diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/README.splashprepare | 13 | ||||
| -rw-r--r-- | doc/README.x86 | 137 |
2 files changed, 141 insertions, 9 deletions
diff --git a/doc/README.splashprepare b/doc/README.splashprepare index 61b4ec53ec..a0f0f3ca51 100644 --- a/doc/README.splashprepare +++ b/doc/README.splashprepare @@ -6,3 +6,16 @@ common/splash.c. It is called as part of the splash screen display sequence. It gives the board an opportunity to prepare the splash image data before it is processed and sent to the frame buffer by U-Boot. Define your own version to use this feature. + +CONFIG_SPLASH_SOURCE + +Use the splash_source.c library. This library provides facilities to declare +board specific splash image locations, routines for loading splash image from +supported locations, and a way of controlling the selected splash location +using the "splashsource" environment variable. + +splashsource works as follows: +- If splashsource is set to a supported location name as defined by board code, + use that splash location. +- If splashsource is undefined, use the first splash location as default. +- If splashsource is set to an unsupported value, do not load a splash screen. diff --git a/doc/README.x86 b/doc/README.x86 index 7df8cc516a..fb87682e05 100644 --- a/doc/README.x86 +++ b/doc/README.x86 @@ -18,11 +18,11 @@ U-Boot supports running as a coreboot [1] payload on x86. So far only Link 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 and Intel Crown Bay board -support running U-Boot 'bare metal'. +aka raw support or bare support. Currently Link, Intel Crown Bay, Intel +Minnowboard Max and Intel Galileo support running U-Boot 'bare metal'. -As for loading 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. +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 ------------------ @@ -47,13 +47,15 @@ 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. -Building ROM version of U-Boot (hereafter referred to as u-boot.rom) is a +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 not turned on by default in the U-Boot source tree. Firstly, you need turn it -on by uncommenting the following line in the main U-Boot Makefile: +on by enabling the ROM build: -# ALL-$(CONFIG_X86_RESET_VECTOR) += u-boot.rom +$ export BUILD_ROM=y + +This tells the Makefile to build u-boot.rom as a target. Link-specific instructions: @@ -108,6 +110,50 @@ Now you can build U-Boot and obtain u-boot.rom $ make crownbay_defconfig $ make all +Intel Minnowboard Max instructions: + +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 +the time of writing). Put it in the board directory: +board/intel/minnowmax/fsp.bin + +Obtain the VGA RAM (Vga.dat at the time of writing) and put it into the same +directory: board/intel/minnowmax/vga.bin + +You still need two more binary blobs. These come from the sample SPI image +provided in the FSP (SPI.bin at the time of writing). + +Use ifdtool in the U-Boot tools directory to extract the images from that +file, for example: + + $ ./tools/ifdtool -x BayleyBay/SPI.bin + $ cp flashregion_2_intel_me.bin board/intel/minnowmax/me.bin + $ cp flashregion_0_flashdescriptor.bin board/intel/minnowmax/descriptor.bin + +Now you can build U-Boot and obtain u-boot.rom + +$ make minnowmax_defconfig +$ make all + +Intel Galileo instructions: + +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 +needed by the Quark SoC itself. + +You can get the binary blob from Quark Board Support Package from Intel website: + +* ./QuarkSocPkg/QuarkNorthCluster/Binary/QuarkMicrocode/RMU.bin + +Rename the file and put it to the board directory by: + + $ cp RMU.bin board/intel/galileo/rmu.bin + +Now you can build U-Boot and obtain u-boot.rom + +$ make galileo_defconfig +$ make all + Test with coreboot ------------------ For testing U-Boot as the coreboot payload, there are things that need be paid @@ -126,11 +172,21 @@ Make sure 0x1110000 matches CONFIG_SYS_TEXT_BASE and 0x1110015 matches the symbol address of _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. +use CONFIG_OF_EMBED instead of CONFIG_OF_SEPARATE. + +To enable video you must enable these options in coreboot: + + - Set framebuffer graphics resolution (1280x1024 32k-color (1:5:5)) + - Keep VESA framebuffer + +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. + CPU Microcode ------------- -Modern CPU usually requires a special bit stream called microcode [5] to be +Modern CPUs usually require a special bit stream called microcode [5] 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. @@ -162,6 +218,69 @@ mtrr - List and set the Memory Type Range Registers (MTRR). These are used to mode to use. U-Boot sets up some reasonable values but you can adjust then with this command. +Development Flow +---------------- +These notes are for those who want to port U-Boot to a new x86 platform. + +Since x86 CPUs boot from SPI flash, a SPI flash emulator is a good investment. +The Dediprog em100 can be used on Linux. The em100 tool is available here: + + http://review.coreboot.org/p/em100.git + +On Minnowboard Max the following command line can be used: + + sudo em100 -s -p LOW -d u-boot.rom -c W25Q64DW -r + +A suitable clip for connecting over the SPI flash chip is here: + + http://www.dediprog.com/pd/programmer-accessories/EM-TC-8 + +This allows you to override the SPI flash contents for development purposes. +Typically you can write to the em100 in around 1200ms, considerably faster +than programming the real flash device each time. The only important +limitation of the em100 is that it only supports SPI bus speeds up to 20MHz. +This means that images must be set to boot with that speed. This is an +Intel-specific feature - e.g. tools/ifttool has an option to set the SPI +speed in the SPI descriptor region. + +If your chip/board uses an Intel Firmware Support Package (FSP) it is fairly +easy to fit it in. You can follow the Minnowboard Max implementation, for +example. Hopefully you will just need to create new files similar to those +in arch/x86/cpu/baytrail which provide Bay Trail support. + +If you are not using an FSP you have more freedom and more responsibility. +The ivybridge support works this way, although it still uses a ROM for +graphics and still has binary blobs containing Intel code. You should aim to +support all important peripherals on your platform including video and storage. +Use the device tree for configuration where possible. + +For the microcode you can create a suitable device tree file using the +microcode tool: + + ./tools/microcode-tool -d microcode.dat create <model> + +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 + +These are written to arch/x86/dts/microcode/ by default. + +Note that it is possible to just add the micrcode for your CPU if you know its +model. U-Boot prints this information when it starts + + CPU: x86_64, vendor Intel, device 30673h + +so here we can use the M0130673322 file. + +If you platform can display POST codes on two little 7-segment displays on +the board, then you can use post_code() calls from C or assembler to monitor +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. + TODO List --------- - Audio |