binary, change the following five bytes values from orginally E8 42 FF FF FF
to B8 00 80 0B 00.
+As for the video ROM, you need manually extract it from the Intel provided
+BIOS for Crown Bay here [6], using the AMI MMTool [7]. Check PCI option ROM
+ID 8086:4108, extract and save it as vga.bin in the board directory.
+
Now you can build U-Boot and obtain u-boot.rom
$ make crownbay_defconfig
$ make minnowmax_defconfig
$ make all
+Checksums are as follows (but note that newer versions will invalidate this):
+
+$ md5sum -b board/intel/minnowmax/*.bin
+ffda9a3b94df5b74323afb328d51e6b4 board/intel/minnowmax/descriptor.bin
+69f65b9a580246291d20d08cbef9d7c5 board/intel/minnowmax/fsp.bin
+894a97d371544ec21de9c3e8e1716c4b board/intel/minnowmax/me.bin
+a2588537da387da592a27219d56e9962 board/intel/minnowmax/vga.bin
+
+The ROM image is broken up into these parts:
+
+Offset Description Controlling config
+------------------------------------------------------------
+000000 descriptor.bin Hard-coded to 0 in ifdtool
+001000 me.bin Set by the descriptor
+500000 <spare>
+700000 u-boot-dtb.bin CONFIG_SYS_TEXT_BASE
+790000 vga.bin CONFIG_X86_OPTION_ROM_ADDR
+7c0000 fsp.bin CONFIG_FSP_ADDR
+7f8000 <spare> (depends on size of fsp.bin)
+7fe000 Environment CONFIG_ENV_OFFSET
+7ff800 U-Boot 16-bit boot CONFIG_SYS_X86_START16
+
+Overall ROM image size is controlled by CONFIG_ROM_SIZE.
+
+
Intel Galileo instructions:
Only one binary blob is needed for Remote Management Unit (RMU) within Intel
show QEMU's VGA console window. Note this will disable QEMU's serial output.
If you want to check both consoles, use '-serial stdio'.
+Multicore is also supported by QEMU via '-smp n' where n is the number of cores
+to instantiate. Currently the default U-Boot built for QEMU supports 2 cores.
+In order to support more cores, you need add additional cpu nodes in the device
+tree and change CONFIG_MAX_CPUS accordingly.
+
CPU Microcode
-------------
-Modern CPUs usually require a special bit stream called microcode [6] to be
+Modern CPUs usually require a special bit stream called microcode [8] to be
loaded on the processor after power up in order to function properly. U-Boot
has already integrated these as hex dumps in the source tree.
have an SMP kernel to discover all of the available processors, U-Boot needs to
prepare configuration tables which contain the multi-CPUs information before
loading the OS kernel. Currently U-Boot supports generating two types of tables
-for SMP, called Simple Firmware Interface (SFI) [7] and Multi-Processor (MP) [8]
-tables. The writing of these two tables are controlled by two Kconfig options
-GENERATE_SFI_TABLE and GENERATE_MP_TABLE.
+for SMP, called Simple Firmware Interface (SFI) [9] and Multi-Processor (MP)
+[10] tables. The writing of these two tables are controlled by two Kconfig
+options GENERATE_SFI_TABLE and GENERATE_MP_TABLE.
Driver Model
------------
mode to use. U-Boot sets up some reasonable values but you can
adjust then with this command.
+Booting Ubuntu
+--------------
+As an example of how to set up your boot flow with U-Boot, here are
+instructions for starting Ubuntu from U-Boot. These instructions have been
+tested on Minnowboard MAX with a SATA driver but are equally applicable on
+other platforms and other media. There are really only four steps and its a
+very simple script, but a more detailed explanation is provided here for
+completeness.
+
+Note: It is possible to set up U-Boot to boot automatically using syslinux.
+It could also use the grub.cfg file (/efi/ubuntu/grub.cfg) to obtain the
+GUID. If you figure these out, please post patches to this README.
+
+Firstly, you will need Ubunutu installed on an available disk. It should be
+possible to make U-Boot start a USB start-up disk but for now let's assume
+that you used another boot loader to install Ubuntu.
+
+Use the U-Boot command line to find the UUID of the partition you want to
+boot. For example our disk is SCSI device 0:
+
+=> part list scsi 0
+
+Partition Map for SCSI device 0 -- Partition Type: EFI
+
+ Part Start LBA End LBA Name
+ Attributes
+ Type GUID
+ Partition GUID
+ 1 0x00000800 0x001007ff ""
+ attrs: 0x0000000000000000
+ type: c12a7328-f81f-11d2-ba4b-00a0c93ec93b
+ guid: 9d02e8e4-4d59-408f-a9b0-fd497bc9291c
+ 2 0x00100800 0x037d8fff ""
+ attrs: 0x0000000000000000
+ type: 0fc63daf-8483-4772-8e79-3d69d8477de4
+ guid: 965c59ee-1822-4326-90d2-b02446050059
+ 3 0x037d9000 0x03ba27ff ""
+ attrs: 0x0000000000000000
+ type: 0657fd6d-a4ab-43c4-84e5-0933c84b4f4f
+ guid: 2c4282bd-1e82-4bcf-a5ff-51dedbf39f17
+ =>
+
+This shows that your SCSI disk has three partitions. The really long hex
+strings are called Globally Unique Identifiers (GUIDs). You can look up the
+'type' ones here [11]. On this disk the first partition is for EFI and is in
+VFAT format (DOS/Windows):
+
+ => fatls scsi 0:1
+ efi/
+
+ 0 file(s), 1 dir(s)
+
+
+Partition 2 is 'Linux filesystem data' so that will be our root disk. It is
+in ext2 format:
+
+ => ext2ls scsi 0:2
+ <DIR> 4096 .
+ <DIR> 4096 ..
+ <DIR> 16384 lost+found
+ <DIR> 4096 boot
+ <DIR> 12288 etc
+ <DIR> 4096 media
+ <DIR> 4096 bin
+ <DIR> 4096 dev
+ <DIR> 4096 home
+ <DIR> 4096 lib
+ <DIR> 4096 lib64
+ <DIR> 4096 mnt
+ <DIR> 4096 opt
+ <DIR> 4096 proc
+ <DIR> 4096 root
+ <DIR> 4096 run
+ <DIR> 12288 sbin
+ <DIR> 4096 srv
+ <DIR> 4096 sys
+ <DIR> 4096 tmp
+ <DIR> 4096 usr
+ <DIR> 4096 var
+ <SYM> 33 initrd.img
+ <SYM> 30 vmlinuz
+ <DIR> 4096 cdrom
+ <SYM> 33 initrd.img.old
+ =>
+
+and if you look in the /boot directory you will see the kernel:
+
+ => ext2ls scsi 0:2 /boot
+ <DIR> 4096 .
+ <DIR> 4096 ..
+ <DIR> 4096 efi
+ <DIR> 4096 grub
+ 3381262 System.map-3.13.0-32-generic
+ 1162712 abi-3.13.0-32-generic
+ 165611 config-3.13.0-32-generic
+ 176500 memtest86+.bin
+ 178176 memtest86+.elf
+ 178680 memtest86+_multiboot.bin
+ 5798112 vmlinuz-3.13.0-32-generic
+ 165762 config-3.13.0-58-generic
+ 1165129 abi-3.13.0-58-generic
+ 5823136 vmlinuz-3.13.0-58-generic
+ 19215259 initrd.img-3.13.0-58-generic
+ 3391763 System.map-3.13.0-58-generic
+ 5825048 vmlinuz-3.13.0-58-generic.efi.signed
+ 28304443 initrd.img-3.13.0-32-generic
+ =>
+
+The 'vmlinuz' files contain a packaged Linux kernel. The format is a kind of
+self-extracting compressed file mixed with some 'setup' configuration data.
+Despite its size (uncompressed it is >10MB) this only includes a basic set of
+device drivers, enough to boot on most hardware types.
+
+The 'initrd' files contain a RAM disk. This is something that can be loaded
+into RAM and will appear to Linux like a disk. Ubuntu uses this to hold lots
+of drivers for whatever hardware you might have. It is loaded before the
+real root disk is accessed.
+
+The numbers after the end of each file are the version. Here it is Linux
+version 3.13. You can find the source code for this in the Linux tree with
+the tag v3.13. The '.0' allows for additional Linux releases to fix problems,
+but normally this is not needed. The '-58' is used by Ubuntu. Each time they
+release a new kernel they increment this number. New Ubuntu versions might
+include kernel patches to fix reported bugs. Stable kernels can exist for
+some years so this number can get quite high.
+
+The '.efi.signed' kernel is signed for EFI's secure boot. U-Boot has its own
+secure boot mechanism - see [12] [13] and cannot read .efi files at present.
+
+To boot Ubuntu from U-Boot the steps are as follows:
+
+1. Set up the boot arguments. Use the GUID for the partition you want to
+boot:
+
+ => setenv bootargs root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro
+
+Here root= tells Linux the location of its root disk. The disk is specified
+by its GUID, using '/dev/disk/by-partuuid/', a Linux path to a 'directory'
+containing all the GUIDs Linux has found. When it starts up, there will be a
+file in that directory with this name in it. It is also possible to use a
+device name here, see later.
+
+2. Load the kernel. Since it is an ext2/4 filesystem we can do:
+
+ => ext2load scsi 0:2 03000000 /boot/vmlinuz-3.13.0-58-generic
+
+The address 30000000 is arbitrary, but there seem to be problems with using
+small addresses (sometimes Linux cannot find the ramdisk). This is 48MB into
+the start of RAM (which is at 0 on x86).
+
+3. Load the ramdisk (to 64MB):
+
+ => ext2load scsi 0:2 04000000 /boot/initrd.img-3.13.0-58-generic
+
+4. Start up the kernel. We need to know the size of the ramdisk, but can use
+a variable for that. U-Boot sets 'filesize' to the size of the last file it
+loaded.
+
+ => zboot 03000000 0 04000000 ${filesize}
+
+Type 'help zboot' if you want to see what the arguments are. U-Boot on x86 is
+quite verbose when it boots a kernel. You should see these messages from
+U-Boot:
+
+ Valid Boot Flag
+ Setup Size = 0x00004400
+ Magic signature found
+ Using boot protocol version 2.0c
+ Linux kernel version 3.13.0-58-generic (buildd@allspice) #97-Ubuntu SMP Wed Jul 8 02:56:15 UTC 2015
+ Building boot_params at 0x00090000
+ Loading bzImage at address 100000 (5805728 bytes)
+ Magic signature found
+ Initial RAM disk at linear address 0x04000000, size 19215259 bytes
+ Kernel command line: "console=ttyS0,115200 root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro"
+
+ Starting kernel ...
+
+U-Boot prints out some bootstage timing. This is more useful if you put the
+above commands into a script since then it will be faster.
+
+ Timer summary in microseconds:
+ Mark Elapsed Stage
+ 0 0 reset
+ 241,535 241,535 board_init_r
+ 2,421,611 2,180,076 id=64
+ 2,421,790 179 id=65
+ 2,428,215 6,425 main_loop
+ 48,860,584 46,432,369 start_kernel
+
+ Accumulated time:
+ 240,329 ahci
+ 1,422,704 vesa display
+
+Now the kernel actually starts:
+
+ [ 0.000000] Initializing cgroup subsys cpuset
+ [ 0.000000] Initializing cgroup subsys cpu
+ [ 0.000000] Initializing cgroup subsys cpuacct
+ [ 0.000000] Linux version 3.13.0-58-generic (buildd@allspice) (gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1) ) #97-Ubuntu SMP Wed Jul 8 02:56:15 UTC 2015 (Ubuntu 3.13.0-58.97-generic 3.13.11-ckt22)
+ [ 0.000000] Command line: console=ttyS0,115200 root=/dev/disk/by-partuuid/965c59ee-1822-4326-90d2-b02446050059 ro
+
+It continues for a long time. Along the way you will see it pick up your
+ramdisk:
+
+ [ 0.000000] RAMDISK: [mem 0x04000000-0x05253fff]
+...
+ [ 0.788540] Trying to unpack rootfs image as initramfs...
+ [ 1.540111] Freeing initrd memory: 18768K (ffff880004000000 - ffff880005254000)
+...
+
+Later it actually starts using it:
+
+ Begin: Running /scripts/local-premount ... done.
+
+You should also see your boot disk turn up:
+
+ [ 4.357243] scsi 1:0:0:0: Direct-Access ATA ADATA SP310 5.2 PQ: 0 ANSI: 5
+ [ 4.366860] sd 1:0:0:0: [sda] 62533296 512-byte logical blocks: (32.0 GB/29.8 GiB)
+ [ 4.375677] sd 1:0:0:0: Attached scsi generic sg0 type 0
+ [ 4.381859] sd 1:0:0:0: [sda] Write Protect is off
+ [ 4.387452] sd 1:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
+ [ 4.399535] sda: sda1 sda2 sda3
+
+Linux has found the three partitions (sda1-3). Mercifully it doesn't print out
+the GUIDs. In step 1 above we could have used:
+
+ setenv bootargs root=/dev/sda2 ro
+
+instead of the GUID. However if you add another drive to your board the
+numbering may change whereas the GUIDs will not. So if your boot partition
+becomes sdb2, it will still boot. For embedded systems where you just want to
+boot the first disk, you have that option.
+
+The last thing you will see on the console is mention of plymouth (which
+displays the Ubuntu start-up screen) and a lot of 'Starting' messages:
+
+ * Starting Mount filesystems on boot [ OK ]
+
+After a pause you should see a login screen on your display and you are done.
+
+If you want to put this in a script you can use something like this:
+
+ setenv bootargs root=UUID=b2aaf743-0418-4d90-94cc-3e6108d7d968 ro
+ setenv boot zboot 03000000 0 04000000 \${filesize}
+ setenv bootcmd "ext2load scsi 0:2 03000000 /boot/vmlinuz-3.13.0-58-generic; ext2load scsi 0:2 04000000 /boot/initrd.img-3.13.0-58-generic; run boot"
+ saveenv
+
+The \ is to tell the shell not to evaluate ${filesize} as part of the setenv
+command.
+
+You will also need to add this to your board configuration file, e.g.
+include/configs/minnowmax.h:
+
+ #define CONFIG_BOOTDELAY 2
+
+Now when you reset your board it wait a few seconds (in case you want to
+interrupt) and then should boot straight into Ubuntu.
+
+You can also bake this behaviour into your build by hard-coding the
+environment variables if you add this to minnowmax.h:
+
+#undef CONFIG_BOOTARGS
+#undef CONFIG_BOOTCOMMAND
+
+#define CONFIG_BOOTARGS \
+ "root=/dev/sda2 ro"
+#define CONFIG_BOOTCOMMAND \
+ "ext2load scsi 0:2 03000000 /boot/vmlinuz-3.13.0-58-generic; " \
+ "ext2load scsi 0:2 04000000 /boot/initrd.img-3.13.0-58-generic; " \
+ "run boot"
+
+#undef CONFIG_EXTRA_ENV_SETTINGS
+#define CONFIG_EXTRA_ENV_SETTINGS "boot=zboot 03000000 0 04000000 ${filesize}"
+
+
Development Flow
----------------
These notes are for those who want to port U-Boot to a new x86 platform.
If not, you can try to get serial working as early as possible. The early
debug serial port may be useful here. See setup_early_uart() for an example.
+During the U-Boot porting, one of the important steps is to write correct PIRQ
+routing information in the board device tree. Without it, device drivers in the
+Linux kernel won't function correctly due to interrupt is not working. Please
+refer to U-Boot doc [14] for the device tree bindings of Intel interrupt router.
+Here we have more details on the intel,pirq-routing property below.
+
+ intel,pirq-routing = <
+ PCI_BDF(0, 2, 0) INTA PIRQA
+ ...
+ >;
+
+As you see each entry has 3 cells. For the first one, we need describe all pci
+devices mounted on the board. For SoC devices, normally there is a chapter on
+the chipset datasheet which lists all the available PCI devices. For example on
+Bay Trail, this is chapter 4.3 (PCI configuration space). For the second one, we
+can get the interrupt pin either from datasheet or hardware via U-Boot shell.
+The reliable source is the hardware as sometimes chipset datasheet is not 100%
+up-to-date. Type 'pci header' plus the device's pci bus/device/function number
+from U-Boot shell below.
+
+ => pci header 0.1e.1
+ vendor ID = 0x8086
+ device ID = 0x0f08
+ ...
+ interrupt line = 0x09
+ interrupt pin = 0x04
+ ...
+
+It shows this PCI device is using INTD pin as it reports 4 in the interrupt pin
+register. Repeat this until you get interrupt pins for all the devices. The last
+cell is the PIRQ line which a particular interrupt pin is mapped to. On Intel
+chipset, the power-up default mapping is INTA/B/C/D maps to PIRQA/B/C/D. This
+can be changed by registers in LPC bridge. So far Intel FSP does not touch those
+registers so we can write down the PIRQ according to the default mapping rule.
+
+Once we get the PIRQ routing information in the device tree, the interrupt
+allocation and assignment will be done by U-Boot automatically. Now you can
+enable CONFIG_GENERATE_PIRQ_TABLE for testing Linux kernel using i8259 PIC and
+CONFIG_GENERATE_MP_TABLE for testing Linux kernel using local APIC and I/O APIC.
+
TODO List
---------
- Audio
[3] http://www.coreboot.org/~stepan/pci8086,0166.rom
[4] http://www.intel.com/content/www/us/en/embedded/design-tools/evaluation-platforms/atom-e660-eg20t-development-kit.html
[5] http://www.intel.com/fsp
-[6] http://en.wikipedia.org/wiki/Microcode
-[7] http://simplefirmware.org
-[8] http://www.intel.com/design/archives/processors/pro/docs/242016.htm
+[6] http://www.intel.com/content/www/us/en/secure/intelligent-systems/privileged/e6xx-35-b1-cmc22211.html
+[7] http://www.ami.com/products/bios-uefi-tools-and-utilities/bios-uefi-utilities/
+[8] http://en.wikipedia.org/wiki/Microcode
+[9] http://simplefirmware.org
+[10] http://www.intel.com/design/archives/processors/pro/docs/242016.htm
+[11] https://en.wikipedia.org/wiki/GUID_Partition_Table
+[12] http://events.linuxfoundation.org/sites/events/files/slides/chromeos_and_diy_vboot_0.pdf
+[13] http://events.linuxfoundation.org/sites/events/files/slides/elce-2014.pdf
+[14] doc/device-tree-bindings/misc/intel,irq-router.txt