STRUCT PRUETH_QUEUE_DESC(9)

💅 struct prueth_queue_desc(9) 🎀

okay bestie, this is a page from the Kernel API Manual and it's literally all about one little struct called struct prueth_queue_desc — the queue descriptor. it's giving "small but runs the whole group chat" energy. 🫶

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✨ NAME ✨

struct prueth_queue_desc — the Queue descriptor, periodt.

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🌸 SYNOPSIS 🌸

here's the whole glow-up, character for character, no cap:

struct prueth_queue_desc {
    u16 rd_ptr;
    u16 wr_ptr;
    u8 busy_s;
    u8 status;
    u8 max_fill_level;
    u8 overflow_cnt;
 };

look at her. six fields. iconic. 👑

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🦋 Members 🦋

so let's do a vibe check on every single member, one by one, no skipping:

• rd_ptr — the read pointer, and she points to a buffer descriptor over in Shared PRU RAM. that's her whole job. 💖
• wr_ptr — the write pointer, also pointing at a buffer descriptor in Shared PRU RAM. her and rd_ptr are literally besties doing the same thing from different directions. ✨
• busy_s — the slave queue busy flag. the slave (that's us, hii 👋) sets this to request access from the master (the PRU). it's the "hey can i get in the chat" flag.
• status — a bit field status register, and the bits are doing the most:
  • Bit 0: Master queue busy flag.
  • Bit 1: Packet has been placed in collision queue.
  • Bit 2: Packet has been discarded due to overflow. 😭
• max_fill_level — the maximum queue usage seen. her peak. her main character era. 🌈
• overflow_cnt — the count of queue overflows. lowkey a sad number but somebody has to track it. 💀

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🧚 Description 🧚

okay so here's the lore: each port has up to 4 queues, and they're variable length. the queue gets processed as a ring buffer with read and write pointers doing their little circular dance. 🎠

both of those pointers are address pointers — and this part matters, so listen up — they increment by 4 for each buffer descriptor position. fr fr, that's the detail. 💅

and the queue has a length defined in constants (not here, go look elsewhere bestie) plus a status. that's the whole thing. slay.

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🔥 SEE ALSO 🔥

go read these next, they're the rest of the friend group:

• Kernel file ./drivers/net/ethernet/ti/icssm/icssm_prueth.h struct prueth_queue_info(9)
• struct prueth_packet_info(9)
• struct prueth_firmware(9)
• struct prueth_private_data(9)

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and that's the whole page, bestie — brought to you by ./drivers/net/ethernet/ti/icssm, dated October 2026. 📅 mark your calendars, mwah 💜🌸