[PATCH v3 4/4] Enabling hardware supported PTP system/device crosstimestamping

["Christopher S. Hall" <christopher.s.hall@intel.com>]

From: Christopher Hall <christopher.s.hall@intel.com>

Add getsynctime() PTP device callback to cross timestamp system device
	clock using ART	translation depends on platform being >= SPT
	and having ART

getsynctime() reads ART (TSC-derived)/device cross timestamp and
	converts to realtime/device time reporting cross timestamp to
	PTP driver

Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
---
 drivers/net/ethernet/intel/e1000e/defines.h |  5 ++
 drivers/net/ethernet/intel/e1000e/ptp.c     | 88 +++++++++++++++++++++++++++++
 drivers/net/ethernet/intel/e1000e/regs.h    |  4 ++
 3 files changed, 97 insertions(+)

diff --git a/drivers/net/ethernet/intel/e1000e/defines.h b/drivers/net/ethernet/intel/e1000e/defines.h
index 133d407..13cff75 100644
--- a/drivers/net/ethernet/intel/e1000e/defines.h
+++ b/drivers/net/ethernet/intel/e1000e/defines.h
@@ -527,6 +527,11 @@
 #define E1000_RXCW_C          0x20000000        /* Receive config */
 #define E1000_RXCW_SYNCH      0x40000000        /* Receive config synch */
 
+/* HH Time Sync */
+#define E1000_TSYNCTXCTL_MAX_ALLOWED_DLY_MASK	0x0000F000 /* max delay */
+#define E1000_TSYNCTXCTL_SYNC_COMP		0x40000000 /* sync complete */
+#define E1000_TSYNCTXCTL_START_SYNC		0x80000000 /* initiate sync */
+
 #define E1000_TSYNCTXCTL_VALID		0x00000001 /* Tx timestamp valid */
 #define E1000_TSYNCTXCTL_ENABLED	0x00000010 /* enable Tx timestamping */
 
diff --git a/drivers/net/ethernet/intel/e1000e/ptp.c b/drivers/net/ethernet/intel/e1000e/ptp.c
index 25a0ad5..228f3f3 100644
--- a/drivers/net/ethernet/intel/e1000e/ptp.c
+++ b/drivers/net/ethernet/intel/e1000e/ptp.c
@@ -25,6 +25,8 @@
  */
 
 #include "e1000.h"
+#include <asm/tsc.h>
+#include <linux/timekeeping.h>
 
 /**
  * e1000e_phc_adjfreq - adjust the frequency of the hardware clock
@@ -98,6 +100,87 @@ static int e1000e_phc_adjtime(struct ptp_clock_info *ptp, s64 delta)
 	return 0;
 }
 
+#define MAX_HW_WAIT_COUNT (3)
+
+static int e1000e_phc_get_ts(struct correlated_ts *cts)
+{
+	struct e1000_adapter *adapter = (struct e1000_adapter *)cts->private;
+	struct e1000_hw *hw = &adapter->hw;
+	int i;
+	u32 tsync_ctrl;
+	int ret;
+
+	tsync_ctrl = er32(TSYNCTXCTL);
+	tsync_ctrl |= E1000_TSYNCTXCTL_START_SYNC |
+		E1000_TSYNCTXCTL_MAX_ALLOWED_DLY_MASK;
+	ew32(TSYNCTXCTL, tsync_ctrl);
+	for (i = 0; i < MAX_HW_WAIT_COUNT; ++i) {
+		udelay(1);
+		tsync_ctrl = er32(TSYNCTXCTL);
+		if (tsync_ctrl & E1000_TSYNCTXCTL_SYNC_COMP)
+			break;
+	}
+
+	if (i == MAX_HW_WAIT_COUNT) {
+		ret = -ETIMEDOUT;
+	} else {
+		ret = 0;
+		cts->system_ts = er32(PLTSTMPH);
+		cts->system_ts <<= 32;
+		cts->system_ts |= er32(PLTSTMPL);
+		cts->device_ts = er32(SYSSTMPH);
+		cts->device_ts <<= 32;
+		cts->device_ts |= er32(SYSSTMPL);
+	}
+
+	return ret;
+}
+
+/**
+ * e1000e_phc_getsynctime - Reads the current time from the hardware clock and
+ * correlated system time
+ * @ptp: ptp clock structure
+ * @devts: timespec structure to hold the current device time value
+ * @systs: timespec structure to hold the current system time value
+ *
+ * Read device and system (ART) clock simultaneously and return the correct
+ * clock values in ns after converting into a struct timespec.
+ **/
+static int e1000e_phc_getsynctime(struct ptp_clock_info *ptp,
+				  struct timespec64 *devts,
+				  struct timespec64 *systs)
+{
+	struct e1000_adapter *adapter = container_of(ptp, struct e1000_adapter,
+						     ptp_clock_info);
+	unsigned long flags;
+	u32 remainder;
+	struct correlated_ts art_correlated_ts;
+	u64 device_time;
+	int ret;
+
+	art_correlated_ts.get_ts = e1000e_phc_get_ts;
+	art_correlated_ts.private = adapter;
+	ret = get_correlated_timestamp(&art_correlated_ts,
+				       &art_timestamper);
+	if (ret != 0)
+		goto bail;
+
+	systs->tv_sec =
+		div_u64_rem(art_correlated_ts.system_real.tv64,
+			    NSEC_PER_SEC, &remainder);
+	systs->tv_nsec = remainder;
+	spin_lock_irqsave(&adapter->systim_lock, flags);
+	device_time = timecounter_cyc2time(&adapter->tc,
+					   art_correlated_ts.device_ts);
+	spin_unlock_irqrestore(&adapter->systim_lock, flags);
+	devts->tv_sec =
+		div_u64_rem(device_time, NSEC_PER_SEC, &remainder);
+	devts->tv_nsec = remainder;
+
+bail:
+	return ret;
+}
+
 /**
  * e1000e_phc_gettime - Reads the current time from the hardware clock
  * @ptp: ptp clock structure
@@ -190,6 +273,7 @@ static const struct ptp_clock_info e1000e_ptp_clock_info = {
 	.adjfreq	= e1000e_phc_adjfreq,
 	.adjtime	= e1000e_phc_adjtime,
 	.gettime64	= e1000e_phc_gettime,
+	.getsynctime64	= e1000e_phc_getsynctime,
 	.settime64	= e1000e_phc_settime,
 	.enable		= e1000e_phc_enable,
 };
@@ -236,6 +320,10 @@ void e1000e_ptp_init(struct e1000_adapter *adapter)
 		break;
 	}
 
+	/* CPU must have ART and GBe must be from Sunrise Point or greater */
+	if (hw->mac.type < e1000_pch_spt || !cpu_has_art)
+		adapter->ptp_clock_info.getsynctime64 = NULL;
+
 	INIT_DELAYED_WORK(&adapter->systim_overflow_work,
 			  e1000e_systim_overflow_work);
 
diff --git a/drivers/net/ethernet/intel/e1000e/regs.h b/drivers/net/ethernet/intel/e1000e/regs.h
index b24e5fe..4dd5b54 100644
--- a/drivers/net/ethernet/intel/e1000e/regs.h
+++ b/drivers/net/ethernet/intel/e1000e/regs.h
@@ -246,6 +246,10 @@
 #define E1000_SYSTIML	0x0B600	/* System time register Low - RO */
 #define E1000_SYSTIMH	0x0B604	/* System time register High - RO */
 #define E1000_TIMINCA	0x0B608	/* Increment attributes register - RW */
+#define E1000_SYSSTMPL  0x0B648 /* HH Timesync system stamp low register */
+#define E1000_SYSSTMPH  0x0B64C /* HH Timesync system stamp hi register */
+#define E1000_PLTSTMPL  0x0B640 /* HH Timesync platform stamp low register */
+#define E1000_PLTSTMPH  0x0B644 /* HH Timesync platform stamp hi register */
 #define E1000_RXMTRL	0x0B634	/* Time sync Rx EtherType and Msg Type - RW */
 #define E1000_RXUDP	0x0B638	/* Time Sync Rx UDP Port - RW */
 
-- 
2.1.4