net: dsa: hellcreek: Add PTP clock support
authorKamil Alkhouri <kamil.alkhouri@hs-offenburg.de>
Tue, 3 Nov 2020 07:10:57 +0000 (08:10 +0100)
committerJakub Kicinski <kuba@kernel.org>
Thu, 5 Nov 2020 22:04:49 +0000 (14:04 -0800)
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>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
drivers/net/dsa/hirschmann/Kconfig
drivers/net/dsa/hirschmann/Makefile
drivers/net/dsa/hirschmann/hellcreek.c
drivers/net/dsa/hirschmann/hellcreek.h
drivers/net/dsa/hirschmann/hellcreek_ptp.c [new file with mode: 0644]
drivers/net/dsa/hirschmann/hellcreek_ptp.h [new file with mode: 0644]

index 7d189cb..222dd35 100644 (file)
@@ -3,6 +3,7 @@ config NET_DSA_HIRSCHMANN_HELLCREEK
        tristate "Hirschmann Hellcreek TSN Switch support"
        depends on HAS_IOMEM
        depends on NET_DSA
+       depends on PTP_1588_CLOCK
        select NET_DSA_TAG_HELLCREEK
        help
          This driver adds support for Hirschmann Hellcreek TSN switches.
index 0e12e14..39de02a 100644 (file)
@@ -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
index a4965a2..eb177f4 100644 (file)
@@ -25,6 +25,7 @@
 #include <net/dsa.h>
 
 #include "hellcreek.h"
+#include "hellcreek_ptp.h"
 
 static const struct hellcreek_counter hellcreek_counter[] = {
        { 0x00, "RxFiltered", },
@@ -959,6 +960,43 @@ static void hellcreek_setup_tc_identity_mapping(struct hellcreek *hellcreek)
        }
 }
 
+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,
+       };
+       int ret;
+
+       mutex_lock(&hellcreek->reg_lock);
+       ret = __hellcreek_fdb_add(hellcreek, &ptp);
+       if (ret)
+               goto out;
+       ret = __hellcreek_fdb_add(hellcreek, &p2p);
+out:
+       mutex_unlock(&hellcreek->reg_lock);
+
+       return ret;
+}
+
 static int hellcreek_setup(struct dsa_switch *ds)
 {
        struct hellcreek *hellcreek = ds->priv;
@@ -1009,6 +1047,14 @@ static int hellcreek_setup(struct dsa_switch *ds)
         */
        ds->vlan_filtering_is_global = true;
 
+       /* 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;
 }
 
@@ -1160,6 +1206,7 @@ static int hellcreek_probe(struct platform_device *pdev)
 
        mutex_init(&hellcreek->reg_lock);
        mutex_init(&hellcreek->vlan_lock);
+       mutex_init(&hellcreek->ptp_lock);
 
        hellcreek->dev = dev;
 
@@ -1175,6 +1222,18 @@ 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");
@@ -1205,15 +1264,27 @@ 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);
 
index 762bf97..1b8050b 100644 (file)
@@ -15,6 +15,7 @@
 #include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/mutex.h>
+#include <linux/workqueue.h>
 #include <linux/platform_data/hirschmann-hellcreek.h>
 #include <linux/ptp_clock_kernel.h>
 #include <linux/timecounter.h>
@@ -237,12 +238,19 @@ struct hellcreek {
        const struct hellcreek_platform_data *pdata;
        struct device *dev;
        struct dsa_switch *ds;
+       struct ptp_clock *ptp_clock;
+       struct ptp_clock_info ptp_clock_info;
        struct hellcreek_port *ports;
+       struct delayed_work overflow_work;
        struct mutex reg_lock;  /* Switch IP register lock */
        struct mutex vlan_lock; /* VLAN bitmaps lock */
+       struct mutex ptp_lock;  /* PTP IP register lock */
        void __iomem *base;
+       void __iomem *ptp_base;
        u16 swcfg;              /* swcfg shadow */
        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 (file)
index 0000000..856fcb9
--- /dev/null
@@ -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;
+
+       mutex_lock(&hellcreek->ptp_lock);
+       ns = __hellcreek_ptp_gettime(hellcreek);
+       mutex_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;
+
+       mutex_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);
+
+       mutex_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;
+
+       mutex_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);
+
+       mutex_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;
+
+       mutex_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);
+
+       mutex_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);
+
+       mutex_lock(&hellcreek->ptp_lock);
+       __hellcreek_ptp_gettime(hellcreek);
+       mutex_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 (file)
index 0000000..2dd8aaa
--- /dev/null
@@ -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_ */