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76f8dbc4f7
SPD revision 1.1 introduced FTB timings, an extra set of SPD values that specify a more precise tCKmin, tAAmin, tRCDmin, tRPmin and tRCmin. For backwards compatibility, the MTB is usually rounded up and the FTB part is negative. For this reason some memories were not set up optimally, as the FTB part was ignored and the resulting timing wasn't set to the minimum value. The tests were performed on a Lenovo X220 with two Micron 8KTF51264HZ-1G9E (1866 MHz): reading only the MTB part, coreboot reports a tCKmin of 1.125 ns, corresponding to a working frequency of 800 MHz; with the additional tCKmin FTB part (-0.054 ns) the new (rounded) value is 1.070 ns, valid for a 933 MHz operation. Tested also with Ballistix DDR3-1866 SODIMM on Lenovo T420: the memory is now detected as DDR3-1866 instead of DDR3-1600. Some manufacturers (like Micron) seems to expect a small rounding on the timings, so a nearest-value rounding is performed. If this assumption isn't correct, an error up to ~2 ps can be committed, which is low enough to be safely ignored. Change-Id: Ib98f2e70820f207429d04ca6421680109a81f457 Signed-off-by: Nicola Corna <nicola@corna.info> Reviewed-on: https://review.coreboot.org/17476 Tested-by: build bot (Jenkins) Reviewed-by: Patrick Rudolph <siro@das-labor.org> Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net> |
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| 3rdparty | ||
| configs | ||
| Documentation | ||
| payloads | ||
| src | ||
| util | ||
| .checkpatch.conf | ||
| .clang-format | ||
| .gitignore | ||
| .gitmodules | ||
| .gitreview | ||
| COPYING | ||
| gnat.adc | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc | ||
| README | ||
| 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 http://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: * http://www.coreboot.org/Supported_Motherboards * http://www.coreboot.org/Supported_Chipsets_and_Devices 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_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this case). * iasl (for targets with ACPI support) Optional: * doxygen (for generating/viewing documentation) * gdb (for better debugging facilities on some targets) * ncurses (for 'make menuconfig' and 'make nconfig') * flex and bison (for regenerating parsers) Building coreboot ----------------- Please consult http://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 http://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: http://www.coreboot.org You can contact us directly on the coreboot mailing list: http://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.