Lup Yuen Lee
b14dc8f8ae
This PR configures the T-Head MMU to cache the the User Text, Data and Heap. We enable the MMU Flags for Shareable, Bufferable and Cacheable, as explained in this article: https://lupyuen.github.io/articles/plic3#appendix-mmu-caching-for-t-head-c906 This PR fixes the Slow Memory Access for NuttX Apps on BL808 and SG2000 SoCs: https://github.com/apache/nuttx/issues/12696. With this fix, SG2000 NuttX CoreMark jumps from 21 to 2,423. (Close to SG2000 Debian CoreMark) We introduce a Kconfig Option: `ARCH_MMU_EXT_THEAD` ("System Type > Enable T-Head MMU extension support"). Enabling this Kconfig Option will configure the T-Head MMU to cache the User Text, Data and Heap. This PR enables the MMU cache for only SG2000 SoC (Milk-V Duo S SBC). The next PR will apply the same settings to BL808 SoC (Pine64 Ox64 SBC). Modified Files: `arch/risc-v/Kconfig`: Added Kconfig Option `ARCH_MMU_EXT_THEAD` that will configure the T-Head MMU. Enabled `ARCH_MMU_EXT_THEAD` for SG2000 SoC. `arch/risc-v/src/common/riscv_mmu.h`: Set the T-Head MMU Flags (Shareable, Bufferable and Cacheable) for User Text, Data and Heap, if `ARCH_MMU_EXT_THEAD` is enabled `arch/risc-v/src/common/riscv_addrenv.c`: Extended the MMU Flags from 32 bits to 64 bits, to accommodate the T-Head MMU Flags `arch/risc-v/src/common/riscv_exception.c`: Extended the MMU Flags from 32 bits to 64 bit, to accommodate the T-Head MMU Flags. This code is enabled only for MMU Paging (`CONFIG_PAGING`). |
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| arch | ||
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| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .gitignore | ||
| .pre-commit-config.yaml | ||
| .yamllint | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| ReleaseNotes | ||
Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).
For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.
Getting Started
First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.
Documentation
You can find the current NuttX documentation on the Documentation Page.
Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.
The old NuttX documentation is still available in the Apache wiki.
Supported Boards
NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.
Contributing
If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.
License
The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.