From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher Hall Subject: [PATCH 0/5] Patchset enabling hardware based cross-timestamps for next gen Intel platforms Date: Mon, 27 Jul 2015 17:46:51 -0700 Message-ID: <1438044416-15588-1-git-send-email-christopher.s.hall@intel.com> Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, Christopher Hall To: john.stultz@linaro.org, tglx@linutronix.de, richardcochran@gmail.com, mingo@redhat.com, jeffrey.t.kirsher@intel.com, john.ronciak@intel.com, hpa@zytor.com, x86@kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Next generation Intel platforms will have an Always Running Timer (ART) that always runs when the system is powered and is available to both the CPU and various on-board devices. Initially, those devices include audio and network. The ART will give these devices the capability of precisely cross timestamping their local device clock with the system clock. A system clock value like TSC or ART is not useful unless translated to system time. The first three patches enable this by changing the timekeeping code to return a system time given a system clock value and translating ART to TSC. The last two patches modify the PTP driver to call a cross timestamp function in the driver when available and perform the cross timestamp in the e1000e driver. Given the precise relationship between the network device clock and system time enables better synchronization of events on multiple network connected devices. Changelog: * The PTP portion of the patch set was posted 7/8/2015 (v3) and rejected because of there wasn't a driver that implemented the new API. Now, the driver patch is added and the PTP patch operation is modified to revert to previous behavior when cross timestamp can't be completed. This is indicated by the driver returning a non-zero value. Christopher Hall (5): Add functions producing system time given a backing counter value Added functions mapping TSC value to system time Add calls to translate Always Running Timer (ART) to system time Add support for driver cross-timestamp to PTP_SYS_OFFSET ioctl Enables cross timestamping in the e1000e driver Documentation/ptp/testptp.c | 6 +- arch/x86/Kconfig | 12 ++ arch/x86/include/asm/art.h | 42 ++++++ arch/x86/include/asm/tsc.h | 5 + arch/x86/kernel/Makefile | 1 + arch/x86/kernel/art.c | 134 ++++++++++++++++++ arch/x86/kernel/tsc.c | 22 +++ drivers/net/ethernet/intel/e1000e/defines.h | 7 + drivers/net/ethernet/intel/e1000e/ptp.c | 77 ++++++++++ drivers/net/ethernet/intel/e1000e/regs.h | 4 + drivers/ptp/ptp_chardev.c | 29 ++-- include/linux/ptp_clock_kernel.h | 7 + include/linux/timekeeping.h | 8 ++ include/uapi/linux/ptp_clock.h | 4 +- kernel/time/timekeeping.c | 211 +++++++++++++++++++++++++--- 15 files changed, 538 insertions(+), 31 deletions(-) create mode 100644 arch/x86/include/asm/art.h create mode 100644 arch/x86/kernel/art.c -- 1.9.1