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: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Fixes: 5cb8805d2366 ("idpf: negotiate PTP capabilities and get PTP clock") Suggested-by: Shachar Raindel <[email protected]> Signed-off-by: Mina Almasry <[email protected]> --- 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); base-commit: 885bebac9909994050bbbeed0829c727e42bd1b7 -- 2.52.0.223.gf5cc29aaa4-goog
