cxl_calc_interleave_pos(9)

✨ cxl_calc_interleave_pos(9) ✨

okay so bestie, we're in the Kernel API Manual today and this function is literally the main character of interleave math 🎀

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🌸 NAME 🌸

cxl_calc_interleave_pos — calculate an endpoint position in a region 💅

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🦋 SYNOPSIS 🦋

int cxl_calc_interleave_pos (struct cxl_endpoint_decoder *cxled , struct
       range *hpa_range );

like, yes, it wraps onto two lines, that's just how it's printed, don't come for me 😭

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🍓 ARGUMENTS 🍓

• cxled — the endpoint decoder that's a member of the given region 🫶
• hpa_range — the endpoint's HPA range, already translated ✨

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💖 DESCRIPTION 💖

okay so the way this works: the endpoint position gets calculated by traversing the topology from the endpoint all the way up to the root decoder, and iteratively applying this calculation:

position = position * parent_ways + parent_pos;

and position is inferred from switch and root decoder target lists. iykyk 🔥

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🌈 RETURN 🌈

• position >= 0 on success — slay 💅
• -ENXIO on failure — 💀

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👑 SEE ALSO 👑

• Kernel file ./drivers/cxl/core/region.c
• cxl core region(9)
• cxl_port_pick_region_decoder(9)
• cxl_port_attach_region(9)
• devm_cxl_add_region(9)
• cxl_validate_translation_params(9)

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and that's the whole page, no cap 🧚 this came out of ./drivers/cxl/core, dated October 2026 — ok bye, go read the source, ily 🫶💜