--- /dev/null
+From 318c1fce4aeef298cbb6153416c499c94ad7cda0 Mon Sep 17 00:00:00 2001
+From: Jonas Gorski <jogo@openwrt.org>
+Date: Tue, 24 Jun 2014 10:53:15 +0200
+Subject: [PATCH RFC v3] MIPS: add support for vmlinux.bin appended DTB
+
+Add support for populating initial_boot_params through a dtb
+blob appended to raw vmlinux.bin.
+
+Signed-off-by: Jonas Gorski <jogo@openwrt.org>
+---
+Changes RFC v2 -> v3
+
+* fixed !smp kernels (TODO: move it to its own patch
+
+Changes RFC v1 -> v2
+
+* changed all occurences of vmlinux to vmlinux.bin
+* clarified this applies to the raw vmlinux.bin without decompressor
+* s/initial_device_params/initial_boot_params/
+
+Initial comments by me still valid:
+
+Mostly adapted from how ARM is doing it.
+
+Sent as an RFC PATCH because I am not sure if this is the right way to
+it, and whether storing the pointer in initial_boot_params is a good
+idea, or a new variable should be introduced.
+
+The reasoning for initial_boot_params is that there is no common
+MIPS interface yet, so the next best thing was using that. This also
+has the advantage of keeping the original fw_args intact.
+
+This patch works for me on bcm63xx, where the bootloader expects
+an lzma compressed kernel, so I didn't want to double compress using
+the in-kernel compressed kernel support.
+
+Completely untested on anything except MIPS32 / big endian.
+
+ arch/mips/Kconfig | 18 ++++++++++++++++++
+ arch/mips/kernel/head.S | 19 +++++++++++++++++++
+ arch/mips/kernel/vmlinux.lds.S | 7 +++++++
+ 3 files changed, 43 insertions(+)
+
+--- a/arch/mips/Kconfig
++++ b/arch/mips/Kconfig
+@@ -2645,6 +2645,24 @@ config RAPIDIO
+
+ source "drivers/rapidio/Kconfig"
+
++config MIPS_APPENDED_DTB
++ bool "Use appended device tree blob to vmlinux.bin (EXPERIMENTAL)"
++ depends on OF
++ help
++ With this option, the boot code will look for a device tree binary
++ DTB) appended to raw vmlinux.bin (without decompressor).
++ (e.g. cat vmlinux.bin <filename>.dtb > vmlinux_w_dtb).
++
++ This is meant as a backward compatibility convenience for those
++ systems with a bootloader that can't be upgraded to accommodate
++ the documented boot protocol using a device tree.
++
++ Beware that there is very little in terms of protection against
++ this option being confused by leftover garbage in memory that might
++ look like a DTB header after a reboot if no actual DTB is appended
++ to vmlinux.bin. Do not leave this option active in a production kernel
++ if you don't intend to always append a DTB.
++
+ endmenu
+
+ menu "Executable file formats"
+--- a/arch/mips/kernel/head.S
++++ b/arch/mips/kernel/head.S
+@@ -100,6 +100,22 @@ NESTED(kernel_entry, 16, sp) # kernel
+ jr t0
+ 0:
+
++#ifdef CONFIG_MIPS_APPENDED_DTB
++ PTR_LA t0, __appended_dtb
++ PTR_LI t3, 0
++
++#ifdef CONFIG_CPU_BIG_ENDIAN
++ PTR_LI t1, 0xd00dfeed
++#else
++ PTR_LI t1, 0xedfe0dd0
++#endif
++ LONG_L t2, (t0)
++ bne t1, t2, not_found
++
++ PTR_LA t3, __appended_dtb
++
++not_found:
++#endif
+ PTR_LA t0, __bss_start # clear .bss
+ LONG_S zero, (t0)
+ PTR_LA t1, __bss_stop - LONGSIZE
+@@ -113,6 +129,10 @@ NESTED(kernel_entry, 16, sp) # kernel
+ LONG_S a2, fw_arg2
+ LONG_S a3, fw_arg3
+
++#ifdef CONFIG_MIPS_APPENDED_DTB
++ LONG_S t3, initial_boot_params
++#endif
++
+ MTC0 zero, CP0_CONTEXT # clear context register
+ PTR_LA $28, init_thread_union
+ /* Set the SP after an empty pt_regs. */
+--- a/arch/mips/kernel/vmlinux.lds.S
++++ b/arch/mips/kernel/vmlinux.lds.S
+@@ -125,8 +125,14 @@ SECTIONS
+ .exit.data : {
+ EXIT_DATA
+ }
+-
++#ifdef CONFIG_SMP
+ PERCPU_SECTION(1 << CONFIG_MIPS_L1_CACHE_SHIFT)
++#endif
++#ifdef CONFIG_MIPS_APPENDED_DTB
++ __appended_dtb = .;
++ /* leave space for appended DTB */
++ . = . + 0x100000;
++#endif
+ /*
+ * Align to 64K in attempt to eliminate holes before the
+ * .bss..swapper_pg_dir section at the start of .bss. This
projects / openwrt / svn-archive / archive.git / blobdiff