STM32: implement CCM as a generic DTCM #100590
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Rename the CCM memory region for STM32F3 and STM32F4 series such that the CCM node can be used as a `zephyr,dtcm`. Signed-off-by: Mathieu Choplain <[email protected]>
The STM32 CCM can be used as `/chosen/zephyr,dtcm` - transition all boards to this chosen to allow deprecation/removal of the legacy `zephyr,ccm`. Signed-off-by: Mathieu Choplain <[email protected]>
Update the ST CCM usage sample to be compatible with CCM as `zephyr,dtcm`. Signed-off-by: Mathieu Choplain <[email protected]>
doc: dts: api: remove documentation of chosen `zephyr,ccm` The `zephyr,ccm` chosen was an ST-specific property which has been replaced by the generic `zephyr,dtcm`. Remove region initialization code from the common arch init code (+ BSS zeroing from common XIP init code). Signed-off-by: Mathieu Choplain <[email protected]>
Remove section names and symbols relating to the STM32 CCM region, `/chosen/zephyr,ccm`, which is replaced by the standard DTCM region `/chosen/zephyr,dtcm`. For backwards compatibility, the old `__ccm_<...>_section` attribute macros are aliased to `__dtcm_<...>_section` (until release 4.5). Signed-off-by: Mathieu Choplain <[email protected]>
The `st,stm32-ccm` is now used though the generic DTCM mechanism: remove all SoC-specific code which was used to implement support for it. Signed-off-by: Mathieu Choplain <[email protected]>
The `zephyr,ccm` chosen was an ST-specific property which has been replaced by the generic `zephyr,dtcm`. Remove it from the DTS documentation. Signed-off-by: Mathieu Choplain <[email protected]>
Document remplacement of the ST-specific `zephyr,ccm` by `zephyr,dtcm` along with actions to take in application code in the migration guide. Signed-off-by: Mathieu Choplain <[email protected]>
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area: Samples
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erwango
approved these changes
Dec 5, 2025
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Once this PR is merged, I will open the backwards compatibility macros removal PR for v4.5. |
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nashif
approved these changes
Dec 6, 2025
teburd
approved these changes
Dec 6, 2025
JarmouniA
approved these changes
Dec 6, 2025
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#4184 introduced
st,stm32-ccmand the associated/chosen/zephyr,ccmto support the ST-specific CCM (Core-Coupled Memory) found in STM32F3 and STM32F4 series SoCs, back when the more genericzephyr,dtcmdid not exist (it was introduced later by #17123).Fast-forward years of tree evolution, the CCM can now easily be supported as a
zephyr,dtcm: move to this more sensible solution which requires less maintenance and allows cleaning up various warts across the tree.samples/boards/st/ccmis kept to allow validation of the feature but really is vendor-agnostic now (besides wording) so it could be moved out ofsamples/boards(to where is up for debate...)Compatibility:
warning: orphan section '.dtcm_noinit' from '...' being placed in section '.dtcm_noinit')s/zephyr,ccm/zephyr,dtcmin DTS__ccm_<...>_sectiontype annotationszephyr,dtcmis built properly__DEPRECATED_MACROwhich allows finding and replacing usage easily__ccm_start), which should not have been used much if everunknown identifier __ccm_<XXX>at use site