, "linux,initrd-end", start + size);

	if (err) {

		pr_err("unable to set initrd-end: %d\n", err);

		return err;

	}



	return 0;

}



static const struct mips_fdt_fixup realtek_fdt_fixups[] __initconst = {

	{ realtek_add_initrd, "add initrd" },

	{},

};



static __init const void *realtek_fixup_fdt(const void *fdt, const void *match_data)

{

	static unsigned char fdt_buf[16 << 10] __initdata;

	int err;



	if (fdt_check_header(fdt))

		panic("Corrupt DT");



	fw_init_cmdline();



	err = apply_mips_fdt_fixups(fdt_buf, sizeof(fdt_buf), fdt, realtek_fdt_fixups);

	if (err)

		panic("Unable to fixup FDT: %d", err);



	return fdt_buf;



}



static const struct of_device_id realtek_of_match[] __initconst = {

	{ .compatible = "realtek,rtl9302-soc" },

	{}

};



MIPS_MACHINE(realtek) = {

	.matches = realtek_of_match,

	.fixup_fdt = realtek_fixup_fdt,

};