uart_parse_earlycon(9)

📦 version 7.3.1, in nixpkgs unstable

💅 uart_parse_earlycon(9) — the Kernel API Manual, bestie edition 🎀

okay so this is a page from the Kernel API Manual and it's literally about one tiny little function called uart_parse_earlycon that does the world's most important admin job: it reads the earlycon options off the kernel command line and tells you what they mean. she's giving parser energy, she's giving decoder ring, she ate 💅✨

✨ NAME ✨

uart_parse_earlycon — parse earlycon options 🧚

like, that's it, that's the whole job, and she does it flawlessly no cap.

🦋 SYNOPSIS 🦋

int uart_parse_earlycon (char *p , enum uart_iotype *iotype ,
resource_size_t *addr , char **options );

literally copy that exactly, do not @ me, the spacing is canon 💀

🌸 ARGUMENTS 🌸

  • p — ptr to 2nd field (ie., just beyond <name>,). so you already walked past the name and the comma, bestie, this is where you hand her the rest of the string 🫶
  • iotype — ptr for decoded iotype (out). she writes the answer here, you just gotta give her somewhere to put it ✨
  • addr — ptr for decoded mapbase/iobase (out). same deal, output pointer, she fills it in 💖
  • options — ptr for <options> field; NULL if not present (out). note the NULL — if there's no options field she'll tell you so, don't panic 🙈
ngl the (out) on all of these is the vibe check you need to pass — these are outputs, she's writing to them, you're just holding the bowl 🍓

🔥 DESCRIPTION 🔥

okay so the whole thing: she decodes the earlycon kernel command line parameters, and they look like this 👑

  • earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
  • console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>

so it's <name>, then one of those six iotype words — io, mmio, mmio16, mmio32, mmio32be, mmio32native — then <addr>, then <options>. iconic. no notes. 🔥

and there's also the optional form, which is highkey the chill version 🦋

  • earlycon=<name>,0x<addr>,<options>
  • console=<name>,0x<addr>,<options>

this one is also accepted — like, she's not gonna throw it out — and when you use it, the returned iotype will be UPIO_MEM. that's the little secret twist at the end of the movie 😭✨

💀 RETURN 💀

  • 0 on success 🌈
  • -EINVAL on failure 😭

that's it. binary mood. she either slayed or she didn't.

👑 SEE ALSO 👑

bestie the guest list is LONG, grab a snack 🍓 this is all from the Kernel file ./drivers/tty/serial/serial_core.c:

twenty entries. twenty. she's popular, she's connected, she has friends 💅👑

respect the source path ./drivers/tty/serial — that's where she lives 🏡 and this page is dated October 2026 (yes, the future, she's ahead of her time ⭐). that's the whole page, mwah, bye bestie 🫶💖🎀

📦 where this page comes from