diff options
Diffstat (limited to 'drivers/net/ethernet/intel/igb/igb_ptp.c')
| -rw-r--r-- | drivers/net/ethernet/intel/igb/igb_ptp.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c index c8254cf1456..c9b71c5bc47 100644 --- a/drivers/net/ethernet/intel/igb/igb_ptp.c +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c @@ -27,6 +27,9 @@ #define ISGN 0x80000000 /* + * The 82580 timesync updates the system timer every 8ns by 8ns, + * and this update value cannot be reprogrammed. + * * Neither the 82576 nor the 82580 offer registers wide enough to hold * nanoseconds time values for very long. For the 82580, SYSTIM always * counts nanoseconds, but the upper 24 bits are not availible. The @@ -38,6 +41,14 @@ * field are needed to provide the nominal 16 nanosecond period, * leaving 19 bits for fractional nanoseconds. * + * We scale the NIC clock cycle by a large factor so that relatively + * small clock corrections can be added or subtracted at each clock + * tick. The drawbacks of a large factor are a) that the clock + * register overflows more quickly (not such a big deal) and b) that + * the increment per tick has to fit into 24 bits. As a result we + * need to use a shift of 19 so we can fit a value of 16 into the + * TIMINCA register. + * * * SYSTIMH SYSTIML * +--------------+ +---+---+------+ @@ -95,6 +106,11 @@ static cycle_t igb_82580_systim_read(const struct cyclecounter *cc) struct igb_adapter *igb = container_of(cc, struct igb_adapter, cc); struct e1000_hw *hw = &igb->hw; + /* + * The timestamp latches on lowest register read. For the 82580 + * the lowest register is SYSTIMR instead of SYSTIML. However we only + * need to provide nanosecond resolution, so we just ignore it. + */ jk = rd32(E1000_SYSTIMR); lo = rd32(E1000_SYSTIML); hi = rd32(E1000_SYSTIMH); @@ -320,3 +336,46 @@ void igb_ptp_remove(struct igb_adapter *adapter) adapter->netdev->name); } } + +/** + * igb_systim_to_hwtstamp - convert system time value to hw timestamp + * @adapter: board private structure + * @hwtstamps: timestamp structure to update + * @systim: unsigned 64bit system time value. + * + * We need to convert the system time value stored in the RX/TXSTMP registers + * into a hwtstamp which can be used by the upper level timestamping functions. + * + * The 'tmreg_lock' spinlock is used to protect the consistency of the + * system time value. This is needed because reading the 64 bit time + * value involves reading two (or three) 32 bit registers. The first + * read latches the value. Ditto for writing. + * + * In addition, here have extended the system time with an overflow + * counter in software. + **/ +void igb_systim_to_hwtstamp(struct igb_adapter *adapter, + struct skb_shared_hwtstamps *hwtstamps, + u64 systim) +{ + u64 ns; + unsigned long flags; + + switch (adapter->hw.mac.type) { + case e1000_i350: + case e1000_82580: + case e1000_82576: + break; + default: + return; + } + + spin_lock_irqsave(&adapter->tmreg_lock, flags); + + ns = timecounter_cyc2time(&adapter->tc, systim); + + spin_unlock_irqrestore(&adapter->tmreg_lock, flags); + + memset(hwtstamps, 0, sizeof(*hwtstamps)); + hwtstamps->hwtstamp = ns_to_ktime(ns); +} |