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Add pico_set_modified_binary_type function #2137

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Add pico_set_modified_binary_type function #2137

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will-v-pi
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@will-v-pi will-v-pi commented Dec 13, 2024 •
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This adds a function to create binaries with modified RAM/SCRATCH addresses

For example, to only use SRAM1 so you can power down SRAM0 in your binary you could use

pico_set_modified_binary_type(<my_exe> flash RAM "0x20040000" "256k")

To create a XIP_SRAM only binary you could use

pico_set_modified_binary_type(<my_exe> sram
    RAM "0x13ffc000" "12k"
    SCRATCH_X "0x13fff000" "2k"
    SCRATCH_Y "0x13fff800" "2k")

The existing memmap_blocked_ram.ld could be created using

pico_set_modified_binary_type(<my_exe> flash RAM "0x21000000" "256k")

This adds some tests to kitchen_sink to ensure that these generated linker scripts match the default ones, to prevent them diverging

@kilograham kilograham self-assigned this Jan 11, 2025
@kilograham kilograham self-requested a review January 11, 2025 19:59
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kilograham commented Jan 11, 2025 •
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this is useful functionality; we need to think about whether this is best as modifying the linker script or injecting as per FLASH_SIZE (either way it should - and i think it is for FLASH_SIZE be modifiable via linker script)

@kilograham kilograham added this to the 2.2.0 milestone Jan 31, 2025
@lurch lurch added the build label Mar 20, 2025
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lurch commented Mar 20, 2025

To create a XIP_SRAM only binary you could use

pico_set_modified_binary_type(<my_exe> no_flash
    RAM "0x13ffc000" "12k"
    SCRATCH_X "0x13fff000" "2k"
    SCRATCH_Y "0x13fff800" "2k")

Perhaps it would be nice if you could use symbolic aliases here, rather than having to use hardcoded addresses? 🤷

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lurch commented Mar 20, 2025

Maybe this is a first step towards #1547 ?

@will-v-pi
Add pico_set_modified_binary_type function
b2dba0e 
Allows creating binaries using an existing binary type & linker script, but with modified RAM/SCRATCH addresses

For example, to only use SRAM1 so you can power down SRAM0 in your binary you could use `pico_set_modified_binary_type(<my_exe> no_flash RAM "0x20040000" "256k"`
@will-v-pi
Create new linker scripts rather than modifying existing
4430502 
New template flash and sram linker scripts, to avoid need for parsing the file

Adds a test to kitchen_sink that these new linker scripts produce the same defaults, to ensure modifications to linker scripts are propogated
@will-v-pi will-v-pi force-pushed the set-modified-binary-type branch from 664d230 to 4430502 Compare September 1, 2025 13:53
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this is useful functionality; we need to think about whether this is best as modifying the linker script or injecting as per FLASH_SIZE (either way it should - and i think it is for FLASH_SIZE be modifiable via linker script)

I've thought it through a bit more - injecting like FLASH_SIZE wouldn't work, because you might need different injected bits for each binary in your project, whereas FLASH_SIZE is set project-wide as it's fixed for a given board

Instead, I've added separate template linker scripts memmap_sram.template.ld and memmap_flash.template.ld, which are copies of memmap_no_flash.ld and memmap_default.ld respectively with the RAM and SCRATCH regions set to be templated. I've also added tests at compile time to kitchen_sink to ensure these files stay in sync.

These template linker scripts could then be extended further to support #1547 - but I think that's probably best for a second PR, I'd like to just get this functionality in first so you can make SRAM1 or XIP_SRAM binaries

lurch
lurch reviewed Sep 1, 2025
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src/rp2_common/pico_crt0/rp2040/memmap_flash.template.ld
@@ -0,0 +1,286 @@
/* Based on GCC ARM embedded samples.
Defines the following symbols for use by code:
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There are a load of double-underscore identifiers (e.g. __logical_binary_start, __embedded_block_end, __binary_info_start) which aren't included in this list. Should they be? 🤷 (I know almost nothing about linker scripts)

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This is an identical copy of memmap_default.ld, so changing anything other than the memory regions is outside the scope of this PR - maybe worth pinging @kilograham about tidying up the linker scripts?

lurch
lurch reviewed Sep 1, 2025
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lurch
lurch reviewed Sep 1, 2025
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