STRUCT EP93XX_DMA_ENGINE(9)

struct ep93xx_dma_engine(9) 💅

okay so bestie, welcome to the Kernel API Manual — this page is the EP93xx DMA engine instance and it's honestly a little iconic. ✨ The star is literally struct ep93xx_dma_engine, and we're gonna go through every field, no skipping, periodt. 🫶

---

🌸 NAME 🌸

struct ep93xx_dma_engine — the EP93xx DMA engine instance. that's the whole name, bestie 💖

---

✨ SYNOPSIS ✨

here's the struct, exact spacing and semicolons and all — we do not "fix" code in this group chat, we respect it 🎀:

       struct ep93xx_dma_engine {
           struct dma_device       dma_dev;
           bool m2m;
           int (*hw_setup)(struct ep93xx_dma_chan *);
           void (*hw_synchronize)(struct ep93xx_dma_chan *);
           void (*hw_shutdown)(struct ep93xx_dma_chan *);
           void (*hw_submit)(struct ep93xx_dma_chan *);
           int (*hw_interrupt)(struct ep93xx_dma_chan *);
         #define INTERRUPT_UNKNOWN       0;
         #define INTERRUPT_DONE          1;
         #define INTERRUPT_NEXT_BUFFER   2;
           size_t num_channels;
           struct ep93xx_dma_chan  channels[];
        };

---

🫶 Members 🫶

• dma_dev — holds the dmaengine device. it's the holder of the dmaengine device, periodt 👑
• m2m — is this an M2M or M2P device? the little bool that answers that exact question 👀
• hw_setup — method which sets the channel up for operation. setup era ✨
• hw_synchronize — synchronizes DMA channel termination to current context. syncing the DMA channel termination to the current context, no cap 🌀
• hw_shutdown — shuts the channel down and flushes whatever is left. shutdown + flush whatever is left 💀
• hw_submit — pushes active descriptor(s) to the hardware. active descriptor(s) go to the hardware 🔥
• hw_interrupt — handle the interrupt. interrupt-handling duty ⚡
• num_channels — number of channels for this instance. the count of channels for this instance 🔢
• channels — array of channels. literally an array of channels 🧚

---

💖 Description 💖

okay so here's the tea: there is one instance of this struct for the M2P channels and one for the M2M channels. 🫶

The hw_xxx methods are used to perform operations which are different on M2M and M2P channels. so yeah, the hw_xxx squad is doing the M2M/M2P-specific work ✨

🚨 important caveat, bestie: these methods are called with channel lock held and interrupts disabled so they cannot sleep. like, do not try to sleep in there — the lock is held and interrupts are disabled. 😭

---

👀 SEE ALSO 👀

Kernel file ./drivers/dma/ep93xx_dma.c is the source. then here's the whole linked bestie squad:

• struct ep93xx_dma_desc(9)
• struct ep93xx_dma_chan(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_prep_dma_cyclic(9)
• ep93xx_dma_synchronize(9)
• ep93xx_dma_terminate_all(9)
• ep93xx_dma_tx_status(9)
• ep93xx_dma_issue_pending(9)

---

mwah 💋 okay that's the page! it lives in ./drivers/dma, it's dated October 2026, and it's the struct ep93xx_dma_engine(9) manual page. go be iconic with your DMA engine, bestie 🌈✨👑