STRUCT SPI_ENGINE_MESSAGE_STATE(9)

🌸 NAME 🌸

okay so bestie, welcome to the Kernel API Manual ✨ — this page is all about struct spi_engine_message_state(9), aka the SPI engine per-message state. it’s giving “bookkeeping for one SPI message” and honestly? iconic. 💅

✨ SYNOPSIS ✨

       struct spi_engine_message_state {
           unsigned cmd_length;
           const uint16_t *cmd_buf;
           struct spi_transfer *tx_xfer;
           unsigned int tx_length;
           const uint8_t *tx_buf;
           struct spi_transfer *rx_xfer;
           unsigned int rx_length;
           uint8_t *rx_buf;
        };

💅 Members 💅

• cmd_length — Number of elements in cmd_buf array. the count bestie 🔢
• cmd_buf — Array of commands not yet written to CMD FIFO. waiting-room energy 🎟️
• tx_xfer — Next xfer with tx_buf not yet fully written to TX FIFO. next up, no cap 📤
• tx_length — Size of tx_buf in bytes. byte math slay 📏
• tx_buf — Bytes not yet written to TX FIFO. still queued, still cute 💌
• rx_xfer — Next xfer with rx_buf not yet fully written to RX FIFO. incoming bestie 📥
• rx_length — Size of tx_buf in bytes. (yes, tx_buf — that’s literally what the page says 💀)
• rx_buf — Bytes not yet written to the RX FIFO. the receive pile 🧺

🦋 SEE ALSO 🦋

• Kernel file ./drivers/spi/spi-axi-spi-engine.c — go peek if you want the source tea 👀📂

mwah 💋 this page lives under ./drivers/spi, dated October 2026, and it’s the struct spi_...essage_state(9) entry — bye bestie, go slay some SPI! 🫶✨