BUS_GET_RESOURCE(9)

📦 version 15.1, in freebsd 14.5, freebsd 15.1, nixpkgs unstable

💅 BUS_GET_RESOURCE(9) — bus_get_resource

okay so bestie, this is a page from the Kernel Developer's Manual (section 9, kernel dev stuff, iykyk) and it's about one little function that just… reads a resource. that's it. that's the whole vibe. and honestly? iconic. ✨

🦋 NAME

bus_get_resource — read a resource range/value with a given resource ID

like, you give it an ID and it hands you back the range or the value. lowkey the whole personality right there. 🎀

🌸 SYNOPSIS

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/rman.h>

int
bus_get_resource(device_t dev, int type, int rid, rman_res_t *startp,
    rman_res_t *countp);

three includes, one function, zero drama. copy it exactly, please, do not freestyle the headers. 🫶

✨ DESCRIPTION

so the bus_get_resource() function reads the range or the value of the resource type, rid pair and stores it in the startp and countp arguments. that's the tea. 🔥

the arguments are, and I'm gonna go through every single one because I would never leave you guessing:

  • dev — the device to read the resource from. the main character, basically. 👑
  • type — the type of resource you want to read. it is one of:
    • SYS_RES_IRQ — for IRQs
    • SYS_RES_DRQ — for ISA DMA lines
    • SYS_RES_MEMORY — for I/O memory
    • SYS_RES_IOPORT — for I/O ports
  • rid — a bus-specific handle that identifies the resource being read. yes it's bus-specific, no you can't just make one up and expect it to slay. 🙈
  • startp — a pointer to the start address of this resource. it's a pointer, bestie, so make sure it points somewhere real. 💀
  • countp — a pointer to the length of the resource. for example, the size of the memory in bytes. so like, a number. a length. the whole point. 🍓

⭐ RETURN VALUES

zero is returned on success, otherwise an error is returned.

no cap, that's it — 0 means you ate, anything else means something went sideways. do with that what you will. 💅

💖 SEE ALSO

go read them, they're friends of this page, fr fr. 🌈

🌷 AUTHORS

this manual page was written by Sascha Wildner. credit where credit is due, periodt. 👏

⚠️ heads up bestie: startp and countp are pointers, so you're handing the function somewhere to write. make sure those pointers are valid before you call this, okay? love you, mean it. 💜

and that's the whole page!! written with love, shipped by Debian on September 26, 2015 — yeah she's a little vintage but she still serves 💅✨🎀 stay hydrated and check your return codes, mwah 🫶

📦 where this page comes from