STRUCT CXL_DPORT(9)

💖 struct cxl_dport(9) 💖

okay bestie, welcome to the Kernel API Manual — we’re looking at the CXL downstream port struct, and it’s lowkey iconic. no cap, every field is here. 💅

✨ NAME ✨

struct cxl_dport — a CXL downstream port, periodt.

🎀 SYNOPSIS 🎀

struct cxl_dport {
    struct device *dport_dev;
    struct cxl_register_map reg_map;
    int port_id;
    struct cxl_rcrb_info rcrb;
    bool rch;
    struct cxl_port *port;
    struct cxl_regs regs;
    struct access_coordinate coord[ACCESS_COORDINATE_MAX];
    long link_latency;
    int gpf_dvsec;
};

💅 Members 💅

okay so these are the fields, and we are not skipping any of them. main character energy only. 🌟

• dport_dev — PCI bridge or firmware device representing the downstream link. literally the device vibe check for the link.
• reg_map — component and ras register mapping parameters. the mapping details live here, bestie.
• port_id — unique hardware identifier for dport in decoder target list. it’s giving “I know exactly which port I am.” 🔥
• rcrb — Data about the Root Complex Register Block layout. yes, all the layout info. 🎀
• rch — Indicate whether this dport was enumerated in RCH or VH mode. tiny bool, big “which mode was I in?” energy.
• port — reference to cxl_port that contains this downstream port. it points back to its port parent, slay. 🫶
• regs — Dport parsed register blocks. parsed and present. ✨
• coord — access coordinates (bandwidth and latency performance attributes). performance attributes stored in an array, iykyk.
• link_latency — calculated PCIe downstream latency. the latency math has already been done, no stress. 💜
• gpf_dvsec — Cached GPF port DVSEC. cached, cute, done. 🦋

🌈 SEE ALSO 🌈

peep these, bestie — the whole friend group is here:

• Kernel file ./drivers/cxl/cxl.h
• cxl objects(9)
• struct cxl_decoder(9)
• struct cxl_endpoint_decoder(9)
• struct cxl_switch_decoder(9)
• struct cxl_rd_ops(9)
• struct cxl_root_decoder(9)
• struct cxl_region_params(9)
• struct cxl_region(9)
• struct cxl_port(9)
• struct cxl_root(9)
• struct cxl_ep(9)
• struct cxl_region_ref(9)
• struct cxl_endpoint_dvsec_info(9)

signed off from ./drivers/cxl, dated October 2026 — mwah, kisses, go be iconic with your downstream ports 💋🌸