[PATCH net-next RFC 2/9] net: dsa: mv88e6xxx: expose switch time as a PTP hardware clock

Brandon Streiff
2017-09-28T15:25:34Z

This patch adds basic support for exposing the 32-bit timestamp counter
inside the mv88e6xxx switch code as a ptp_clock.

Signed-off-by: Brandon Streiff <brandon.streiff@ni.com>
---
drivers/net/dsa/mv88e6xxx/Kconfig | 10 +++
drivers/net/dsa/mv88e6xxx/Makefile | 1 +
drivers/net/dsa/mv88e6xxx/chip.c | 20 +++++
drivers/net/dsa/mv88e6xxx/chip.h | 16 ++++
drivers/net/dsa/mv88e6xxx/ptp.c | 180 +++++++++++++++++++++++++++++++++++++
drivers/net/dsa/mv88e6xxx/ptp.h | 83 +++++++++++++++++
6 files changed, 310 insertions(+)
create mode 100644 drivers/net/dsa/mv88e6xxx/ptp.c
create mode 100644 drivers/net/dsa/mv88e6xxx/ptp.h

diff --git a/drivers/net/dsa/mv88e6xxx/Kconfig b/drivers/net/dsa/mv88e6xxx/Kconfig
index 1aaa7a9..ae9e7f7 100644
--- a/drivers/net/dsa/mv88e6xxx/Kconfig
+++ b/drivers/net/dsa/mv88e6xxx/Kconfig
@@ -18,3 +18,13 @@ config NET_DSA_MV88E6XXX_GLOBAL2

It is required on most chips. If the chip you compile the support for
doesn't have such registers set, say N here. In doubt, say Y.
+
+config NET_DSA_MV88E6XXX_PTP
+ bool "PTP support for Marvell 88E6xxx"
+ default n
+ depends on NET_DSA_MV88E6XXX_GLOBAL2
+ imply NETWORK_PHY_TIMESTAMPING
+ imply PTP_1588_CLOCK
+ help
+ Say Y to enable PTP hardware timestamping on Marvell 88E6xxx switch
+ chips that support it.
diff --git a/drivers/net/dsa/mv88e6xxx/Makefile b/drivers/net/dsa/mv88e6xxx/Makefile
index 5cd5551..47eda30 100644
--- a/drivers/net/dsa/mv88e6xxx/Makefile
+++ b/drivers/net/dsa/mv88e6xxx/Makefile
@@ -6,4 +6,5 @@ mv88e6xxx-objs += global1_vtu.o
mv88e6xxx-$(CONFIG_NET_DSA_MV88E6XXX_GLOBAL2) += global2.o
mv88e6xxx-objs += phy.o
mv88e6xxx-objs += port.o
+mv88e6xxx-$(CONFIG_NET_DSA_MV88E6XXX_PTP) += ptp.o
mv88e6xxx-objs += serdes.o
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 67efa7b..2ed37d8 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c
@@ -38,6 +38,7 @@
#include "global2.h"
#include "phy.h"
#include "port.h"
+#include "ptp.h"
#include "serdes.h"

static void assert_reg_lock(struct mv88e6xxx_chip *chip)
@@ -2033,6 +2034,13 @@ static int mv88e6xxx_setup(struct dsa_switch *ds)
if (err)
goto unlock;

+ /* Setup PTP Hardware Clock */
+ if (chip->info->ptp_support) {
+ err = mv88e6xxx_ptp_setup(chip);
+ if (err)
+ goto unlock;
+ }
+
unlock:
mutex_unlock(&chip->reg_lock);

@@ -3418,6 +3426,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
.pvt = true,
.multi_chip = true,
.tag_protocol = DSA_TAG_PROTO_DSA,
+ .ptp_support = true,
.ops = &mv88e6191_ops,
},

@@ -3438,6 +3447,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
.pvt = true,
.multi_chip = true,
.tag_protocol = DSA_TAG_PROTO_EDSA,
+ .ptp_support = true,
.ops = &mv88e6240_ops,
},

@@ -3458,6 +3468,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
.pvt = true,
.multi_chip = true,
.tag_protocol = DSA_TAG_PROTO_DSA,
+ .ptp_support = true,
.ops = &mv88e6290_ops,
},

@@ -3477,6 +3488,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
.pvt = true,
.multi_chip = true,
.tag_protocol = DSA_TAG_PROTO_EDSA,
+ .ptp_support = true,
.ops = &mv88e6320_ops,
},

@@ -3495,6 +3507,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
.atu_move_port_mask = 0xf,
.multi_chip = true,
.tag_protocol = DSA_TAG_PROTO_EDSA,
+ .ptp_support = true,
.ops = &mv88e6321_ops,
},

@@ -3514,6 +3527,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
.pvt = true,
.multi_chip = true,
.tag_protocol = DSA_TAG_PROTO_EDSA,
+ .ptp_support = true,
.ops = &mv88e6341_ops,
},

@@ -3574,6 +3588,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
.pvt = true,
.multi_chip = true,
.tag_protocol = DSA_TAG_PROTO_EDSA,
+ .ptp_support = true,
.ops = &mv88e6352_ops,
},
[MV88E6390] = {
@@ -3593,6 +3608,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
.pvt = true,
.multi_chip = true,
.tag_protocol = DSA_TAG_PROTO_DSA,
+ .ptp_support = true,
.ops = &mv88e6390_ops,
},
[MV88E6390X] = {
@@ -3612,6 +3628,7 @@ static const struct mv88e6xxx_info mv88e6xxx_table[] = {
.pvt = true,
.multi_chip = true,
.tag_protocol = DSA_TAG_PROTO_DSA,
+ .ptp_support = true,
.ops = &mv88e6390x_ops,
},
};
@@ -3949,6 +3966,9 @@ static void mv88e6xxx_remove(struct mdio_device *mdiodev)
struct dsa_switch *ds = dev_get_drvdata(&mdiodev->dev);
struct mv88e6xxx_chip *chip = ds->priv;

+ if (chip->info->ptp_support)
+ mv88e6xxx_ptp_free(chip);
+
mv88e6xxx_phy_destroy(chip);
mv88e6xxx_unregister_switch(chip);
mv88e6xxx_mdios_unregister(chip);
diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index d99d592..648bd50 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -16,6 +16,8 @@
#include <linux/irq.h>
#include <linux/gpio/consumer.h>
#include <linux/phy.h>
+#include <linux/ptp_clock_kernel.h>
+#include <linux/timecounter.h>
#include <net/dsa.h>

#ifndef UINT64_MAX
@@ -126,6 +128,9 @@ struct mv88e6xxx_info {
*/
u8 atu_move_port_mask;
const struct mv88e6xxx_ops *ops;
+
+ /* Supports PTP */
+ bool ptp_support;
};

struct mv88e6xxx_atu_entry {
@@ -208,6 +213,17 @@ struct mv88e6xxx_chip {
int irq;
int device_irq;
int watchdog_irq;
+
+ /* This cyclecounter abstracts the switch PTP time.
+ * reg_lock must be held for any operation that read()s.
+ */
+ struct cyclecounter tstamp_cc;
+ struct timecounter tstamp_tc;
+ struct delayed_work overflow_work;
+ unsigned long last_overflow_check;
+
+ struct ptp_clock *ptp_clock;
+ struct ptp_clock_info ptp_clock_info;
};

struct mv88e6xxx_bus_ops {
diff --git a/drivers/net/dsa/mv88e6xxx/ptp.c b/drivers/net/dsa/mv88e6xxx/ptp.c
new file mode 100644
index 0000000..155f8e9
--- /dev/null
+++ b/drivers/net/dsa/mv88e6xxx/ptp.c
@@ -0,0 +1,180 @@
+/*
+ * Marvell 88E6xxx Switch PTP support
+ *
+ * Copyright (c) 2008 Marvell Semiconductor
+ *
+ * Copyright (c) 2017 National Instruments
+ * Erik Hons <erik.hons@ni.com>
+ * Brandon Streiff <brandon.streiff@ni.com>
+ * Dane Wagner <dane.wagner@ni.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include "chip.h"
+#include "global2.h"
+#include "ptp.h"
+
+static int mv88e6xxx_tai_read(struct mv88e6xxx_chip *chip, int addr,
+ u16 *data, int len)
+{
+ if (!chip->info->ops->avb_ops->tai_read)
+ return -EOPNOTSUPP;
+
+ return chip->info->ops->avb_ops->tai_read(chip, addr, data, len);
+}
+
+static u64 mv88e6xxx_ptp_clock_read(const struct cyclecounter *cc)
+{
+ struct mv88e6xxx_chip *chip =
+ container_of(cc, struct mv88e6xxx_chip, tstamp_cc);
+ int err;
+ u16 phc_time[2];
+
+ err = mv88e6xxx_tai_read(chip, MV88E6XXX_TAI_TIME_LO, phc_time,
+ ARRAY_SIZE(phc_time));
+ if (err)
+ return 0;
+ else
+ return ((u32)phc_time[1] << 16) | phc_time[0];
+}
+
+static int mv88e6xxx_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
+{
+ if (scaled_ppm == 0)
+ return 0;
+
+ return -EOPNOTSUPP;
+}
+
+static int mv88e6xxx_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+ struct mv88e6xxx_chip *chip =
+ container_of(ptp, struct mv88e6xxx_chip, ptp_clock_info);
+
+ mutex_lock(&chip->reg_lock);
+ timecounter_adjtime(&chip->tstamp_tc, delta);
+ mutex_unlock(&chip->reg_lock);
+
+ return 0;
+}
+
+static int mv88e6xxx_ptp_gettime(struct ptp_clock_info *ptp,
+ struct timespec64 *ts)
+{
+ struct mv88e6xxx_chip *chip =
+ container_of(ptp, struct mv88e6xxx_chip, ptp_clock_info);
+ u64 ns;
+
+ mutex_lock(&chip->reg_lock);
+ ns = timecounter_read(&chip->tstamp_tc);
+ chip->last_overflow_check = jiffies;
+ mutex_unlock(&chip->reg_lock);
+
+ *ts = ns_to_timespec64(ns);
+
+ return 0;
+}
+
+static int mv88e6xxx_ptp_settime(struct ptp_clock_info *ptp,
+ const struct timespec64 *ts)
+{
+ struct mv88e6xxx_chip *chip =
+ container_of(ptp, struct mv88e6xxx_chip, ptp_clock_info);
+ u64 ns;
+
+ ns = timespec64_to_ns(ts);
+
+ mutex_lock(&chip->reg_lock);
+ timecounter_init(&chip->tstamp_tc, &chip->tstamp_cc, ns);
+ mutex_unlock(&chip->reg_lock);
+
+ return 0;
+}
+
+static int mv88e6xxx_ptp_enable(struct ptp_clock_info *ptp,
+ struct ptp_clock_request *rq, int on)
+{
+ return -EOPNOTSUPP;
+}
+
+static int mv88e6xxx_ptp_verify(struct ptp_clock_info *ptp, unsigned int pin,
+ enum ptp_pin_function func, unsigned int chan)
+{
+ return -EOPNOTSUPP;
+}
+
+/* The 32-bit timestamp counter overflows every ~34.3 seconds; this task
+ * forces periodic reads so that we don't miss any wraparounds.
+ */
+#define MV88E6XXX_TAI_OVERFLOW_PERIOD (34 * HZ / 2)
+static void mv88e6xxx_ptp_overflow_check(struct work_struct *work)
+{
+ struct delayed_work *dw = to_delayed_work(work);
+ struct mv88e6xxx_chip *chip =
+ container_of(dw, struct mv88e6xxx_chip, overflow_work);
+ bool timeout = time_is_before_jiffies(chip->last_overflow_check +
+ MV88E6XXX_TAI_OVERFLOW_PERIOD);
+
+ if (timeout) {
+ mutex_lock(&chip->reg_lock);
+ timecounter_read(&chip->tstamp_tc);
+ chip->last_overflow_check = jiffies;
+ mutex_unlock(&chip->reg_lock);
+ }
+
+ schedule_delayed_work(&chip->overflow_work,
+ MV88E6XXX_TAI_OVERFLOW_PERIOD);
+}
+
+int mv88e6xxx_ptp_setup(struct mv88e6xxx_chip *chip)
+{
+ /* Set up the cycle counter */
+ memset(&chip->tstamp_cc, 0, sizeof(chip->tstamp_cc));
+ chip->tstamp_cc.read = mv88e6xxx_ptp_clock_read;
+ chip->tstamp_cc.mask = CYCLECOUNTER_MASK(32);
+ /* Raw timestamps are in units of 8-ns clock periods. */
+ chip->tstamp_cc.mult = 8;
+ chip->tstamp_cc.shift = 0;
+
+ timecounter_init(&chip->tstamp_tc, &chip->tstamp_cc,
+ ktime_to_ns(ktime_get_real()));
+
+ chip->last_overflow_check = jiffies;
+
+ INIT_DELAYED_WORK(&chip->overflow_work, mv88e6xxx_ptp_overflow_check);
+
+ chip->ptp_clock_info.owner = THIS_MODULE;
+ snprintf(chip->ptp_clock_info.name, sizeof(chip->ptp_clock_info.name),
+ dev_name(chip->dev));
+ chip->ptp_clock_info.max_adj = 0;
+
+ chip->ptp_clock_info.adjfine = mv88e6xxx_ptp_adjfine;
+ chip->ptp_clock_info.adjtime = mv88e6xxx_ptp_adjtime;
+ chip->ptp_clock_info.gettime64 = mv88e6xxx_ptp_gettime;
+ chip->ptp_clock_info.settime64 = mv88e6xxx_ptp_settime;
+ chip->ptp_clock_info.enable = mv88e6xxx_ptp_enable;
+ chip->ptp_clock_info.verify = mv88e6xxx_ptp_verify;
+
+ chip->ptp_clock = ptp_clock_register(&chip->ptp_clock_info, chip->dev);
+ if (IS_ERR(chip->ptp_clock))
+ return PTR_ERR(chip->ptp_clock);
+
+ schedule_delayed_work(&chip->overflow_work,
+ MV88E6XXX_TAI_OVERFLOW_PERIOD);
+
+ return 0;
+}
+
+void mv88e6xxx_ptp_free(struct mv88e6xxx_chip *chip)
+{
+ if (chip->ptp_clock) {
+ cancel_delayed_work_sync(&chip->overflow_work);
+
+ ptp_clock_unregister(chip->ptp_clock);
+ chip->ptp_clock = NULL;
+ }
+}
diff --git a/drivers/net/dsa/mv88e6xxx/ptp.h b/drivers/net/dsa/mv88e6xxx/ptp.h
new file mode 100644
index 0000000..c662953
--- /dev/null
+++ b/drivers/net/dsa/mv88e6xxx/ptp.h
@@ -0,0 +1,83 @@
+/*
+ * Marvell 88E6xxx Switch PTP support
+ *
+ * Copyright (c) 2008 Marvell Semiconductor
+ *
+ * Copyright (c) 2017 National Instruments
+ * Erik Hons <erik.hons@ni.com>
+ * Brandon Streiff <brandon.streiff@ni.com>
+ * Dane Wagner <dane.wagner@ni.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef _MV88E6XXX_PTP_H
+#define _MV88E6XXX_PTP_H
+
+#include "chip.h"
+
+/* Offset 0x00: TAI Global Config */
+#define MV88E6XXX_TAI_CFG 0x00
+
+/* Offset 0x01: Timestamp Clock Period (ps) */
+#define MV88E6XXX_TAI_CLOCK_PERIOD 0x01
+
+/* Offset 0x02/0x03: Trigger Generation Amount */
+#define MV88E6XXX_TAI_TRIG_GEN_AMOUNT_LO 0x02
+#define MV88E6XXX_TAI_TRIG_GEN_AMOUNT_HI 0x03
+
+/* Offset 0x04: Clock Compensation */
+#define MV88E6XXX_TAI_TRIG_CLOCK_COMP 0x04
+
+/* Offset 0x05: Trigger Configuration */
+#define MV88E6XXX_TAI_TRIG_CFG 0x05
+
+/* Offset 0x06: Ingress Rate Limiter Clock Generation Amount */
+#define MV88E6XXX_TAI_IRL_AMOUNT 0x06
+
+/* Offset 0x07: Ingress Rate Limiter Compensation */
+#define MV88E6XXX_TAI_IRL_COMP 0x07
+
+/* Offset 0x08: Ingress Rate Limiter Compensation */
+#define MV88E6XXX_TAI_IRL_COMP_PS 0x08
+
+/* Offset 0x09: Event Status */
+#define MV88E6XXX_TAI_EVENT_STATUS 0x09
+
+/* Offset 0x0A/0x0B: Event Time */
+#define MV88E6XXX_TAI_EVENT_TIME_LO 0x0a
+#define MV88E6XXX_TAI_EVENT_TYPE_HI 0x0b
+
+/* Offset 0x0E/0x0F: PTP Global Time */
+#define MV88E6XXX_TAI_TIME_LO 0x0e
+#define MV88E6XXX_TAI_TIME_HI 0x0f
+
+/* Offset 0x10/0x11: Trig Generation Time */
+#define MV88E6XXX_TAI_TRIG_TIME_LO 0x10
+#define MV88E6XXX_TAI_TRIG_TIME_HI 0x11
+
+/* Offset 0x12: Lock Status */
+#define MV88E6XXX_TAI_LOCK_STATUS 0x12
+
+#ifdef CONFIG_NET_DSA_MV88E6XXX_PTP
+
+int mv88e6xxx_ptp_setup(struct mv88e6xxx_chip *chip);
+void mv88e6xxx_ptp_free(struct mv88e6xxx_chip *chip);
+
+#else /* !CONFIG_NET_DSA_MV88E6XXX_PTP */
+
+static inline int mv88e6xxx_ptp_setup(struct mv88e6xxx_chip *chip)
+{
+ return -EOPNOTSUPP;
+}
+
+static void mv88e6xxx_ptp_free(struct mv88e6xxx_chip *chip)
+{
+}
+
+#endif /* CONFIG_NET_DSA_MV88E6XXX_PTP */
+
+#endif /* _MV88E6XXX_PTP_H */
--
2.1.4