sdio_memcpy_toio(9)

💅 sdio_memcpy_toio(9) — the kernel API manual, but make it make sense

okay bestie, welcome to the Kernel API Manual ✨ — today's main character is sdio_memcpy_toio(9), and honestly? she's lowkey iconic. sit down, grab a boba, we're writing bytes to an SDIO function 🫶

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✨ NAME ✨

sdio_memcpy_toio — write a chunk of memory to a SDIO function 💾🦋

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🌸 SYNOPSIS 🌸

int sdio_memcpy_toio (struct sdio_func *func , unsigned int addr , void
*src , int count );

that's the whole vibe check right there, no cap 👑

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🎀 ARGUMENTS 🎀

• func — the SDIO function we're accessing, she's the one getting the data 💌
• addr — the address where the writing starts, aka the drop-off spot 📍
• src — the buffer holding the data we're about to write, the payload, the moment ✨
• count — how many bytes we're writing, literally just the number of bytes 🔢

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💖 DESCRIPTION 💖

So here's the tea: this writes to the address space of a given SDIO function. That's it, that's the whole gig 💅

The return value tells you whether the transfer succeeded or not — so like, check it, bestie, don't just assume she slayed 🙈

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🔥 SEE ALSO 🔥

the whole friend group fr fr — kernel file ./drivers/mmc/core/sdio_io.c, plus:

• sdio_claim_host(9)
• sdio_release_host(9)
• sdio_enable_func(9)
• sdio_disable_func(9)
• sdio_set_block_size(9)
• sdio_align_size(9)
• sdio_readb(9)
• sdio_writeb(9)
• sdio_writeb_readb(9)
• sdio_memcpy_fromio(9)
• sdio_readsb(9)
• sdio_writesb(9)
• sdio_readw(9)
• sdio_writew(9)
• sdio_readl(9)
• sdio_writel(9)
• sdio_f0_readb(9)
• sdio_f0_writeb(9)
• sdio_get_host_pm_caps(9)
• sdio_set_host_pm_flags(9)
• sdio_retune_crc_disable(9)
• sdio_retune_crc_enable(9)
• sdio_retune_hold_now(9)
• sdio_retune_release(9)

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and that's the page, periodt 💜 this masterpiece lives over in ./drivers/mmc/core, stamped October 2026 — date her, don't debate her ⭐🧚