STRUCT SPI_MEM_DIRMAP_DESC(9)

🎀 NAME 🎀

okay so bestie, this is struct spi_mem_dirmap_desc(9) from the Kernel API Manual: the direct mapping descriptor. that’s the name, and yes it’s giving “tiny struct, big responsibilities” energy 💅✨

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✨ SYNOPSIS ✨

here’s the literal shape of it, no cap:

struct spi_mem_dirmap_desc {
    struct spi_mem *mem;
    struct spi_mem_dirmap_info info;
    unsigned int nodirmap;
    void *priv;
 };

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🫶 Members 🫶

• mem — the SPI memory device this direct mapping is attached to. literally the memory device this mapping is glued to 🫶
• info — information passed at direct mapping creation time. iykyk, it’s the creation-time info 🌸
• nodirmap — set to 1 if the SPI controller does not implement ->mem_ops->dirmap_create or when this function returned an error. if nodirmap is true, all spi_mem_dirmap_{read,write}() calls will use spi_mem_exec_op to access the memory. this is a degraded mode that allows spi_mem drivers to use the same code no matter whether the controller supports direct mapping or not 🔥
• priv — field pointing to controller specific data. that’s the controller’s own little private stash 🎀

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🌸 Description 🌸

Common part of a direct mapping descriptor. this object is created by spi_mem_dirmap_create and controller implementation of ->create_dirmap can create/attach direct mapping resources to the descriptor in the ->priv field. periodt 💖

it’s literally the shared common piece, and the controller gets to hang its own resources off ->priv — iconic behavior, honestly ✨

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🦋 SEE ALSO 🦋

Kernel file ./include/linux/spi/spi-mem.h is the main character here, and the whole squad is:

• enum spi_mem_data_dir(9)
• struct spi_mem_op(9)
• struct spi_mem_dirmap_info(9)
• struct spi_mem(9)
• spi_mem_set_drvdata(9)
• spi_mem_get_drvdata(9)
• struct spi_controller_mem_ops(9)
• struct spi_controller_mem_caps(9)
• struct spi_mem_driver(9)

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okay that’s the whole vibe check, bestie! big kisses from source file ./include/linux/spi, dated October 2026, and this little page signs off as struct spi_mem_dirmap_desc(9) 💖✨🌈