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Self-refresh is entered during a refresh event, when the rank was previously in a precharge power-down state. The original code would enter self-refresh after a refresh was issued. The device subsequently will issue a refresh on self-refresh entry. On self-refresh exit, the controller will issue another refresh command. Devices require at least one additional refresh to be issued between self-refresh exit and re-entry. This ensures that enough refreshes occur in the case when the device narrowly missed a refresh on self-refresh exit. To minimize the number of refresh operations and still maintain the device requirement, the current logic does the following: 1) The controller will still enter self-refresh from a refresh event, when the previous state was precharge power-down. However, the refresh itself will be bypassed and the controller will immediately issue a self-refresh entry. 2) On a self-refresh exit, the controller will immediately issue a refresh command (per the original logic). This ensures the devices requirements are met and is a convenient way to kick off the command state machine. Change-Id: I1c4b0dcbfa3bdafd755f3ccd65e267fcd700c491 Reviewed-by: Curtis Dunham <curtis.dunham@arm.com> Reviewed-on: https://gem5-review.googlesource.com/10102 Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com> Reviewed-by: Jason Lowe-Power <jason@lowepower.com> Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
This is the gem5 simulator. The main website can be found at http://www.gem5.org A good starting point is http://www.gem5.org/Introduction, and for more information about building the simulator and getting started please see http://www.gem5.org/Documentation and http://www.gem5.org/Tutorials. To build gem5, you will need the following software: g++ or clang, Python (gem5 links in the Python interpreter), SCons, SWIG, zlib, m4, and lastly protobuf if you want trace capture and playback support. Please see http://www.gem5.org/Dependencies for more details concerning the minimum versions of the aforementioned tools. Once you have all dependencies resolved, type 'scons build/<ARCH>/gem5.opt' where ARCH is one of ALPHA, ARM, NULL, MIPS, POWER, SPARC, or X86. This will build an optimized version of the gem5 binary (gem5.opt) for the the specified architecture. See http://www.gem5.org/Build_System for more details and options. With the simulator built, have a look at http://www.gem5.org/Running_gem5 for more information on how to use gem5. The basic source release includes these subdirectories: - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - src: source code of the gem5 simulator - system: source for some optional system software for simulated systems - tests: regression tests - util: useful utility programs and files To run full-system simulations, you will need compiled system firmware (console and PALcode for Alpha), kernel binaries and one or more disk images. Please see the gem5 download page for these items at http://www.gem5.org/Download If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.