STRUCT CDNSP_REV_CAP(9)

💅 struct cdnsp_rev_cap(9) — controller capabilities, bestie

okay so picture this: you're deep in the Kernel API Manual (section 9, the big-kid section, we love her) and you stumble into struct cdnsp_rev_cap. That's the whole vibe. She's a struct, she's about controller capabilities, and she's got exactly six members and zero drama. ✨

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🌸 SYNOPSIS 🌸

struct cdnsp_rev_cap {
    __le32 ext_cap;
    __le32 rtl_revision;
    __le32 rx_buff_size;
    __le32 tx_buff_size;
    __le32 ep_supported;
    __le32 ctrl_revision;
 };

look at her. six __le32s. no pointers, no unions, no cursed nesting — just clean little fields living their truth. we stan a low-maintenance struct 🫶

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🎀 Members 🎀

okay let's meet the cast, one by one, main character energy only:

• ext_cap — the header for the RTL Revision Extended Capability. yes, header, she's the intro card, she announces the extended capability before the actual info walks in. iconic behaviour honestly.
• rtl_revision — the RTL revision. that's it. that's the whole job. she tells you which RTL revision it is and she does it flawlessly 💅
• rx_buff_size — the Rx buffer sizes. receiving side, buffer, sizes. slay.
• tx_buff_size — the Tx buffer sizes. same energy, sending side this time. twins fr fr 🦋
• ep_supported — the supported endpoints. like, which endpoints are even invited to the party. no cap, this is the guest list.
• ctrl_revision — the Controller revision ID. the ID card of the controller itself. show it at the door please 👑

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🔥 SEE ALSO 🔥

so there's a whole friend group and she's not the only one. this is the kernel file to go look at:

./drivers/usb/cdns3/cdnsp-gadget.h

and the rest of the squad (seriously, tag yourself, I'm struct cdnsp_ring(9)):

• struct cdnsp_cap_regs(9)
• struct cdnsp_op_regs(9)
• struct cdnsp_port_regs(9)
• struct cdnsp_intr_reg(9)
• struct cdnsp_run_regs(9)
• struct cdnsp_doorbell_array(9)
• struct cdnsp_container_ctx(9)
• struct cdnsp_slot_ctx(9)
• struct cdnsp_ep_ctx(9)
• struct cdnsp_stream_info(9)
• struct cdnsp_ep(9)
• struct cdnsp_device_context_array(9)
• struct cdnsp_transfer_event(9)
• struct cdnsp_link_trb(9)
• struct cdnsp_event_cmd(9)
• struct cdnsp_segment(9)
• struct cdnsp_td(9)
• struct cdnsp_dequeue_state(9)
• struct cdnsp_ring(9)
• struct cdnsp_erst_entry(9)
• struct cdnsp_erst(9)
• struct cdnsp_request(9)
• struct cdnsp_port(9)
• struct cdnsp_device(9)
• next_request(9)

like I said — a whole friend group. go read them all, iykyk 🌈

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lowkey the most important thing here: every single one of those fields is a __le32, so don't go assuming host byte order, bestie. little-endian, always, no exceptions, periodt. 💀

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and that's the page!! brought to you by the fine people at ./drivers/usb/cdns3, dated October 2026 — stars, butterflies, and one (1) extremely well-documented controller capability struct. go forth and slay, and remember: 🧚 the kernel is literally just structs all the way down 🧚