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author | Olof Johansson <olof@lixom.net> | 2020-03-03 16:40:54 -0800 |
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committer | Olof Johansson <olof@lixom.net> | 2020-03-03 16:40:56 -0800 |
commit | 820d15632ec10bc0cf79595c5a635b795d149520 (patch) | |
tree | 9deb7defafc350a3c74365ebe370634f0406d821 /drivers/net/ethernet/sfc/ptp.c | |
parent | Merge tag 'arm-soc/for-5.6/defconfig-fixes' of https://github.com/Broadcom/stblinux into arm/fixes (diff) | |
parent | arm64: dts: socfpga: agilex: Fix gmac compatible (diff) | |
download | linux-dev-820d15632ec10bc0cf79595c5a635b795d149520.tar.xz linux-dev-820d15632ec10bc0cf79595c5a635b795d149520.zip |
Merge tag 'socfpga_dts_fix_for_v5.6_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux into arm/fixes
arm64: dts: agilex: fix gmac compatible
- The compatible for Agilex GMAC should be "altr,socfpga-stmmac-a10-s10"
* tag 'socfpga_dts_fix_for_v5.6_v2' of git://git.kernel.org/pub/scm/linux/kernel/git/dinguyen/linux: (578 commits)
arm64: dts: socfpga: agilex: Fix gmac compatible
Linux 5.6-rc4
KVM: VMX: check descriptor table exits on instruction emulation
ext4: potential crash on allocation error in ext4_alloc_flex_bg_array()
macintosh: therm_windtunnel: fix regression when instantiating devices
jbd2: fix data races at struct journal_head
kvm: x86: Limit the number of "kvm: disabled by bios" messages
KVM: x86: avoid useless copy of cpufreq policy
KVM: allow disabling -Werror
KVM: x86: allow compiling as non-module with W=1
KVM: Pre-allocate 1 cpumask variable per cpu for both pv tlb and pv ipis
KVM: Introduce pv check helpers
KVM: let declaration of kvm_get_running_vcpus match implementation
KVM: SVM: allocate AVIC data structures based on kvm_amd module parameter
MAINTAINERS: Correct Cadence PCI driver path
io_uring: fix 32-bit compatability with sendmsg/recvmsg
net: dsa: mv88e6xxx: Fix masking of egress port
mlxsw: pci: Wait longer before accessing the device after reset
sfc: fix timestamp reconstruction at 16-bit rollover points
vsock: fix potential deadlock in transport->release()
...
Link: https://lore.kernel.org/r/20200303153509.28248-1-dinguyen@kernel.org
Signed-off-by: Olof Johansson <olof@lixom.net>
Diffstat (limited to 'drivers/net/ethernet/sfc/ptp.c')
-rw-r--r-- | drivers/net/ethernet/sfc/ptp.c | 38 |
1 files changed, 35 insertions, 3 deletions
diff --git a/drivers/net/ethernet/sfc/ptp.c b/drivers/net/ethernet/sfc/ptp.c index af15a737c675..59b4f16896a8 100644 --- a/drivers/net/ethernet/sfc/ptp.c +++ b/drivers/net/ethernet/sfc/ptp.c @@ -560,13 +560,45 @@ efx_ptp_mac_nic_to_ktime_correction(struct efx_nic *efx, u32 nic_major, u32 nic_minor, s32 correction) { + u32 sync_timestamp; ktime_t kt = { 0 }; + s16 delta; if (!(nic_major & 0x80000000)) { WARN_ON_ONCE(nic_major >> 16); - /* Use the top bits from the latest sync event. */ - nic_major &= 0xffff; - nic_major |= (last_sync_timestamp_major(efx) & 0xffff0000); + + /* Medford provides 48 bits of timestamp, so we must get the top + * 16 bits from the timesync event state. + * + * We only have the lower 16 bits of the time now, but we do + * have a full resolution timestamp at some point in past. As + * long as the difference between the (real) now and the sync + * is less than 2^15, then we can reconstruct the difference + * between those two numbers using only the lower 16 bits of + * each. + * + * Put another way + * + * a - b = ((a mod k) - b) mod k + * + * when -k/2 < (a-b) < k/2. In our case k is 2^16. We know + * (a mod k) and b, so can calculate the delta, a - b. + * + */ + sync_timestamp = last_sync_timestamp_major(efx); + + /* Because delta is s16 this does an implicit mask down to + * 16 bits which is what we need, assuming + * MEDFORD_TX_SECS_EVENT_BITS is 16. delta is signed so that + * we can deal with the (unlikely) case of sync timestamps + * arriving from the future. + */ + delta = nic_major - sync_timestamp; + + /* Recover the fully specified time now, by applying the offset + * to the (fully specified) sync time. + */ + nic_major = sync_timestamp + delta; kt = ptp->nic_to_kernel_time(nic_major, nic_minor, correction); |