[PATCH v1 3/8] net: dsa: hellcreek: Add PTP clock support

Kurt Kanzenbach
2020-07-10T11:36:37Z

From: Kamil Alkhouri <kamil.alkhouri@hs-offenburg.de>

The switch has internal PTP hardware clocks. Add support for it. There are three
clocks:

* Synchronized
* Syntonized
* Free running

Currently the synchronized clock is exported to user space which is a good
default for the beginning. The free running clock might be exported later
e.g. for implementing 802.1AS-2011/2020 Time Aware Bridges (TAB). The switch
also supports cross time stamping for that purpose.

The implementation adds support setting/getting the time as well as offset and
frequency adjustments. However, the clock only holds a partial timeofday
timestamp. This is why we track the seconds completely in software (see overflow
work and last_ts).

Furthermore, add the PTP multicast addresses into the FDB to forward that
packages only to the CPU port where they are processed by a PTP program.

Signed-off-by: Kamil Alkhouri <kamil.alkhouri@hs-offenburg.de>
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
---
drivers/net/dsa/hirschmann/Makefile | 4 +-
drivers/net/dsa/hirschmann/hellcreek.c | 72 ++++++
drivers/net/dsa/hirschmann/hellcreek.h | 7 +
drivers/net/dsa/hirschmann/hellcreek_ptp.c | 283 +++++++++++++++++++++
drivers/net/dsa/hirschmann/hellcreek_ptp.h | 69 +++++
5 files changed, 434 insertions(+), 1 deletion(-)
create mode 100644 drivers/net/dsa/hirschmann/hellcreek_ptp.c
create mode 100644 drivers/net/dsa/hirschmann/hellcreek_ptp.h

diff --git a/drivers/net/dsa/hirschmann/Makefile b/drivers/net/dsa/hirschmann/Makefile
index 0e12e149e40f..39de02a03640 100644
--- a/drivers/net/dsa/hirschmann/Makefile
+++ b/drivers/net/dsa/hirschmann/Makefile
@@ -1,2 +1,4 @@
# SPDX-License-Identifier: GPL-2.0
-obj-$(CONFIG_NET_DSA_HIRSCHMANN_HELLCREEK) += hellcreek.o
+obj-$(CONFIG_NET_DSA_HIRSCHMANN_HELLCREEK) += hellcreek_sw.o
+hellcreek_sw-objs := hellcreek.o
+hellcreek_sw-objs += hellcreek_ptp.o
diff --git a/drivers/net/dsa/hirschmann/hellcreek.c b/drivers/net/dsa/hirschmann/hellcreek.c
index f51e2362a33c..9901d6435d97 100644
--- a/drivers/net/dsa/hirschmann/hellcreek.c
+++ b/drivers/net/dsa/hirschmann/hellcreek.c
@@ -25,6 +25,7 @@
#include <net/dsa.h>

#include "hellcreek.h"
+#include "hellcreek_ptp.h"

static const struct hellcreek_counter hellcreek_counter[] = {
{ 0x00, "RxFiltered", },
@@ -972,6 +973,44 @@ static void hellcreek_setup_tc_identity_mapping(struct hellcreek *hellcreek)
spin_unlock_irqrestore(&hellcreek->reg_lock, flags);
}

+static int hellcreek_setup_fdb(struct hellcreek *hellcreek)
+{
+ static struct hellcreek_fdb_entry ptp = {
+ /* MAC: 01-1B-19-00-00-00 */
+ .mac = { 0x01, 0x1b, 0x19, 0x00, 0x00, 0x00 },
+ .portmask = 0x03, /* Management ports */
+ .age = 0,
+ .is_obt = 0,
+ .pass_blocked = 0,
+ .is_static = 1,
+ .reprio_tc = 6, /* TC: 6 as per IEEE 802.1AS */
+ .reprio_en = 1,
+ };
+ static struct hellcreek_fdb_entry p2p = {
+ /* MAC: 01-80-C2-00-00-0E */
+ .mac = { 0x01, 0x80, 0xc2, 0x00, 0x00, 0x0e },
+ .portmask = 0x03, /* Management ports */
+ .age = 0,
+ .is_obt = 0,
+ .pass_blocked = 0,
+ .is_static = 1,
+ .reprio_tc = 6, /* TC: 6 as per IEEE 802.1AS */
+ .reprio_en = 1,
+ };
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&hellcreek->reg_lock, flags);
+ ret = __hellcreek_fdb_add(hellcreek, &ptp);
+ if (ret)
+ goto out;
+ ret = __hellcreek_fdb_add(hellcreek, &p2p);
+out:
+ spin_unlock_irqrestore(&hellcreek->reg_lock, flags);
+
+ return ret;
+}
+
static int hellcreek_setup(struct dsa_switch *ds)
{
struct hellcreek *hellcreek = ds->priv;
@@ -1011,6 +1050,14 @@ static int hellcreek_setup(struct dsa_switch *ds)
/* Configure PCP <-> TC mapping */
hellcreek_setup_tc_identity_mapping(hellcreek);

+ /* Intercept _all_ PTP multicast traffic */
+ ret = hellcreek_setup_fdb(hellcreek);
+ if (ret) {
+ dev_err(hellcreek->dev,
+ "Failed to insert static PTP FDB entries\n");
+ return ret;
+ }
+
return 0;
}

@@ -1091,6 +1138,7 @@ static int hellcreek_probe(struct platform_device *pdev)
}

spin_lock_init(&hellcreek->reg_lock);
+ spin_lock_init(&hellcreek->ptp_lock);

hellcreek->dev = dev;

@@ -1106,6 +1154,18 @@ static int hellcreek_probe(struct platform_device *pdev)
return PTR_ERR(hellcreek->base);
}

+ res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "ptp");
+ if (!res) {
+ dev_err(dev, "No PTP memory region provided!\n");
+ return -ENODEV;
+ }
+
+ hellcreek->ptp_base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(hellcreek->ptp_base)) {
+ dev_err(dev, "No memory available!\n");
+ return PTR_ERR(hellcreek->ptp_base);
+ }
+
ret = hellcreek_detect(hellcreek);
if (ret) {
dev_err(dev, "No (known) chip found!\n");
@@ -1136,15 +1196,27 @@ static int hellcreek_probe(struct platform_device *pdev)
return ret;
}

+ ret = hellcreek_ptp_setup(hellcreek);
+ if (ret) {
+ dev_err(dev, "Failed to setup PTP!\n");
+ goto err_ptp_setup;
+ }
+
platform_set_drvdata(pdev, hellcreek);

return 0;
+
+err_ptp_setup:
+ dsa_unregister_switch(hellcreek->ds);
+
+ return ret;
}

static int hellcreek_remove(struct platform_device *pdev)
{
struct hellcreek *hellcreek = platform_get_drvdata(pdev);

+ hellcreek_ptp_free(hellcreek);
dsa_unregister_switch(hellcreek->ds);
platform_set_drvdata(pdev, NULL);

diff --git a/drivers/net/dsa/hirschmann/hellcreek.h b/drivers/net/dsa/hirschmann/hellcreek.h
index a08a10cb5ab7..2d4422fd2567 100644
--- a/drivers/net/dsa/hirschmann/hellcreek.h
+++ b/drivers/net/dsa/hirschmann/hellcreek.h
@@ -234,10 +234,17 @@ struct hellcreek_fdb_entry {
struct hellcreek {
struct device *dev;
struct dsa_switch *ds;
+ struct ptp_clock *ptp_clock;
+ struct ptp_clock_info ptp_clock_info;
struct hellcreek_port ports[4];
+ struct delayed_work overflow_work;
spinlock_t reg_lock; /* Switch IP register lock */
+ spinlock_t ptp_lock; /* PTP IP register lock */
void __iomem *base;
+ void __iomem *ptp_base;
u8 *vidmbrcfg; /* vidmbrcfg shadow */
+ u64 seconds; /* PTP seconds */
+ u64 last_ts; /* Used for overflow detection */
size_t fdb_entries;
};

diff --git a/drivers/net/dsa/hirschmann/hellcreek_ptp.c b/drivers/net/dsa/hirschmann/hellcreek_ptp.c
new file mode 100644
index 000000000000..c606a26a130e
--- /dev/null
+++ b/drivers/net/dsa/hirschmann/hellcreek_ptp.c
@@ -0,0 +1,283 @@
+// SPDX-License-Identifier: (GPL-2.0 OR MIT)
+/*
+ * DSA driver for:
+ * Hirschmann Hellcreek TSN switch.
+ *
+ * Copyright (C) 2019,2020 Hochschule Offenburg
+ * Copyright (C) 2019,2020 Linutronix GmbH
+ * Authors: Kamil Alkhouri <kamil.alkhouri@hs-offenburg.de>
+ * Kurt Kanzenbach <kurt@linutronix.de>
+ */
+
+#include <linux/ptp_clock_kernel.h>
+#include "hellcreek.h"
+#include "hellcreek_ptp.h"
+
+static u16 hellcreek_ptp_read(struct hellcreek *hellcreek, unsigned int offset)
+{
+ return readw(hellcreek->ptp_base + offset);
+}
+
+static void hellcreek_ptp_write(struct hellcreek *hellcreek, u16 data,
+ unsigned int offset)
+{
+ writew(data, hellcreek->ptp_base + offset);
+}
+
+/* Get nanoseconds from PTP clock */
+static u64 hellcreek_ptp_clock_read(struct hellcreek *hellcreek)
+{
+ u16 nsl, nsh;
+
+ /* Take a snapshot */
+ hellcreek_ptp_write(hellcreek, PR_COMMAND_C_SS, PR_COMMAND_C);
+
+ /* The time of the day is saved as 96 bits. However, due to hardware
+ * limitations the seconds are not or only partly kept in the PTP
+ * core. Currently only three bits for the seconds are available. That's
+ * why only the nanoseconds are used and the seconds are tracked in
+ * software. Anyway due to internal locking all five registers should be
+ * read.
+ */
+ nsh = hellcreek_ptp_read(hellcreek, PR_SS_SYNC_DATA_C);
+ nsh = hellcreek_ptp_read(hellcreek, PR_SS_SYNC_DATA_C);
+ nsh = hellcreek_ptp_read(hellcreek, PR_SS_SYNC_DATA_C);
+ nsh = hellcreek_ptp_read(hellcreek, PR_SS_SYNC_DATA_C);
+ nsl = hellcreek_ptp_read(hellcreek, PR_SS_SYNC_DATA_C);
+
+ return (u64)nsl | ((u64)nsh << 16);
+}
+
+static u64 __hellcreek_ptp_gettime(struct hellcreek *hellcreek)
+{
+ u64 ns;
+
+ ns = hellcreek_ptp_clock_read(hellcreek);
+ if (ns < hellcreek->last_ts)
+ hellcreek->seconds++;
+ hellcreek->last_ts = ns;
+ ns += hellcreek->seconds * NSEC_PER_SEC;
+
+ return ns;
+}
+
+static int hellcreek_ptp_gettime(struct ptp_clock_info *ptp,
+ struct timespec64 *ts)
+{
+ struct hellcreek *hellcreek = ptp_to_hellcreek(ptp);
+ u64 ns;
+
+ spin_lock(&hellcreek->ptp_lock);
+ ns = __hellcreek_ptp_gettime(hellcreek);
+ spin_unlock(&hellcreek->ptp_lock);
+
+ *ts = ns_to_timespec64(ns);
+
+ return 0;
+}
+
+static int hellcreek_ptp_settime(struct ptp_clock_info *ptp,
+ const struct timespec64 *ts)
+{
+ struct hellcreek *hellcreek = ptp_to_hellcreek(ptp);
+ u16 secl, nsh, nsl;
+
+ secl = ts->tv_sec & 0xffff;
+ nsh = ((u32)ts->tv_nsec & 0xffff0000) >> 16;
+ nsl = ts->tv_nsec & 0xffff;
+
+ spin_lock(&hellcreek->ptp_lock);
+
+ /* Update overflow data structure */
+ hellcreek->seconds = ts->tv_sec;
+ hellcreek->last_ts = ts->tv_nsec;
+
+ /* Set time in clock */
+ hellcreek_ptp_write(hellcreek, 0x00, PR_CLOCK_WRITE_C);
+ hellcreek_ptp_write(hellcreek, 0x00, PR_CLOCK_WRITE_C);
+ hellcreek_ptp_write(hellcreek, secl, PR_CLOCK_WRITE_C);
+ hellcreek_ptp_write(hellcreek, nsh, PR_CLOCK_WRITE_C);
+ hellcreek_ptp_write(hellcreek, nsl, PR_CLOCK_WRITE_C);
+
+ spin_unlock(&hellcreek->ptp_lock);
+
+ return 0;
+}
+
+static int hellcreek_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
+{
+ struct hellcreek *hellcreek = ptp_to_hellcreek(ptp);
+ u16 negative = 0, addendh, addendl;
+ u32 addend;
+ u64 adj;
+
+ if (scaled_ppm < 0) {
+ negative = 1;
+ scaled_ppm = -scaled_ppm;
+ }
+
+ /* IP-Core adjusts the nominal frequency by adding or subtracting 1 ns
+ * from the 8 ns (period of the oscillator) every time the accumulator
+ * register overflows. The value stored in the addend register is added
+ * to the accumulator register every 8 ns.
+ *
+ * addend value = (2^30 * accumulator_overflow_rate) /
+ * oscillator_frequency
+ * where:
+ *
+ * oscillator_frequency = 125 MHz
+ * accumulator_overflow_rate = 125 MHz * scaled_ppm * 2^-16 * 10^-6 * 8
+ */
+ adj = scaled_ppm;
+ adj <<= 11;
+ addend = (u32)div_u64(adj, 15625);
+
+ addendh = (addend & 0xffff0000) >> 16;
+ addendl = addend & 0xffff;
+
+ negative = (negative << 15) & 0x8000;
+
+ spin_lock(&hellcreek->ptp_lock);
+
+ /* Set drift register */
+ hellcreek_ptp_write(hellcreek, negative, PR_CLOCK_DRIFT_C);
+ hellcreek_ptp_write(hellcreek, 0x00, PR_CLOCK_DRIFT_C);
+ hellcreek_ptp_write(hellcreek, 0x00, PR_CLOCK_DRIFT_C);
+ hellcreek_ptp_write(hellcreek, addendh, PR_CLOCK_DRIFT_C);
+ hellcreek_ptp_write(hellcreek, addendl, PR_CLOCK_DRIFT_C);
+
+ spin_unlock(&hellcreek->ptp_lock);
+
+ return 0;
+}
+
+static int hellcreek_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
+{
+ struct hellcreek *hellcreek = ptp_to_hellcreek(ptp);
+ u16 negative = 0, counth, countl;
+ u32 count_val;
+
+ /* If the offset is larger than IP-Core slow offset resources. Don't
+ * consider slow adjustment. Rather, add the offset directly to the
+ * current time
+ */
+ if (abs(delta) > MAX_SLOW_OFFSET_ADJ) {
+ struct timespec64 now, then = ns_to_timespec64(delta);
+
+ hellcreek_ptp_gettime(ptp, &now);
+ now = timespec64_add(now, then);
+ hellcreek_ptp_settime(ptp, &now);
+
+ return 0;
+ }
+
+ if (delta < 0) {
+ negative = 1;
+ delta = -delta;
+ }
+
+ /* 'count_val' does not exceed the maximum register size (2^30) */
+ count_val = div_s64(delta, MAX_NS_PER_STEP);
+
+ counth = (count_val & 0xffff0000) >> 16;
+ countl = count_val & 0xffff;
+
+ negative = (negative << 15) & 0x8000;
+
+ spin_lock(&hellcreek->ptp_lock);
+
+ /* Set offset write register */
+ hellcreek_ptp_write(hellcreek, negative, PR_CLOCK_OFFSET_C);
+ hellcreek_ptp_write(hellcreek, MAX_NS_PER_STEP, PR_CLOCK_OFFSET_C);
+ hellcreek_ptp_write(hellcreek, MIN_CLK_CYCLES_BETWEEN_STEPS,
+ PR_CLOCK_OFFSET_C);
+ hellcreek_ptp_write(hellcreek, countl, PR_CLOCK_OFFSET_C);
+ hellcreek_ptp_write(hellcreek, counth, PR_CLOCK_OFFSET_C);
+
+ spin_unlock(&hellcreek->ptp_lock);
+
+ return 0;
+}
+
+static int hellcreek_ptp_enable(struct ptp_clock_info *ptp,
+ struct ptp_clock_request *rq, int on)
+{
+ return -EOPNOTSUPP;
+}
+
+static void hellcreek_ptp_overflow_check(struct work_struct *work)
+{
+ struct delayed_work *dw = to_delayed_work(work);
+ struct hellcreek *hellcreek;
+
+ hellcreek = dw_overflow_to_hellcreek(dw);
+
+ spin_lock(&hellcreek->ptp_lock);
+ __hellcreek_ptp_gettime(hellcreek);
+ spin_unlock(&hellcreek->ptp_lock);
+
+ schedule_delayed_work(&hellcreek->overflow_work,
+ HELLCREEK_OVERFLOW_PERIOD);
+}
+
+int hellcreek_ptp_setup(struct hellcreek *hellcreek)
+{
+ u16 status;
+
+ /* Set up the overflow work */
+ INIT_DELAYED_WORK(&hellcreek->overflow_work,
+ hellcreek_ptp_overflow_check);
+
+ /* Setup PTP clock */
+ hellcreek->ptp_clock_info.owner = THIS_MODULE;
+ snprintf(hellcreek->ptp_clock_info.name,
+ sizeof(hellcreek->ptp_clock_info.name),
+ dev_name(hellcreek->dev));
+
+ /* IP-Core can add up to 0.5 ns per 8 ns cycle, which means
+ * accumulator_overflow_rate shall not exceed 62.5 MHz (which adjusts
+ * the nominal frequency by 6.25%)
+ */
+ hellcreek->ptp_clock_info.max_adj = 62500000;
+ hellcreek->ptp_clock_info.n_alarm = 0;
+ hellcreek->ptp_clock_info.n_pins = 0;
+ hellcreek->ptp_clock_info.n_ext_ts = 0;
+ hellcreek->ptp_clock_info.n_per_out = 0;
+ hellcreek->ptp_clock_info.pps = 0;
+ hellcreek->ptp_clock_info.adjfine = hellcreek_ptp_adjfine;
+ hellcreek->ptp_clock_info.adjtime = hellcreek_ptp_adjtime;
+ hellcreek->ptp_clock_info.gettime64 = hellcreek_ptp_gettime;
+ hellcreek->ptp_clock_info.settime64 = hellcreek_ptp_settime;
+ hellcreek->ptp_clock_info.enable = hellcreek_ptp_enable;
+
+ hellcreek->ptp_clock = ptp_clock_register(&hellcreek->ptp_clock_info,
+ hellcreek->dev);
+ if (IS_ERR(hellcreek->ptp_clock))
+ return PTR_ERR(hellcreek->ptp_clock);
+
+ /* Enable the offset correction process, if no offset correction is
+ * already taking place
+ */
+ status = hellcreek_ptp_read(hellcreek, PR_CLOCK_STATUS_C);
+ if (!(status & PR_CLOCK_STATUS_C_OFS_ACT))
+ hellcreek_ptp_write(hellcreek,
+ status | PR_CLOCK_STATUS_C_ENA_OFS,
+ PR_CLOCK_STATUS_C);
+
+ /* Enable the drift correction process */
+ hellcreek_ptp_write(hellcreek, status | PR_CLOCK_STATUS_C_ENA_DRIFT,
+ PR_CLOCK_STATUS_C);
+
+ schedule_delayed_work(&hellcreek->overflow_work,
+ HELLCREEK_OVERFLOW_PERIOD);
+
+ return 0;
+}
+
+void hellcreek_ptp_free(struct hellcreek *hellcreek)
+{
+ cancel_delayed_work_sync(&hellcreek->overflow_work);
+ if (hellcreek->ptp_clock)
+ ptp_clock_unregister(hellcreek->ptp_clock);
+ hellcreek->ptp_clock = NULL;
+}
diff --git a/drivers/net/dsa/hirschmann/hellcreek_ptp.h b/drivers/net/dsa/hirschmann/hellcreek_ptp.h
new file mode 100644
index 000000000000..2dd8aaa532d0
--- /dev/null
+++ b/drivers/net/dsa/hirschmann/hellcreek_ptp.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: (GPL-2.0 OR MIT) */
+/*
+ * DSA driver for:
+ * Hirschmann Hellcreek TSN switch.
+ *
+ * Copyright (C) 2019,2020 Hochschule Offenburg
+ * Copyright (C) 2019,2020 Linutronix GmbH
+ * Authors: Kurt Kanzenbach <kurt@linutronix.de>
+ * Kamil Alkhouri <kamil.alkhouri@hs-offenburg.de>
+ */
+
+#ifndef _HELLCREEK_PTP_H_
+#define _HELLCREEK_PTP_H_
+
+#include <linux/bitops.h>
+#include <linux/ptp_clock_kernel.h>
+
+#include "hellcreek.h"
+
+/* Every jump in time is 7 ns */
+#define MAX_NS_PER_STEP 7L
+
+/* Correct offset at every clock cycle */
+#define MIN_CLK_CYCLES_BETWEEN_STEPS 0
+
+/* Maximum available slow offset resources */
+#define MAX_SLOW_OFFSET_ADJ \
+ ((unsigned long long)((1 << 30) - 1) * MAX_NS_PER_STEP)
+
+/* four times a second overflow check */
+#define HELLCREEK_OVERFLOW_PERIOD (HZ / 4)
+
+/* PTP Register */
+#define PR_SETTINGS_C (0x09 * 2)
+#define PR_SETTINGS_C_RES3TS BIT(4)
+#define PR_SETTINGS_C_TS_SRC_TK_SHIFT 8
+#define PR_SETTINGS_C_TS_SRC_TK_MASK GENMASK(9, 8)
+#define PR_COMMAND_C (0x0a * 2)
+#define PR_COMMAND_C_SS BIT(0)
+
+#define PR_CLOCK_STATUS_C (0x0c * 2)
+#define PR_CLOCK_STATUS_C_ENA_DRIFT BIT(12)
+#define PR_CLOCK_STATUS_C_OFS_ACT BIT(13)
+#define PR_CLOCK_STATUS_C_ENA_OFS BIT(14)
+
+#define PR_CLOCK_READ_C (0x0d * 2)
+#define PR_CLOCK_WRITE_C (0x0e * 2)
+#define PR_CLOCK_OFFSET_C (0x0f * 2)
+#define PR_CLOCK_DRIFT_C (0x10 * 2)
+
+#define PR_SS_FREE_DATA_C (0x12 * 2)
+#define PR_SS_SYNT_DATA_C (0x14 * 2)
+#define PR_SS_SYNC_DATA_C (0x16 * 2)
+#define PR_SS_DRAC_DATA_C (0x18 * 2)
+
+#define STATUS_OUT (0x60 * 2)
+#define STATUS_OUT_SYNC_GOOD BIT(0)
+#define STATUS_OUT_IS_GM BIT(1)
+
+int hellcreek_ptp_setup(struct hellcreek *hellcreek);
+void hellcreek_ptp_free(struct hellcreek *hellcreek);
+
+#define ptp_to_hellcreek(ptp) \
+ container_of(ptp, struct hellcreek, ptp_clock_info)
+
+#define dw_overflow_to_hellcreek(dw) \
+ container_of(dw, struct hellcreek, overflow_work)
+
+#endif /* _HELLCREEK_PTP_H_ */
--
2.20.1