STRUCT STEDMA40_PLATFORM_DATA(9)

💖 struct stedma40_platform_data(9) 💖

okay bestie, welcome to the Kernel API Manual ✨ — this is the page for struct stedma40_platform_data, no cap. It's the configuration struct for the dma device, and honestly it's giving "small struct, big responsibilities" energy 👑

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🌸 NAME 🌸

struct stedma40_platform_data — Configuration struct for the dma device.

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🎀 SYNOPSIS 🎀

struct stedma40_platform_data {
    int disabled_channels[STEDMA40_MAX_PHYS];
    int *soft_lli_chans;
    int num_of_soft_lli_chans;
    bool use_esram_lcla;
    int num_of_memcpy_chans;
    int num_of_phy_chans;
 };

like, look at her. six fields. main character struct fr fr 💅

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🦋 Members 🦋

• disabled_channels — a vector, ending with -1, that marks physical channels that are, for different reasons, not available for the driver. so basically the "do not touch, she's busy" list 🙈 and yeah, it's terminated by -1, don't forget the -1.
• soft_lli_chans — a vector that marks which physical channels will use LLI by SW, which avoids a HW bug that exists in some versions of the controller. lowkey iconic workaround ✨ but heads up: SoftLLI introduces relink overhead that could impact performance for certain use cases. so, tradeoffs, bestie 😭
• num_of_soft_lli_chans — the number of channels that needs to be configured to use SoftLLI. count them. accurately. 🧮
• use_esram_lcla — flag for mapping the lcla into esram region. a flag! it's a flag! 🚩
• num_of_memcpy_chans — the number of channels reserved for memcpy. reserved! like a VIP section 🎟️
• num_of_phy_chans — the number of physical channels implemented in HW. 0 means reading the number of channels from DMA HW, but — and this is the important part, don't skip it — this is only valid for 'multiple of 4' channels, like 8. so 0 is not a free-for-all, it's a whole vibe check on your channel count ⭐

ngl the 0 case and the 'multiple of 4' thing are the bits people mess up, so like… read them twice bestie 🫶

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🌈 SEE ALSO 🌈

go read the Kernel file ./drivers/dma/ste_dma40.c — that's the mothership 🚀 — plus these iconique friends:

• enum d40_command(9)
• struct d40_interrupt_lookup(9)
• struct d40_reg_val(9)
• struct d40_lli_pool(9)
• struct d40_desc(9)
• struct d40_lcla_pool(9)
• struct d40_phy_res(9)
• struct d40_chan(9)
• struct d40_gen_dmac(9)
• struct d40_base(9)

a whole friend group, honestly 💜

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okay that's the page!! this one lives in ./drivers/dma, it's dated October 2026, and it's literally struct stedma40_platform_data(9) — go forth and configure your dma device responsibly, bestie 🍓✨💖