[U-Boot,v5,7/8] board: intel: Add new slimbootloader board
diff mbox series

Message ID A1484485FD99714DB2AB2C5EF81E7AC2AA746889@ORSMSX116.amr.corp.intel.com
State Superseded
Delegated to: Bin Meng
Headers show
Series
  • x86: Add basic Slim Bootloader payload support
Related show

Commit Message

Park, Aiden July 17, 2019, 4:42 a.m. UTC
Add slimbootloader board to run U-boot as a Slim Bootloader payload
- Add new board/intel/slimbootloader directory with minimum codes
- Add slimbootloader configuration files
- Add README in board/intel/slimbootloader

Signed-off-by: Aiden Park <aiden.park@intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
---

Changes in v5:
  * Remove X86_LOAD_FROM_32_BIT from slimbootloader_defconfig

Changes in v3:
  * Remove VENDOR_SLIMBOOTLOADER
  * Use VENDOR_INTEL
  * Move slimbootloader under board/intel/
  * Enable generic CONFIGs in slimbootloader_defconfig
  * Add more description in board/intel/slimbootloader/README

 board/intel/Kconfig                         |  14 +++
 board/intel/slimbootloader/Kconfig          |  51 ++++++++
 board/intel/slimbootloader/Makefile         |   5 +
 board/intel/slimbootloader/README           | 133 ++++++++++++++++++++
 board/intel/slimbootloader/slimbootloader.c |  17 +++
 board/intel/slimbootloader/start.S          |   9 ++
 configs/slimbootloader_defconfig            |  21 ++++
 include/configs/slimbootloader.h            |  59 +++++++++
 8 files changed, 309 insertions(+)
 create mode 100644 board/intel/slimbootloader/Kconfig
 create mode 100644 board/intel/slimbootloader/Makefile
 create mode 100644 board/intel/slimbootloader/README
 create mode 100644 board/intel/slimbootloader/slimbootloader.c
 create mode 100644 board/intel/slimbootloader/start.S
 create mode 100644 configs/slimbootloader_defconfig
 create mode 100644 include/configs/slimbootloader.h

--
2.20.1

Comments

Andy Shevchenko July 22, 2019, 3:48 p.m. UTC | #1
On Wed, Jul 17, 2019 at 7:42 AM Park, Aiden <aiden.park@intel.com> wrote:
>
> Add slimbootloader board to run U-boot as a Slim Bootloader payload
> - Add new board/intel/slimbootloader directory with minimum codes
> - Add slimbootloader configuration files
> - Add README in board/intel/slimbootloader

>  board/intel/slimbootloader/README           | 133 ++++++++++++++++++++

Shouldn't become reST one?

> +Stitch IFWI:
> +  Refer to https://slimbootloader.github.io/supported-hardware/apollo-lake-crb.html#stitching.
> +  > python Platform/ApollolakeBoardPkg/Script/StitchLoader.py -i <Existing IFWI> -s Outputs/apl/Stitch_Components.zip -o <Output IFWI>

It reminds me that DnX protocol.

> +Flash IFWI:
> +  Use DediProg to flash IFWI.
> +  Now, you should reach at U-Boot serial console.

Can't it be done via DFU?

> +int board_early_init_r(void)
> +{
> +       /*
> +        * Make sure PCI bus is enumerated so that peripherals on the PCI bus
> +        * can be discovered by their drivers
> +        */
> +       pci_init();

I'm not sure this is how U-Boot is designed with DM.
At least my expectations that bus gets initialized followed by the
certain driver in a lazy way.
Isn't it the case? Bin?

> +
> +       return 0;
> +}


> +++ b/board/intel/slimbootloader/start.S
> @@ -0,0 +1,9 @@

> +/* board early initialization */
> +.globl early_board_init
> +early_board_init:
> +       jmp     early_board_init_ret

Do you need this stub at all? How other CPUs work without it?

> +++ b/include/configs/slimbootloader.h
> @@ -0,0 +1,59 @@

> +#undef CONFIG_NFSBOOTCOMMAND
> +#undef CONFIG_RAMBOOTCOMMAND
> +#undef CONFIG_EXTRA_ENV_SETTINGS
> +#undef CONFIG_BOOTCOMMAND

Do we really need all these in the header?
Can't some at least be done via configuration?

> +#ifdef CONFIG_SYS_NS16550_MEM32
> +#undef CONFIG_SYS_NS16550_PORT_MAPPED
> +#endif
Bin Meng July 23, 2019, 6:15 a.m. UTC | #2
Hi Andy,

On Mon, Jul 22, 2019 at 11:49 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Wed, Jul 17, 2019 at 7:42 AM Park, Aiden <aiden.park@intel.com> wrote:
> >
> > Add slimbootloader board to run U-boot as a Slim Bootloader payload
> > - Add new board/intel/slimbootloader directory with minimum codes
> > - Add slimbootloader configuration files
> > - Add README in board/intel/slimbootloader
>
> >  board/intel/slimbootloader/README           | 133 ++++++++++++++++++++
>
> Shouldn't become reST one?

I think this will need be converted to reST after my doc series are applied.

>
> > +Stitch IFWI:
> > +  Refer to https://slimbootloader.github.io/supported-hardware/apollo-lake-crb.html#stitching.
> > +  > python Platform/ApollolakeBoardPkg/Script/StitchLoader.py -i <Existing IFWI> -s Outputs/apl/Stitch_Components.zip -o <Output IFWI>
>
> It reminds me that DnX protocol.
>
> > +Flash IFWI:
> > +  Use DediProg to flash IFWI.
> > +  Now, you should reach at U-Boot serial console.
>
> Can't it be done via DFU?
>
> > +int board_early_init_r(void)
> > +{
> > +       /*
> > +        * Make sure PCI bus is enumerated so that peripherals on the PCI bus
> > +        * can be discovered by their drivers
> > +        */
> > +       pci_init();
>
> I'm not sure this is how U-Boot is designed with DM.
> At least my expectations that bus gets initialized followed by the
> certain driver in a lazy way.
> Isn't it the case? Bin?

For most x86 board, yes, PCI gets enumerated automatically if some PCI
APIs are called in the early initialization codes: eg: pci_{read,
write}_config().

But for boards like coreboot/slimbootloader, if there is no touch to
any PCI config register on that board in the early phase, PCI bus
remains not probed.

>
> > +
> > +       return 0;
> > +}
>
>
> > +++ b/board/intel/slimbootloader/start.S
> > @@ -0,0 +1,9 @@
>
> > +/* board early initialization */
> > +.globl early_board_init
> > +early_board_init:
> > +       jmp     early_board_init_ret
>
> Do you need this stub at all? How other CPUs work without it?

This hook is currently needed by every board.

>
> > +++ b/include/configs/slimbootloader.h
> > @@ -0,0 +1,59 @@
>
> > +#undef CONFIG_NFSBOOTCOMMAND
> > +#undef CONFIG_RAMBOOTCOMMAND
> > +#undef CONFIG_EXTRA_ENV_SETTINGS
> > +#undef CONFIG_BOOTCOMMAND
>
> Do we really need all these in the header?
> Can't some at least be done via configuration?

I suspect not all of these are converted to Kconfig yet.

Regards,
Bin
Andy Shevchenko July 23, 2019, 12:26 p.m. UTC | #3
On Tue, Jul 23, 2019 at 9:15 AM Bin Meng <bmeng.cn@gmail.com> wrote:
> On Mon, Jul 22, 2019 at 11:49 PM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Wed, Jul 17, 2019 at 7:42 AM Park, Aiden <aiden.park@intel.com> wrote:

> > >  board/intel/slimbootloader/README           | 133 ++++++++++++++++++++
> >
> > Shouldn't become reST one?
>
> I think this will need be converted to reST after my doc series are applied.

I had an impression that reST conversion is targeting 2019.10. It
means in your branch you will have it applied earlier.

> > > +int board_early_init_r(void)
> > > +{
> > > +       /*
> > > +        * Make sure PCI bus is enumerated so that peripherals on the PCI bus
> > > +        * can be discovered by their drivers
> > > +        */
> > > +       pci_init();
> >
> > I'm not sure this is how U-Boot is designed with DM.
> > At least my expectations that bus gets initialized followed by the
> > certain driver in a lazy way.
> > Isn't it the case? Bin?
>
> For most x86 board, yes, PCI gets enumerated automatically if some PCI
> APIs are called in the early initialization codes: eg: pci_{read,
> write}_config().
>
> But for boards like coreboot/slimbootloader, if there is no touch to
> any PCI config register on that board in the early phase, PCI bus
> remains not probed.

Thanks for explanation!
Perhaps this needs a comment in the code.
Park, Aiden July 24, 2019, 3:18 a.m. UTC | #4
Hi Andy,

> -----Original Message-----
> From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com]
> Sent: Tuesday, July 23, 2019 5:27 AM
> To: Bin Meng <bmeng.cn@gmail.com>
> Cc: Park, Aiden <aiden.park@intel.com>; U-Boot Mailing List <u-
> boot@lists.denx.de>; Simon Glass <sjg@chromium.org>
> Subject: Re: [PATCH v5 7/8] board: intel: Add new slimbootloader board
> 
> On Tue, Jul 23, 2019 at 9:15 AM Bin Meng <bmeng.cn@gmail.com> wrote:
> > On Mon, Jul 22, 2019 at 11:49 PM Andy Shevchenko
> > <andy.shevchenko@gmail.com> wrote:
> > > On Wed, Jul 17, 2019 at 7:42 AM Park, Aiden <aiden.park@intel.com> wrote:
> 
> > > >  board/intel/slimbootloader/README           | 133 ++++++++++++++++++++
> > >
> > > Shouldn't become reST one?
> >
> > I think this will need be converted to reST after my doc series are applied.
> 
> I had an impression that reST conversion is targeting 2019.10. It means in your
> branch you will have it applied earlier.
> 
Let me change this to reST if necessary.
Hi Bin, do you want me to change this one to reST or later? Let me know.

> > > > +int board_early_init_r(void)
> > > > +{
> > > > +       /*
> > > > +        * Make sure PCI bus is enumerated so that peripherals on the PCI bus
> > > > +        * can be discovered by their drivers
> > > > +        */
> > > > +       pci_init();
> > >
> > > I'm not sure this is how U-Boot is designed with DM.
> > > At least my expectations that bus gets initialized followed by the
> > > certain driver in a lazy way.
> > > Isn't it the case? Bin?
> >
> > For most x86 board, yes, PCI gets enumerated automatically if some PCI
> > APIs are called in the early initialization codes: eg: pci_{read,
> > write}_config().
> >
> > But for boards like coreboot/slimbootloader, if there is no touch to
> > any PCI config register on that board in the early phase, PCI bus
> > remains not probed.
> 
> Thanks for explanation!
> Perhaps this needs a comment in the code.
> 
Thanks Bin for your explanation. Slim Bootloader have done PCI config space setup
and PCI device enumeration in Slim Bootloader stages.

> --
> With Best Regards,
> Andy Shevchenko

Best Regards,
Aiden
Bin Meng July 24, 2019, 5:13 a.m. UTC | #5
Hi Aiden,

On Wed, Jul 24, 2019 at 11:18 AM Park, Aiden <aiden.park@intel.com> wrote:
>
> Hi Andy,
>
> > -----Original Message-----
> > From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com]
> > Sent: Tuesday, July 23, 2019 5:27 AM
> > To: Bin Meng <bmeng.cn@gmail.com>
> > Cc: Park, Aiden <aiden.park@intel.com>; U-Boot Mailing List <u-
> > boot@lists.denx.de>; Simon Glass <sjg@chromium.org>
> > Subject: Re: [PATCH v5 7/8] board: intel: Add new slimbootloader board
> >
> > On Tue, Jul 23, 2019 at 9:15 AM Bin Meng <bmeng.cn@gmail.com> wrote:
> > > On Mon, Jul 22, 2019 at 11:49 PM Andy Shevchenko
> > > <andy.shevchenko@gmail.com> wrote:
> > > > On Wed, Jul 17, 2019 at 7:42 AM Park, Aiden <aiden.park@intel.com> wrote:
> >
> > > > >  board/intel/slimbootloader/README           | 133 ++++++++++++++++++++
> > > >
> > > > Shouldn't become reST one?
> > >
> > > I think this will need be converted to reST after my doc series are applied.
> >
> > I had an impression that reST conversion is targeting 2019.10. It means in your
> > branch you will have it applied earlier.
> >
> Let me change this to reST if necessary.
> Hi Bin, do you want me to change this one to reST or later? Let me know.

I have no preference. You can either convert to reST later, or rebase
on top of this series to get it converted to reST now:
http://patchwork.ozlabs.org/project/uboot/list/?series=120139

>
> > > > > +int board_early_init_r(void)
> > > > > +{
> > > > > +       /*
> > > > > +        * Make sure PCI bus is enumerated so that peripherals on the PCI bus
> > > > > +        * can be discovered by their drivers
> > > > > +        */
> > > > > +       pci_init();
> > > >
> > > > I'm not sure this is how U-Boot is designed with DM.
> > > > At least my expectations that bus gets initialized followed by the
> > > > certain driver in a lazy way.
> > > > Isn't it the case? Bin?
> > >
> > > For most x86 board, yes, PCI gets enumerated automatically if some PCI
> > > APIs are called in the early initialization codes: eg: pci_{read,
> > > write}_config().
> > >
> > > But for boards like coreboot/slimbootloader, if there is no touch to
> > > any PCI config register on that board in the early phase, PCI bus
> > > remains not probed.
> >
> > Thanks for explanation!
> > Perhaps this needs a comment in the code.
> >
> Thanks Bin for your explanation. Slim Bootloader have done PCI config space setup
> and PCI device enumeration in Slim Bootloader stages.
>

Yes, and we should not re-program registers like BARs in U-Boot to
avoid mismatch, so that's why in coreboot/slimbootloader defconfig we
have:
# CONFIG_PCI_PNP is not set

Regards,
Bin
Bin Meng July 25, 2019, 2:44 p.m. UTC | #6
On Wed, Jul 24, 2019 at 1:13 PM Bin Meng <bmeng.cn@gmail.com> wrote:
>
> Hi Aiden,
>
> On Wed, Jul 24, 2019 at 11:18 AM Park, Aiden <aiden.park@intel.com> wrote:
> >
> > Hi Andy,
> >
> > > -----Original Message-----
> > > From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com]
> > > Sent: Tuesday, July 23, 2019 5:27 AM
> > > To: Bin Meng <bmeng.cn@gmail.com>
> > > Cc: Park, Aiden <aiden.park@intel.com>; U-Boot Mailing List <u-
> > > boot@lists.denx.de>; Simon Glass <sjg@chromium.org>
> > > Subject: Re: [PATCH v5 7/8] board: intel: Add new slimbootloader board
> > >
> > > On Tue, Jul 23, 2019 at 9:15 AM Bin Meng <bmeng.cn@gmail.com> wrote:
> > > > On Mon, Jul 22, 2019 at 11:49 PM Andy Shevchenko
> > > > <andy.shevchenko@gmail.com> wrote:
> > > > > On Wed, Jul 17, 2019 at 7:42 AM Park, Aiden <aiden.park@intel.com> wrote:
> > >
> > > > > >  board/intel/slimbootloader/README           | 133 ++++++++++++++++++++
> > > > >
> > > > > Shouldn't become reST one?
> > > >
> > > > I think this will need be converted to reST after my doc series are applied.
> > >
> > > I had an impression that reST conversion is targeting 2019.10. It means in your
> > > branch you will have it applied earlier.
> > >
> > Let me change this to reST if necessary.
> > Hi Bin, do you want me to change this one to reST or later? Let me know.
>
> I have no preference. You can either convert to reST later, or rebase
> on top of this series to get it converted to reST now:
> http://patchwork.ozlabs.org/project/uboot/list/?series=120139

Now the doc series lands in mainline, so please rebase this series on
top of u-boot-x86/master. Thanks!

[snip]

Regards,
Bin
Park, Aiden July 26, 2019, 12:22 a.m. UTC | #7
Hi Bin,

> -----Original Message-----
> From: Bin Meng [mailto:bmeng.cn@gmail.com]
> Sent: Thursday, July 25, 2019 11:44 PM
> To: Park, Aiden <aiden.park@intel.com>
> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>; U-Boot Mailing List <u-
> boot@lists.denx.de>; Simon Glass <sjg@chromium.org>
> Subject: Re: [PATCH v5 7/8] board: intel: Add new slimbootloader board
> 
> On Wed, Jul 24, 2019 at 1:13 PM Bin Meng <bmeng.cn@gmail.com> wrote:
> >
> > Hi Aiden,
> >
> > On Wed, Jul 24, 2019 at 11:18 AM Park, Aiden <aiden.park@intel.com> wrote:
> > >
> > > Hi Andy,
> > >
> > > > -----Original Message-----
> > > > From: Andy Shevchenko [mailto:andy.shevchenko@gmail.com]
> > > > Sent: Tuesday, July 23, 2019 5:27 AM
> > > > To: Bin Meng <bmeng.cn@gmail.com>
> > > > Cc: Park, Aiden <aiden.park@intel.com>; U-Boot Mailing List <u-
> > > > boot@lists.denx.de>; Simon Glass <sjg@chromium.org>
> > > > Subject: Re: [PATCH v5 7/8] board: intel: Add new slimbootloader
> > > > board
> > > >
> > > > On Tue, Jul 23, 2019 at 9:15 AM Bin Meng <bmeng.cn@gmail.com> wrote:
> > > > > On Mon, Jul 22, 2019 at 11:49 PM Andy Shevchenko
> > > > > <andy.shevchenko@gmail.com> wrote:
> > > > > > On Wed, Jul 17, 2019 at 7:42 AM Park, Aiden <aiden.park@intel.com>
> wrote:
> > > >
> > > > > > >  board/intel/slimbootloader/README           | 133
> ++++++++++++++++++++
> > > > > >
> > > > > > Shouldn't become reST one?
> > > > >
> > > > > I think this will need be converted to reST after my doc series are applied.
> > > >
> > > > I had an impression that reST conversion is targeting 2019.10. It
> > > > means in your branch you will have it applied earlier.
> > > >
> > > Let me change this to reST if necessary.
> > > Hi Bin, do you want me to change this one to reST or later? Let me know.
> >
> > I have no preference. You can either convert to reST later, or rebase
> > on top of this series to get it converted to reST now:
> > http://patchwork.ozlabs.org/project/uboot/list/?series=120139
> 
> Now the doc series lands in mainline, so please rebase this series on top of u-
> boot-x86/master. Thanks!
> 
Thanks Bin. Let me rebase this series on top of latest u-boot-x86 and I will do reST.

> [snip]
> 
> Regards,
> Bin

Best Regards,
Aiden

Patch
diff mbox series

diff --git a/board/intel/Kconfig b/board/intel/Kconfig
index 5131836cb0..01702ae502 100644
--- a/board/intel/Kconfig
+++ b/board/intel/Kconfig
@@ -73,6 +73,19 @@  config TARGET_MINNOWMAX
          Note that PCIE_ECAM_BASE is set up by the FSP so the value used
          by U-Boot matches that value.

+config TARGET_SLIMBOOTLOADER
+       bool "slimbootloader"
+       help
+         This target is used for running U-Boot on top of Slim Bootloader
+         boot firmware as a payload. Slim Bootloader does memory initialization
+         and silicon initialization, and it passes necessary information in
+         HOB(Hand Off Block) to a payload. The payload consumes HOB data
+         which is generated by Slim Bootloader for its driver initialization.
+         Slim Bootloader consumes FSP and its HOB, but FSP HOB is cleared
+         Before launching a payload. Instead, Slim Bootloader generates its
+         HOB data such as memory info, serial port info and so on.
+         Refer to board/intel/slimbootloader/README for the details.
+
 endchoice

 source "board/intel/bayleybay/Kconfig"
@@ -82,5 +95,6 @@  source "board/intel/crownbay/Kconfig"
 source "board/intel/edison/Kconfig"
 source "board/intel/galileo/Kconfig"
 source "board/intel/minnowmax/Kconfig"
+source "board/intel/slimbootloader/Kconfig"

 endif
diff --git a/board/intel/slimbootloader/Kconfig b/board/intel/slimbootloader/Kconfig
new file mode 100644
index 0000000000..b0c15f4ba2
--- /dev/null
+++ b/board/intel/slimbootloader/Kconfig
@@ -0,0 +1,51 @@ 
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2019 Intel Corporation <www.intel.com>
+
+if TARGET_SLIMBOOTLOADER
+
+config SYS_BOARD
+       default "slimbootloader"
+
+config SYS_VENDOR
+       default "intel"
+
+config SYS_SOC
+       default "slimbootloader"
+
+config SYS_TEXT_BASE
+       default 0x00100000
+
+comment "slimbootloader-specific options"
+
+config SYS_CONFIG_NAME
+       string "Board configuration file"
+       default "slimbootloader"
+       help
+         This option selects the board configuration file in include/configs/
+         directory to be used to build U-Boot for Slim Bootloader.
+
+config DEFAULT_DEVICE_TREE
+       string "Board Device Tree Source (dts) file"
+       default "slimbootloader"
+       help
+         This option selects the board Device Tree Source (dts) file in
+         arch/x86/dts/ directory to be used to build U-Boot for Slim Bootloader.
+
+config SYS_CAR_ADDR
+       hex "Board specific Cache-As-RAM (CAR) address"
+       default 0x00000000
+       help
+         This option specifies the board specific Cache-As-RAM (CAR) address.
+         But, CAR is not required for Slim Bootloader environment since it
+         has already initialized memory and launched u-boot as a payload.
+
+config SYS_CAR_SIZE
+       hex "Board specific Cache-As-RAM (CAR) size"
+       default 0x0000
+       help
+         This option specifies the board specific Cache-As-RAM (CAR) size.
+         But, CAR is not required for Slim Bootloader environment since it
+         has already initialized memory and launched u-boot as a payload.
+
+endif
diff --git a/board/intel/slimbootloader/Makefile b/board/intel/slimbootloader/Makefile
new file mode 100644
index 0000000000..fd8fa98a8d
--- /dev/null
+++ b/board/intel/slimbootloader/Makefile
@@ -0,0 +1,5 @@ 
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2019 Intel Corporation <www.intel.com>
+
+obj-y  += start.o slimbootloader.o
diff --git a/board/intel/slimbootloader/README b/board/intel/slimbootloader/README
new file mode 100644
index 0000000000..d1c5108a75
--- /dev/null
+++ b/board/intel/slimbootloader/README
@@ -0,0 +1,133 @@ 
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2019 Intel Corporation <www.intel.com>
+
+Introduction
+============
+This target is to enable U-Boot as a payload of Slim Bootloader(a.k.a SBL)
+boot firmware(https://github.com/slimbootloader) which currently supports
+QEMU, Apollolake, Whiskeylake, Coffeelake-R platforms.
+
+The Slim Bootloader is designed with multi-stages(Stage1A/B, Stage2, Payload)
+architecture to cover from reset vector to OS booting and it consumes Intel FSP
+(https://github.com/IntelFsp) for silicon initialization.
+* Stage1A: Reset vector, CAR init with FSP-T
+* Stage1B: Memory init with FSP-M, CAR teardown, Continue execution in memory
+* Stage2 : Rest of Silicon init with FSP-S, Create HOB, Hand-off to Payload
+* Payload: Payload init with HOB, Load OS from media, Booting OS
+
+
+
+Here is the step-by-step to launch U-Boot on Slim Bootloader.
+
+Compile U-Boot
+==============
+
+  > make distclean
+  > make slimbootloader_defconfig
+  > make all
+
+
+
+Prepare Slim Bootloader with u-boot-dtb.bin
+===================================================
+
+For build environment:
+  https://slimbootloader.github.io/getting-started
+
+Get source code:
+  > git clone https://github.com/slimbootloader/slimbootloader.git
+
+Copy the built u-boot-dtb.bin to Slim Bootloader source tree:
+  > mkdir -p <slimbootloader_home>/PayloadPkg/PayloadBins/
+  > cp <u-boot_home>/u-boot-dtb.bin <slimbootloader_home>/PayloadPkg/PayloadBins/u-boot-dtb.bin
+
+
+
+Compile Slim Bootloader with U-Boot for QEMU target
+===================================================
+
+Update default payload to U-Boot (PayloadId is 4 Bytes):
+  Any 4 Bytes PayloadId is okay, but use 'U-BT' as an example.
+  > vi Platform/QemuBoardPkg/CfgData/CfgDataExt_Brd1.dlt
+    -GEN_CFG_DATA.PayloadId                     | 'AUTO'
+    +GEN_CFG_DATA.PayloadId                     | 'U-BT'
+
+Update payload text base in QEMU BoardConfig.py:
+  PAYLOAD_EXE_BASE must be the same as u-boot text base in board/intel/slimbootloader/Kconfig.
+  PAYLOAD_LOAD_HIGH must be 0.
+  > vi Platform/QemuBoardPkg/BoardConfig.py
+    +               self.PAYLOAD_LOAD_HIGH    = 0
+    +               self.PAYLOAD_EXE_BASE     = 0x00100000
+
+Compile for QEMU target:
+  Make sure u-boot-dtb.bin and U-BT PayloadId in build command.
+  > python BuildLoader.py build qemu -p "OsLoader.efi:LLDR:Lz4;u-boot-dtb.bin:U-BT:Lzma"
+  The output is Outputs/qemu/SlimBootloader.bin
+
+Launch Slim Bootloader on QEMU:
+  > qemu-system-x86_64 -machine q35 -m 256 -nographic -serial mon:stdio
+                       -pflash Outputs/qemu/SlimBootloader.bin
+  Now, you should reach at U-Boot serial console.
+
+
+
+Compile Slim Bootloader with U-Boot for LeafHill(APL) target
+============================================================
+
+Compile U-Boot with CONFIG_SYS_NS16550_MEM32:
+  LeafHill has PCI UART2 MMIO32 serial port. Set CONFIG_SYS_NS16550_MEM32.
+  > vi include/configs/slimbootloader.h
+    +#define CONFIG_SYS_NS16550_MEM32
+     #ifdef CONFIG_SYS_NS16550_MEM3
+  > make disclean
+  > make slimbootloader_defconfig
+  > make all
+
+Copy the built u-boot-dtb.bin to Slim Bootloader source tree:
+  > mkdir -p <slimbootloader_home>/PayloadPkg/PayloadBins/
+  > cp <u-boot_home>/u-boot-dtb.bin <slimbootloader_home>/PayloadPkg/PayloadBins/u-boot-dtb.bin
+
+Update default payload to U-Boot (PayloadId is 4 Bytes):
+  Any 4 Bytes PayloadId is okay, but use 'U-BT' as an example.
+  > vi Platform/ApollolakeBoardPkg/CfgData/CfgData_Int_LeafHill.dlt
+    -GEN_CFG_DATA.PayloadId                     | 'AUTO'
+    +GEN_CFG_DATA.PayloadId                     | 'U-BT'
+
+Update payload text base in APL BoardConfig.py:
+  PAYLOAD_EXE_BASE must be the same as u-boot text base in board/intel/slimbootloader/Kconfig.
+  PAYLOAD_LOAD_HIGH must be 0.
+  > vi Platform/ApollolakeBoardPkg/BoardConfig.py
+    +               self.PAYLOAD_LOAD_HIGH    = 0
+    +               self.PAYLOAD_EXE_BASE     = 0x00100000
+
+Compile for APL target:
+  Make sure u-boot-dtb.bin and U-BT PayloadId in build command.
+  > python BuildLoader.py build apl -p "OsLoader.efi:LLDR:Lz4;u-boot-dtb.bin:U-BT:Lzma"
+  The output is Outputs/apl/Stitch_Components.zip
+
+Stitch IFWI:
+  Refer to https://slimbootloader.github.io/supported-hardware/apollo-lake-crb.html#stitching.
+  > python Platform/ApollolakeBoardPkg/Script/StitchLoader.py -i <Existing IFWI> -s Outputs/apl/Stitch_Components.zip -o <Output IFWI>
+
+Flash IFWI:
+  Use DediProg to flash IFWI.
+  Now, you should reach at U-Boot serial console.
+
+
+
+To use ELF U-Boot
+=================
+
+Compile U-Boot with CONFIG_OF_EMBED:
+  > vi configs/slimbootloader_defconfig
+    +CONFIG_OF_EMBED=y
+  > make distclean
+  > make slimbootloader_defconfig
+  > make all
+  > strip u-boot (To reduce image size by removing symbol)
+
+Do the same steps as above:
+  Copy u-boot to PayloadBins directory
+  Use u-boot in build command instead of u-boot-dtb.bin
+  No need to set PAYLOAD_LOAD_HIGH and PAYLOAD_EXE_BASE
diff --git a/board/intel/slimbootloader/slimbootloader.c b/board/intel/slimbootloader/slimbootloader.c
new file mode 100644
index 0000000000..d88aa622a0
--- /dev/null
+++ b/board/intel/slimbootloader/slimbootloader.c
@@ -0,0 +1,17 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Intel Corporation <www.intel.com>
+ */
+
+#include <common.h>
+
+int board_early_init_r(void)
+{
+       /*
+        * Make sure PCI bus is enumerated so that peripherals on the PCI bus
+        * can be discovered by their drivers
+        */
+       pci_init();
+
+       return 0;
+}
diff --git a/board/intel/slimbootloader/start.S b/board/intel/slimbootloader/start.S
new file mode 100644
index 0000000000..5c3f3df09e
--- /dev/null
+++ b/board/intel/slimbootloader/start.S
@@ -0,0 +1,9 @@ 
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2019 Intel Corporation <www.intel.com>
+ */
+
+/* board early initialization */
+.globl early_board_init
+early_board_init:
+       jmp     early_board_init_ret
diff --git a/configs/slimbootloader_defconfig b/configs/slimbootloader_defconfig
new file mode 100644
index 0000000000..a2acdb22da
--- /dev/null
+++ b/configs/slimbootloader_defconfig
@@ -0,0 +1,21 @@ 
+CONFIG_X86=y
+CONFIG_VENDOR_INTEL=y
+CONFIG_TARGET_SLIMBOOTLOADER=y
+CONFIG_REGMAP=y
+CONFIG_SYSCON=y
+CONFIG_SYS_CONSOLE_INFO_QUIET=y
+CONFIG_BOARD_EARLY_INIT_R=y
+CONFIG_LAST_STAGE_INIT=y
+CONFIG_HUSH_PARSER=y
+CONFIG_CMD_MMC=y
+CONFIG_CMD_EXT2=y
+CONFIG_CMD_FAT=y
+CONFIG_CMD_USB=y
+CONFIG_DOS_PARTITION=y
+CONFIG_EFI_PARTITION=y
+CONFIG_OF_CONTROL=y
+CONFIG_BOOTSTAGE=y
+CONFIG_BOOTSTAGE_REPORT=y
+CONFIG_BOOTDELAY=10
+CONFIG_CONSOLE_SCROLL_LINES=5
+# CONFIG_PCI_PNP is not set
diff --git a/include/configs/slimbootloader.h b/include/configs/slimbootloader.h
new file mode 100644
index 0000000000..f79e456414
--- /dev/null
+++ b/include/configs/slimbootloader.h
@@ -0,0 +1,59 @@ 
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2019 Intel Corporation <www.intel.com>
+ */
+
+#ifndef __SLIMBOOTLOADER_CONFIG_H__
+#define __SLIMBOOTLOADER_CONFIG_H__
+
+#include <configs/x86-common.h>
+
+#undef CONFIG_NFSBOOTCOMMAND
+#undef CONFIG_RAMBOOTCOMMAND
+#undef CONFIG_EXTRA_ENV_SETTINGS
+#undef CONFIG_BOOTCOMMAND
+
+/*
+ * By default, CONFIG_SYS_NS16550_PORT_MAPPED is enabled for port io serial.
+ * To use mmio base serial, enable CONFIG_SYS_NS16550_MEM32 and disable
+ * CONFIG_SYS_NS16550_PORT_MAPPED until ns16550 driver supports serial port
+ * configuration in run-time.
+ *
+ * #define CONFIG_SYS_NS16550_MEM32
+ * #undef CONFIG_SYS_NS16550_PORT_MAPPED
+ */
+#ifdef CONFIG_SYS_NS16550_MEM32
+#undef CONFIG_SYS_NS16550_PORT_MAPPED
+#endif
+
+#define CONFIG_STD_DEVICES_SETTINGS            \
+       "stdin=serial,i8042-kbd,usbkbd\0"       \
+       "stdout=serial\0"                       \
+       "stderr=serial\0"
+
+#define CONFIG_EXTRA_ENV_SETTINGS              \
+       CONFIG_STD_DEVICES_SETTINGS             \
+       "netdev=eth0\0"                         \
+       "consoledev=ttyS0\0"                    \
+       "ramdiskaddr=0x4000000\0"               \
+       "ramdiskfile=initrd\0"                  \
+       "bootdev=usb\0"                         \
+       "bootdevnum=0\0"                        \
+       "bootdevpart=0\0"                       \
+       "bootfsload=fatload\0"                  \
+       "bootusb=setenv bootdev usb; boot\0"    \
+       "bootscsi=setenv bootdev scsi; boot\0"  \
+       "bootmmc=setenv bootdev mmc; boot\0"    \
+       "bootargs=console=ttyS0,115200 console=tty0\0"
+
+#define CONFIG_BOOTCOMMAND                                             \
+       "if test ${bootdev} = \"usb\"; then ${bootdev} start; fi; "     \
+       "if test ${bootdev} = \"scsi\"; then ${bootdev} scan; fi; "     \
+       "${bootdev} info; "                                             \
+       "${bootfsload} ${bootdev} ${bootdevnum}:${bootdevpart} "        \
+       "${loadaddr} ${bootfile}; "                                     \
+       "${bootfsload} ${bootdev} ${bootdevnum}:${bootdevpart} "        \
+       "${ramdiskaddr} ${ramdiskfile}; "                               \
+       "zboot ${loadaddr} 0 ${ramdiskaddr} ${filesize}"
+
+#endif /* __SLIMBOOTLOADER_CONFIG_H__ */