1 files changed, 332 insertions, 0 deletions
diff --git a/drivers/ptp/ptp_dfl_tod.c b/drivers/ptp/ptp_dfl_tod.c
new file mode 100644
index 000000000..f699d541b
--- /dev/null
+++ b/drivers/ptp/ptp_dfl_tod.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DFL device driver for Time-of-Day (ToD) private feature
+ *
+ * Copyright (C) 2023 Intel Corporation
+ */
+
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/dfl.h>
+#include <linux/gcd.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/ptp_clock_kernel.h>
+#include <linux/spinlock.h>
+#include <linux/units.h>
+
+#define FME_FEATURE_ID_TOD		0x22
+
+/* ToD clock register space. */
+#define TOD_CLK_FREQ			0x038
+
+/*
+ * The read sequence of ToD timestamp registers: TOD_NANOSEC, TOD_SECONDSL and
+ * TOD_SECONDSH, because there is a hardware snapshot whenever the TOD_NANOSEC
+ * register is read.
+ *
+ * The ToD IP requires writing registers in the reverse order to the read sequence.
+ * The timestamp is corrected when the TOD_NANOSEC register is written, so the
+ * sequence of write TOD registers: TOD_SECONDSH, TOD_SECONDSL and TOD_NANOSEC.
+ */
+#define TOD_SECONDSH			0x100
+#define TOD_SECONDSL			0x104
+#define TOD_NANOSEC			0x108
+#define TOD_PERIOD			0x110
+#define TOD_ADJUST_PERIOD		0x114
+#define TOD_ADJUST_COUNT		0x118
+#define TOD_DRIFT_ADJUST		0x11c
+#define TOD_DRIFT_ADJUST_RATE		0x120
+#define PERIOD_FRAC_OFFSET		16
+#define SECONDS_MSB			GENMASK_ULL(47, 32)
+#define SECONDS_LSB			GENMASK_ULL(31, 0)
+#define TOD_SECONDSH_SEC_MSB		GENMASK_ULL(15, 0)
+
+#define CAL_SECONDS(m, l)		((FIELD_GET(TOD_SECONDSH_SEC_MSB, (m)) << 32) | (l))
+
+#define TOD_PERIOD_MASK		GENMASK_ULL(19, 0)
+#define TOD_PERIOD_MAX			FIELD_MAX(TOD_PERIOD_MASK)
+#define TOD_PERIOD_MIN			0
+#define TOD_DRIFT_ADJUST_MASK		GENMASK_ULL(15, 0)
+#define TOD_DRIFT_ADJUST_FNS_MAX	FIELD_MAX(TOD_DRIFT_ADJUST_MASK)
+#define TOD_DRIFT_ADJUST_RATE_MAX	TOD_DRIFT_ADJUST_FNS_MAX
+#define TOD_ADJUST_COUNT_MASK		GENMASK_ULL(19, 0)
+#define TOD_ADJUST_COUNT_MAX		FIELD_MAX(TOD_ADJUST_COUNT_MASK)
+#define TOD_ADJUST_INTERVAL_US		10
+#define TOD_ADJUST_MS			\
+		(((TOD_PERIOD_MAX >> 16) + 1) * (TOD_ADJUST_COUNT_MAX + 1))
+#define TOD_ADJUST_MS_MAX		(TOD_ADJUST_MS / MICRO)
+#define TOD_ADJUST_MAX_US		(TOD_ADJUST_MS_MAX * USEC_PER_MSEC)
+#define TOD_MAX_ADJ			(500 * MEGA)
+
+struct dfl_tod {
+	struct ptp_clock_info ptp_clock_ops;
+	struct device *dev;
+	struct ptp_clock *ptp_clock;
+
+	/* ToD Clock address space */
+	void __iomem *tod_ctrl;
+
+	/* ToD clock registers protection */
+	spinlock_t tod_lock;
+};
+
+/*
+ * A fine ToD HW clock offset adjustment. To perform the fine offset adjustment, the
+ * adjust_period and adjust_count argument are used to update the TOD_ADJUST_PERIOD
+ * and TOD_ADJUST_COUNT register for in hardware. The dt->tod_lock spinlock must be
+ * held when calling this function.
+ */
+static int fine_adjust_tod_clock(struct dfl_tod *dt, u32 adjust_period,
+				 u32 adjust_count)
+{
+	void __iomem *base = dt->tod_ctrl;
+	u32 val;
+
+	writel(adjust_period, base + TOD_ADJUST_PERIOD);
+	writel(adjust_count, base + TOD_ADJUST_COUNT);
+
+	/* Wait for present offset adjustment update to complete */
+	return readl_poll_timeout_atomic(base + TOD_ADJUST_COUNT, val, !val, TOD_ADJUST_INTERVAL_US,
+				  TOD_ADJUST_MAX_US);
+}
+
+/*
+ * A coarse ToD HW clock offset adjustment. The coarse time adjustment performs by
+ * adding or subtracting the delta value from the current ToD HW clock time.
+ */
+static int coarse_adjust_tod_clock(struct dfl_tod *dt, s64 delta)
+{
+	u32 seconds_msb, seconds_lsb, nanosec;
+	void __iomem *base = dt->tod_ctrl;
+	u64 seconds, now;
+
+	if (delta == 0)
+		return 0;
+
+	nanosec = readl(base + TOD_NANOSEC);
+	seconds_lsb = readl(base + TOD_SECONDSL);
+	seconds_msb = readl(base + TOD_SECONDSH);
+
+	/* Calculate new time */
+	seconds = CAL_SECONDS(seconds_msb, seconds_lsb);
+	now = seconds * NSEC_PER_SEC + nanosec + delta;
+
+	seconds = div_u64_rem(now, NSEC_PER_SEC, &nanosec);
+	seconds_msb = FIELD_GET(SECONDS_MSB, seconds);
+	seconds_lsb = FIELD_GET(SECONDS_LSB, seconds);
+
+	writel(seconds_msb, base + TOD_SECONDSH);
+	writel(seconds_lsb, base + TOD_SECONDSL);
+	writel(nanosec, base + TOD_NANOSEC);
+
+	return 0;
+}
+
+static int dfl_tod_adjust_fine(struct ptp_clock_info *ptp, long scaled_ppm)
+{
+	struct dfl_tod *dt = container_of(ptp, struct dfl_tod, ptp_clock_ops);
+	u32 tod_period, tod_rem, tod_drift_adjust_fns, tod_drift_adjust_rate;
+	void __iomem *base = dt->tod_ctrl;
+	unsigned long flags, rate;
+	u64 ppb;
+
+	/* Get the clock rate from clock frequency register offset */
+	rate = readl(base + TOD_CLK_FREQ);
+
+	/* add GIGA as nominal ppb */
+	ppb = scaled_ppm_to_ppb(scaled_ppm) + GIGA;
+
+	tod_period = div_u64_rem(ppb << PERIOD_FRAC_OFFSET, rate, &tod_rem);
+	if (tod_period > TOD_PERIOD_MAX)
+		return -ERANGE;
+
+	/*
+	 * The drift of ToD adjusted periodically by adding a drift_adjust_fns
+	 * correction value every drift_adjust_rate count of clock cycles.
+	 */
+	tod_drift_adjust_fns = tod_rem / gcd(tod_rem, rate);
+	tod_drift_adjust_rate = rate / gcd(tod_rem, rate);
+
+	while ((tod_drift_adjust_fns > TOD_DRIFT_ADJUST_FNS_MAX) ||
+	       (tod_drift_adjust_rate > TOD_DRIFT_ADJUST_RATE_MAX)) {
+		tod_drift_adjust_fns >>= 1;
+		tod_drift_adjust_rate >>= 1;
+	}
+
+	if (tod_drift_adjust_fns == 0)
+		tod_drift_adjust_rate = 0;
+
+	spin_lock_irqsave(&dt->tod_lock, flags);
+	writel(tod_period, base + TOD_PERIOD);
+	writel(0, base + TOD_ADJUST_PERIOD);
+	writel(0, base + TOD_ADJUST_COUNT);
+	writel(tod_drift_adjust_fns, base + TOD_DRIFT_ADJUST);
+	writel(tod_drift_adjust_rate, base + TOD_DRIFT_ADJUST_RATE);
+	spin_unlock_irqrestore(&dt->tod_lock, flags);
+
+	return 0;
+}
+
+static int dfl_tod_adjust_time(struct ptp_clock_info *ptp, s64 delta)
+{
+	struct dfl_tod *dt = container_of(ptp, struct dfl_tod, ptp_clock_ops);
+	u32 period, diff, rem, rem_period, adj_period;
+	void __iomem *base = dt->tod_ctrl;
+	unsigned long flags;
+	bool neg_adj;
+	u64 count;
+	int ret;
+
+	neg_adj = delta < 0;
+	if (neg_adj)
+		delta = -delta;
+
+	spin_lock_irqsave(&dt->tod_lock, flags);
+
+	/*
+	 * Get the maximum possible value of the Period register offset
+	 * adjustment in nanoseconds scale. This depends on the current
+	 * Period register setting and the maximum and minimum possible
+	 * values of the Period register.
+	 */
+	period = readl(base + TOD_PERIOD);
+
+	if (neg_adj) {
+		diff = (period - TOD_PERIOD_MIN) >> PERIOD_FRAC_OFFSET;
+		adj_period = period - (diff << PERIOD_FRAC_OFFSET);
+		count = div_u64_rem(delta, diff, &rem);
+		rem_period = period - (rem << PERIOD_FRAC_OFFSET);
+	} else {
+		diff = (TOD_PERIOD_MAX - period) >> PERIOD_FRAC_OFFSET;
+		adj_period = period + (diff << PERIOD_FRAC_OFFSET);
+		count = div_u64_rem(delta, diff, &rem);
+		rem_period = period + (rem << PERIOD_FRAC_OFFSET);
+	}
+
+	ret = 0;
+
+	if (count > TOD_ADJUST_COUNT_MAX) {
+		ret = coarse_adjust_tod_clock(dt, delta);
+	} else {
+		/* Adjust the period by count cycles to adjust the time */
+		if (count)
+			ret = fine_adjust_tod_clock(dt, adj_period, count);
+
+		/* If there is a remainder, adjust the period for an additional cycle */
+		if (rem)
+			ret = fine_adjust_tod_clock(dt, rem_period, 1);
+	}
+
+	spin_unlock_irqrestore(&dt->tod_lock, flags);
+
+	return ret;
+}
+
+static int dfl_tod_get_timex(struct ptp_clock_info *ptp, struct timespec64 *ts,
+			     struct ptp_system_timestamp *sts)
+{
+	struct dfl_tod *dt = container_of(ptp, struct dfl_tod, ptp_clock_ops);
+	u32 seconds_msb, seconds_lsb, nanosec;
+	void __iomem *base = dt->tod_ctrl;
+	unsigned long flags;
+	u64 seconds;
+
+	spin_lock_irqsave(&dt->tod_lock, flags);
+	ptp_read_system_prets(sts);
+	nanosec = readl(base + TOD_NANOSEC);
+	seconds_lsb = readl(base + TOD_SECONDSL);
+	seconds_msb = readl(base + TOD_SECONDSH);
+	ptp_read_system_postts(sts);
+	spin_unlock_irqrestore(&dt->tod_lock, flags);
+
+	seconds = CAL_SECONDS(seconds_msb, seconds_lsb);
+
+	ts->tv_nsec = nanosec;
+	ts->tv_sec = seconds;
+
+	return 0;
+}
+
+static int dfl_tod_set_time(struct ptp_clock_info *ptp,
+			    const struct timespec64 *ts)
+{
+	struct dfl_tod *dt = container_of(ptp, struct dfl_tod, ptp_clock_ops);
+	u32 seconds_msb = FIELD_GET(SECONDS_MSB, ts->tv_sec);
+	u32 seconds_lsb = FIELD_GET(SECONDS_LSB, ts->tv_sec);
+	u32 nanosec = FIELD_GET(SECONDS_LSB, ts->tv_nsec);
+	void __iomem *base = dt->tod_ctrl;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dt->tod_lock, flags);
+	writel(seconds_msb, base + TOD_SECONDSH);
+	writel(seconds_lsb, base + TOD_SECONDSL);
+	writel(nanosec, base + TOD_NANOSEC);
+	spin_unlock_irqrestore(&dt->tod_lock, flags);
+
+	return 0;
+}
+
+static struct ptp_clock_info dfl_tod_clock_ops = {
+	.owner = THIS_MODULE,
+	.name = "dfl_tod",
+	.max_adj = TOD_MAX_ADJ,
+	.adjfine = dfl_tod_adjust_fine,
+	.adjtime = dfl_tod_adjust_time,
+	.gettimex64 = dfl_tod_get_timex,
+	.settime64 = dfl_tod_set_time,
+};
+
+static int dfl_tod_probe(struct dfl_device *ddev)
+{
+	struct device *dev = &ddev->dev;
+	struct dfl_tod *dt;
+
+	dt = devm_kzalloc(dev, sizeof(*dt), GFP_KERNEL);
+	if (!dt)
+		return -ENOMEM;
+
+	dt->tod_ctrl = devm_ioremap_resource(dev, &ddev->mmio_res);
+	if (IS_ERR(dt->tod_ctrl))
+		return PTR_ERR(dt->tod_ctrl);
+
+	dt->dev = dev;
+	spin_lock_init(&dt->tod_lock);
+	dev_set_drvdata(dev, dt);
+
+	dt->ptp_clock_ops = dfl_tod_clock_ops;
+
+	dt->ptp_clock = ptp_clock_register(&dt->ptp_clock_ops, dev);
+	if (IS_ERR(dt->ptp_clock))
+		return dev_err_probe(dt->dev, PTR_ERR(dt->ptp_clock),
+				     "Unable to register PTP clock\n");
+
+	return 0;
+}
+
+static void dfl_tod_remove(struct dfl_device *ddev)
+{
+	struct dfl_tod *dt = dev_get_drvdata(&ddev->dev);
+
+	ptp_clock_unregister(dt->ptp_clock);
+}
+
+static const struct dfl_device_id dfl_tod_ids[] = {
+	{ FME_ID, FME_FEATURE_ID_TOD },
+	{ }
+};
+MODULE_DEVICE_TABLE(dfl, dfl_tod_ids);
+
+static struct dfl_driver dfl_tod_driver = {
+	.drv = {
+		.name = "dfl-tod",
+	},
+	.id_table = dfl_tod_ids,
+	.probe = dfl_tod_probe,
+	.remove = dfl_tod_remove,
+};
+module_dfl_driver(dfl_tod_driver);
+
+MODULE_DESCRIPTION("FPGA DFL ToD driver");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL");