shdma_add_desc(9)

shdma_add_desc(9) 🎀

okay so bestie, welcome to the Kernel API Manual corner of the group chat — this page is all about shdma_add_desc, and we're gonna get, set up and return one transfer descriptor together ✨ no cap.

🌸 NAME 🌸

shdma_add_desc — get, set up and return one transfer descriptor 💖

✨ SYNOPSIS ✨

struct shdma_desc * shdma_add_desc (struct shdma_chan *schan , unsigned long flags , dma_addr_t *dst , dma_addr_t *src , size_t *len , struct shdma_desc **first , enum dma_transfer_direction direction );

🫶 ARGUMENTS 🫶

vibe check on the arguments, bestie — every one matters:

• schan — the DMA channel, main character energy 🎀
• flags — DMA transfer flags, iconic little switches ✨
• dst — destination DMA address; it gets incremented when direction equals DMA_DEV_TO_MEM or DMA_MEM_TO_MEM 🔥
• src — source DMA address; it gets incremented when direction equals DMA_MEM_TO_DEV or DMA_MEM_TO_MEM 💫
• len — DMA transfer length, literally the length 💅
• first — if it's NULL, it gets set to the current descriptor and the cookie gets set to -EBUSY 😭
• direction — needed for slave DMA to decide which address to keep constant; it equals DMA_MEM_TO_MEM for MEMCPY 🌈

Also, for the record: Returns 0 or an error. Locks: called with desc_lock held — respect the lock, bestie, no cap 💅.

👑 SEE ALSO 👑

• Kernel file — ./drivers/dma/sh/shdma-base.c 🧚

mwah 💋 — source/version: ./drivers/dma/sh; date: October 2026. that's the whole page, bestie, periodt 🎀