e1000e: add support for hardware timestamping on some devices

On 82574, 82583, 82579, I217 and I218 add support for hardware time
stamping of all or no Rx packets and Tx packets which have the
SKBTX_HW_TSTAMP flag set.  Update the .get_ts_info ethtool operation to
report the supported time stamping modes, and enable and disable hardware
time stamping with the SIOCSHWTSTAMP ioctl.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Jeff Pieper <jeffrey.e.pieper@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

1 files changed, 45 insertions, 1 deletions

diff --git a/drivers/net/ethernet/intel/e1000e/e1000.h b/drivers/net/ethernet/intel/e1000e/e1000.h
index b89b181..dea9e55 100644
--- a/drivers/net/ethernet/intel/e1000e/e1000.h
+++ b/drivers/net/ethernet/intel/e1000e/e1000.h
@@ -41,6 +41,8 @@
 #include <linux/pci-aspm.h>
 #include <linux/crc32.h>
 #include <linux/if_vlan.h>
+#include <linux/clocksource.h>
+#include <linux/net_tstamp.h>
 
 #include "hw.h"
 
@@ -353,6 +355,7 @@ struct e1000_adapter {
 	u64 gorc_old;
 	u32 alloc_rx_buff_failed;
 	u32 rx_dma_failed;
+	u32 rx_hwtstamp_cleared;
 
 	unsigned int rx_ps_pages;
 	u16 rx_ps_bsize0;
@@ -402,6 +405,14 @@ struct e1000_adapter {
 
 	u16 tx_ring_count;
 	u16 rx_ring_count;
+
+	struct hwtstamp_config hwtstamp_config;
+	struct delayed_work systim_overflow_work;
+	struct sk_buff *tx_hwtstamp_skb;
+	struct work_struct tx_hwtstamp_work;
+	spinlock_t systim_lock;	/* protects SYSTIML/H regsters */
+	struct cyclecounter cc;
+	struct timecounter tc;
 };
 
 struct e1000_info {
@@ -416,6 +427,38 @@ struct e1000_info {
 	const struct e1000_nvm_operations *nvm_ops;
 };
 
+/* The system time is maintained by a 64-bit counter comprised of the 32-bit
+ * SYSTIMH and SYSTIML registers.  How the counter increments (and therefore
+ * its resolution) is based on the contents of the TIMINCA register - it
+ * increments every incperiod (bits 31:24) clock ticks by incvalue (bits 23:0).
+ * For the best accuracy, the incperiod should be as small as possible.  The
+ * incvalue is scaled by a factor as large as possible (while still fitting
+ * in bits 23:0) so that relatively small clock corrections can be made.
+ *
+ * As a result, a shift of INCVALUE_SHIFT_n is used to fit a value of
+ * INCVALUE_n into the TIMINCA register allowing 32+8+(24-INCVALUE_SHIFT_n)
+ * bits to count nanoseconds leaving the rest for fractional nonseconds.
+ */
+#define INCVALUE_96MHz		125
+#define INCVALUE_SHIFT_96MHz	17
+#define INCPERIOD_SHIFT_96MHz	2
+#define INCPERIOD_96MHz		(12 >> INCPERIOD_SHIFT_96MHz)
+
+#define INCVALUE_25MHz		40
+#define INCVALUE_SHIFT_25MHz	18
+#define INCPERIOD_25MHz		1
+
+/* Another drawback of scaling the incvalue by a large factor is the
+ * 64-bit SYSTIM register overflows more quickly.  This is dealt with
+ * by simply reading the clock before it overflows.
+ *
+ * Clock	ns bits	Overflows after
+ * ~~~~~~	~~~~~~~	~~~~~~~~~~~~~~~
+ * 96MHz	47-bit	2^(47-INCPERIOD_SHIFT_96MHz) / 10^9 / 3600 = 9.77 hrs
+ * 25MHz	46-bit	2^46 / 10^9 / 3600 = 19.55 hours
+ */
+#define E1000_SYSTIM_OVERFLOW_PERIOD	(HZ * 60 * 60 * 4)
+
 /* hardware capability, feature, and workaround flags */
 #define FLAG_HAS_AMT                      (1 << 0)
 #define FLAG_HAS_FLASH                    (1 << 1)
@@ -431,7 +474,7 @@ struct e1000_info {
 #define FLAG_HAS_SMART_POWER_DOWN         (1 << 11)
 #define FLAG_IS_QUAD_PORT_A               (1 << 12)
 #define FLAG_IS_QUAD_PORT                 (1 << 13)
-/* reserved bit14 */
+#define FLAG_HAS_HW_TIMESTAMP             (1 << 14)
 #define FLAG_APME_IN_WUC                  (1 << 15)
 #define FLAG_APME_IN_CTRL3                (1 << 16)
 #define FLAG_APME_CHECK_PORT_B            (1 << 17)
@@ -463,6 +506,7 @@ struct e1000_info {
 #define FLAG2_NO_DISABLE_RX               (1 << 10)
 #define FLAG2_PCIM2PCI_ARBITER_WA         (1 << 11)
 #define FLAG2_DFLT_CRC_STRIPPING          (1 << 12)
+#define FLAG2_CHECK_RX_HWTSTAMP           (1 << 13)
 
 #define E1000_RX_DESC_PS(R, i)	    \
 	(&(((union e1000_rx_desc_packet_split *)((R).desc))[i]))