target/linux/brcm63xx/patches-4.1/001-4.2-MIPS-Add-support-for-vmlinux.bin-appended-dtb.patch

   1 From 1da8f1798e307fb8422753984339beb00025f97d Mon Sep 17 00:00:00 2001
   2 From: Jonas Gorski <jogo@openwrt.org>
   3 Date: Sun, 12 Apr 2015 12:24:58 +0200
   4 Subject: [PATCH] MIPS: Add support for vmlinux.bin appended dtb
   5
   6 Add support for detecting a vmlinux.bin appended dtb and overriding
   7 the boot arguments to match the UHI interface.
   8
   9 Due to the PERCPU section being empty for !SMP, but still modifying
  10 the current address by aligning it to the page size, do not define
  11 it for !SMP builds to allow __appended_dtb to still point to
  12 the actual end of the data.
  13
  14 Signed-off-by: Jonas Gorski <jogo@openwrt.org>
  15 Cc: linux-mips@linux-mips.org
  16 Cc: devicetree@vger.kernel.org
  17 Cc: John Crispin <blogic@openwrt.org>
  18 Cc: Kevin Cernekee <cernekee@gmail.com>
  19 Cc: Florian Fainelli <f.fainelli@gmail.com>
  20 Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
  21 Cc: Markos Chandras <markos.chandras@imgtec.com>
  22 Cc: Andrew Bresticker <abrestic@chromium.org>
  23 Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
  24 Cc: Paul Burton <paul.burton@imgtec.com>
  25 Cc: James Hartley <James.Hartley@imgtec.com>
  26 Patchwork: https://patchwork.linux-mips.org/patch/9739/
  27 Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
  28 ---
  29  arch/mips/Kconfig              | 27 +++++++++++++++++++++++++++
  30  arch/mips/kernel/head.S        | 16 ++++++++++++++++
  31  arch/mips/kernel/vmlinux.lds.S |  8 +++++++-
  32  3 files changed, 50 insertions(+), 1 deletion(-)
  33
  34 --- a/arch/mips/Kconfig
  35 +++ b/arch/mips/Kconfig
  36 @@ -2702,6 +2702,33 @@ config BOOT_RAW
  37
  38
  39
  40 +choice
  41 +       prompt "Kernel appended dtb support" if OF
  42 +       default MIPS_NO_APPENDED_DTB
  43 +
  44 +       config MIPS_NO_APPENDED_DTB
  45 +               bool "None"
  46 +               help
  47 +                 Do not enable appended dtb support.
  48 +
  49 +       config MIPS_RAW_APPENDED_DTB
  50 +               bool "vmlinux.bin"
  51 +               help
  52 +                 With this option, the boot code will look for a device tree binary
  53 +                 DTB) appended to raw vmlinux.bin (without decompressor).
  54 +                 (e.g. cat vmlinux.bin <filename>.dtb > vmlinux_w_dtb).
  55 +
  56 +                 This is meant as a backward compatibility convenience for those
  57 +                 systems with a bootloader that can't be upgraded to accommodate
  58 +                 the documented boot protocol using a device tree.
  59 +
  60 +                 Beware that there is very little in terms of protection against
  61 +                 this option being confused by leftover garbage in memory that might
  62 +                 look like a DTB header after a reboot if no actual DTB is appended
  63 +                 to vmlinux.bin.  Do not leave this option active in a production kernel
  64 +                 if you don't intend to always append a DTB.
  65 +endchoice
  66 +
  67  endmenu
  68
  69  config LOCKDEP_SUPPORT
  70 --- a/arch/mips/kernel/head.S
  71 +++ b/arch/mips/kernel/head.S
  72 @@ -100,6 +100,22 @@ NESTED(kernel_entry, 16, sp)                       # kernel
  73         jr      t0
  74  0:
  75
  76 +#ifdef CONFIG_MIPS_RAW_APPENDED_DTB
  77 +       PTR_LA          t0, __appended_dtb
  78 +
  79 +#ifdef CONFIG_CPU_BIG_ENDIAN
  80 +       li              t1, 0xd00dfeed
  81 +#else
  82 +       li              t1, 0xedfe0dd0
  83 +#endif
  84 +       lw              t2, (t0)
  85 +       bne             t1, t2, not_found
  86 +        nop
  87 +
  88 +       move            a1, t0
  89 +       PTR_LI          a0, -2
  90 +not_found:
  91 +#endif
  92         PTR_LA          t0, __bss_start         # clear .bss
  93         LONG_S          zero, (t0)
  94         PTR_LA          t1, __bss_stop - LONGSIZE
  95 --- a/arch/mips/kernel/vmlinux.lds.S
  96 +++ b/arch/mips/kernel/vmlinux.lds.S
  97 @@ -125,8 +125,14 @@ SECTIONS
  98         .exit.data : {
  99                 EXIT_DATA
 100         }
 101 -
 102 +#ifdef CONFIG_SMP
 103         PERCPU_SECTION(1 << CONFIG_MIPS_L1_CACHE_SHIFT)
 104 +#endif
 105 +#ifdef CONFIG_MIPS_RAW_APPENDED_DTB
 106 +       __appended_dtb = .;
 107 +       /* leave space for appended DTB */
 108 +       . += 0x100000;
 109 +#endif
 110         /*
 111          * Align to 64K in attempt to eliminate holes before the
 112          * .bss..swapper_pg_dir section at the start of .bss.  This