bcm2835_dma_create_cb_chain(9)

💅 bcm2835_dma_create_cb_chain(9) — the kernel API manual, bestie edition 🎀

okay so this is the man page for bcm2835_dma_create_cb_chain(9), straight out of the Linux Kernel API Manual, and honestly? it's giving "let me build you a whole chain of control blocks real quick" energy. stay with me, we're gonna get through it together 🫶

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✨ NAME ✨

bcm2835_dma_create_cb_chain — create a control block and fills data in 💫

like, the whole job. makes the cb, drops the data inside. no cap.

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🌸 SYNOPSIS 🌸

struct bcm2835_desc * bcm2835_dma_create_cb_chain (struct dma_chan *chan
, enum dma_transfer_direction direction , bool cyclic , u32 info , u32
finalextrainfo , size_t frames , dma_addr_t src , dma_addr_t dst ,
size_t buf_len , size_t period_len , gfp_t gfp );

she takes eleven arguments and returns a struct bcm2835_desc *. iconic behavior, honestly 👑

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🦋 ARGUMENTS 🦋

okay so here's the whole cast of characters, one by one, no skips, we're doing all of them:

• chan — the dma_chan that we're running this whole thing for. main character, literally.
• direction — the direction in which we transfer. which way the vibe is flowing 🌈
• cyclic — it is a cyclic transfer. bool, so it's a yes/no moment.
• info — the default info bits to apply per controlblock. the everyday fit, the baseline lewk.
• finalextrainfo — additional bits in the last controlblock (or when period_len is reached in case of cyclic). the little sprinkle at the end ✨
• frames — number of controlblocks to allocate. how many we're making, count it out 🎀
• src — the src address to assign (if the S_INC bit is set in info, then it gets incremented). yes, it moves — mind the bit, bestie.
• dst — the dst address to assign (if the D_INC bit is set in info, then it gets incremented). same deal, other side 🦋
• buf_len — the full buffer length (may also be 0). zero is a valid vibe, no worries.
• period_len — the period length when to apply finalextrainfo in addition to the last transfer; this will also break some controlblocks early. lowkey important: it ✨breaks things early✨ on purpose, that's the whole point, not a bug.
• gfp — the GFP flag to use for allocation. the allocation mood ring 💀

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👀 SEE ALSO 👀

go touch these files, iykyk:

• Kernel file ./drivers/dma/bcm2835-dma.c
• struct bcm2835_dmadev(9)

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🫶 the sign-off 🫶

this beauty lives under ./drivers/dma, it's the October 2026 edition, and the page itself is filed as bcm2835_dma_create_cb_chain(9). go forth and chain those control blocks, bestie — slay 💖🔥👑