STRUCT SCMI_VIO_CHANNEL(9)

💖 struct scmi_vio_channel(9) — the kernel API manual, but make it make sense 💖

okay so bestie, we're in the struct scmi_vio_channel(9) page of the Kernel API Manual, and honestly? it's giving "backstage pass to the virtio transport." this one's a struct, not a function — so it's literally just a bundle of fields that describe transport channel information. think of it as the group chat every message in a channel passes through. 🎀

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✨ NAME ✨

struct scmi_vio_channel — transport channel information. that's it, that's the vibe. it's the lil data home for one channel. 🦋

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✨ SYNOPSIS ✨

struct scmi_vio_channel {
    struct virtqueue *vqueue;
    struct scmi_chan_info *cinfo;
    spinlock_t free_lock;
    struct list_head free_list;
    spinlock_t pending_lock;
    struct list_head pending_cmds_list;
    struct work_struct deferred_tx_work;
    struct workqueue_struct *deferred_tx_wq;
    bool is_rx;
    unsigned int max_msg;
    spinlock_t lock;
    struct completion *shutdown_done;
    refcount_t users;
 };

like, look at her. twelve fields, zero notes. 👑

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🌸 Members 🌸

here's the field-by-field breakdown, bestie. no skipping, i promise. 💅

• vqueue — the associated virtqueue. yes girl, the actual queue. 🧚
• cinfo — the SCMI Tx or Rx channel. this is which channel we're on, periodt.
• free_lock — protects access to the free_list. a whole tiny lock just for that list. 🔥
• free_list — list of unused scmi_vio_msg, and listen: it's maintained for Tx channels only. Rx, you're not invited to this one. 🙈
• pending_lock — protects access to the pending_cmds_list. same energy, different list.
• pending_cmds_list — list of pre-fetched commands queued up for later processing. holding it down until it's their turn. ⭐
• deferred_tx_work — the worker for TX deferred replies processing. the main character of the deferral arc. 💀
• deferred_tx_wq — the workqueue for TX deferred replies. where that worker actually lives. 🏠
• is_rx — a bool saying whether the channel is an Rx channel. yes/no, iconic/slay.
• max_msg — maximum number of pending messages for this channel. an unsigned int, so, y'know. capacities. 📬
• lock — protects access to all members except users, free_list and pending_cmds_list. read that again. it's the big lock but not the biggest. those three have their own situation going on. ⚠️
• shutdown_done — a reference to a completion used when freeing this channel. the "we're done here" signal. 🫶
• users — a reference count to currently active users of this channel. refcount_t doing refcount things. 💜

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/firmware/arm_scmi/transports/virtio.c
• Theory of Operation(9)
• struct scmi_vio_msg(9)
• virtio_mark_txdone(9)
• virtio_poll_done(9)

go read those, iykyk. 📚✨

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ngl bestie, the lock field does not cover users, free_list or pending_cmds_list — those three have their own locks/refcounts (free_lock, pending_lock). don't come for the big lock for stuff it never promised to protect. 😭

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and that's the page, babe 🫶 source says ./drivers/firmware/arm_scmi/tr... and it's dated October 2026 — written for struct scmi_vio_channel(9), obviously. slay, go ship it. 💅💖🎀