igb: access to NIC time

Adds the register definitions and code to read the time
register.

Signed-off-by: John Ronciak <john.ronciak@intel.com>
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 143 insertions, 0 deletions

diff --git a/drivers/net/igb/e1000_regs.h b/drivers/net/igb/e1000_regs.h
index 5038b73c78e9..64d95cd71f2e 100644
--- a/drivers/net/igb/e1000_regs.h
+++ b/drivers/net/igb/e1000_regs.h
@@ -75,6 +75,34 @@
 #define E1000_FCRTH    0x02168  /* Flow Control Receive Threshold High - RW */
 #define E1000_RDFPCQ(_n)  (0x02430 + (0x4 * (_n)))
 #define E1000_FCRTV    0x02460  /* Flow Control Refresh Timer Value - RW */
+
+/* IEEE 1588 TIMESYNCH */
+#define E1000_TSYNCTXCTL 0x0B614
+#define E1000_TSYNCRXCTL 0x0B620
+#define E1000_TSYNCRXCFG 0x05F50
+
+#define E1000_SYSTIML 0x0B600
+#define E1000_SYSTIMH 0x0B604
+#define E1000_TIMINCA 0x0B608
+
+#define E1000_RXMTRL     0x0B634
+#define E1000_RXSTMPL 0x0B624
+#define E1000_RXSTMPH 0x0B628
+#define E1000_RXSATRL 0x0B62C
+#define E1000_RXSATRH 0x0B630
+
+#define E1000_TXSTMPL 0x0B618
+#define E1000_TXSTMPH 0x0B61C
+
+#define E1000_ETQF0   0x05CB0
+#define E1000_ETQF1   0x05CB4
+#define E1000_ETQF2   0x05CB8
+#define E1000_ETQF3   0x05CBC
+#define E1000_ETQF4   0x05CC0
+#define E1000_ETQF5   0x05CC4
+#define E1000_ETQF6   0x05CC8
+#define E1000_ETQF7   0x05CCC
+
 /* Split and Replication RX Control - RW */
 /*
  * Convenience macros
diff --git a/drivers/net/igb/igb.h b/drivers/net/igb/igb.h
index e507449b3cc2..797a9fe107ad 100644
--- a/drivers/net/igb/igb.h
+++ b/drivers/net/igb/igb.h
@@ -34,6 +34,8 @@
 #include "e1000_mac.h"
 #include "e1000_82575.h"
 
+#include <linux/clocksource.h>
+
 struct igb_adapter;
 
 /* Interrupt defines */
@@ -251,6 +253,8 @@ struct igb_adapter {
         struct napi_struct napi;
         struct pci_dev *pdev;
         struct net_device_stats net_stats;
+        struct cyclecounter cycles;
+        struct timecounter clock;
 
         /* structs defined in e1000_hw.h */
         struct e1000_hw hw;
diff --git a/drivers/net/igb/igb_main.c b/drivers/net/igb/igb_main.c
index f8c2919bcec0..8b2ba4245090 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -175,6 +175,54 @@ MODULE_DESCRIPTION("Intel(R) Gigabit Ethernet Network Driver");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(DRV_VERSION);
 
+/**
+ * Scale the NIC clock cycle by a large factor so that
+ * relatively small clock corrections can be added or
+ * substracted 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.
+ *
+ * Note that
+ *   TIMINCA = IGB_TSYNC_CYCLE_TIME_IN_NANOSECONDS *
+ *             IGB_TSYNC_SCALE
+ *   TIMINCA += TIMINCA * adjustment [ppm] / 1e9
+ *
+ * The base scale factor is intentionally a power of two
+ * so that the division in %struct timecounter can be done with
+ * a shift.
+ */
+#define IGB_TSYNC_SHIFT (19)
+#define IGB_TSYNC_SCALE (1<<IGB_TSYNC_SHIFT)
+
+/**
+ * The duration of one clock cycle of the NIC.
+ *
+ * @todo This hard-coded value is part of the specification and might change
+ * in future hardware revisions. Add revision check.
+ */
+#define IGB_TSYNC_CYCLE_TIME_IN_NANOSECONDS 16
+
+#if (IGB_TSYNC_SCALE * IGB_TSYNC_CYCLE_TIME_IN_NANOSECONDS) >= (1<<24)
+# error IGB_TSYNC_SCALE and/or IGB_TSYNC_CYCLE_TIME_IN_NANOSECONDS are too large to fit into TIMINCA
+#endif
+
+/**
+ * igb_read_clock - read raw cycle counter (to be used by time counter)
+ */
+static cycle_t igb_read_clock(const struct cyclecounter *tc)
+{
+        struct igb_adapter *adapter =
+                container_of(tc, struct igb_adapter, cycles);
+        struct e1000_hw *hw = &adapter->hw;
+        u64 stamp;
+
+        stamp =  rd32(E1000_SYSTIML);
+        stamp |= (u64)rd32(E1000_SYSTIMH) << 32ULL;
+
+        return stamp;
+}
+
 #ifdef DEBUG
 /**
  * igb_get_hw_dev_name - return device name string
@@ -185,6 +233,29 @@ char *igb_get_hw_dev_name(struct e1000_hw *hw)
         struct igb_adapter *adapter = hw->back;
         return adapter->netdev->name;
 }
+
+/**
+ * igb_get_time_str - format current NIC and system time as string
+ */
+static char *igb_get_time_str(struct igb_adapter *adapter,
+                              char buffer[160])
+{
+        cycle_t hw = adapter->cycles.read(&adapter->cycles);
+        struct timespec nic = ns_to_timespec(timecounter_read(&adapter->clock));
+        struct timespec sys;
+        struct timespec delta;
+        getnstimeofday(&sys);
+
+        delta = timespec_sub(nic, sys);
+
+        sprintf(buffer,
+                "NIC %ld.%09lus, SYS %ld.%09lus, NIC-SYS %lds + %09luns",
+                (long)nic.tv_sec, nic.tv_nsec,
+                (long)sys.tv_sec, sys.tv_nsec,
+                (long)delta.tv_sec, delta.tv_nsec);
+
+        return buffer;
+}
 #endif
 
 /**
@@ -1298,6 +1369,46 @@ static int __devinit igb_probe(struct pci_dev *pdev,
         }
 #endif
 
+        /*
+         * Initialize hardware timer: we keep it running just in case
+         * that some program needs it later on.
+         */
+        memset(&adapter->cycles, 0, sizeof(adapter->cycles));
+        adapter->cycles.read = igb_read_clock;
+        adapter->cycles.mask = CLOCKSOURCE_MASK(64);
+        adapter->cycles.mult = 1;
+        adapter->cycles.shift = IGB_TSYNC_SHIFT;
+        wr32(E1000_TIMINCA,
+             (1<<24) |
+             IGB_TSYNC_CYCLE_TIME_IN_NANOSECONDS * IGB_TSYNC_SCALE);
+#if 0
+        /*
+         * Avoid rollover while we initialize by resetting the time counter.
+         */
+        wr32(E1000_SYSTIML, 0x00000000);
+        wr32(E1000_SYSTIMH, 0x00000000);
+#else
+        /*
+         * Set registers so that rollover occurs soon to test this.
+         */
+        wr32(E1000_SYSTIML, 0x00000000);
+        wr32(E1000_SYSTIMH, 0xFF800000);
+#endif
+        wrfl();
+        timecounter_init(&adapter->clock,
+                         &adapter->cycles,
+                         ktime_to_ns(ktime_get_real()));
+
+#ifdef DEBUG
+        {
+                char buffer[160];
+                printk(KERN_DEBUG
+                        "igb: %s: hw %p initialized timer\n",
+                        igb_get_time_str(adapter, buffer),
+                        &adapter->hw);
+        }
+#endif
+
         dev_info(&pdev->dev, "Intel(R) Gigabit Ethernet Network Connection\n");
         /* print bus type/speed/width info */
         dev_info(&pdev->dev, "%s: (PCIe:%s:%s) %pM\n",