From c6d5f1933085f9a92ed5c256a859ab31c7a35f88 Mon Sep 17 00:00:00 2001 From: Kurt Kanzenbach Date: Mon, 22 Nov 2021 12:19:31 +0100 Subject: net: stmmac: Calculate CDC error only once The clock domain crossing error (CDC) is calculated at every fetch of Tx or Rx timestamps. It includes a division. Especially on arm32 based systems it is expensive. It also requires two conditionals in the hotpath. Add a compensation value cache to struct plat_stmmacenet_data and subtract it unconditionally in the RX/TX functions which spares the conditionals. The value is initialized to 0 and if supported calculated in the PTP initialization code. Suggested-by: Thomas Gleixner Signed-off-by: Kurt Kanzenbach Link: https://lore.kernel.org/r/20211122111931.135135-1-kurt@linutronix.de Signed-off-by: Jakub Kicinski --- include/linux/stmmac.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/stmmac.h') diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h index a6f03b36fc4f..89b8e208cd7b 100644 --- a/include/linux/stmmac.h +++ b/include/linux/stmmac.h @@ -241,6 +241,7 @@ struct plat_stmmacenet_data { unsigned int clk_ref_rate; unsigned int mult_fact_100ns; s32 ptp_max_adj; + u32 cdc_error_adj; struct reset_control *stmmac_rst; struct reset_control *stmmac_ahb_rst; struct stmmac_axi *axi; -- cgit v1.2.3