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159f2ef03a
Accessing the flash part where the ramstage resides can be slow when loading it. In order to save time in the S3 resume path a copy of the relocated ramstage is saved just below the location the ramstage was loaded. Then on S3 resume the cached version of the relocated ramstage is copied back to the loaded address. This is achieved by saving the ramstage entry point in the romstage_handoff structure as reserving double the amount of memory required for ramstage. This approach saves the engineering time to make the ramstage reentrant. The fast path in this change will only be taken when the chipset's romstage code properly initializes the s3_resume field in the romstage_handoff structure. If that is never set up properly then the fast path will never be taken. e820 entries from Linux: BIOS-e820: [mem 0x000000007bf21000-0x000000007bfbafff] reserved BIOS-e820: [mem 0x000000007bfbb000-0x000000007bffffff] type 16 The type 16 is the cbmem table and the reserved section contains the two copies of the ramstage; one has been executed already and one is the cached relocated program. With this change the S3 resume path on the basking ridge CRB shows to be ~200ms to hand off to the kernel: 13 entries total: 1:95,965 2:97,191 (1,225) 3:131,755 (34,564) 4:132,890 (1,135) 8:135,165 (2,274) 9:135,840 (675) 10:135,973 (132) 30:136,016 (43) 40:136,581 (564) 50:138,280 (1,699) 60:138,381 (100) 70:204,538 (66,157) 98:204,615 (77) Change-Id: I9c7a6d173afc758eef560e09d2aef5f90a25187a Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: http://review.coreboot.org/2800 Tested-by: build bot (Jenkins) Reviewed-by: Ronald G. Minnich <rminnich@gmail.com> |
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| 3rdparty@ba8caa30bd | ||
| documentation | ||
| payloads | ||
| src | ||
| util | ||
| .gitignore | ||
| .gitmodules | ||
| .gitreview | ||
| COPYING | ||
| Makefile | ||
| Makefile.inc | ||
| README | ||
------------------------------------------------------------------------------- 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 ------------------ * gcc / g++ * make Optional: * doxygen (for generating/viewing documentation) * iasl (for targets with ACPI support) * gdb (for better debugging facilities on some targets) * ncurses (for 'make menuconfig') * 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.