STRUCT D40_DESC(9)

🌸 NAME 🌸

okay bestie, meet struct d40_desc from the Kernel API Manual — a descriptor is literally one DMA job. 💅

🎀 SYNOPSIS 🎀

struct d40_desc {
    struct d40_phy_lli_bidir         lli_phy;
    struct d40_log_lli_bidir         lli_log;
    struct d40_lli_pool              lli_pool;
    int lli_len;
    int lli_current;
    int lcla_alloc;
    struct dma_async_tx_descriptor   txd;
    struct list_head                 node;
    bool is_in_client_list;
    bool cyclic;
 };

🫶 Members 🫶

• lli_phy — LLI settings for the physical channel. Both src and dst= point into the lli_pool — to base when lli_len > 1, or to pre_alloc_lli when lli_len equals one. ✨
• lli_log — same as above, but for logical channels. 🦋
• lli_pool — the pool, with two entries pre-allocated. 🎀
• lli_len — number of llis of the current descriptor. 🔢
• lli_current — number of transferred llis. 🚚
• lcla_alloc — number of LCLA entries allocated. 👑
• txd — DMA engine struct. Among other things, it’s used for communication during a transfer. 📡
• node — a list entry. 🔗
• is_in_client_list — true if the client owns this descriptor. 🫶
• cyclic — true if this is a cyclic job. 🔁

💖 Description 💖

This descriptor is used for both logical and physical transfers. no cap. ✨

🔗 SEE ALSO 🔗

• Kernel file ./drivers/dma/ste_dma40.c
• struct stedma40_platform_data(9)
• enum d40_command(9)
• struct d40_interrupt_lookup(9)
• struct d40_reg_val(9)
• struct d40_lli_pool(9)
• struct d40_lcla_pool(9)
• struct d40_phy_res(9)
• struct d40_chan(9)
• struct d40_gen_dmac(9)
• struct d40_base(9)

mwah 💋 this page’s source/version is ./drivers/dma, it’s dated October 2026, and it’s still struct d40_desc(9) — bye bestie! 🫶🎀