[RFC PATCH 10/12] igb: access to NIC time

Patrick Ohly
2008-12-15T14:59:45Z

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

Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
---
drivers/net/igb/e1000_regs.h | 28 +++++++++++
drivers/net/igb/igb.h | 4 ++
drivers/net/igb/igb_main.c | 106 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 138 insertions(+), 0 deletions(-)

diff --git a/drivers/net/igb/e1000_regs.h b/drivers/net/igb/e1000_regs.h
index bdf5d83..d225601 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 2121b8b..2db4c64 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;

#ifdef CONFIG_IGB_LRO
@@ -262,6 +264,8 @@ 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 e9ad560..c2b6da6 100644
--- a/drivers/net/igb/igb_main.c
+++ b/drivers/net/igb/igb_main.c
@@ -179,6 +179,54 @@ 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
@@ -189,6 +237,28 @@ 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

/**
@@ -1286,6 +1356,42 @@ 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",
--
1.5.5.3