From bdfc7b55adcd04834ccc1b6b13e55e3fd7eaa789 Mon Sep 17 00:00:00 2001 From: Mina Almasry Date: Thu, 11 Dec 2025 10:19:29 +0000 Subject: [PATCH] idpf: read lower clock bits inside the time sandwich PCIe reads need to be done inside the time sandwich because PCIe writes may get buffered in the PCIe fabric and posted to the device after the _postts completes. Doing the PCIe read inside the time sandwich guarantees that the write gets flushed before the _postts timestamp is taken. Cc: lrizzo@google.com Cc: namangulati@google.com Cc: willemb@google.com Cc: intel-wired-lan@lists.osuosl.org Cc: milena.olech@intel.com Cc: jacob.e.keller@intel.com Fixes: 5cb8805d2366 ("idpf: negotiate PTP capabilities and get PTP clock") Suggested-by: Shachar Raindel Signed-off-by: Mina Almasry Reviewed-by: Jacob Keller Reviewed-by: Aleksandr Loktionov Tested-by: Samuel Salin Signed-off-by: Tony Nguyen --- drivers/net/ethernet/intel/idpf/idpf_ptp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/idpf/idpf_ptp.c b/drivers/net/ethernet/intel/idpf/idpf_ptp.c index 3e1052d070cf..0a8b50350b86 100644 --- a/drivers/net/ethernet/intel/idpf/idpf_ptp.c +++ b/drivers/net/ethernet/intel/idpf/idpf_ptp.c @@ -108,11 +108,11 @@ static u64 idpf_ptp_read_src_clk_reg_direct(struct idpf_adapter *adapter, ptp_read_system_prets(sts); idpf_ptp_enable_shtime(adapter); + lo = readl(ptp->dev_clk_regs.dev_clk_ns_l); /* Read the system timestamp post PHC read */ ptp_read_system_postts(sts); - lo = readl(ptp->dev_clk_regs.dev_clk_ns_l); hi = readl(ptp->dev_clk_regs.dev_clk_ns_h); spin_unlock(&ptp->read_dev_clk_lock); -- 2.47.3