udma_get_tr_counters(9)

👑 udma_get_tr_counters(9) — calculate TR counters for a given length

okay so this page is from the Kernel API Manual, section 9, bestie. today's main character is udma_get_tr_counters, and it is literally here to calculate TR counters for a given length. it's giving “let me do the math so you don't have to” energy fr fr. 🦋

🌸 NAME 🌸

udma_get_tr_counters — calculate TR counters for a given length. periodt. 💅

✨ SYNOPSIS ✨

int udma_get_tr_counters (size_t len , unsigned long align_to , u16
       *tr0_cnt0 , u16 *tr0_cnt1 , u16 *tr1_cnt0 );

🎀 ARGUMENTS 🎀

• len — Length of the trasnfer. yes, that spelling is in the page, not me, iykyk 🙈
• align_to — Preferred alignment. the alignment you want it to vibe with.
• tr0_cnt0 — First TR icnt0. first TR counter slot, iconic.
• tr0_cnt1 — First TR icnt1. second counter for the first TR.
• tr1_cnt0 — Second (if used) TR icnt0. only relevant when the second TR actually gets used.

💅 DESCRIPTION 💅

For len < SZ_64K only one TR is enough, and tr1_cnt0 is not updated. that's the lowkey simple case 🎀

For len >= SZ_64K two TRs are used in a simple way:

• First TR: SZ_64K-alignment blocks (tr0_cnt0, tr0_cnt1)
• Second TR: the remaining length (tr1_cnt0)

Returns the number of TRs the length needs (1 or 2). If the length can not be supported, it returns -EINVAL. no cap, that's the whole vibe check 🔥

🌈 SEE ALSO 🌈

Kernel file ./drivers/dma/ti/k3-udma.c — and also __udma_alloc_gp_rflow_range(9). go read those if you're obsessed like me 🫶

mwah 💖 — source/version: ./drivers/dma/ti; date: October 2026. periodt, bestie. slay ✨