[PATCH net-next RFC 9/9] net: dsa: mv88e6xxx: add workaround for 6341 timestamping

Brandon Streiff
2017-09-28T15:25:41Z

88E6341 devices default to timestamping at the PHY, but due to a
hardware issue, timestamps via this component are unreliable. For
this family, configure the PTP hardware to force the timestamping
to occur at the MAC.

Signed-off-by: Brandon Streiff <brandon.streiff@ni.com>
---
drivers/net/dsa/mv88e6xxx/hwtstamp.c | 13 +++++++++++++
drivers/net/dsa/mv88e6xxx/hwtstamp.h | 9 +++++++++
2 files changed, 22 insertions(+)

diff --git a/drivers/net/dsa/mv88e6xxx/hwtstamp.c b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
index 825d6f0..b6aee88 100644
--- a/drivers/net/dsa/mv88e6xxx/hwtstamp.c
+++ b/drivers/net/dsa/mv88e6xxx/hwtstamp.c
@@ -523,6 +523,19 @@ int mv88e6xxx_hwtstamp_setup(struct mv88e6xxx_chip *chip)
return err;
}

+ /* 88E6341 devices default to timestamping at the PHY, but this has
+ * a hardware issue that results in unreliable timestamps. Force
+ * these devices to timestamp at the MAC.
+ */
+ if (chip->info->family == MV88E6XXX_FAMILY_6341) {
+ u16 val = MV88E6341_PTP_CFG_UPDATE |
+ MV88E6341_PTP_CFG_MODE_IDX |
+ MV88E6341_PTP_CFG_MODE_TS_AT_MAC;
+ err = mv88e6xxx_ptp_write(chip, MV88E6341_PTP_CFG, val);
+ if (err)
+ return err;
+ }
+
return 0;
}

diff --git a/drivers/net/dsa/mv88e6xxx/hwtstamp.h b/drivers/net/dsa/mv88e6xxx/hwtstamp.h
index 1d24220..550711a 100644
--- a/drivers/net/dsa/mv88e6xxx/hwtstamp.h
+++ b/drivers/net/dsa/mv88e6xxx/hwtstamp.h
@@ -34,6 +34,15 @@
/* Offset 0x02: Timestamp Arrival Capture Pointers */
#define MV88E6XXX_PTP_TS_ARRIVAL_PTR 0x02

+/* Offset 0x07: PTP Global Configuration */
+#define MV88E6341_PTP_CFG 0x07
+#define MV88E6341_PTP_CFG_UPDATE 0x8000
+#define MV88E6341_PTP_CFG_IDX_MASK 0x7f00
+#define MV88E6341_PTP_CFG_DATA_MASK 0x00ff
+#define MV88E6341_PTP_CFG_MODE_IDX 0x0
+#define MV88E6341_PTP_CFG_MODE_TS_AT_PHY 0x00
+#define MV88E6341_PTP_CFG_MODE_TS_AT_MAC 0x80
+
/* Offset 0x08: PTP Interrupt Status */
#define MV88E6XXX_PTP_IRQ_STATUS 0x08

--
2.1.4