784c6519de
The nRF5340 application core comes out of reset with its flash cache disabled and nothing in the tree turns it on. nrf53_start() does call nrf53_enable_icache(), but that drives NVMC ICACHECNF and is gated on NRF53_FLASH_PREFETCH, which depends on NRF53_NETCORE -- so it is not even compiled for an application core build. The nRF5340 places the application core cache in a separate CACHE peripheral at 0x50001000. NRF53_CACHE_BASE is already defined in hardware/nrf53_memorymap_cpuapp.h, but there was no register header and no enable. Add both, behind a new NRF53_CACHE option. The option defaults to n, matching ARMV7M_ICACHE and ARMV8M_ICACHE/DCACHE, so that upgrading does not silently change the behaviour of an existing configuration. Measured on nrf5340-dk at 64 MHz with apps/benchmarks/scbench: protected-build syscall round trip 64.1 us -> 29.6 us userspace sem wait + post pair 4.75 us -> 1.95 us Flat builds benefit equally; the gain is on any flash-resident code path. Per the nRF5340 Product Specification, 'CACHE - Instruction and data cache', 'both instruction and data accesses towards flash memory or XIP code regions are cached'. The cache does not observe NVMC programming, so nrf53_flash.c has to account for it: both up_progmem_eraseblock() and up_progmem_write() read back what they just programmed to verify it, and up_progmem_ispageerased() reads a whole page, so lines covering the region being programmed are commonly resident. Bypass the cache for the duration of an erase or a write and invalidate it before re-enabling, so the verify reads the array and later readers do too. That file is built only when NRF53_PROGMEM is selected, which is not the default. Signed-off-by: AlmAck <gluca86@gmail.com> |
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| .github | ||
| arch | ||
| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .codespell-ignore-lines | ||
| .codespellrc | ||
| .editorconfig | ||
| .gitignore | ||
| .gitmessage | ||
| .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.