This commit includes, but does not apply, a patch that I was
experimenting with while solving the boot-hang problem.
This patch does not appear necessary, so it is not applied. However
I don't want to forget what I was experimenting with at the time, so
it is included here to make it part of the git history.
This commit adds a one-line coreboot patch which has finally solved
100% of my got-stuck-while-booting problems.
Upstream coreboot contains the following code:
/* Reset for HT, FIDVID, PLL and errata changes to take effect. */
if (!warm_reset_detect(0)) {
printk(BIOS_INFO, "...WARM RESET...\n\n\n");
soft_reset();
However `warm_reset_detect(0)` is *not* the complement of "cold
reset" (i.e. power supply was disconnected and reconnected).
Apparently there is a whole other category of "other resets" which
are neither warm nor cold. These conditions are detected by
`other_reset_detected()`.
The patch being added expands the condition above to include these:
if (other_reset_detected() || !warm_reset_detect(0)) {
After including this patch I have experienced zero of the infamous
"Assigning resources...<hang>" problems. Hooray!
This commit moves the `fmap` and `payload` arguments to `coreboot`
into the top-level scope, so they can be provided without needing to
override the `coreboot` expression.
This commit causes the coreboot payload (i.e. the Linux kernel,
initramfs, and any necessary DTBs) to be inserted into the coreboot
image as part of a separate derivation from the one which compiles
coreboot.
As a result, changing the contents of the initramfs is extremely
fast -- it can now be done without any recompilation.
As a result of this, the attribute name for the final image to be
flashed has changed from `coreboot` to `image`. The `coreboot`
attribute now builds a payloadless `coreboot.rom`.
This commit adds a coreboot patch which enables
CONFIG_USE_WATCHDOG_ON_BOOT for kgpe-d16; in upstream coreboot this
feature is found on only a few intel cpu platforms.
When enabled, this feature starts the hardware watchdog very early
in the boot process -- before PNP enumeration or DRAM
initialization. This ensures that any hangs or freezes due to
transient conditions (flakiness, temperature, electrical noise)
won't prevent the machine from eventually booting. This is very
useful for unattended servers.
On kgpe-d16 the watchdog is cancelled immediately before jumping to
the payload (i.e. Linux kernel). I found that if I left the
watchdog enabled, any attempt to use it (for example, to cancel it
or extend it) from Linux resulted in the machine resetting. Perhaps
this can be fixed, but for now I am content to simply re-enable the
watchdog from Linux rather than leaving it running.
Previously, the flashrom scripts would pass --fmap to every
invocation of flashrom, even when overwriting the entire image.
This was unnecessary, and would cause issues if the chip being
written to had a corrupted fmap table. This commit passes the
--fmap flag only when it is needed due to the -i flag being present.
This commit adds a coreboot patch which causes kgpe-d16 to skip the
PNP enumeration/assignment process for the "hardware monitor"
(basically a temperature sensor and fan-speed controller) block on
the southbridge chip.
I have found this patch solves the last remaining boot reliability
problem I was having with my unattended kgpe-d16 machines.
The commit message for this patch is below:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
The hardware monitor is one of the blocks within the w83667hg-a chip
(there are many others). It is basically a bunch of ADCs (analog to
digital converters) hooked up to voltage, current, and temperature
sensors in various locations on the motherboard.
This block has the ability to generate several different interrupts
(SMI#, OVT#, etc) in response to thermal conditions. It appears to
sometimes (about 10% of boot-ups, depending on temperature) spew
erroneous alarm interrupts the instant you enable it, when doing so
from within coreboot. This causes the w83667hg-a chip and the
entire system to hang, and the watchdog cannot recover from this
state because it is part of the w83667hg-a chip too.
An even bigger problem is that the hardware monitor is initialized
*before* the fans are brought up to full speed. So if the CPU is
above the critical temperature it will remain there because the fans
are in their default low-speed boot state. The chip just keeps
getting hotter and hotter -- not enough to damage itself, but hot
enough that it won't come down to an acceptable temperature with
simple reboots and power-cycles; you have to leave the system off
for a while. Since the fans aren't running while the system is off
this takes quite a while (several minutes). It's a very fussy and
fidgety process, and not something you want to walk a remote-hands
guy at the datacenter through over the phone.
To avoid this whole mess, let's simply not assign PNP resources to
the hardware monitor from coreboot. Linux doesn't need these
anyways; it communicates with the hardware using I2C.
This commit reorders the (rather large) list of patches to coreboot,
sorts them by category, and adds comments to explain them.
No change in the post-patchPhase source.
Now that 6deb86f6138265a715dd005c310ad33a2e2865ff has merged
upstream in nixpkgs we can directly reference arm-trusted-firmware
as part of the nixpkgs package set. This allows to eliminate a
<nixpkgs>-style path reference.
In order to write to the chromebook embedded controller flash we
need to use Google's fork of flashrom. However for writing to the
chromebook CPU firmware flash (which is a different flash chip) we
can use mainline flashrom. So let's do that.
On x86 platforms, it is necessary to wrap the entire image in a
BIOS@0 region which marks the memory-mapped flash image as needing
SMM protection. Unfortunately this creates overlapping FMAP
regions, which flashrom cannot handle without a patch.
On arm64 platforms, the BIOS@0 region is not needed. So let's not
include it. This allows us to skip the flashrom patch on arm64.
This commit changes a few path-references into `<nixpkgs/..>` so
they use attrset references instead. This way it is not necessary
to have nixpkgs accessible via $NIX_PATH when you build ownerboot.
Upstream describes this option as "Enable this option if coreboot
shall read options from the CMOS NVRAM instead of using hard-coded
values."
The RTC_BOOT_BYTE (which controls normal/fallback) indicator is
always taken from CMOS NVRAM, regardless of how this option is set.
When set to `no`, no other parts of the CMOS NVRAM are read or
written.
On KGPE-D16 I have found that USE_OPTION_TABLE=yes is frustratingly
flaky and unstable; about 1 in 20 boots will hang in the PNP device
enumeration. Apparently during SMP boot, multiple cores attempt to
access the (single) CMOS NVRAM concurrently, causing massive
headaches. Please don't turn this option on unless you are willing
to deal with extreme frustration.
Trying to write to a chip using --fmap will fail if the chip does
not yet have a valid fmap table (for example, a blank chip). Let's
omit this flag when writing the entire image.
This commit drops the verbatim `.config` files for coreboot that
were previously in the repository and converts them to NixOS-style
module configurations.
The big benefit of doing this is that the perl script in nixpkgs
that handles this will check to make sure that coreboot's Kconfig
machinery isn't silently ignoring any of our settings. It also
makes this configuration easier for end-users to customize.
This commit cleans up the selection of the serial console device and
gives it sensible default values (usually, the DB9 header on the
back I/O panel) on each platform.
This commit integrates five more kgpe-d16 patches from my local
tree:
treewide: reduce many messages to BIOS_SPEW
southbridge/amd/sb700/lpc.c: leave LPC timeout mechanism enabled
I've been experiencing boot hangs during PNP enumeration of the LPC
bus. The southbridge chip comes with a mechanism to prevent
unresponsive/syncflooding LPC devices from wedging the system; let's
use it.
mainboard/asus/kgpe-d16/romstage.c: support console on ttyS1
Currently the romstage serial console initialization always
initializes SP1 (the DB9 header on the back of the motherboard).
Changing UART_FOR_CONSOLE simply causes the romstage to map the same
serial port at a different address (0x2f8).
This commit accounts for UART_FOR_CONSOLE (and its effect on
TTYS0_BASE) correctly: if UART_FOR_CONSOLE is changed from 0 to 1,
the romstage console output will be printed on the SP2 header (the
IDC ribbon header on the motherboard).
southbridge/amd/sb700/lpc.c: set SPI flash aperture to 16MB
The SPI flash aperture for the southbridge chip is set to 8MB, even
when a 16MB chip is used. Let's make the aperture large enough for
the maximum size chip that this board can accomodate.
amd/sb700/early_setup.c: select console properly
Currently, sb700/early_setup.c has this comment:
// XXX Serial port decode on LPC is hardcoded to 0x3f8
... and it unconditionally sets the output enable for ttyS0, even if
ttyS1 is also enabled. As a result, if coreboot is configured to
use ttyS1 for serial output, the romstage console output will appear
on *both* consoles.
This commit fixes that.
kgpe-d16: disable TPM
I have never heard of anybody using a TPM on this board, and the
fewer things we need to deal with during the somewhat-flaky LPC
init, the better.
On kgpe-d16 coreboot has long been plagued with occasional boot
hangs somewhere deep within the PNP initialization code. I'm still
hunting down the root cause, but for the moment reducing the logging
level helps.
Reducing the log level results in fewer fewer writes to the serial
port. The serial port has a very finicky initialization sequence,
because it needs to be usable *before* the PNP initialization has
run.
This commit adds several useful scripts (alongside the coreboot
image) in a `main` expression, which should be the primary build
expression going forward.
The following scripts should exists on all platforms:
- flashrom wrappers:
- `flashrom.sh`
- `flash-write-all.sh`
- `flash-write-fallback.sh`
- `flash-write-normal.sh`
- scripts to select which image (normal or fallback) is used for the
next boot:
- `nextboot-show.sh`
- `nextboot-use-fallback.sh`
- `nextboot-use-normal.sh`
- a script to write an image to the em100 flash-chip-emulator device:
- `em100-write.sh`
This commit generalizes the selection and activation of the serial
console by promoting it to a top-level package-set member.
The top-level package set is starting to attract clutter, so I will
soon be moving all the non-package constitutents into a `config`
attrset.
This commit exposes the `fmap` (flash chip partition table) used to
build the coreboot image as the `passthru.fmap` attribute so it can
be referenced from other expressions.
Sadly we need at least two different forks of flashrom, with
different patches (and therefore different capabilities) applied to
each. This commit parameterizes the flashrom expression and
includes those parameters in the `passthru` so downstream
expressions can check whether various needed features are present.
This commit makes `hostPlatform` part of the packageset for more
consistent handling. A top-level `hostPlatform` argument is exposed
to the caller, in case they want to customize the `hostPlatform`
(compiler flags, etc).
The `hostPlatform` argument is inherited into the ownerboot package
set, where it will be overridden by `src/platform/*.nix` if it has
not been set explicitly.
Making `hostPlatform` part of the package set allows for more
sophisticated overriding schemes, for example adding additional
compiler flags or sanity-checking the flags that the user has
provided.
Since we (unfortunately) need to use different forks of flashrom for
different platforms, flashrom must be overrideable. Moving it into
the ownerboot packageset is the way to do that.
On amd64 platforms, booting ownerboot with the recovery jumper
installed will wipe the battery-backed nvram (aka "cmos" aka "rtc
nvram") and overwrite it with known-safe values taken from the
coreboot source code (`src/mainboard/asus/kgpe-d16/cmos.default`).
You should always do this when flashing a motherboard with ownerboot
for the first time.
This commit allows the user to customize the set of known-safe
values which are written when the recovery jumper is installed. To
do so, copy `src/mainboard/asus/kgpe-d16/cmos.default` out of
coreboot, edit to suit your tastes, and then override
`cmos-defaults` with the path to your customized `cmos.default`
file.
The microcode blob is only needed for Opteron 63xx chips. I have a
few of these, so I add the blob in a local overlay.
If other people are interested in this I will publish the overlay.
The 63xx chips are kind of rare and more expensive than the 62xx
chips -- their only real benefit is lower power draw. I ended up
receiving some by accident due to an incorrect eBay listing.
Adam Joseph