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.
+U-Boot supports loading an x86 VxWorks kernel. Please check README.vxworks
+for more details.
Build Instructions for U-Boot as coreboot payload
-------------------------------------------------
000000 descriptor.bin Hard-coded to 0 in ifdtool
001000 me.bin Set by the descriptor
500000 <spare>
+6f0000 MRC cache CONFIG_ENABLE_MRC_CACHE
700000 u-boot-dtb.bin CONFIG_SYS_TEXT_BASE
-790000 vga.bin CONFIG_X86_OPTION_ROM_ADDR
+790000 vga.bin CONFIG_VGA_BIOS_ADDR
7c0000 fsp.bin CONFIG_FSP_ADDR
7f8000 <spare> (depends on size of fsp.bin)
7fe000 Environment CONFIG_ENV_OFFSET
# in the coreboot root directory
$ ./build/util/cbfstool/cbfstool build/coreboot.rom add-flat-binary \
- -f u-boot-dtb.bin -n fallback/payload -c lzma -l 0x1110000 -e 0x1110015
+ -f u-boot-dtb.bin -n fallback/payload -c lzma -l 0x1110000 -e 0x1110000
-Make sure 0x1110000 matches CONFIG_SYS_TEXT_BASE and 0x1110015 matches the
-symbol address of _start (in arch/x86/cpu/start.S).
+Make sure 0x1110000 matches CONFIG_SYS_TEXT_BASE, which is the symbol address
+of _x86boot_start (in arch/x86/cpu/start.S).
If you want to use ELF as the coreboot payload, change U-Boot configuration to
use CONFIG_OF_EMBED instead of CONFIG_OF_SEPARATE.
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.
+to instantiate. Note, the maximum supported CPU number in QEMU is 255.
+
+The fw_cfg interface in QEMU also provides information about kernel data, initrd,
+command-line arguments and more. U-Boot supports directly accessing these informtion
+from fw_cfg interface, this saves the time of loading them from hard disk or
+network again, through emulated devices. To use it , simply providing them in
+QEMU command line:
+
+$ qemu-system-i386 -nographic -bios path/to/u-boot.rom -m 1024 -kernel /path/to/bzImage
+ -append 'root=/dev/ram console=ttyS0' -initrd /path/to/initrd -smp 8
+
+Note: -initrd and -smp are both optional
+
+Then start QEMU, in U-Boot command line use the following U-Boot command to setup kernel:
+
+ => qfw
+qfw - QEMU firmware interface
+
+Usage:
+qfw <command>
+ - list : print firmware(s) currently loaded
+ - cpus : print online cpu number
+ - load <kernel addr> <initrd addr> : load kernel and initrd (if any) and setup for zboot
+
+=> qfw load
+loading kernel to address 01000000 size 5d9d30 initrd 04000000 size 1b1ab50
+
+Here the kernel (bzImage) is loaded to 01000000 and initrd is to 04000000. Then, 'zboot'
+can be used to boot the kernel:
+
+=> zboot 02000000 - 04000000 1b1ab50
CPU Microcode
-------------
adjust internal settings, there are several x86-specific commands that may be
useful:
-hob - Display information about Firmware Support Package (FSP) Hand-off
- Block. This is only available on platforms which use FSP, mostly
- Atom.
+fsp - Display information about Intel Firmware Support Package (FSP).
+ This is only available on platforms which use FSP, mostly Atom.
iod - Display I/O memory
iow - Write I/O memory
mtrr - List and set the Memory Type Range Registers (MTRR). These are used to
For the microcode you can create a suitable device tree file using the
microcode tool:
- ./tools/microcode-tool -d microcode.dat create <model>
+ ./tools/microcode-tool -d microcode.dat -m <model> create
or if you only have header files and not the full Intel microcode.dat database:
./tools/microcode-tool -H BAY_TRAIL_FSP_KIT/Microcode/M0130673322.h \
-H BAY_TRAIL_FSP_KIT/Microcode/M0130679901.h \
- create all
+ -m all create
These are written to arch/x86/dts/microcode/ by default.
boot progress. This can be good for debugging.
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.
+debug serial port may be useful here. See setup_internal_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
PCI_BDF(0, 3, 0) INTA PIRQA
...
+Porting Hints
+-------------
+
+Quark-specific considerations:
+
+To port U-Boot to other boards based on the Intel Quark SoC, a few things need
+to be taken care of. The first important part is the Memory Reference Code (MRC)
+parameters. Quark MRC supports memory-down configuration only. All these MRC
+parameters are supplied via the board device tree. To get started, first copy
+the MRC section of arch/x86/dts/galileo.dts to your board's device tree, then
+change these values by consulting board manuals or your hardware vendor.
+Available MRC parameter values are listed in include/dt-bindings/mrc/quark.h.
+The other tricky part is with PCIe. Quark SoC integrates two PCIe root ports,
+but by default they are held in reset after power on. In U-Boot, PCIe
+initialization is properly handled as per Quark's firmware writer guide.
+In your board support codes, you need provide two routines to aid PCIe
+initialization, which are board_assert_perst() and board_deassert_perst().
+The two routines need implement a board-specific mechanism to assert/deassert
+PCIe PERST# pin. Care must be taken that in those routines that any APIs that
+may trigger PCI enumeration process are strictly forbidden, as any access to
+PCIe root port's configuration registers will cause system hang while it is
+held in reset. For more details, check how they are implemented by the Intel
+Galileo board support codes in board/intel/galileo/galileo.c.
+
TODO List
---------
- Audio
projects / people / ms / u-boot.git / blobdiff