STRUCT CXL_DEV_STATE(9)

💅 struct cxl_dev_state(9) — like, the whole Kernel API Manual, but make it make sense

okay bestie, so this is struct cxl_dev_state(9) from the Kernel API Manual, and honestly? it's kind of a main character. it's the driver device state. let's get into it 🫶

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✨ NAME ✨

struct cxl_dev_state — the driver device state. that's it, that's the vibe.

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🌸 SYNOPSIS 🌸

struct cxl_dev_state {
    struct device *dev;
    struct cxl_memdev *cxlmd;
    struct cxl_register_map reg_map;
    struct cxl_device_regs regs;
    int cxl_dvsec;
    bool rcd;
    bool media_ready;
    struct resource dpa_res;
    struct cxl_dpa_partition part[CXL_NR_PARTITIONS_MAX];
    unsigned int nr_partitions;
    u64 serial;
    enum cxl_devtype type;
    struct cxl_mailbox cxl_mbox;
  #ifdef CONFIG_CXL_FEATURES;
    struct cxl_features_state *cxlfs;
  #endif;
 };

no cap, that #ifdef CONFIG_CXL_FEATURES; block is conditional — only shows up when features are compiled in 💖

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🎀 Members 🎀

okay so let's go member by member, because every single one is here for a reason:

• dev — the device associated with this CXL state. like, the actual device it's all about 💅
• cxlmd — the device representing the CXL.mem capabilities of dev
• reg_map — component and ras register mapping parameters
• regs — Parsed register blocks
• cxl_dvsec — Offset to the PCIe device DVSEC
• rcd — operating in RCD mode (CXL 3.0 9.11.8 CXL Devices Attached to an RCH). yes, the spec section is included, we don't skip citations here 🧚
• media_ready — Indicate whether the device media is usable
• dpa_res — Overall DPA resource tree for the device
• part — DPA partition array
• nr_partitions — Number of DPA partitions
• serial — PCIe Device Serial Number
• type — Generic Memory Class device or Vendor Specific Memory device
• cxl_mbox — CXL mailbox context
• cxlfs — CXL features context

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👑 Description 👑

cxl_dev_state represents the CXL driver/device state. it gives you an interface to mailbox commands, plus some cached data about the device. lowkey iconic of it.

and a heads up so you're not surprised: Currently only memory devices are represented. that's the whole scope, bestie, don't come looking for anything else 😭

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🦋 SEE ALSO 🦋

• Kernel file ./include/cxl/cxl.h — enum cxl_devtype(9)
• struct cxl_register_map(9)
• struct cxl_dpa_perf(9)
• struct cxl_dpa_partition(9)

go read those next, iykyk 💜

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alright that's the whole page, periodt. this lil beauty lives at ./include/cxl, dated October 2026, and yes it's filed under struct cxl_dev_state(9) ✨ slay ✨