ep93xx_dma_prep_dma_cyclic(9)

🎀 ep93xx_dma_prep_dma_cyclic 🎀

okay bestie, this is the Kernel API Manual page for ep93xx_dma_prep_dma_cyclic — and yes, the name is a whole mouthful, but we’re gonna get through it together 💅✨

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🌸 NAME 🌸

ep93xx_dma_prep_dma_cyclic — prepare a cyclic DMA operation 🌀

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✨ SYNOPSIS ✨

struct dma_async_tx_descriptor * ep93xx_dma_prep_dma_cyclic (struct
       dma_chan *chan , dma_addr_t dma_addr , size_t buf_len , size_t
       period_len , enum dma_transfer_direction dir , unsigned long flags );

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🫶 ARGUMENTS 🫶

• chan — the channel. the main character of this whole operation, lowkey 👑
• dma_addr — the DMA mapped address of the buffer. yes bestie, it’s already mapped, don’t come for me 🙈
• buf_len — length of the buffer, in bytes. numbers, but make them make sense 📏
• period_len — length of a single period. this one matters a lot for the cyclic vibe check ⏳
• dir — direction of the operation. which way are we going? dma_transfer_direction said “yes” 🧭
• flags — tx descriptor status flags. little descriptor mood markers 🚩

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💖 DESCRIPTION 💖

so this function prepares a descriptor for a cyclic DMA operation ✨ that means once the descriptor is submitted, it keeps submitting buffers sized period_len and calls the callback once the period has elapsed. it’s giving “round and round, nonstop” energy 🎠

and like — the transfer does not just stop on its own. it terminates only when the client calls dmaengine_terminate_all for this channel. so yeah, that’s the off switch, bestie 🔌💀

it returns a valid DMA descriptor, or NULL if something went wrong. no cap, that NULL is the failure case 😭

ngl, that “terminates only when the client calls dmaengine_terminate_all for this channel” part is important — do not forget it, i’m begging 🫶

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👀 SEE ALSO 👀

• Kernel file ./drivers/dma/ep93xx_dma.c
• struct ep93xx_dma_desc(9)
• struct ep93xx_dma_chan(9)
• struct ep93xx_dma_engine(9)
• ep93xx_dma_set_active(9)
• ep93xx_dma_advance_active(9)
• ep93xx_dma_advance_work(9)
• ep93xx_dma_tx_submit(9)
• ep93xx_dma_alloc_chan_resources(9)
• ep93xx_dma_free_chan_resources(9)
• ep93xx_dma_prep_dma_memcpy(9)
• ep93xx_dma_prep_slave_sg(9)
• ep93xx_dma_synchronize(9)
• ep93xx_dma_terminate_all(9)
• ep93xx_dma_tx_status(9)
• ep93xx_dma_issue_pending(9)

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and that’s the whole page, bestie 🫶 source is ./drivers/dma, date is October 2026, and the page is ep93xx_dma_prep_dma_cyclic(9) — iconic, honestly 💅🎀✨