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This change adds support for a common block memory driver that can be used for performing the required operations to read SPD data for different memory channel DIMMs. This data can then be used by the SoC code to populate different memory related UPDs. Most recent Intel platforms follow a similar pattern for configuring FSP-M UPDs for initializing memory. These platforms use one of the following topologies: 1. Memory down 2. DIMM modules 3. Mixed Thus, SPD data is either obtained from CBFS (for memory down topology) or from on-module EEPROM (for DIMM modules). This SPD data read from CBFS or EEPROM is then passed into FSP-M using SPD UPDs for different channels/DIMMs as per the memory organization. Similarly, DQ/DQS configuration is accepted from mainboard and passed into FSP-M using UPDs as per the FSP-M/MRC organization of memory channels. Different memory technologies on a platform support physical channels of different widths. Since the data bus width is fixed for a platform, the number of physical channels is determined by data bus width / physical channel width. The number of physical channels are different depending upon the size of physical channel supported by the memory technology. FSP-M for a platform uses the same set of UPDs for different memory technologies and aims at providing maximum flexibility. Thus, the platform code needs to format mainboard inputs for DQ, DQS and SPD into the UPDs appropriately as per the memory technology used by the board. Example: DDR4 on TGL supports 2 physical channels each 64-bit wide. However, FSP-M UPDs assume channels 16-bit wide. Thus, FSP-M provides 16 UPDs for SPDs (considering 2 DIMMs per channel and 8 channels with each channel 16-bit wide). Hence, for DDR4, only the SPD UPDs for MRC channel 0 and 4 are supposed to be used. This common driver allows the SoC to define the attributes of the platform: 1. DIMMS_PER_CHANNEL: Maximum DIMMs that are supported per channel by any memory technology on the platform 2. DATA_BUS_WIDTH: Width of the data bus. 3. MRC_CHANNEL_WIDTH: Width of the channel as used by the MRC to define UPDs. In addition to this, the SoC can define different attributes of each memory technology supported by the platform using `struct soc_mem_cfg`: 1. Number of physical channels 2. Physical channel to MRC channel mapping 3. Masks for memory down topologies Using the above information about different memory technologies supported by the platform and the mainboard configuration for SPD, the common block memory driver reads SPD data and provides pointers to this data for each dimm within each channel back to the SoC code. SoC code can then use this information to configure FSP-M UPDs accordingly. In addition to that, the common block driver also returns information about how the channels are populated so that the SoC code can use this information to expose DQ/DQS information in FSP-M UPDs. This driver aims at minimizing the effort required for supporting different memory technologies on any new Intel SoC by reducing per-SoC effort to a table of configurations rather than having to implement similar logic for each SoC. BUG=b:172978729 Change-Id: I256747f0ffc49fb326cd8bc54a6a7b493af139c0 Signed-off-by: Furquan Shaikh <furquan@google.com> Reviewed-on: https://review.coreboot.org/c/coreboot/+/49040 Reviewed-by: Angel Pons <th3fanbus@gmail.com> Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org> Reviewed-by: EricR Lai <ericr_lai@compal.corp-partner.google.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org> |
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| .checkpatch.conf | ||
| .clang-format | ||
| .editorconfig | ||
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| .gitreview | ||
| AUTHORS | ||
| COPYING | ||
| gnat.adc | ||
| MAINTAINERS | ||
| Makefile | ||
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| README.md | ||
| toolchain.inc | ||
coreboot README
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.
Payloads
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.
Supported Hardware
coreboot supports a wide range of chipsets, devices, and mainboards.
For details please consult:
Build Requirements
- make
- gcc / g++
Because Linux distribution compilers tend to use lots of patches. coreboot
does lots of "unusual" things in its build system, some of which break due
to those patches, sometimes by gcc aborting, sometimes - and that's worse -
by generating broken object code.
Two options: use our toolchain (eg. make crosstools-i386) or enable the
ANY_TOOLCHAINKconfig option if you're feeling lucky (no support in this case). - iasl (for targets with ACPI support)
- pkg-config
- libssl-dev (openssl)
Optional:
- doxygen (for generating/viewing documentation)
- gdb (for better debugging facilities on some targets)
- ncurses (for
make menuconfigandmake nconfig) - flex and bison (for regenerating parsers)
Building coreboot
Please consult https://www.coreboot.org/Build_HOWTO for details.
Testing coreboot Without Modifying Your Hardware
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.
Website and Mailing List
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
Copyright and License
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.