STRUCT SDMA_CHANNEL(9)

💖 struct sdma_channel(9) 💖

okay so bestie, this is straight from the Kernel API Manual, and it's the housekeeping struct for a SDMA channel. no cap, it's giving “tiny control room for one DMA channel” energy 🫶✨

✨ NAME ✨

struct sdma_channel — housekeeping for a SDMA channel.

🦋 SYNOPSIS 🦋

here's the whole struct, copied exactly so you can trust the vibe 💅

       struct sdma_channel {
           struct virt_dma_chan            vc;
           struct sdma_desc                *desc;
           struct sdma_engine              *sdma;
           unsigned int                    channel;
           enum dma_transfer_direction             direction;
           struct dma_slave_config         slave_config;
           enum sdma_peripheral_type       peripheral_type;
           unsigned int                    event_id0;
           unsigned int                    event_id1;
           enum dma_slave_buswidth         word_size;
           unsigned int                    pc_from_device, pc_to_device;
           unsigned int                    device_to_device;
           unsigned int                    pc_to_pc;
           unsigned long                   flags;
           dma_addr_t per_address, per_address2;
           unsigned long                   event_mask[2];
           unsigned long                   watermark_level;
           u32 shp_addr, per_addr;
           enum dma_status                 status;
           struct imx_dma_data             data;
           struct work_struct              terminate_worker;
           struct list_head                terminated;
           bool is_ram_script;
           unsigned int                    n_fifos_src;
           unsigned int                    n_fifos_dst;
           unsigned int                    stride_fifos_src;
           unsigned int                    stride_fifos_dst;
           unsigned int                    words_per_fifo;
           bool sw_done;
        };

🎀 Members 🎀

• vc — virt_dma base structure. the foundation, bestie 💖
• desc — sdma description including vd and other special member.
• sdma — pointer to the SDMA engine for this channel.
• channel — the channel number, matches dmaengine chan_id + 1.
• direction — transfer type. Needed for setting SDMA script.
• slave_config — Slave configuration.
• peripheral_type — Peripheral type. Needed for setting SDMA script.
• event_id0 — aka dma request line.
• event_id1 — for channels that use 2 events.
• word_size — peripheral access size.
• pc_from_device — script address for those device_2_memory moments.
• pc_to_device — script address for those memory_2_device moments.
• device_to_device — script address for those device_2_device moments.
• pc_to_pc — script address for those memory_2_memory moments.
• flags — loop mode or not.
• per_address — peripheral source or destination address in common case; destination address in p_2_p case.
• per_address2 — peripheral source address in p_2_p case.
• event_mask[2] — event mask used in p_2_p script.
• watermark_level — value for gReg[7], some script will extend it from basic watermark such as p_2_p.
• shp_addr — value for gReg[6].
• per_addr — value for gReg[2].
• status — status of dma channel.
• data — specific sdma interface structure.
• terminate_worker — used to call back into terminate work function.
• terminated — terminated list.
• is_ram_script — flag for script in ram.
• n_fifos_src — number of source device fifos.
• n_fifos_dst — number of destination device fifos.
• stride_fifos_src — stride for source device FIFOs.
• stride_fifos_dst — stride for destination device FIFOs.
• words_per_fifo — copy number of words one time for one FIFO.
• sw_done — software done flag.

🌈 SEE ALSO 🌈

Kernel file ./drivers/dma/imx-sdma.c — and the whole friend group: struct sdma_channel_control(9), struct sdma_state_registers(9), struct sdma_context_data(9), struct sdma_desc(9), struct sdma_firmware_header(9). iykyk 💅

xoxo, bestie 💖 this page's source/version is ./drivers/dma, dated October 2026. 🎀⭐