bcm2835_spi_undo_prologue(9)

✨ bcm2835_spi_undo_prologue(9) ✨

okay so bestie, this page comes from the Kernel API Manual — section 9, kernel-API energy — and it's all about bcm2835_spi_undo_prologue. It's giving “put it back exactly how you found it,” and honestly? Iconic cleanup behavior 💅.

🌸 NAME 🌸

bcm2835_spi_undo_prologue — reconstruct original sglist state. That's the mission, fr fr: get the sglist back to its original state.

🦋 SYNOPSIS 🦋

void bcm2835_spi_undo_prologue (struct bcm2835_spi *bs );

🎀 ARGUMENTS 🎀

• bs — BCM2835 SPI controller. Yep, that's the controller bestie — main character energy, no cap 👑.

🔥 DESCRIPTION 🔥

okay so picture this: changes were made to an SPI transfer's sglist when transmitting the prologue. bcm2835_spi_undo_prologue undoes those changes. That's the whole arc.

This is lowkey a cleanup moment and highkey necessary to ensure the same memory ranges are unmapped that were originally mapped. Matching maps to unmaps? That's the assignment, iykyk. Periodt. 💖

🌈 SEE ALSO 🌈

• Kernel file ./drivers/spi/spi-bcm2835.c
• struct bcm2835_spi(9)
• struct bcm2835_spidev(9)
• bcm2835_rd_fifo_count(9)
• bcm2835_wr_fifo_count(9)
• bcm2835_wait_tx_fifo_empty(9)
• bcm2835_rd_fifo_blind(9)
• bcm2835_wr_fifo_blind(9)
• bcm2835_spi_transfer_prologue(9)
• bcm2835_spi_dma_rx_done(9)
• bcm2835_spi_dma_tx_done(9)
• bcm2835_spi_prepare_sg(9)
• bcm2835_spi_transfer_one_dma(9)

xoxo, your kernel bestie 💖 this page is from source/version ./drivers/spi, dated October 2026, and it's bcm2835_spi_undo_prologue(9) — mwah 🎀