[U-Boot] [RFC PATCH 3/3] spl: add support to booting with ATF
Kever Yang
kever.yang at rock-chips.com
Fri Jan 6 08:09:03 CET 2017
Hi Michal,
Thanks for your comments.
On 01/02/2017 11:05 PM, Michal Simek wrote:
> On 29.12.2016 11:25, Kever Yang wrote:
>> ATF(ARM Trust Firmware) is used by ARM arch64 SoCs, find more infomation
>> about ATF at:
>>
>> SPL is consider as BL2 in ATF, it needs to load other part of ATF binary
> SPL replaces BL2 in ATF
OK, will follow your comment in next patch.
>
>> like BL31, BL32, SCP-BL30, and BL33(U-Boot). And needs to prepare the
>> parameter for BL31 which including entry and image information for all
>> other images. Then the SPL handle PC to BL31 with the parameter, the
>> BL31 will do the rest of work and at last get into U-Boot(BL33).
> But the main question for this is how do load that images and in which
> format. It means I would think that you will introduce fit format which
> contain BL33(U-Boot), BL32(secure os) and BL31(ATF) and SPL will be able
> to load all of them.
Yes, I use FIT format to contain BL33 and BL32 and SPL load all of them.
>
> If you look at zynqmp I did a small trick where I consider case that
> with ATF it is OS boot where kernel is ATF and dtb is full u-boot to get
> it boot.
This is a good idea, and it look fine for support ATF in SPL in local
source code,
but it will be better if we have an official support for ATF, right?
>
> If you adopt fit format then I expect SPL will be able to remember which
> part is where and based on that fill structure for ATF.
> Then SPL_ATF_TEXT_BASE address is not needed because it will be read
> from fit format.
Yes, you are right, SPL_ATF_TEXT_BASE is not a must, we gen get it from fit.
>
>
>
>> Signed-off-by: Kever Yang <kever.yang at rock-chips.com>
>> ---
>>
>> common/spl/Kconfig | 14 +++
>> common/spl/Makefile | 1 +
>> common/spl/spl.c | 4 +
>> common/spl/spl_atf.c | 91 ++++++++++++++++
>> include/atf_common.h | 295 +++++++++++++++++++++++++++++++++++++++++++++++++++
>> include/spl.h | 1 +
>> 6 files changed, 406 insertions(+)
>> create mode 100644 common/spl/spl_atf.c
>> create mode 100644 include/atf_common.h
>>
>> diff --git a/common/spl/Kconfig b/common/spl/Kconfig
>> index cba51f5..1bb4360 100644
>> --- a/common/spl/Kconfig
>> +++ b/common/spl/Kconfig
>> @@ -577,6 +577,20 @@ config SPL_YMODEM_SUPPORT
>> means of transmitting U-Boot over a serial line for using in SPL,
>> with a checksum to ensure correctness.
>>
>> +config SPL_ATF_SUPPORT
>> + bool "Support ARM trust firmware"
>> + depends on SPL
>> + help
>> + ATF(ARM Trust Firmware) is component for ARM arch64 which need to
>> + load by SPL(consider as BL2 in ATF).
>> + More detail at: https://github.com/ARM-software/arm-trusted-firmware
>> +
>> +config SPL_ATF_TEXT_BASE
>> + depends on SPL_ATF_SUPPORT
>> + hex "ATF TEXT BASE addr"
>> + help
>> + This is the base address in memory for ATF text and entry point.
>> +
>> config TPL_ENV_SUPPORT
>> bool "Support an environment"
>> depends on TPL
>> diff --git a/common/spl/Makefile b/common/spl/Makefile
>> index ed02635..620ae90 100644
>> --- a/common/spl/Makefile
>> +++ b/common/spl/Makefile
>> @@ -20,6 +20,7 @@ endif
>> obj-$(CONFIG_SPL_UBI) += spl_ubi.o
>> obj-$(CONFIG_SPL_NET_SUPPORT) += spl_net.o
>> obj-$(CONFIG_SPL_MMC_SUPPORT) += spl_mmc.o
>> +obj-$(CONFIG_SPL_ATF_SUPPORT) += spl_atf.o
>> obj-$(CONFIG_SPL_USB_SUPPORT) += spl_usb.o
>> obj-$(CONFIG_SPL_FAT_SUPPORT) += spl_fat.o
>> obj-$(CONFIG_SPL_EXT_SUPPORT) += spl_ext.o
>> diff --git a/common/spl/spl.c b/common/spl/spl.c
>> index 1729034..7daf7bd 100644
>> --- a/common/spl/spl.c
>> +++ b/common/spl/spl.c
>> @@ -390,6 +390,10 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
>> gd->malloc_ptr / 1024);
>> #endif
>>
>> +#ifdef CONFIG_SPL_ATF_SUPPORT
>> + bl31_entry();
>> +#endif
>> +
>> debug("loaded - jumping to U-Boot...");
>> spl_board_prepare_for_boot();
>> jump_to_image_no_args(&spl_image);
>> diff --git a/common/spl/spl_atf.c b/common/spl/spl_atf.c
>> new file mode 100644
>> index 0000000..cf23b7a
>> --- /dev/null
>> +++ b/common/spl/spl_atf.c
>> @@ -0,0 +1,91 @@
>> +/*
>> + * Copyright (C) 2016 Rockchip Electronic Co.,Ltd
>> + * Written by Kever Yang <kever.yang at rock-chips.com>
>> + *
>> + * origin from arm-trust-firmware
>> + * plat/arm/common/arm_bl2_setup.c
>> + * SPDX-License-Identifier: GPL-2.0+
> this is not based on gpl file that's why license should be different.
Sorry, I do not get what your mean, I'm not good at license policy,
ARM ATF use its own license, what should I do for license when I use code
from ATF?
>
>
>> + */
>> +
>> +#include <common.h>
>> +#include <errno.h>
>> +#include <spl.h>
>> +#include <atf_common.h>
>> +
>> +static struct bl2_to_bl31_params_mem_t bl31_params_mem;
>> +static struct bl31_params_t *bl2_to_bl31_params;
>> +
>> +/*******************************************************************************
>> + * This function assigns a pointer to the memory that the platform has kept
>> + * aside to pass platform specific and trusted firmware related information
>> + * to BL31. This memory is allocated by allocating memory to
>> + * bl2_to_bl31_params_mem_t structure which is a superset of all the
>> + * structure whose information is passed to BL31
>> + * NOTE: This function should be called only once and should be done
>> + * before generating params to BL31
>> + ******************************************************************************/
>> +struct bl31_params_t *bl2_plat_get_bl31_params(void)
>> +{
>> + struct entry_point_info_t *bl33_ep_info;
>> +
>> + /*
>> + * Initialise the memory for all the arguments that needs to
>> + * be passed to BL31
>> + */
>> + memset(&bl31_params_mem, 0, sizeof(struct bl2_to_bl31_params_mem_t));
>> +
>> + /* Assign memory for TF related information */
>> + bl2_to_bl31_params = &bl31_params_mem.bl31_params;
>> + SET_PARAM_HEAD(bl2_to_bl31_params, PARAM_BL31, VERSION_1, 0);
>> +
>> + /* Fill BL31 related information */
>> + SET_PARAM_HEAD(bl2_to_bl31_params->bl31_image_info, PARAM_IMAGE_BINARY,
>> + VERSION_1, 0);
>> +
>> + /* Fill BL32 related information if it exists */
>> +#ifdef BL32_BASE
>> + bl2_to_bl31_params->bl32_ep_info = &bl31_params_mem.bl32_ep_info;
>> + SET_PARAM_HEAD(bl2_to_bl31_params->bl32_ep_info, PARAM_EP,
>> + VERSION_1, 0);
>> + bl2_to_bl31_params->bl32_image_info = &bl31_params_mem.bl32_image_info;
>> + SET_PARAM_HEAD(bl2_to_bl31_params->bl32_image_info, PARAM_IMAGE_BINARY,
>> + VERSION_1, 0);
>> +#endif /* BL32_BASE */
> Is this used?
Not use for me now, but it may useful later, because we need to fill
info about bl32 if there is.
>
>> +
>> + /* Fill BL33 related information */
>> + bl2_to_bl31_params->bl33_ep_info = &bl31_params_mem.bl33_ep_info;
>> + bl33_ep_info = &bl31_params_mem.bl33_ep_info;
>> + SET_PARAM_HEAD(bl33_ep_info, PARAM_EP, VERSION_1, EP_NON_SECURE);
>> +
>> + /* BL33 expects to receive the primary CPU MPID (through x0) */
>> + bl33_ep_info->args.arg0 = 0xffff & read_mpidr();
>> + bl33_ep_info->pc = CONFIG_SYS_TEXT_BASE;
>> + bl33_ep_info->spsr = SPSR_64(MODE_EL2, MODE_SP_ELX,
>> + DISABLE_ALL_EXECPTIONS);
>> +
>> + bl2_to_bl31_params->bl33_image_info = &bl31_params_mem.bl33_image_info;
>> + SET_PARAM_HEAD(bl2_to_bl31_params->bl33_image_info, PARAM_IMAGE_BINARY,
>> + VERSION_1, 0);
>> +
>> +
> double lines.
Will fix in next patch, confuse why checkpatch did not find this.
>
>> + return bl2_to_bl31_params;
>> +}
>> +
>> +void raw_write_daif(uint32_t daif)
>> +{
>> + __asm__ __volatile__("msr DAIF, %0\n\t" : : "r" (daif) : "memory");
>> +}
>> +
>> +void bl31_entry(void)
>> +{
>> + struct bl31_params_t *bl31_params;
>> + void (*entry)(struct bl31_params_t *params, void *plat_params) = NULL;
>> +
>> + bl31_params = bl2_plat_get_bl31_params();
>> + entry = (void *)CONFIG_SPL_ATF_TEXT_BASE;
>> +
>> + raw_write_daif(SPSR_EXCEPTION_MASK);
>> + dcache_disable();
>> +
>> + entry(bl31_params, NULL);
>> +}
>> diff --git a/include/atf_common.h b/include/atf_common.h
>> new file mode 100644
>> index 0000000..8351302
>> --- /dev/null
>> +++ b/include/atf_common.h
>> @@ -0,0 +1,295 @@
>> +/*
>> + * Copyright (c) 2013-2016, ARM Limited and Contributors. All rights reserved.
>> + *
>> + * Redistribution and use in source and binary forms, with or without
>> + * modification, are permitted provided that the following conditions are met:
>> + *
>> + * Redistributions of source code must retain the above copyright notice, this
>> + * list of conditions and the following disclaimer.
>> + *
>> + * Redistributions in binary form must reproduce the above copyright notice,
>> + * this list of conditions and the following disclaimer in the documentation
>> + * and/or other materials provided with the distribution.
>> + *
>> + * Neither the name of ARM nor the names of its contributors may be used
>> + * to endorse or promote products derived from this software without specific
>> + * prior written permission.
>> + *
>> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
>> + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
>> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
>> + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
>> + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
>> + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
>> + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
>> + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
>> + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
>> + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
>> + * POSSIBILITY OF SUCH DAMAGE.
> This should be probably in SPDX format.
Like previous reply, I don't know how to deal with this license, do you
mean I can use
SPDX license without any information about the origin License?
Thanks,
- Kever
>
>
>> + */
>> +
>> +#ifndef __BL_COMMON_H__
>> +#define __BL_COMMON_H__
>> +
>> +#define SECURE 0x0
>> +#define NON_SECURE 0x1
>> +#define sec_state_is_valid(s) (((s) == SECURE) || ((s) == NON_SECURE))
>> +
>> +#define UP 1
>> +#define DOWN 0
>> +
>> +/*******************************************************************************
>> + * Constants to identify the location of a memory region in a given memory
>> + * layout.
>> +******************************************************************************/
>> +#define TOP 0x1
>> +#define BOTTOM !TOP
>> +
>> +/*******************************************************************************
>> + * Constants that allow assembler code to access members of and the
>> + * 'entry_point_info' structure at their correct offsets.
>> + ******************************************************************************/
>> +#define ENTRY_POINT_INFO_PC_OFFSET 0x08
>> +#define ENTRY_POINT_INFO_ARGS_OFFSET 0x18
>> +
>> +/* The following are used to set/get image attributes. */
>> +#define PARAM_EP_SECURITY_MASK (0x1)
>> +
>> +#define GET_SECURITY_STATE(x) (x & PARAM_EP_SECURITY_MASK)
>> +#define SET_SECURITY_STATE(x, security) \
>> + ((x) = ((x) & ~PARAM_EP_SECURITY_MASK) | (security))
>> +
>> +
>> +/*
>> + * The following are used for image state attributes.
>> + * Image can only be in one of the following state.
>> + */
>> +#define IMAGE_STATE_RESET 0
>> +#define IMAGE_STATE_COPIED 1
>> +#define IMAGE_STATE_COPYING 2
>> +#define IMAGE_STATE_AUTHENTICATED 3
>> +#define IMAGE_STATE_EXECUTED 4
>> +#define IMAGE_STATE_INTERRUPTED 5
>> +
>> +#define EP_SECURE 0x0
>> +#define EP_NON_SECURE 0x1
>> +
>> +#define EP_EE_MASK 0x2
>> +#define EP_EE_LITTLE 0x0
>> +#define EP_EE_BIG 0x2
>> +#define EP_GET_EE(x) (x & EP_EE_MASK)
>> +#define EP_SET_EE(x, ee) ((x) = ((x) & ~EP_EE_MASK) | (ee))
>> +
>> +#define EP_ST_MASK 0x4
>> +#define EP_ST_DISABLE 0x0
>> +#define EP_ST_ENABLE 0x4
>> +#define EP_GET_ST(x) (x & EP_ST_MASK)
>> +#define EP_SET_ST(x, ee) ((x) = ((x) & ~EP_ST_MASK) | (ee))
>> +
>> +#define EP_EXE_MASK 0x8
>> +#define NON_EXECUTABLE 0x0
>> +#define EXECUTABLE 0x8
>> +#define EP_GET_EXE(x) (x & EP_EXE_MASK)
>> +#define EP_SET_EXE(x, ee) ((x) = ((x) & ~EP_EXE_MASK) | (ee))
>> +
>> +#define PARAM_EP 0x01
>> +#define PARAM_IMAGE_BINARY 0x02
>> +#define PARAM_BL31 0x03
>> +
>> +#define VERSION_1 0x01
>> +
>> +#define INVALID_IMAGE_ID (0xFFFFFFFF)
>> +
>> +#define SET_PARAM_HEAD(_p, _type, _ver, _attr) do { \
>> + (_p)->h.type = (uint8_t)(_type); \
>> + (_p)->h.version = (uint8_t)(_ver); \
>> + (_p)->h.size = (uint16_t)sizeof(*_p); \
>> + (_p)->h.attr = (uint32_t)(_attr) ; \
>> + } while (0)
>> +
>> +/* Following is used for populating structure members statically. */
>> +#define SET_STATIC_PARAM_HEAD(_p, _type, _ver, _p_type, _attr) \
>> + ._p.h.type = (uint8_t)(_type), \
>> + ._p.h.version = (uint8_t)(_ver), \
>> + ._p.h.size = (uint16_t)sizeof(_p_type), \
>> + ._p.h.attr = (uint32_t)(_attr)
>> +
>> +#define MODE_RW_SHIFT 0x4
>> +#define MODE_RW_MASK 0x1
>> +#define MODE_RW_64 0x0
>> +#define MODE_RW_32 0x1
>> +
>> +#define MODE_EL_SHIFT 0x2
>> +#define MODE_EL_MASK 0x3
>> +#define MODE_EL3 0x3
>> +#define MODE_EL2 0x2
>> +#define MODE_EL1 0x1
>> +#define MODE_EL0 0x0
>> +
>> +#define MODE_SP_SHIFT 0x0
>> +#define MODE_SP_MASK 0x1
>> +#define MODE_SP_EL0 0x0
>> +#define MODE_SP_ELX 0x1
>> +
>> +#define SPSR_DAIF_SHIFT 6
>> +#define SPSR_DAIF_MASK 0x0f
>> +
>> +#define DAIF_FIQ_BIT (1<<0)
>> +#define DAIF_IRQ_BIT (1<<0)
>> +#define DAIF_ABT_BIT (1<<0)
>> +#define DAIF_DBG_BIT (1<<0)
>> +#define DISABLE_ALL_EXECPTIONS \
>> + (DAIF_FIQ_BIT | DAIF_IRQ_BIT | DAIF_ABT_BIT | DAIF_DBG_BIT)
>> +
>> +#define SPSR_64(el, sp, daif) \
>> + (MODE_RW_64 << MODE_RW_SHIFT | \
>> + ((el) & MODE_EL_MASK) << MODE_EL_SHIFT | \
>> + ((sp) & MODE_SP_MASK) << MODE_SP_SHIFT | \
>> + ((daif) & SPSR_DAIF_MASK) << SPSR_DAIF_SHIFT)
>> +
>> +/*******************************************************************************
>> + * Constants to indicate type of exception to the common exception handler.
>> + ******************************************************************************/
>> +#define SYNC_EXCEPTION_SP_EL0 0x0
>> +#define IRQ_SP_EL0 0x1
>> +#define FIQ_SP_EL0 0x2
>> +#define SERROR_SP_EL0 0x3
>> +#define SYNC_EXCEPTION_SP_ELX 0x4
>> +#define IRQ_SP_ELX 0x5
>> +#define FIQ_SP_ELX 0x6
>> +#define SERROR_SP_ELX 0x7
>> +#define SYNC_EXCEPTION_AARCH64 0x8
>> +#define IRQ_AARCH64 0x9
>> +#define FIQ_AARCH64 0xa
>> +#define SERROR_AARCH64 0xb
>> +#define SYNC_EXCEPTION_AARCH32 0xc
>> +#define IRQ_AARCH32 0xd
>> +#define FIQ_AARCH32 0xe
>> +#define SERROR_AARCH32 0xf
>> +
>> +#define SPSR_USE_L 0
>> +#define SPSR_USE_H 1
>> +#define SPSR_L_H_MASK 1
>> +#define SPSR_M_SHIFT 4
>> +#define SPSR_ERET_32 (1 << SPSR_M_SHIFT)
>> +#define SPSR_ERET_64 (0 << SPSR_M_SHIFT)
>> +#define SPSR_FIQ (1 << 6)
>> +#define SPSR_IRQ (1 << 7)
>> +#define SPSR_SERROR (1 << 8)
>> +#define SPSR_DEBUG (1 << 9)
>> +#define SPSR_EXCEPTION_MASK (SPSR_FIQ | SPSR_IRQ | SPSR_SERROR | SPSR_DEBUG)
>> +
>> +#ifndef __ASSEMBLY__
>> +
>> +/*******************************************************************************
>> + * Structure used for telling the next BL how much of a particular type of
>> + * memory is available for its use and how much is already used.
>> + ******************************************************************************/
>> +struct aapcs64_params_t {
>> + unsigned long arg0;
>> + unsigned long arg1;
>> + unsigned long arg2;
>> + unsigned long arg3;
>> + unsigned long arg4;
>> + unsigned long arg5;
>> + unsigned long arg6;
>> + unsigned long arg7;
>> +};
>> +
>> +/***************************************************************************
>> + * This structure provides version information and the size of the
>> + * structure, attributes for the structure it represents
>> + ***************************************************************************/
>> +struct param_header_t {
>> + uint8_t type; /* type of the structure */
>> + uint8_t version; /* version of this structure */
>> + uint16_t size; /* size of this structure in bytes */
>> + uint32_t attr; /* attributes: unused bits SBZ */
>> +};
>> +
>> +/*****************************************************************************
>> + * This structure represents the superset of information needed while
>> + * switching exception levels. The only two mechanisms to do so are
>> + * ERET & SMC. Security state is indicated using bit zero of header
>> + * attribute
>> + * NOTE: BL1 expects entrypoint followed by spsr at an offset from the start
>> + * of this structure defined by the macro `ENTRY_POINT_INFO_PC_OFFSET` while
>> + * processing SMC to jump to BL31.
>> + *****************************************************************************/
>> +struct entry_point_info_t {
>> + struct param_header_t h;
>> + uintptr_t pc;
>> + uint32_t spsr;
>> + struct aapcs64_params_t args;
>> +};
>> +
>> +/*****************************************************************************
>> + * Image info binary provides information from the image loader that
>> + * can be used by the firmware to manage available trusted RAM.
>> + * More advanced firmware image formats can provide additional
>> + * information that enables optimization or greater flexibility in the
>> + * common firmware code
>> + *****************************************************************************/
>> +struct atf_image_info_t {
>> + struct param_header_t h;
>> + uintptr_t image_base; /* physical address of base of image */
>> + uint32_t image_size; /* bytes read from image file */
>> +};
>> +
>> +/*****************************************************************************
>> + * The image descriptor struct definition.
>> + *****************************************************************************/
>> +struct image_desc_t {
>> + /* Contains unique image id for the image. */
>> + unsigned int image_id;
>> + /*
>> + * This member contains Image state information.
>> + * Refer IMAGE_STATE_XXX defined above.
>> + */
>> + unsigned int state;
>> + uint32_t copied_size; /* image size copied in blocks */
>> + struct atf_image_info_t atf_image_info;
>> + struct entry_point_info_t ep_info;
>> +};
>> +
>> +/*******************************************************************************
>> + * This structure represents the superset of information that can be passed to
>> + * BL31 e.g. while passing control to it from BL2. The BL32 parameters will be
>> + * populated only if BL2 detects its presence. A pointer to a structure of this
>> + * type should be passed in X0 to BL31's cold boot entrypoint.
>> + *
>> + * Use of this structure and the X0 parameter is not mandatory: the BL31
>> + * platform code can use other mechanisms to provide the necessary information
>> + * about BL32 and BL33 to the common and SPD code.
>> + *
>> + * BL31 image information is mandatory if this structure is used. If either of
>> + * the optional BL32 and BL33 image information is not provided, this is
>> + * indicated by the respective image_info pointers being zero.
>> + ******************************************************************************/
>> +struct bl31_params_t {
>> + struct param_header_t h;
>> + struct atf_image_info_t *bl31_image_info;
>> + struct entry_point_info_t *bl32_ep_info;
>> + struct atf_image_info_t *bl32_image_info;
>> + struct entry_point_info_t *bl33_ep_info;
>> + struct atf_image_info_t *bl33_image_info;
>> +};
>> +
>> +/*******************************************************************************
>> + * This structure represents the superset of information that is passed to
>> + * BL31, e.g. while passing control to it from BL2, bl31_params
>> + * and other platform specific params
>> + ******************************************************************************/
>> +struct bl2_to_bl31_params_mem_t {
>> + struct bl31_params_t bl31_params;
>> + struct atf_image_info_t bl31_image_info;
>> + struct atf_image_info_t bl32_image_info;
>> + struct atf_image_info_t bl33_image_info;
>> + struct entry_point_info_t bl33_ep_info;
>> + struct entry_point_info_t bl32_ep_info;
>> + struct entry_point_info_t bl31_ep_info;
>> +};
>> +
>> +#endif /*__ASSEMBLY__*/
>> +
>> +#endif /* __BL_COMMON_H__ */
>> diff --git a/include/spl.h b/include/spl.h
>> index 918c464..ab5eaca 100644
>> --- a/include/spl.h
>> +++ b/include/spl.h
>> @@ -251,4 +251,5 @@ int spl_dfu_cmd(int usbctrl, char *dfu_alt_info, char *interface, char *devstr);
>> int spl_mmc_load_image(struct spl_image_info *spl_image,
>> struct spl_boot_device *bootdev);
>>
>> +void bl31_entry(void);
>> #endif
>>
> Thanks,
> Michal
>
>
>
>
More information about the U-Boot
mailing list