__iowrite32_copy(9)

💅 NAME 💅

__iowrite32_copy(9) — copy data to MMIO space, in 32-bit units. This one is from the Kernel API Manual, and it’s lowkey iconic for yeeting data into MMIO in neat little 32-bit pieces. ✨🦋

✨ SYNOPSIS ✨

       void __iowrite32_copy (void __iomem *to , const void *from , size_t
       count );

🎀 ARGUMENTS 🎀

• to — destination, in MMIO space (must be 32-bit aligned). This is the MMIO destination, and yes, alignment is mandatory, bestie.
• from — source (must be 32-bit aligned). Your source pointer, also alignment-checked.
• count — number of 32-bit quantities to copy. That’s the number of 32-bit chunks on the move.

🌸 DESCRIPTION 🌸

Okay so real talk: this copies data from kernel space to MMIO space, in units of 32 bits at a time. 💖

Two things are very much not guaranteed:

Order of access is not guaranteed, and a memory barrier is not performed afterwards.

So don’t build your whole personality on access order here, and don’t expect a barrier after — fr fr, no cap. 😭

🔥 SEE ALSO 🔥

• Kernel file ./lib/iomap_copy.c
• __ioread32_copy(9)
• __iowrite64_copy(9)

That’s the page, bestie 🫶 Source/version: ./lib, date: October 2026, and the manual name is __iowrite32_copy(9). Mwah 💋