Add option to use CCMRAM on F303xE. #11756
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@JammuKekkonen, thank you for your changes. |
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CI started |
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@ARMmbed/team-st-mcd for your review, too. |
Test run: SUCCESSSummary: 11 of 11 test jobs passed |
| @@ -56,6 +56,10 @@ LR_IROM1 MBED_APP_START MBED_APP_SIZE { ; load region size_region | |||
| .ANY (+RW +ZI) | |||
| } | |||
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| RW_IRAM2 (0x10000000) (0x4000) { ; RW data | |||
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Could you reorder this? It's confusing because you've put the CCM RAM in between RW_IRAM1 and ARM_LIB_STACK, which are adjacent.
It's probably a good idea to name the execution region CCMRAM too, if you're manually directing stuff there. RW_IRAM2 could be construed as general-purpose RAM.
(I'm assuming you're not viewing it as general-purpose RAM, or you would be directing general stuff there. Comment should probably say that rather than "RW data").
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Current way follows the naming and location in F437xG.
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Feel free to fix that too.
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Ooh, 437's sct is a mess. It's got 5 RAM regions, three of which are adjacent, but they're all separated in the map.
The three together are (RW_m_crash_data, RW_IRAM1, ARM_LIB_STACK) in that order, then RW_IRAM2 (CCMRAM) and RW_IRAM3 (BKPSRAM) are separate.
Its GCC ld and IAR icf seem neat enough.
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fixed the order and renamed to CCMRAM
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General thought, which you don't need to address here. Any platform which does have CCM RAM probably should use it for at least the boot/interrupt stack, and maybe the main thread stack. Those are a lot of your scratch space which you'd want to be fast, and you probably get away with avoiding any bus mastering issues that stop you viewing it as general-purpose static/heap RAM - you won't be generally trying to DMA into the stack. And gives you a RAM saving without any explicit application area attribute additions. |
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@ARMmbed/team-st-mcd ^^ review the suggestion above |
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Discussed with @JammuKekkonen - this is fine as-is, but the F303 doesn't have Ethernet, and there's no DMA in the HAL, so we can see no reason not to treat the CCMRAM as general-purpose RAM for Mbed OS. So a later extension might be to pop a The F437 does have Ethernet, but some boards don't. Maybe the F437 scatter file could do the same based on a |
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CI started Still waiting for @ARMmbed/team-st-mcd review |
Test run: SUCCESSSummary: 11 of 11 test jobs passed |
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Add option to place data to ccm ram on STM32F303xE. Similar functionality exists already for at least STM32F437xG target.
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