coreboot conference in Europe, October 2015

Dear coreboot developers, users and interested parties,

we are currently trying to organize a coreboot conference and developer meeting in October 2015 in Germany.

This is not intended to be a pure developer meeting, we also hope to reach out to manufacturers of processors, chipsets, mainboards and servers/laptops/tablets/desktops with an interest in coreboot and the possibilities it offers.

My plan (which is not final yet) is to have the Federal Office for Information Security (BSI) in Germany host the conference in Bonn, Germany. As a national cyber security authority, the goal of the BSI is to promote IT security in Germany. For this reason, the BSI has funded coreboot development in the past for security reasons.

The preliminary plans are to coordinate the exact date of the conference to be before or after Embedded Linux Conference Europe, scheduled for October 5-7 in Dublin, Ireland. Planned duration is 3-4 days. This means we can either use the time window from Thursday Oct 1 to Sunday Oct 4, or from Thursday Oct 8 to Monday Oct 12. The former has the advantage of having cheaper hotel rooms available in Bonn, while the latter has the advantage of avoiding Oct 3, a national holiday in Germany (all shops closed).

ATTENTION vendors/manufacturers: If your main interest is forging business relationships and/or strategic coordination and you want to skip the technical workshops and soldering, we’ll try make sure there is one outreach day of talks, presentations and discussions on a regular business day. Please indicate that with “(strategic)” next to your name in the doodle linked below.

If you wonder about how to reach Bonn, there are three options available by plane:
The closest is Cologne Airport (CGN), 30 minutes by bus to Bonn main station.
Next is Düsseldorf Airport (DUS), 1 hour by train to Bonn main station.
The airport with most international destinations is Frankfurt Airport (FRA), 2.5 hours by train to Bonn main station.
There’s the option to travel by train as well. Bonn is reachable by high-speed train (ICE), and other high-speed train stations are reasonably close (30 minutes).

What I’m looking for right now is a rough show of hands who’d like to attend so I can book a conference venue. I’d also like feedback on which weekend would be preferable for you. If you have any questions, please feel free to ask me directly <> or our mailing list <>.

Please enter your participation abilities in the doodle below:

Carl-Daniel Hailfinger

coreboot changelog – Week of 2015-07-20

This covers commits 406effd5 up to commit ef0158ec

Apart from adding the google/glados board, this week’s activity concentrated on bug fixes in chipsets and mainboards, spanning AMD K8 and Hudson, Intel Sandy Bridge, Braswell and Skylake, Nvidia Tegra, Rockchip RK3288 and RISC-V. Most of the changes are too small individually and too spread out across the code base for a shout-out (or this report becomes just a fancy kind of “git log”), but two changes stand out:

Native RAM init on Sandybridge gained support for multiple DIMMs on the same channel, further improving the reverse engineered code base for that chipset.

To improve Skylake support, our 8250mem serial port driver now also supports Skylake’s 32bit UART access mode. This may also be useful when reducing code duplication in our serial console drivers (such as on ARM SoCs).

[GSoC] EC/H8S firmware week #7|#8

Week #7 was is little bit frustrating, because of no real progress, only more unfinished things which aren’t working. Week #8 was a lot better.

1. Sniffing the communication between the 2 embedded controllers H8S and PMH4.

I’ve tried to build an protocol analyser with the msp430, but the data output was somehow strange. For testing purpose I used my H8S firmware to produce testing data. But the msp430 decoded only wrong data. I’m using IRQs on the clock to do the magic and writing it to a buffer before transmitting it via UART. Maybe the msp430 is too slow for that? Possible. Set a GPIO to high when the IRQ routing start and to low when it ends. Visualize the clock signal and connect the  IRQ measure pin to an oscilloscope. The msp430 is far too slow. I’m using memory dereference in the IRQ routine, which takes a lot of time. Maybe the msp430 is fast enough, when using asm routine and registers to buffer the 3 byte transmission. But a logic analyser would definitely work. So I borrowed two logic analyser. An OLS (Openbench Logic Sniffer) and a Saleae Logic16.

There isn’t so much data on the lines. Every 50 ms there is a short transmission of 3 byte. But I don’t want to decode the data by hand. So it needs a decoder for the logic analyser. sigrok looks like the best start point and both analyser are supported.

I’ve started with the Openbench Logic Sniffer, but unfortunately it doesn’t have enough RAM to buffer the input long enough. Maybe the external trigger input can be used. But before doing additional things I would like to test with the Logic16.

The Logic16 doesn’t support any triggers but it can stream all data over USB even with multiple MHz. Good enough to capture all data. I found out that the best samplerate is 2 MHz. Otherwise the LE signal isn’t captured, because it’s a lot shorter than a clock change. In the end I created a decoder with libsigrokdecode.

sigrok-cli -i –channels 0-3 -P ec_xp:clk=2:data=3:le=1:oe=0 | uniq -c 

67 0x01 0x07 0xc8
3 0x01 0x04 0xc8 
4 0x01 0x10 0x48
1120 0x01 0x17 0x48
67 0x01 0x07 0xc8

0x01 0x07 0xc8 is called when only power is plugged in, like a watchdog(every 500ms)
0x01 0x17 0x48 is called when the device is powered on, like a watchdog (every 50ms)
0x01 0x04 0xc8 around the time power button pressed
0x01 0x10 0x48 around the time power button pressed

2. Flash back the OEM H8S firmare

The OEM H8S firmware is included in the bios updates. cabextract and strings is enough for extracting it out of the update. Look for SREC lines. Put the SREC lines into a separate file and flash them back via UART bootloader and the renesas flash tool. The display powers up and it’s booting again with OEM BIOS.
I could imagine they are using a similar update method like the UART bootloader. First transfer a flasher application into RAM and afterwards communicate with the flasher to transfer the new firmware, but the communication works over LPC instead of UART.

3. Progress on the bootloader

I’ve implemented the ADC converter to enable the speaker amp and the display backlight brightness.

Written down LPC registers and just enable the Interface in order to get GateA20 working. Still unclear how far this works.

4. How to break into the bootloader?

The idea of the bootloader is providing a brick free environment for further development. The bootloader loads the application which adds full support for everything. It should be possible to stop the loading application and flash a new application into the EC flash. When starting development on the x60 or x201 I want to use I2C line as debug interface. I2C chips have a big footstep and are easy to access. But there must be a way to abort the loading. I will use the function key in combination with the leds.

  1. Remove the battery and power plug.
  2. Press the function key
  3. Put the power plug in
  4. Wait until leds blinking
  5. release the function key within 5 seconds after the leds starting to blink to enter the bootloader.

The H8S will become I2C slave on a specific address.

What next?

  • Add new PMH4 commands to the H8S
  • solder additional pins to MAINOFF PWRSW_H8 A20 KBRC
  • use the logic analyser to put the communication in relation with these signals
  • UART shell
  • I2C master & client
  • solder LPC pins to analyse firmware update process
  • test T40 board with new PMH4 commands and look if all power rails are on

[GSoC] coreboot for ARM64 Qemu – Week #7

This was a tough week. After having passed the coreboot building stage, I thought my work would be easier now. But I had another thing coming.

As I had mentioned in my last post, I didn’t have any output while booting on qemu. So, the first aim was to get qemu monitor working. After some debug, I was able to get qemu monitor working to print onto my terminal (stdio)
This gave me then following :

qemu: fatal: Trying to execute code outside RAM or ROM at 0x0000000008000000

R00=00000950 R01=ffffffff R02=44000000 R03=00000000
R04=00000000 R05=00000000 R06=00000000 R07=00000000
R08=00000000 R09=00000000 R10=00000000 R11=00000000
R12=00000000 R13=00000000 R14=40010010 R15=08000000
PSR=400001db -Z– A und32
s00=00000000 s01=00000000 d00=0000000000000000
s02=00000000 s03=00000000 d01=0000000000000000
s04=00000000 s05=00000000 d02=0000000000000000
s06=00000000 s07=00000000 d03=0000000000000000
s08=00000000 s09=00000000 d04=0000000000000000
s10=00000000 s11=00000000 d05=0000000000000000
s12=00000000 s13=00000000 d06=0000000000000000
s14=00000000 s15=00000000 d07=0000000000000000
s16=00000000 s17=00000000 d08=0000000000000000
s18=00000000 s19=00000000 d09=0000000000000000
s20=00000000 s21=00000000 d10=0000000000000000
s22=00000000 s23=00000000 d11=0000000000000000
s24=00000000 s25=00000000 d12=0000000000000000
s26=00000000 s27=00000000 d13=0000000000000000
s28=00000000 s29=00000000 d14=0000000000000000
s30=00000000 s31=00000000 d15=0000000000000000
s32=00000000 s33=00000000 d16=0000000000000000
s34=00000000 s35=00000000 d17=0000000000000000
s36=00000000 s37=00000000 d18=0000000000000000
s38=00000000 s39=00000000 d19=0000000000000000
s40=000000 Abort trap: 6

I did some searching, this meant that the bootloader could not be loaded. And realised maybe the ROM qemu is being allotted is not sufficient. The ‘execute outside ram or rom’ is usually a jump to somewhere that qemu does not recognize as ROM/RAM.
Since we expect
i.e ROM to start at 64k. So I ran qemu by giving a -m 2048M (for testing) and got over this fatal qemu error, but still wasn’t able to get coreboot to boot (no output on serial). This meant, some more debugging was needed.

I started to debug this using gdb. I created a gdb stub in the qemu boot (by using -s -S), but running gdb to connect to it gave me :
(gdb) target remote localhost:1234
Remote debugging using localhost:1234
warning: Architecture rejected target-supplied description
0x40080000 in ?? ()

Which probably meant I will have to have to build a cross gdb (aarch64-linux-gnu-gdb) and use that.
For this, on linux we could have something called gdb-multiarch, but this is not available for macOSX.

I then turned to using Valgrind. There are Valgrind tools available that can help detect many memory management bugs.

This is what I got on valgrind,

==2070== Memcheck, a memory error detector
==2070== Copyright (C) 2002-2013, and GNU GPL’d, by Julian Seward et al.
==2070== Using Valgrind-3.10.1 and LibVEX; rerun with -h for copyright info
==2070== Command: aarch64-softmmu/qemu-system-aarch64 -machine virt -cpu cortex-a57 -machine type=virt -nographic -m 2048 -kernel /Users/naman/gsoc/coreboot2.0/coreboot/build/coreboot.rom
–2070– aarch64-softmmu/qemu-system-aarch64:
–2070– dSYM directory is missing; consider using –dsymutil=yes
UNKNOWN __pthread_sigmask is unsupported. This warning will not be repeated.
–2070– WARNING: unhandled syscall: unix:330
–2070– You may be able to write your own handler.
–2070– Nevertheless we consider this a bug.  Please report
–2070– it at
==2070== Warning: set address range perms: large range [0x1053c5040, 0x1253c5040) (undefined)
==2070== Warning: set address range perms: large range [0x239e56040, 0x255e55cc0) (undefined)
==2070== Warning: set address range perms: large range [0x255e56000, 0x2d5e56000) (defined)

2070 set address range perms means that the permissions changed on a particularly large block of memory.
That can happen because when a very large memory allocation or deallocation occurs – a mmap or umap call. Which meant we are leaking some memory, but we need to find where. I read some documentations and believe something called a massif tool (in valgrind) could be used. I am now looking at how to find where this memory gets eaten.

On the target now is getting some answers on valgrind if possible. But if I dont get sufficient leads, I would have to switch to gdb (aarch64 on macOSX) and continue my debugging.


coreboot changelog – Week of 2015-07-13

This covers commits 6cb3a59 (which is the 4.1 tag) up to commit 406effd5

This week brought the addition of one new chipset and four new mainboards: Welcome the Intel Skylake SoC, and the new mainboards google/cyan, intel/kunimitsu, intel/sklrvp, and intel/strago, which are Braswell or Skylake based.

As for tools, the script that generated the 4.1 release was added to the tree. To aid with debugging build issues, buildgcc shows the URLs it uses to download the sources to the toolchain. The standard git hook now uses a customized version of Linux’s utility for better coding style compliance tests. The cbmem utility gained OpenBSD compatibility when reading timestamps.

The USB host drivers in libpayload saw improvements both for USB3, supporting SuperSpeed hubs and showing more robustness in the presence of strangely behaving USB devices, and for DWC2 controllers, which now support LowSpeed devices behind HighSpeed hubs. coreboot also passes more information to libpayload on where to find the flash part as well as the parameters of the CBFS that was used during boot.

The CBFS format is seeing new development: The default alignment for files is now hardcoded to 64 bytes, which was already the default. There are no known instances where this value was changed, and it simplifies development going forward. The change is forward compatible in that old users can still read new CBFS images. New users run into problems if they work on a CBFS image with a different alignment configuration.

Furthermore there were discussions on how to extend the CBFS format compatibly. So far this led to numerous refactorings in cbfstool to simplify further development.

Finally, there were a whole lot of bug fixes: ARM64, the code for Nvidia’s Tegra210 chipset and the google/foster and google/smaug boards saw lots of development, from making them boot again to various hardware enablement. AMD’s RS780 chipset was effectively disabled due to a typo in the build system. There’s an ongoing effort to bring AMD K8/Fam10h into shape again, which also positively affected HD Audio configuration. CBMEM timestamps are more complete than ever.

There was also the usual bunch of cleanups that get rid of unused Kconfig symbols and configuration options, deal with wrong indentation, and replace magic numbers with meaningful names.

[GSoC] End user flash tool – week #6

Hello again! During week 6 I worked on two things:

  • functional tests of libflashrom on T60
  • GUI improvements – filtering and searching list of supported hardware

For testing I used Lenovo T60 with Macronix chip and Raspberry Pi. I connected to the chip with SOIC clip and attached it to Raspberry SPI. I needed to disassemble my laptop almost completely because on T60 BIOS chip is blocked by a magnesium frame which must be removed. It is important for me to have easier access to the chip without disassembling everything every time so  I removed a part of frame that covered the chip.


Tested functions:

  • fl_flash_probe: function returns proper flash context if we provide a specific chip as its argument, if we probe for all known chips and there are multiple chips found (like in Lenovo T60 with Macronix chip) correct error code is returned (I also needed to implement a way to output multiple flash chips to GUI and then select a proper one, I will describe it in my next post).
  • fl_image_read: correct data is loaded to buffer
  • fl_flash_erase:  chip has been properly erased
  • fl_image_verify: verification succeeded
  • fl_image_write: data has been correctly written on the chip
filtering and searching supported hardware

It is possible now to find a specific chip, board or chipset on the list by selecting filtering options like vendor, size or test status. You can also search by entering a name of a particular hardware (or part of a name). I plan to extend this screen and provide more filtering options when I will finish implementing higher priority features like automating a process of creating a working coreboot image and checking hardware compatibility.


Announcing coreboot 4.1

Dear coreboot community,

It has been more than 5 years since we have “released” coreboot ‘4.0’.
That last release marked some very important milestones that we originally prototyped in the abandoned LinuxBIOS v3 efforts, like the coreboot filesystem (CBFS), Kconfig support, and (strictly) separate device trees, build logic and configuration.

Since then there have been as many significant original developments, such as support for many new architectures (ARM, ARM64, MIPS, RISC-V), and related architectural changes like access to non-memory mapped SPI flash, or better insight about the internals of coreboot at runtime through the cbmem console, timestamp collection, or code coverage support.

It became clear that a new release is overdue. With our new release process only slowly getting in shape, I decided to take a random commit and call it ‘4.1’.

The release itself happens at an arbitrary point in time, but will serve as a starting point for other activities that require some kind of ‘starting point’ to build on, described below.

Future releases will happen more frequently, and with more guarantees about the state of the release, like having a cool down phase where boards can be tested and so on. I plan to create a release every three months, so the changes between any two release don’t become too

With the release of coreboot 4.1, you get an announcement (this email), a git tag (4.1), and tar archives at, for the coreboot sources and the redistributable blobs.

Starting with coreboot 4.1, we will maintain a high level changelog and ‘flag days’ document. The latter will provide a concise list of changes which went into coreboot that require chipset or mainboard code to change to keep it working with the latest upstream coreboot.

For the time being, I will run these efforts, but I’ll happily share documentation duties with somebody else – it is a great opportunity to keep track of things, learn about the project and its design and various internals, while contributing to the project without the need to code.

Please contact me (for example by email or on IRC) if you’re interested, and we’ll work out how to collaborate on this.

The process should enable users of coreboot to follow releases if they want a more static base to build on, while making it easier to follow along with new developments by providing upgrade documentation.

Since moving away from a rolling (non-)release model is new for coreboot, things may still be a bit rough around the edges, but I’ll provide support for any issues that arise from the release process.


[GSoC] coreboot for ARM64 Qemu – Week #6

This week I worked on completing the build and sorting all complications imposed by it. As I talked in the last post, I was facing some issues regarding setting up smp for this port. I solved this issue by adding an assembly file which declared smp_processor_id and then defined it by setting the right registers. I had to do some background reading on arm64 details. This provided me with the information I needed.

Next up, was another hitch. During the build, ‘mmu_enable()’ and ‘arch_secondary_cpu_init()’ function calls are happening for all stages but the definitions for these functions are getting compiled only for ramstage. So this gave recurrent errors since the compiler couldn’t find these definitions. While attempting to sort this, I stumbled across something on the chromium tree. There was a patch which dealt with some of the issues, similar to mine. I had to cherry pick and apply this change.

After debugging and sorting through some more errors, I was finally able to get it to build successfully.

coreboot.rom: 4096 kB, bootblocksize 37008, romsize 4194304, offset 0x90c0 alignment: 64 bytes, architecture: arm64

Name                                       Offset     Type         Size
fallback/romstage               0x90c0     stage        12108
fallback/ramstage               0xc080     stage        17768
config                                    0x10640    raw          2034
revision                                0x10e80    raw          577
(empty)                                 0x11100    null         4124312
      HOSTCC     cbfstool/rmodtool.o
     HOSTCC     cbfstool/rmodule.o
     HOSTCC     cbfstool/rmodtool (link)
The complete build can be found here.
I attempted to boot off on qemu after this,
$qemu-system-aarch64 -machine type=virt -nographic -bios ~/coreboot/build/coreboot.rom
This did not give any output, which meant probably I had to make some changes in the uart set up. I attempted to debug this by adding few printks early in bootblock once the console_init is done. This process ongoing, I hope to get through. Another aspect in question is the bootblock initialisation. The src/arch/arm64/armv8/bootblock_simple.c calls for an appropriate bootblock_cpu_init(). This is another thing I will be working on in the coming days.

[GSoC] EC/H8S firmware week #6

This week I looked at the communication between the EC H8S and the PMH4. The PMH4 (likely power management hub) is an ASIC which takes care of the power control. It controls who get’s power and who not. It doesn’t do any high level work, more like a big logic gatter. The PMH4 has inputs from several power good pins from different power rails and chips. On the output side it controls some power rails. It can also reset the H8S. The PMH4 also knows over some pins in which power state (ACPI S0,S4,S5) the board is. It doesn’t do any high level work. It’s more like a big logic gatter. There are no ADC on any power lines.

The PMH4 is connected to the H8S via 4 Pins. ~OE LE DATA CLK.

gsoc 2015 pmh4 connector t40

I connected a buspirate in SPI sniffer mode to debug the protocol. But the output looked a little bit strange. There was no data from the PMH4 to H8S (MISO) and the data comes in burst. To get more knowledge on the protocol I used a digital oscilloscope.

pmh4 oscilloscope

The protocol doesn’t look like SPI. LE get’s low after every transmission, ~OE is just high, clock and data just transfer the data. Sometimes when the H8S gets an interupt the Clock pause for some time and continues with the data afterwards. The clock is around ~400kHz.

I confirmed the protocol via the oscilloscope, but still I don’t get any sign from the board. No fan, nothing else. There must be more than this single transmisison. Maybe the board is to much damaged. My modified board was already broken when I got it. There is a loose connection related to the cardbus. Maybe this is my problem I don’t know.

I’ve two board with two connectors for the PMH4 here. Why not using the OEM one as starter help for the other one?

t42 gives some starting help

I think the PMH4 does what it should do. The H8S has an digital-analog-converter pin connected to the video brightness. But I haven’t implemented it yet. But I don’t think the device booted, because neither the CPU nor the chipset produce any heat. Ok, maybe it does, I only used my finger as thermometer. A thermal camera would help here. I’ll borrow a thermal camera for that.

There are lot of pins which I ignore atm. E.g. A20 pin. Is there something to do in a specific time serie?

What’s next?

  • build a small protocol sniffer for the PMH4 XP using a msp430 or stellaris arm
  • make progress on the bootloader
  • find a way to flash back the OEM H8S firmware
  • find a way to flash my bootloader via OEM flash tools

My requirements to the bootloader are

  • UART flashing via XMODEM
  • a simple UART shell
  • I2C as recovery and shell as well

I2C pins are a lot easier to find and modify than the H8S UART. I’m not yet sure if the H8S should be the master or the slave and on what address he should use? Multiple? UART tx is working. Rx is a task to do.

PMH4 / PMH7 / Thinker communication

On newer board the PMH interfaces changed (>= x60, t60, …). They merge the LPC interface and the XP interface into an protocol over SPI. And the new PMH is used as GPIO expander as well.

pmh4 pmh7 thinker communication


[GSoC] EC/H8S firmware week #5

The T40 is flashing leds! The toolchain is still a little bit tricky. I’m using the debian package gcc-h8300-hms, written a small linker script and took the startup assembly routine from Johann Gysin’s led radiator.

Now I can flash leds. But what about booting the board? I would say it’s enough to put

  • (!MAINOFF) = high
  • FAN ON = high
  • pulse high on (!PWRSW_H8)

But it’s not enough. Also the FAN isn’t starting to rotate. I’ll try to debug every pin this week and solder some debug pins for the 2nd EC (PMHx) to the my modified T40 as well as to an unmodified T42p. The H8S is talking to the PMHx via SPI, while the H8S is the master and is doing bit banging SPI in software, because it doesn’t have a hardware unit for that. I’ll also use these pins for testing my SPI implementation. I’ll try to reuse an open source SPI implementation.

I also asked me if it’s a good idea to port coreboot for the T40 before continuing any efforts to the EC, but it’s a little bit harder, because the T40 uses a LPC/FWH flash in a TSOP40 case. Another option is changing the hardware to a board which is already supported by coreboot like a x60/t60 or x201. But it’s much more harder to access the 8 pins for flashing the EC on these boards.

Before switching to another board, the powersequencing must work and I need a robust recovery way, because when you kill the EC by flashing a new firmware, you don’t get a second chance, unless you solder a lot. Chrome EC fix this problem by splitting the EC firmware into 2 parts. One read-only part and one read-write’able part. Only the second part gets updated and the read-only part can at least boots the device.

Before starting the H8S port for Chrome EC I want to have a bootloader. Because it would improve developing speed. I think implement this is much faster than doing the full Chrome EC support and most of the bootloader code can be re-used for Chrome EC.

I’m also not perfectly sure Chrome EC is the best solution. It’s special use-case is EC, which is perfect. But neither the documentation (I think there is more than one page) nor the bugtracker is public. Thus it makes difficult to use. I’m also not sure if Chrome EC would apply my H8S port into their repository.