[U-Boot] [PATCH] x86: Add clarifications to the x86 README

[Bin Meng]

On Thu, Aug 13, 2015 at 9:43 PM, Igor Stoppa <igor.stoppa at intel.com> wrote:
> * Explicitly list the targets supported in each section of the
> instructions from the x86 README.
>
> * Drop references to 'raw mode', in favor of 'bare mode'.
>
> Signed-off-by: Igor Stoppa <igor.stoppa at intel.com>
> ---
>  doc/README.x86 | 32 +++++++++++++++++++++-----------
>  1 file changed, 21 insertions(+), 11 deletions(-)
>
> diff --git a/doc/README.x86 b/doc/README.x86
> index af2459c..9012541 100644
> --- a/doc/README.x86
> +++ b/doc/README.x86
> @@ -18,15 +18,16 @@ U-Boot supports running as a coreboot [1] payload on x86. So far only Link
>  work with minimal adjustments on other x86 boards since coreboot deals with
>  most of the low-level details.
>
> -U-Boot also supports booting directly from x86 reset vector without coreboot,
> -aka raw support or bare support. Currently Link, QEMU x86 targets and all
> -Intel boards support running U-Boot 'bare metal'.
> +U-Boot also supports booting directly from x86 reset vector, without coreboot.
> +In this case, known as bare mode, from the fact that it runs on the
> +'bare metal', U-Boot acts like a BIOS replacement. Currently Link, QEMU x86
> +targets and all Intel boards support running U-Boot 'bare metal'.
>
>  As for loading an OS, U-Boot supports directly booting a 32-bit or 64-bit
>  Linux kernel as part of a FIT image. It also supports a compressed zImage.
>
> -Build Instructions
> -------------------
> +Build Instructions for U-Boot as coreboot payload
> +-------------------------------------------------
>  Building U-Boot as a coreboot payload is just like building U-Boot for targets
>  on other architectures, like below:
>
> @@ -48,6 +49,8 @@ Change the 'Board configuration file' and 'Board Device Tree Source (dts) file'
>  to point to a new board. You can also change the Cache-As-RAM (CAR) related
>  settings here if the default values do not fit your new board.
>
> +Build Instructions for U-Boot as BIOS replacement (bare mode)
> +-------------------------------------------------------------
>  Building a ROM version of U-Boot (hereafter referred to as u-boot.rom) is a
>  little bit tricky, as generally it requires several binary blobs which are not
>  shipped in the U-Boot source tree. Due to this reason, the u-boot.rom build is
> @@ -58,7 +61,9 @@ $ export BUILD_ROM=y
>
>  This tells the Makefile to build u-boot.rom as a target.
>
> -Link-specific instructions:
> +---
> +
> +Chromebook Link specific instructions for bare mode:
>
>  First, you need the following binary blobs:
>
> @@ -87,7 +92,9 @@ Now you can build U-Boot and obtain u-boot.rom:
>  $ make chromebook_link_defconfig
>  $ make all
>
> -Intel Crown Bay specific instructions:
> +---
> +
> +Intel Crown Bay specific instructions for bare mode:
>
>  U-Boot support of Intel Crown Bay board [4] relies on a binary blob called
>  Firmware Support Package [5] to perform all the necessary initialization steps
> @@ -122,7 +129,9 @@ Now you can build U-Boot and obtain u-boot.rom
>  $ make crownbay_defconfig
>  $ make all
>
> -Intel Minnowboard Max instructions:
> +---
> +
> +Intel Minnowboard Max instructions for bare mode:
>
>  This uses as FSP as with Crown Bay, except it is for the Atom E3800 series.
>  Download this and get the .fd file (BAYTRAIL_FSP_GOLD_003_16-SEP-2014.fd at
> @@ -188,8 +197,9 @@ Offset   Description         Controlling config
>
>  Overall ROM image size is controlled by CONFIG_ROM_SIZE.
>
> +---
>
> -Intel Galileo instructions:
> +Intel Galileo instructions for bare mode:
>
>  Only one binary blob is needed for Remote Management Unit (RMU) within Intel
>  Quark SoC. Not like FSP, U-Boot does not call into the binary. The binary is
> @@ -252,8 +262,8 @@ At present it seems that for Minnowboard Max, coreboot does not pass through
>  the video information correctly (it always says the resolution is 0x0). This
>  works correctly for link though.
>
> -Test with QEMU
> ---------------
> +Test with QEMU for bare mode
> +----------------------------
>  QEMU is a fancy emulator that can enable us to test U-Boot without access to
>  a real x86 board. Please make sure your QEMU version is 2.3.0 or above test
>  U-Boot. To launch QEMU with u-boot.rom, call QEMU as follows:
> --

Reviewed-by: Bin Meng <bmeng.cn at gmail.com>