STRUCT MHUV3(9)

💖 struct mhuv3(9) 💖

okay so bestie, welcome to the glow-up of struct mhuv3(9) — a Kernel API Manual moment, and honestly? it's giving main character energy for the MHUv3 mailbox controller data 🎀 this is the struct that holds all the deets about one of those blocks, and we're gonna walk through every single field together, no cap.

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✨ NAME ✨

struct mhuv3 — the MHUv3 mailbox controller data. that's it, that's the whole vibe 🦋

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🌸 SYNOPSIS 🌸

struct mhuv3 {
    enum mhuv3_frame frame;
    bool auto_op_full;
    unsigned int major;
    unsigned int minor;
    unsigned int implem;
    unsigned int rev;
    unsigned int var;
    unsigned int prod_id;
    unsigned int num_chans;
    int cmb_irq;
    struct ctrl_page __iomem *ctrl;
    union {
      struct mhu3_pbx_frame_reg __iomem *pbx;
      struct mhu3_mbx_frame_reg __iomem *mbx;
    };
    struct mhuv3_extension *ext[NUM_EXT];
    struct mbox_controller mbox;
 };

literally copy this exactly, okay? no fixing, no "improving", no nothing 😤 the compiler does not care about your aesthetics.

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💅 Members 💅

• frame — the frame type, bestie. it's either MBX_FRAME or PBX_FRAME, pick your fighter ⚔️
• auto_op_full — a flag that tells you whether this MHU supports AutoOp full mode. just a lil yes/no, iconic behaviour ✨
• major — the MHUv3 controller architectural major version. the big number 👑
• minor — the MHUv3 controller architectural minor version. the smol number 🍓
• implem — the MHUv3 controller IIDR implementer. who made it, basically 🫶
• rev — the MHUv3 controller IIDR revision. the revision, ngl 🌈
• var — the MHUv3 controller IIDR variant. the variant, fr fr 🦋
• prod_id — the MHUv3 controller IIDR product_id. the product id itself, we love a literal queen 💜
• num_chans — the total number of channels discovered across all extensions. all of them. every last one 🔥
• cmb_irq — the combined IRQ number, but only if one was found defined. if not, it's just vibes 🙈
• ctrl — a reference to the MHUv3 control page for this block. your map to the control page, iykyk 🎀
• {unnamed_union} — anonymous. yes it's anonymous, no we can't name it, it's mysterious like that 💀
  • pbx — base address of the PBX register mapping region 📍
  • mbx — base address of the MBX register mapping region 📍
• ext — an array holding descriptors for any found implemented extension. it's struct mhuv3_extension *ext[NUM_EXT];, so you know it's an array of pointers, one slot per extension, slay 💅
• mbox — the mailbox controller belonging to the MHU frame. the actual mailbox controller, the whole point, the main event 🌟

lowkey reminder bestie: the union with pbx and mbx is anonymous — that's not me being weird, that's literally in the page. {unnamed_union}. periodt.

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🔥 SEE ALSO 🔥

• Kernel file ./drivers/mailbox/arm_mhuv3.c
• struct mhuv3_protocol_ops(9)
• struct mhuv3_mbox_chan_priv(9)
• struct mhuv3_extension(9)

go read those next, bestie, they're all connected and it's a whole storyline 🧚

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okay so that's the whole page!! and for the cute sign-off: this lives in ./drivers/mailbox, and it's dated October 2026 — so yeah, we're reading a manual from the future, which is honestly very main character of us ⭐💖 byeee 🫶