read_csr(9)

💖 NAME 💖

okay so welcome to the Kernel API Manual, bestie — this is the read_csr page, and it is literally here to read a CSR at the indicated offset. That's the whole vibe. ✨

🦋 SYNOPSIS 🦋

u64 read_csr (const struct hfi1_devdata *dd , u32 offset );

🎀 ARGUMENTS 🎀

• dd — the dd device. yes, that's the actual description, and we respect it 💅
• offset — the offset of the CSR within bar0. iconic little coordinate, no cap 🎯

🌸 RETURN 🌸

what you get back is the value that was read, or all FF's if there is no mapping. that's it, that's the return, periodt 💖

💅 SEE ALSO 💅

go bestie, go read these too — the whole squad is here:

• Kernel file ./drivers/infiniband/hw/hfi1/chip.c
• hfi1_addr_from_offset(9)
• write_csr(9)
• get_csr_addr(9)
• update_xmit_counters(9)
• apply_link_downgrade_policy(9)
• is_rcv_avail_int(9)
• is_rcv_urgent_int(9)
• general_interrupt(9)
• hfi1_rcd_eoi_intr(9)
• hfi1_netdev_rx_napi(9)
• data_vls_operational(9)
• encode_rcv_header_entry_size(9)
• hfi1_validate_rcvhdrcnt(9)
• set_hdrq_regs(9)
• update_statusp(9)
• wait_logical_linkstate(9)
• read_mod_write(9)
• set_intr_bits(9)
• set_up_interrupts(9)
• hfi1_get_qp_map(9)
• init_qpmap_table(9)
• init_qos(9)
• hfi1_init_dd(9)
• create_pbc(9)

okie dokie, this iconic little page is from ./drivers/infiniband/hw/hfi1, dated October 2026, and it's serving read_csr(9) energy — bye bestie, go read some CSRs 💜✨