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<noinclude> | <noinclude>{{ApplicableFor | ||
{{ | |MPUs list=STM32MP13x, STM32MP15x | ||
|MPUs checklist=STM32MP13x, STM32MP15x | |||
}}</noinclude> | |||
</noinclude> | |||
== Article purpose == | == Article purpose == | ||
The '''Reserved-memory''' mechanism<ref>https://www.kernel.org/doc/Documentation/devicetree/bindings/reserved-memory/reserved-memory. | The '''Reserved-memory''' mechanism<ref>https://www.kernel.org/doc/Documentation/devicetree/bindings/reserved-memory/reserved-memory.yaml</ref> allows reserving memory regions in the kernel. This mechanism is used by drivers to allocate buffers in specific memory regions (such as internal SRAM) or to get a dedicated memory pool that will not be managed by Linux<sup>®</sup> conventionnal memory allocator (in DDR).<br /> | ||
== Use cases == | == Use cases == | ||
In | In OpenSTLinux, the '''reserved-memory''' is used: | ||
* the [[Dmaengine overview|dmaengine driver]] to reserve the region where [[DMA internal peripheral|DMA]] buffers are allocated, typically [[MCU SRAM internal memory|MCU SRAM]]. | * On {{MicroprocessorDevice | device=1}} by: | ||
* the [[Linux remoteproc framework overview|remoteproc driver]] to reserve the regions in [[RETRAM internal memory|RETRAM]] and [[MCU SRAM internal memory|MCU SRAM]] where the coprocessor firmware will be loaded. | :* the [[Dmaengine overview|dmaengine driver]] to reserve the region where [[DMA internal peripheral|DMA]] buffers are allocated, typically in internal SRAM ([[STM32MP13 SRAM internal memory|STM32MP13 SRAM]] or [[STM32MP15 MCU SRAM internal memory|STM32MP15 MCU SRAM]]). | ||
* the [[Linux_RPMsg_framework_overview|RPMsg driver]] to reserve the region where [[Linux RPMsg framework overview|RPMsg]] buffers used for interprocess communication with the coprocessor, are allocated, typically [[MCU SRAM internal memory|MCU SRAM]]. | * On {{MicroprocessorDevice | device=15}} by: | ||
* the | :* the [[Linux remoteproc framework overview|remoteproc driver]] to reserve the regions in [[RETRAM internal memory|RETRAM]] and [[STM32MP15 MCU SRAM internal memory|MCU SRAM]] where the coprocessor firmware will be loaded. | ||
:* the [[Linux_RPMsg_framework_overview|RPMsg driver]] to reserve the region where [[Linux RPMsg framework overview|RPMsg]] buffers used for interprocess communication with the coprocessor, are allocated, typically [[STM32MP15 MCU SRAM internal memory|MCU SRAM]]. | |||
:* the Vivante Gcnano driver to reserve the region where the GPU working memory is allocated, typically the [[DDRCTRL and DDRPHYC internal peripherals|DDR]]. | |||
== References == | == References == | ||
<references/> | <references/> | ||
<noinclude> | |||
[[Category:RAM]] | |||
{{PublicationRequestId | 8903 | 2018-09-25 - AnneJ}} | |||
</noinclude> | |||
Latest revision as of 17:37, 24 October 2023
1. Article purpose
The Reserved-memory mechanism[1] allows reserving memory regions in the kernel. This mechanism is used by drivers to allocate buffers in specific memory regions (such as internal SRAM) or to get a dedicated memory pool that will not be managed by Linux® conventionnal memory allocator (in DDR).
2. Use cases
In OpenSTLinux, the reserved-memory is used:
- On STM32MP1 series by:
- the dmaengine driver to reserve the region where DMA buffers are allocated, typically in internal SRAM (STM32MP13 SRAM or STM32MP15 MCU SRAM).
- On STM32MP15x lines
by:
- the remoteproc driver to reserve the regions in RETRAM and MCU SRAM where the coprocessor firmware will be loaded.
- the RPMsg driver to reserve the region where RPMsg buffers used for interprocess communication with the coprocessor, are allocated, typically MCU SRAM.
- the Vivante Gcnano driver to reserve the region where the GPU working memory is allocated, typically the DDR.
3. References