Difference between revisions of "Reserved memory"

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1 Article purpose[edit]

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 MCU SRAM) or to get a dedicated memory pool that will not be managed by Linux® conventionnal memory allocator (in DDR).

2 Use cases[edit]

In STM32 MPU Linux OS, the reserved-memory is used by:

  • the dmaengine driver to reserve the region where DMA buffers are allocated, typically MCU SRAM.
  • 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[edit]


== Article purpose ==
The '''Reserved-memory''' mechanism<ref>https://www.kernel.org/doc/Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt</ref> allows reserving memory regions in the kernel. This mechanism is used by drivers to allocate buffers in specific memory regions (such as [[MCU SRAM internal memory|MCU SRAM]]) or to get a dedicated memory pool that will not be managed by Linux<sup>&reg;</sup> conventionnal memory allocator (in [[DDRCTRL and DDRPHYC internal peripherals|DDR]]).<br />


== Use cases ==
In STM32 MPU Linux OS, the '''reserved-memory''' is used by:
* the [[Dmaengine overview|dmaengine driver]] to reserve the region where [[DMA internal peripheral|DMA]] buffers are allocated, typically [[MCU SRAM internal memory|MCU SRAM]].
* 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 [[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]].
* the [[Vivante_GCNANO_GPU_overview#Vivante_Gcnano_kernel_driver|Vivante Gcnano driver]] Gcnano driver to reserve the region where the GPU working memory is allocated, typically the [[DDRCTRL and DDRPHYC internal peripherals|DDR]].

== References ==<references/>

<noinclude>

[[Category:RAM]]
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* 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 [[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 [[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]].
 
* 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]].
* the [[Vivante_GCNANO_GPU_overview#Vivante_Gcnano_kernel_driver|Vivante Gcnano driver]] to reserve the region where the GPU working memory is allocated, typically the [[DDRCTRL and DDRPHYC internal peripherals|DDR]].
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* 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 ==