| commit | 5e8afce88f3bd4914be0b472559486c59fe58f41 | [log] [tgz] |
|---|---|---|
| author | Nico Huber <nico.h@gmx.de> | Sat Oct 12 15:16:33 2019 +0200 |
| committer | Nico Huber <nico.h@gmx.de> | Sat Nov 16 11:11:36 2019 +0000 |
| tree | cc3c362130d881dde6b81dec7bcd5447bb562bd9 | |
| parent | 7843bd560e65b0a83e99b42bdd58dd6363656c56 [diff] |
soc/intel: Implement PCIe RP devicetree update based on LCAP
Most of the current implementations for FSP-based platforms
make (sometimes wrong) assumptions how FSP reorders root ports
and what is specified in the devicetree. We don't have to make
assumptions though, and can read the root-port number from the
PCIe link capapilities (LCAP) instead. This is also what we do
in ASL code for years already.
This new implementation acts solely on information read from
the PCI config space. In a first round, we scan all possible
DEVFNs and store which root port has that DEVFN now. Then, we
walk through the devicetree that still only knows devices that
were originally mentioned in `devicetree.cb`, update device
paths and unlink vanished devices.
To be most compatible, we work with the following constraints:
o Use only standard PCI config registers.
o Most notable, don't try to read the registers that
configure the function numbers. FSP has undocumented
ways to block access to non-standard registers.
o Don't make assumptions what function is assigned to
hidden devices.
The following assumptions were made, though:
o The absolute root-port numbering as documented in
datasheets matches what is read from LCAP.
o This numbering doesn't contain any gaps.
o Original root-port function numbers below a PCI
device start at function zero and also don't
contain any gaps.
Change-Id: Ib17d2b6fd34608603db3936d638bdf5acb46d717
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35985
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Michael Niewöhner
Reviewed-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
coreboot is a Free Software project aimed at replacing the proprietary BIOS (firmware) found in most computers. coreboot performs a little bit of hardware initialization and then executes additional boot logic, called a payload.
With the separation of hardware initialization and later boot logic, coreboot can scale from specialized applications that run directly firmware, run operating systems in flash, load custom bootloaders, or implement firmware standards, like PC BIOS services or UEFI. This allows for systems to only include the features necessary in the target application, reducing the amount of code and flash space required.
coreboot was formerly known as LinuxBIOS.
After the basic initialization of the hardware has been performed, any desired "payload" can be started by coreboot.
See https://www.coreboot.org/Payloads for a list of supported payloads.
coreboot supports a wide range of chipsets, devices, and mainboards.
For details please consult:
ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this case).Optional:
make menuconfig and make nconfig)Please consult https://www.coreboot.org/Build_HOWTO for details.
If you want to test coreboot without any risks before you really decide to use it on your hardware, you can use the QEMU system emulator to run coreboot virtually in QEMU.
Please see https://www.coreboot.org/QEMU for details.
Further details on the project, a FAQ, many HOWTOs, news, development guidelines and more can be found on the coreboot website:
You can contact us directly on the coreboot mailing list:
https://www.coreboot.org/Mailinglist
The copyright on coreboot is owned by quite a large number of individual developers and companies. Please check the individual source files for details.
coreboot is licensed under the terms of the GNU General Public License (GPL). Some files are licensed under the "GPL (version 2, or any later version)", and some files are licensed under the "GPL, version 2". For some parts, which were derived from other projects, other (GPL-compatible) licenses may apply. Please check the individual source files for details.
This makes the resulting coreboot images licensed under the GPL, version 2.